Variable Temperature Synthesis of Tunable Flame-Generated Carbon Nanoparticles

In this study, flame-formed carbon nanoparticles of different nanostructures have been produced by changing the flame temperature. Raman spectroscopy has been used for the characterization of the carbon nanoparticles, while the particle size has been obtained by online measurements made by electrical mobility analysis. The results show that, in agreement with recent literature data, a large variety of carbon nanoparticles, with a different degree of graphitization, can be produced by changing the flame temperature. This methodology allows for the synthesis of very small carbon nanoparticles with a size of about 3–4 nm and with different graphitic orders. Under the perspective of the material synthesis process, the variable-temperature flame-synthesis of carbon nanoparticles appears as an attractive procedure for a cost-effective and easily scalable production of highly tunable carbon nanoparticles

Soot inception: A DFT study of σ and π dimerization of resonantly stabilized aromatic radicals

Recent advances in the soot studies have shown experimental evidences of π-radicals and cross-linked structures among the molecular constituents of just-nucleated soot particles. π-radicals could have an important role in particle nucleation by increasing the binding energy between polycyclic aromatic hydrocarbons with respect to pure van der Waals interactions. In this work we use density functional theory by Grimme D3 dispersion correction (DFT-D3) with hybrid functional and localized Gaussian basis set (B3LYP/6-31G**) to analyze and classify the clustering behaviors of two aromatic radicals visualized experimentally by atomic force microscopy (Commodo et al. Combust. Flame 205: 154–164, 2019). These aromatic radicals have different topological structures and delocalization of the unpaired electron. The binding energy and energy bandgap characteristics of the clusters are calculated. The theoretical results show a different clustering behavior for the two aromatic radicals. The one with a partial localization of the unpaired electron tends to form a σ-dimer; conversely, the radical with a greater delocalization of the unpaired electron leads to π-stacking formation with a slight overbinding of few kcal mol−1 with respect to pure van der Waals interactions and a marked lowering of the energy bandgap. The formation of π-stacking induced by delocalized π-radicals could in part explain some spectroscopic evidences observed during soot nucleation. © 2020 Elsevier Lt

π-Diradical Aromatic Soot Precursors in Flames.

Soot emitted from incomplete combustion of hydrocarbon fuels contributes to global warming and causes human disease. The mechanism by which soot nanoparticles form within hydrocarbon flames is still an unsolved problem in combustion science. Mechanisms proposed to date involving purely chemical growth are limited by slow reaction rates, whereas mechanisms relying on solely physical interactions between molecules are limited by weak intermolecular interactions that are unstable at flame temperatures. Here, we show evidence for a reactive π-diradical aromatic soot precursor imaged using non-contact atomic force microscopy. Localization of π-electrons on non-hexagonal rings was found to allow for Kekulé aromatic soot precursors to possess a triplet diradical ground state. Barrierless chain reactions are shown between these reactive sites, which provide thermally stable aromatic rim-linked hydrocarbons under flame conditions. Quantum molecular dynamics simulations demonstrate physical condensation of aromatics that survive for tens of picoseconds. Bound internal rotors then enable the reactive sites to find each other and become chemically cross-linked before dissociation. These species provide a rapid, thermally stable chain reaction toward soot nanoparticle formation and could provide molecular targets for limiting the emission of these toxic combustion products

The Bortoluzzi Mud Volcano (Ionian Sea, Italy) and its potential for tracking the seismic cycle of active faults

The Ionian Sea in southern Italy is at the center of active interaction and convergence between the Eurasian and African–Adriatic plates in the Mediterranean. This area is seismically active with instrumentally and/or historically recorded Mw > 7:0 earthquakes, and it is affected by recently discovered long strike-slip faults across the active Calabrian accretionary wedge. Many mud volcanoes occur on top of the wedge. A recently discovered one (called the Bortoluzzi Mud Volcano or BMV) was surveyed during the Seismofaults 2017 cruise (May 2017). Bathymetric backscatter surveys, seismic reflection profiles, geochemical and earthquake data, and a gravity core are used here to geologically, geochemically, and geophysically characterize this structure. The BMV is a circular feature ' 22m high and ' 1100m in diameter with steep slopes (up to a dip of 22 ). It sits atop the Calabrian accretionary wedge and a system of flowerlike oblique-slip faults that are probably seismically active as demonstrated by earthquake hypocentral and focal data. Geochemistry of water samples from the seawater column on top of the BMV shows a significant contamination of the bottom waters from saline (evaporite-type) CH4-dominated crustalderived fluids similar to the fluids collected from a mud volcano located on the Calabria mainland over the same accretionary wedge. These results attest to the occurrence of open crustal pathways for fluids through the BMV down to at least the Messinian evaporites at about 3000 m. This evidence is also substantiated by helium isotope ratios and by comparison and contrast with different geochemical data from three seawater columns located over other active faults in the Ionian Sea area. One conclusion is that the BMV may be useful for tracking the seismic cycle of active faults through geochemical monitoring. Due to the widespread diffusion of mud volcanoes in seismically active settings, this study contributes to indicating a future path for the use of mud volcanoes in the monitoring and mitigation of natural hazards.Published1-233SR TERREMOTI - Attività dei CentriJCR Journa

Long-acting combination of cabotegravir plus rilpivirine: A picture of potential eligible and ineligible HIV-positive individuals from the Italian ARCA cohort

Objectives: We aimed to evaluate the prevalence and characteristics of people living with HIV (PLWH) eligible for the long-acting injectable (LAI) regimen with cabotegravir (CAB) and rilpivirine (RPV), in comparison with ineligible individuals. Methods: This was an observational, cross-sectional study from the ARCA cohort, including virologically suppressed PLWH with at least one genotypic resistance testing (GRT) for reverse transcriptase and integrase from plasma and/or PBMCs. Eligibility criteria for LAI CAB+RPV were: negative HBsAg, absence of previous virological failures and/or resistance-associated mutations for non-nucleoside reverse transcriptase inhibitors (NNRTIs) and/or integrase strand transfer inhibitors. Potential differences between eligible and ineligible individuals were investigated by univariable and multivariable analyses. Results: A total of 514 individuals were included: 377 (73.3%) were male, median age was 51 (IQR: 43–58), on ART for 9 years (IQR: 4–17), virologically suppressed for 63 months (IQR: 35–105). Eligible individuals for CAB+RPV were 229 (44.5%, 95%CI: 40.8–48.8); compared with ineligible individuals, they received a lower number of previous regimens (aOR 0.76, 95% CI 0.71–0.83, P < 0.001) and were on current NNRTIs (aOR 2.16, 95% CI 1.38–3.37, P = 0.001). Conclusions: Less than half of virologically suppressed PLWH in the ARCA cohort were potentially eligible for CAB+RPV. They seem to be “less complicated” with shorter exposure to ART and preferably already on NNRTIs

Determinants of worse liver-related outcome according to HDV infection among HBsAg positive persons living with HIV: Data from the ICONA cohort

Objectives: We aimed to study hepatitis D virus (HDV) prevalence and risk of progression to severe liver-related events (SLRE) in HBsAg positive people living with HIV (PLWH) in Italy; role of HDV-RNA copy levels, HCV coinfection and nadir CD4 counts were also investigated.Methods: People living with HIV (PLWH) from Italian Foundation cohort Naive antiretrovirals (ICONA) with available HBsAg and HDV Ab were enrolled. HBsAg, HDV Ab, HDV-RNA and HDV genotypes were tested. Primary end-point: time from first HDV screening to Severe Liver Related Events (SLRE: decompensated cirrhosis, liver transplantation, HCC). Fine-grey regression models were used to evaluate the association of HDV Ab, HDV-RNA, HDV/HCV coinfection, CD4 nadir and outcome. Secondary end-points: time to SLRE or death; HDV Ab and HDV-RNA prevalence.Results: A total of 152/809 (18.8%) HBsAg positive PLWH showed HDV Ab reactivity; 63/93 (67.7%) were HDV-RNA positive. Being male, persons who inject drugs (PWID), HCV Ab positive, with FIB-4 &gt; 3.25 were independent factors of HDV Ab positivity. In a median follow-up of 5 years, 37 PLWH (4.1% at 5-year) developed SLRE and 97 (12.0%) reached the SLRE or death end-point. HDV-RNA positive (independently from HDV-RNA copy level) PLWH had a 4.6-fold (95%CI 2.0-10.5) higher risk of SLRE than HDV negatives. PLWH positive for both HCV Ab and HDV Ab showed the highest independent risk of SLRE (ASHR: 11.9, 95%CI: 4.6-30.9 vs. HCV neg/HDV neg). Nadir CD4 &lt; 200/mL was associated with SLRE (ASHR: 3.9, 95% 1.0-14.5).Conclusions: One-fifth of the HBsAg positive PLWH harbour HDV infection, and are at high risk of progression to advanced liver disease. HCV contributes to worse outcomes. This population needs urgently effective treatments

Rates and Predictors of Perioperative Complications in Cytoreductive Nephrectomy: Analysis of the Registry for Metastatic Renal Cell Carcinoma

Background: Cytoreductive nephrectomy (CN) plays an important role in the treatment of a subgroup of metastatic renal cell carcinoma (mRCC) patients. Objective: We aimed to evaluate morbidity associated with this procedure and identify potential predictors thereof to aid patient selection for this procedure and potentially improve patient outcomes. Design, setting, and participants: Data from 736 mRCC patients undergoing CN at 14 institutions were retrospectively recorded in the Registry for Metastatic RCC (REMARCC). Outcome measurements and statistical analysis: Logistic regression analysis was used to identify predictors for intraoperative, any-grade (AGCs), low-grade, and high-grade (HGCs) postoperative complications (according to the Clavien-Dindo classification) as well as 30-d readmission rates. Results and limitations: Intraoperative complications were observed in 69 patients (10.9%). Thrombectomy (odds ratio [OR] 1.38, 95% confidence interval [CI] 1.08-1.75, p = 0.009) and adjacent organ removal (OR 2.7, 95% CI 1.38-5.30) were significant predictors of intraoperative complications at multivariable analysis. Two hundred seventeen patients (29.5%) encountered AGCs, while 45 (6.1%) encountered an HGC, of whom 10 (1.4%) died. Twenty-four (3.3%) patients had multiple postoperative complications. Estimated blood loss (EBL; OR 1.49, 95% CI 1.08-2.05, p = 0.01) was a significant predictor of AGCs at multivariable analysis. CN case load (OR 0.13, 95% CI 0.03-0.59, p = 0.009) and EBL (OR 2.93, 95% CI 1.20-7.15, p = 0.02) were significant predictors solely for HGCs at multivariable analysis. Forty-one patients (11.5%) were readmitted within 30 d of surgery. No significant predictors were identified. Results were confirmed in a subanalysis focusing solely on patients treated in the contemporary targeted therapy era. Conclusions: Morbidity associated with CN is not negligible. Predictors of high-grade postoperative morbidity are predominantly indicators of complex surgery. EBL is a strong predictor of postoperative complications. CN case load correlates with lower high-grade morbidity and highlights the benefit of centralization of complex surgery. However, risks and benefits should be balanced when considering CN in mRCC patients. Patient summary: We studied patients with metastatic renal cancer to evaluate the outcomes associated with the surgical removal of the primary kidney tumor. We found that this procedure is often complex and adverse events are not uncommon. High intraoperative blood loss and a small number of cases performed at the treating center are associated with a higher rate of postoperative complications

Determinants of worse liver-related outcome according to HDV infection among HBsAg positive persons living with HIV: Data from the ICONA cohort

Objectives: We aimed to study hepatitis D virus (HDV) prevalence and risk of progression to severe liver-related events (SLRE) in HBsAg positive people living with HIV (PLWH) in Italy; role of HDV-RNA copy levels, HCV coinfection and nadir CD4 counts were also investigated. Methods: People living with HIV (PLWH) from Italian Foundation cohort Naïve antiretrovirals (ICONA) with available HBsAg and HDV Ab were enrolled. HBsAg, HDV Ab, HDV-RNA and HDV genotypes were tested. Primary end-point: time from first HDV screening to Severe Liver Related Events (SLRE: decompensated cirrhosis, liver transplantation, HCC). Fine-grey regression models were used to evaluate the association of HDV Ab, HDV-RNA, HDV/HCV coinfection, CD4 nadir and outcome. Secondary end-points: time to SLRE or death;&nbsp;HDV Ab and HDV-RNA prevalence. Results: A total of 152/809 (18.8%) HBsAg positive PLWH showed HDV Ab reactivity; 63/93 (67.7%) were HDV-RNA positive. Being male, persons who inject drugs (PWID), HCV Ab positive, with FIB-4 &gt; 3.25 were independent factors of HDV Ab positivity. In a median follow-up of 5 years, 37 PLWH (4.1% at 5-year) developed SLRE and 97 (12.0%) reached the SLRE or death end-point. HDV-RNA positive (independently from HDV-RNA copy level) PLWH had a 4.6-fold (95%CI 2.0-10.5) higher risk of SLRE than HDV negatives. PLWH positive for both HCV Ab and HDV Ab showed the highest independent risk of SLRE (ASHR: 11.9, 95%CI: 4.6-30.9 vs. HCV neg/HDV neg). Nadir CD4 &lt; 200/mL was associated with SLRE (ASHR: 3.9, 95% 1.0-14.5). Conclusions: One-fifth of the HBsAg positive PLWH harbour HDV infection, and are at high risk of progression to advanced liver disease. HCV contributes to worse outcomes. This population needs urgently effective treatments