Characterization Techniques Coupled With Mathematical Tools for Deepening Asphaltenes Structure

Asphaltenes are the heavy fraction of fossil fuels, whose characterization remains a very difficult and challenging issue due to the still-persisting uncertainties about their structure and/or composition and molecular weight. Asphaltene components are highly condensed aromatic molecules having some heteroatoms and aliphatic functionalities. Their molecular weights distribution spans in a wide range, from hundreds to millions of mass units, depending on the diagnostic used, which is mainly due to the occurrence of self-aggregation. In the present work, mass spectrometry along with size exclusion chromatography and X-ray diffraction analysis have been applied to asphaltenes for giving some further insights into their molecular weight distribution and structural characteristics. Relatively small polycyclic aromatic hydrocarbons (PAHs) with a significant degree of aliphaticity were individuated by applying fast Fourier transform (FFT) and double bond equivalent (DBE) number analysis to the mass spectra. X-ray diffraction (XRD) confirmed some aliphaticity, showing peaks specific of aliphatic functionalities. Size exclusion chromatography indicated higher molecular weight, probably due to the aliphatic substituents. Mass spectrometry at high laser power enabled observing a downward shift of molecular masses corresponding to the loss of about 10 carbon atoms, suggesting the occurrence of aryl-linked core structures assumed to feature asphaltenes along with island and archipelago structures

The (Mis)Reporting of Male Circumcision Status among Men and Women in Zambia and Swaziland: A Randomized Evaluation of Interview Methods

BACKGROUND: To date, male circumcision prevalence has been estimated using surveys of men self-reporting their circumcision status. HIV prevention trials and observational studies involving female participants also collect data on partners' circumcision status as a risk factor for HIV/STIs. A number of studies indicate that reports of circumcision status may be inaccurate. This study assessed different methods for improving self- and partner reporting of circumcision status. METHODS/FINDINGS: The study was conducted in urban and rural Zambia and urban Swaziland. Men (N = 1264) aged 18-50 and their female partners (N = 1264), and boys (N = 840) aged 13-17 were enrolled. Participants were recruited from HIV counseling and testing sites, health centers, and surrounding communities. The study experimentally assessed methods for improving the reporting of circumcision status, including: a) a simple description of circumcision, b) a detailed description of circumcision, c) an illustration of a circumcised and uncircumcised penis, and d) computerized self-interviewing. Self-reports were compared to visual examination. For men, the error in reporting was largely unidirectional: uncircumcised men more often reported they were circumcised (2-7%), depending on setting. Fewer circumcised men misrepresented their status (0.05-5%). Misreporting by women was significantly higher (11-15%), with the error in both directions. A sizable number of women reported that they did not know their partner's circumcision status (3-8%). Computerized interviewing did not improve accuracy. Providing an illustration, particularly for illiterate participants, significantly improved reporting of circumcision status, decreasing misreporting among illiterate participants from 13% to 10%, although misreporting was not eliminated. CONCLUSIONS: Study results suggest that the prevalence of circumcision may be overestimated in Zambia and Swaziland; the error in reporting is higher among women than among men. Improved reporting when a description or illustration is provided suggests that the source of the error is a lack of understanding of male circumcision

Assessing and improving self-reporting of male circumcision in Zambia and Swaziland

The Male Circumcision (MC) Partnership was established with the support of the Gates Foundation and PEPFAR to scale up MC services in Zambia, in collaboration with the Zambian government. The MC Partnership is a five-year project led by Population Services International (Society for Family Health, Zambia), in partnership with Jhpiego, Marie Stopes International (MSI), and the Population Council. The ultimate objective of this study is to provide researchers and program managers with evidence-based recommendations for the collection of self-reported data on MC status through an assessment of different methods to describe and explain MC. Specifically, the study assessed tools for improving the reporting of circumcision status, including a) a detailed verbal description of male circumcision, b) an illustration of a circumcised and an uncircumcised penis, and c) computerized self-interviewing technology

On the Formation and Accumulation of Solid Carbon Particles in High-Enthalpy Flows Mimicking Re-Entry in the Titan Atmosphere

The problem relating to the formation of solid particles enabled by hypersonic re-entry in methane-containing atmospheres (such as that of Titan) has been tackled in the framework of a combined experimental-numerical approach implemented via a three-level analysis hierarchy. First experimental tests have been conducted using a wind tunnel driven by an industrial arc-heated facility operating with nitrogen as working gas (the SPES, i.e., the Small Planetary Entry Simulator). The formation of solid phases as a result of the complex chemical reactions established in such conditions has been detected and quantitatively measured with high accuracy. In a second stage of the study, insights into the related formation process have been obtained by using multispecies models relying on the NASA CEA code and the Direct Simulation Monte Carlo (DSMC) method. Through this approach the range of flow enthalpies in which carbonaceous deposits can be formed has been identified, obtaining good agreement with the experimental findings. Finally, the deposited substance has been analyzed by means of a set of complementary diagnostic techniques, i.e., SEM, spectroscopy (Raman, FTIR, UV-visible absorption and fluorescence), GC-MS and TGA. It has been found that carbon produced by the interaction of the simulated Titan atmosphere with a solid probe at very high temperatures can be separated into two chemically different fractions, which also include "tholins"

Size-Based Effects of Anthropogenic Ultrafine Particles on Lysosomal TRPML1 Channel and Autophagy in Motoneuron-like Cells

An emerging body of evidence indicates an association between anthropogenic particulate matter (PM) and neurodegeneration. Although the historical focus of PM toxicity has been on the cardiopulmonary system, ultrafine PM particles can also exert detrimental effects in the brain. However, only a few studies are available on the harmful interaction between PM and CNS and on the putative pathomechanisms

Evaluation of the informed consent process for male circumcision scale-up in Swaziland

This report evaluates the informed consent process for male circumcision conducted through the Male Circumcision Partnership for Swaziland, led by Population Services International, in partnership with Jhpiego, Marie Stopes International, and the Population Council. The study assesses participants\u27 comprehension of the circumcision process, the informed consent process, as well as the affect of male circumcision counseling on their experience

Evaluation of the informed consent process for male circumcision scale-up in Zambia

This report evaluates the informed consent process for male circumcision conducted through the Male Circumcision Partnership for Zambia, led by Population Services International (Society for Family Health, Zambia), in partnership with Jhpiego, Marie Stopes International, and the Population Council. The objectives of the study were to assess male circumcision clients\u27 comprehension of the informed consent process, examine social norms and practices regarding informed consent for adolescents, compare clients\u27 expectations and experiences, and make additional recommendations for improving the informed consent process

Thermal treatment under high-vacuum of tars relevant in combustion and material science

The composition of tars, typically derived from coal and heavy fuel processing or formed in fuel-rich combustion, determines their transformation into carbons relevant in combustion and environmental fields as well as for material production. The speciation of the huge number of aromatic components of tars, usually found in form of viscous black liquid or solid, is not straightforward because of the tar complexity and high molecular weight, spanning from few hundreds up to thousands of Da. To this regard, the pre-separation of tar in lighter and heavier fractions simplifies the further characterization of its composition. The present work reports a fractionation method of a typical sample of combustion-formed tar based on moderate heating in high-vacuum conditions (10-6 mbar). It was preliminarily tested on a single polycyclic aromatic hydrocarbon, coronene, and on synthetic mixtures of polycyclic aromatic hydrocarbons, presumed to be the basic aromatic moieties of tar components. Lighter components obtained by condensation/deposition as thin films and/or crystals, as well as the heavier residue, were analysed by optical microscopy and spectroscopy. The separation procedure allowed to get more information on the components distribution also inferring the self-organization in cluster assembly and/or crystal forms

Solid carbon produced during the simulation of re-entry in the Titan atmosphere by means of an arc-driven flow facility

Spacecraft entry into Titan’s atmosphere has been investigated using a dedicated (Small Planetary Entry Simulator) facility (SPES). While in earlier works much attention was paid to the joint numerical-experimental simulation of typical entry physical parameters (namely, heat flux and total enthalpy); in the present analysis we focus on some unexpected results recently obtained at the University of Naples, in collaboration with CNR, in the framework of a new test campaign dedicated to various planetary atmospheres (including Titan itself). Such findings concern the presence of a carbon-like substance on the surface of the measuring probes used for the experiments, which seem to align with the results yielded by other authors with other strategies (an inductive plasma torch). We have confirmed the carbonaceous nature of such particulate matter via various diagnostic techniques such as SEM, Raman, FT-IR, UV-visible absorption and fluorescence spectroscopy, GC-MS and TGA. The present work is devoted to the presentation of such results together with a critical discussion of the novelty relating to the present experimental approach (arc plasma versus inductive torch) and an analysis of the chemical-physical differences pertaining to the carbon obtained with the two different methods

Size-based effects of anthropogenic ultrafine particles on activation of human lung macrophages

The anthropogenic particulate matter (PM), suspended air dust that can be inhaled by humans and deposited in the lungs, is one of the main pollutants in the industrialized cities atmosphere. Recent studies have shown that PM has adverse effects on respiratory diseases. These effects are mainly due to the ultrafine particles (PM0.1, PM < 100 nm), which, thanks to their PM size, are efficiently deposited in nasal, tracheobronchial, and alveolar regions. Pulmonary macrophages are a heterogeneous cell population distributed in different lung compartments, whose role in inflammatory response to injury is of particular relevance. In this study, we investigated the effect of PM0.1 on Human Lung Macrophages (HLMs) activation evaluated as proinflammatory cytokines and chemokine release, Reactive Oxygen Species (ROS) production and intracellular Ca2+concentration ([Ca2+]i). Furthermore, PM0.1, after removal of organic fraction, was fractionated in nanoparticles both smaller (NP20) and bigger (NP100) than 20 nm by a properlydeveloped analytical protocol, allowed isolating their individual contribution. Interestingly, while PM0.1 and NP20 induced stimulatory effects on HLM cytokines release, NP100 had not effect. In particular, PM0.1 induced IL-6, IL-1β, TNF-α, but not CXCL8, release from HLMs. Moreover, PM0.1, NP20 and NP100 did not induce β-glucuronidase release, a preformed mediator contained in HLMs. The long time necessary for cytokines release (18 h) suggested that PM0.1 and NP20 could induce ex-novo production of the tested mediators. Accordingly, after 6 h of incubation, PM0.1 and NP20 induced mRNA expression of IL-6, TNF-α and IL-1β. Moreover, NP20 induced ROS production and [Ca2+]i increase in a time-dependent manner, without producing cytotoxicity. Collectively, the present data highlight the main proinflammatory role of NP20 among PM fractions. This is particularly of concern because this fraction is not currently covered by legal limits as it is not easily measured at the exhausts by the available technical methodologies, suggesting that it is mandatory to search for new monitoring techniques and strategies for limiting NP20 formation