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result(s) for
"Sironi, Luca"
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Recreational inhalation of butane and propane in adolescents: Two forensic cases of accidental death
2016
•The recreational use of inhalants is a fairly widespread habit among adolescents.•Two cases of accidental death after sniffing of a mixture of propane and butane are presented.•The role of propane and butane in causing death was demonstrated with toxicological analyses.•The importance of correct sampling procedures and surveys was highlighted.
The recreational use of inhalants is a fairly widespread habit among adolescents because of the ease of availability and methods of assumption. Their use is however not free of risks, both for direct toxicity on several target organs and for a mechanism of gas replacement with lack of oxygen. The first case concerns a 12-year-old boy who died suddenly after sniffing a mix of butane and propane contained in a can of air freshener. The second case concerns a 14-year-old boy who died by acute poisoning by the same mixture contained in a refill for lighters. High concentrations of the compounds were found in the tissues by analysis with gas chromatography–mass spectrometry. The compounds found in tissues and biological fluids were perfectly compatible with those contained in the containers used for the inhalation. The mechanisms of death were therefore assessed in a combination of the direct toxicity of the compound and oxygen replacement, thus highlighting the crucial help that toxicological analyses can provide in such cases.
Journal Article
On the solubility of azodicarbonamide in water/DMSO mixtures: an experimental and computational study
by
Macetti, Giovanni
,
Geremia, Ilaria
,
Sironi, Luca
in
azodicarbonamide
,
Chemistry
,
Hydrogen bonds
2024
This work aims at studying why azodicarbonamide (ADCA), a formally apolar compound with good hydrogen bond (HB) acceptors, is soluble only in polar aprotic solvents like dimethyl sulfoxide (DMSO) but not in water. Solubility measurements, as well as quantum mechanical and classical molecular dynamics simulations, were employed to tackle the problem. We found that in the liquid phase a polar conformer of ADCA ( µ = 8.7 D), unreported to date, is favoured under the enthalpic drive provided by a highly polar solvent. At the same time, the very high hydrogen bond propensity of water with itself prevents this solvent from providing an effective hydrogen bond-mediated solvation. Solvents bearing good HB acceptors, while lacking strong HB donors, contribute to further stabilizing solute–solvent adducts through weak and fluxional HBs that involve the amide groups of ADCA. Implications for the solubility of ADCA down to µ M concentrations were evaluated, also with the aid of classical simulations of solution nanodroplets.
Journal Article
Death due to acute tetrachloroethylene intoxication in a chronic abuser
2015
Volatile substances are used widespread, especially among young people, as a cheap and easily accessible drug. Tetrachloroethylene is one of the solvents exerting effects on the central nervous system with experiences of disinhibition and euphoria. The case presented is that of a 27-year-old female, found dead by her father at home with cotton swabs dipped in the nostrils. She was already known for this type of abuse and previously admitted twice to the hospital for nonfatal acute poisonings. The swabs were still soaked in tetrachloroethylene. Toxicological and histological investigations demonstrated the presence of an overlap between chronic intake of the substance (with high concentrations in sites of accumulation, e.g., the adipose tissue, and contemporary tissue damage, as histologically highlighted) and acute intoxication as final cause of death, with a concentration of 158 mg/L in cardiac blood and 4915 mg/kg in the adipose tissue. No other drugs or medicines were detected in body fluids or tissues, and to our knowledge, this is the highest concentration ever detected in forensic cases. This peculiar case confirms the toxicity of this substance and focuses on the importance of complete histological and toxicological investigations in the distinction between chronic abuse and acute intoxication.
Journal Article
Drug analysis in blowfly larvae and in human tissues: a comparative study
by
Introna, Francesco
,
Caligara, Marina
,
Sironi, Luca
in
Animals
,
Antidepressants
,
Antidepressive Agents - analysis
2004
The present study investigates the correlation between concentrations of drugs in human tissues and Diptera larvae feeding on these tissues. Samples of liver were taken from 18 cases in which preliminary toxicological screening indicated the presence of drugs. Blowfly larvae (Diptera: Calliphoridae) were reared on these samples and subsequently analyzed for drug content. Toxicological analyses were carried out using ONLINE Abuscreen (Roche) and GC/MS for available body fluids (blood, urine and bile) as well as liver samples and maggots. All drugs detected in human tissues were also detected in insect specimens. Opiates, cocaine and barbiturates as well as some antidepressants (clomipramine, amitryptiline, nortryptiline, levomepromezine and tioridazine) were observed. Comparisons of drug concentrations between those in human tissues and blowfly larvae showed different patterns of distribution that may be attributed to differences in physiology. Results confirm the reliability of entomological specimens for qualitative analyses, although quantitative extrapolations are unreliable. All xenobiotics detected were in higher concentrations in human tissues than in maggots. Concentrations in post-feeding maggots were significantly lower than for feeding maggots, suggesting that the feeding state of maggots may affect toxicological analyses as they metabolize and eliminate drugs during development.
Journal Article
Incidence of xenobiotics among drivers killed in single-vehicle crashes
by
Marozzi, Franco
,
Sironi, Luca
,
Bernabei, Carlo
in
Accidents, Traffic - mortality
,
Accidents, Traffic - statistics & numerical data
,
Adolescent
1999
The authors have performed a study of single-vehicle crashes (SVCs) in order to verify a correlation between the loss of vehicle control and the presence of drugs in the body. Overall, 129 cases were recorded and occurred in the catchment area of the Institute of Legal Medicine in Milan between 1986 to 1996. Among the 129 cases under study, respectively 121 men and eight women, 101 were car-drivers and 28 motor-cyclists. The median age was equal to 29 years, while the average age to 32.0 years (range 15–65 years). Fifty eight cases (45.0%) were “positive” for the presence of ethanol≥0.8 g/l or other drugs. The sample of “positive cases” was studied according to sex, age, day, hour and type of vehicle. Considering the cases with presence of ethanol, although under the legal limit (20 cases), the total amount of cases (78) becomes even more consistent. The amount of ethanol was found to be respectively 0.34 g/l in daily drivers and 0.87 g/l in nightly drivers (
p<0.01). Our considerations confirm the importance of toxicological analyses in the forensic investigation of traffic deaths being the sample under study recorded following criteria which minimised other possible factors effecting road accidents.
Journal Article
Ion and Electron Acceleration in Fully Kinetic Plasma Turbulence
2022
Turbulence is often invoked to explain the origin of nonthermal particles in space and astrophysical plasmas. By means of 3D fully kinetic particle-in-cell simulations, we demonstrate that turbulence in low-β plasmas (β is the ratio of plasma pressure to magnetic pressure) accelerates ions and electrons into a nonthermal energy distribution with a power-law energy range. The ion spectrum is harder than the electron one, and both distributions get steeper for higher β. We show that the energization of electrons is accompanied by a significant energy-dependent pitch-angle anisotropy, with most electrons moving parallel to the local magnetic field, while ions stay roughly isotropic. We demonstrate that particle injection from the thermal pool occurs in regions of high current density. Parallel electric fields associated with magnetic reconnection are responsible for the initial energy gain of electrons, whereas perpendicular electric fields control the overall energization of ions. Our findings have important implications for the origin of nonthermal particles in space and astrophysical plasmas.
Journal Article
Chest X-ray for predicting mortality and the need for ventilatory support in COVID-19 patients presenting to the emergency department
by
Sverzellati, Nicola
,
Balbi, Maurizio
,
Di Marco, Fabiano
in
Abnormalities
,
Cardiovascular diseases
,
Chest
2021
Objectives
To evaluate the inter-rater agreement of chest X-ray (CXR) findings in coronavirus disease 2019 (COVID-19) and to determine the value of initial CXR along with demographic, clinical, and laboratory data at emergency department (ED) presentation for predicting mortality and the need for ventilatory support.
Methods
A total of 340 COVID-19 patients who underwent CXR in the ED setting (March 1–13, 2020) were retrospectively included. Two reviewers independently assessed CXR abnormalities, including ground-glass opacities (GGOs) and consolidation. Two scoring systems (
Brixia
score and percentage of lung involvement) were applied. Inter-rater agreement was assessed by weighted Cohen’s kappa (
κ
) or intraclass correlation coefficient (ICC). Predictors of death and respiratory support were identified by logistic or Poisson regression.
Results
GGO admixed with consolidation (
n
= 235, 69%) was the most common CXR finding. The inter-rater agreement was almost perfect for type of parenchymal opacity (
κ
= 0.90),
Brixia
score (ICC = 0.91), and percentage of lung involvement (ICC = 0.95). The
Brixia
score (OR: 1.19; 95% CI: 1.06, 1.34;
p
= 0.003), age (OR: 1.16; 95% CI: 1.11, 1.22;
p
< 0.001), PaO
2
/FiO
2
ratio (OR: 0.99; 95% CI: 0.98, 1;
p
= 0.002), and cardiovascular diseases (OR: 3.21; 95% CI: 1.28, 8.39;
p
= 0.014) predicted death. Percentage of lung involvement (OR: 1.02; 95% CI: 1.01, 1.03;
p
= 0.001) and PaO
2
/FiO
2
ratio (OR: 0.99; 95% CI: 0.99, 1.00;
p
< 0.001) were significant predictors of the need for ventilatory support.
Conclusions
CXR is a reproducible tool for assessing COVID-19 and integrates with patient history, PaO
2
/FiO
2
ratio, and SpO
2
values to early predict mortality and the need for ventilatory support.
Key Points
• Chest X-ray is a reproducible tool for assessing COVID-19 pneumonia.
•
The Brixia score and percentage of lung involvement on chest X-ray integrate with patient history, PaO
2
/FIO
2
ratio, and SpO
2
values to early predict mortality and the need for ventilatory support in COVID-19 patients presenting to the emergency department.
Journal Article
TeV Neutrinos and Hard X-Rays from Relativistic Reconnection in the Corona of NGC 1068
2024
The recent discovery of astrophysical neutrinos from the Seyfert galaxy NGC 1068 suggests the presence of nonthermal protons within a compact “coronal” region close to the central black hole. The acceleration mechanism of these nonthermal protons remains elusive. We show that a large-scale magnetic reconnection layer, of the order of a few gravitational radii, may provide such a mechanism. In such a scenario, rough energy equipartition between magnetic fields, X-ray photons, and nonthermal protons is established in the reconnection region. Motivated by recent 3D particle-in-cell simulations of relativistic reconnection, we assume that the spectrum of accelerated protons is a broken power law, with the break energy being constrained by energy conservation (i.e., the energy density of accelerated protons is at most comparable to the magnetic energy density). The proton spectrum is dnp/dEp∝Ep−1 below the break and dnp/dEp∝Ep−s above the break, with IceCube neutrino observations suggesting s ≃ 3. Protons above the break lose most of their energy within the reconnection layer via photohadronic collisions with the coronal X-rays, producing a neutrino signal in good agreement with the recent observations. Gamma rays injected in photohadronic collisions are cascaded to lower energies, sustaining the population of electron–positron pairs that makes the corona moderately Compton thick.
Journal Article
The Role of Three-dimensional Effects on Ion Injection and Acceleration in Perpendicular Shocks
by
Caprioli, Damiano
,
Sironi, Lorenzo
,
Orusa, Luca
in
Cosmic ray showers
,
Cosmic rays
,
Fluid flow
2026
Understanding the conditions that enable particle acceleration at nonrelativistic collisionless shocks is essential to unveil the origin of cosmic rays. We employ 2D and 3D hybrid simulations (with kinetic ions and fluid electrons) to explore particle acceleration and magnetic field amplification in nonrelativistic perpendicular shocks, focusing on the role of shock drift acceleration and its dependence on the shock Mach number. We perform an analysis of the ion injection process and demonstrate why efficient acceleration is only observed in 3D. In particular, we show that ion injection critically depends on the “porosity” of the magnetic turbulence in the downstream region near the shock, a property describing how easily the postshock region allows particles to traverse it and return upstream without being trapped. This effect can only be properly captured in 3D. Additionally, we explore the impact of numerical resolution on ion energization, highlighting how resolving small-scale turbulence—on scales below the thermal ion gyroradius—is essential for accurately modeling particle injection. Overall, our results emphasize the necessity of high-resolution 3D simulations to capture the fundamental microphysics driving particle acceleration at perpendicular shocks.
Journal Article
A Magnetized Strongly Turbulent Corona as the Source of Neutrinos from NGC 1068
by
Fiorillo, Damiano F. G
,
Sironi, Lorenzo
,
Comisso, Luca
in
Active galactic nuclei
,
Active galaxies
,
Black holes
2024
The cores of active galactic nuclei are potential accelerators of 10–100 TeV cosmic rays, in turn producing high-energy neutrinos. This picture was confirmed by the compelling evidence of a TeV neutrino signal from the nearby active galaxy NGC 1068, leaving open the question of what is the site and mechanism of cosmic-ray acceleration. One candidate is the magnetized turbulence surrounding the central supermassive black hole. Recent particle-in-cell simulations of magnetized turbulence indicate that stochastic cosmic-ray acceleration is nonresonant, in contrast to the assumptions of previous studies. We show that this has important consequences on a self-consistent theory of neutrino production in the corona, leading to a more rapid cosmic-ray acceleration than previously considered. The turbulent magnetic-field fluctuations needed to explain the neutrino signal are consistent with a magnetically powered corona. We find that strong turbulence, with turbulent magnetic energy density higher than 1% of the rest-mass energy density, naturally explains the normalization of the IceCube neutrino flux, in addition to the neutrino spectral shape. Only a fraction of the protons in the corona, which can be directly inferred from the neutrino signal, are accelerated to high energies. Thus, in this framework, the neutrino signal from NGC 1068 provides a testbed for particle acceleration in magnetized turbulence.
Journal Article