3,919 research outputs found

    Environmental, human health and socio-economic effects of cement powders: The multicriteria analysis as decisional methodology

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    The attention to sustainability-related issues has grown fast in recent decades. The experience gained with these themes reveals the importance of considering this topic in the construction industry, which represents an important sector throughout the world. This work consists on conducting a multicriteria analysis of four cement powders, with the objective of calculating and analysing the environmental, human health and socio-economic effects of their production processes. The economic, technical, environmental and safety performances of the examined powders result from official, both internal and public, documents prepared by the producers. The Analytic Hierarchy Process permitted to consider several indicators (i.e., environmental, human health related and socio-economic parameters) and to conduct comprehensive and unbiased analyses which gave the best, most sustainable cement powder. As assumed in this study, the contribution of each considered parameter to the overall sustainability has a different incidence, therefore the procedure could be used to support on-going sustainability efforts under different conditions. The results also prove that it is not appropriate to regard only one parameter to identify the ‘best’ cement powder, but several impact categories should be considered and analysed if there is an interest for pursuing different, often conflicting interests

    Salt-induced reentrant stability of polyion-decorated particles with tunable surface charge density

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    The electrostatic complexation between DOTAP-DOPC unilamellar liposomes and an oppositely charged polyelectrolyte (NaPA) has been investigated in a wide range of the liposome surface charge density. We systematically characterized the "reentrant condensation" and the charge inversion of polyelectrolyte-decorated liposomes by means of dynamic light scattering and electrophoresis. We explored the stability of this model polyelectrolyte/colloid system by fixing each time the charge of the bare liposomes and by changing two independent control parameters of the suspensions: the polyelectrolyte/colloid charge ratio and the ionic strength of the aqueous suspending medium. The progressive addition of neutral DOPC lipid within the liposome membrane gave rise to a new intriguing phenomenon: the stability diagram of the suspensions showed a novel reentrance due to the crossing of the desorption threshold of the polyelectrolyte. Indeed, at fixed charge density of the bare DOTAP/DOPC liposomes and for a wide range of polyion concentrations, we showed that the simple electrolyte addition first (low salt regime) destabilizes the suspensions because of the enhanced screening of the residual repulsion between the complexes, and then (high salt regime) determines the onset of a new stable phase, originated by the absence of polyelectrolyte adsorption on the particle surfaces. We show that the observed phenomenology can be rationalized within the Velegol-Thwar model for heterogeneously charged particles and that the polyelectrolyte desorption fits well the predictions of the adsorption theory of Winkler and Cherstvy. Our findings unambiguously support the picture of the reentrant condensation as driven by the correlated adsorption of the polyelectrolyte chains on the particle surface, providing interesting insights into possible mechanisms for tailoring complex colloids via salt-induced effects.Comment: 34 pages, 7 figure

    Life and non-life insurance demand: the different effects of influence factors in emerging countries from Europe and Asia

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    Urbanisation, incomes and their distributions, and the population degree of education are relevant factors for the development of insurance sector. This study estimates the different effects of the previously mentioned factors for life and non-life sector. We used the econometrics of panel data on 17 emerging economies from Asia and Europe over a 10-year period. We showed that urbanisation influenced significantly the life insurance demand in Asia, but not in Europe. Also, education was found to be significant only for the non-life sector in both regions and income was nonsignificant in Asia for non-life sector

    Contribution of proteomics to understanding the role of tumor-derived exosomes in cancer progression: State of the art and new perspectives

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    Exosomes are nanometer-sized vesicles (40–100 nm diameter) of endocytic origin released from different cell types under both normal and pathological conditions. They function as cell free messengers, playing a relevant role in the cell–cell communication that is strongly related to the nature of the molecules (proteins, mRNAs, miRNAs, and lipids) that they transport. Tumor cells actively shed exosomes into their surrounding microenvironment and growing evidence indicates that these vesicles have pleiotropic functions in the regulation of tumor progression, promoting immune escape, tumor invasion, neovascularization, and metastasis. During the last few years remarkable efforts have been made to obtain an accurate definition of the protein content of tumor-derived exosomes (TDEs) by applying MS-based proteomic technologies. To date, TDEs proteomic studies have been mainly utilized to catalog TDEs proteins with the purpose of identifying disease biomarkers. The future challenge for improving our understanding and characterization of TDEs will be the implementation of new systemsdriven and proteomic integrative strategies. The aim of this article is to provide an overview of the most characterized exosomes-mediated mechanisms that contribute to the pathogenesis of cancer and to review recent proteomics data that support the protumorigenic role of TDEs

    The influence of habitat quality on the foraging strategies of the entomopathogenic nematodes Steinernema carpocapsae and Heterorhabditis megidis

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    Entomopathogenic nematodes (EPN) are soil-transmitted parasites and their foraging strategies are believed to range from ‘ambush’ to ‘cruise’ foragers. However, research on their behaviour has not considered the natural habitat of these nematodes. We hypothesized that EPN behaviour would be influenced by soil habitat quality and tested this hypothesis using 2 EPN species Steinernema carpocapsae (an ‘ambusher’) and Heterorhabditis megidis (a ‘cruiser’) in 2 contrasting habitats, sand and peat. As predicted from previous studies, in sand most S. carpocapsae remained at the point of application and showed no taxis towards hosts, but in peat S. carpocapsae dispersed much more and showed a highly significant taxis towards hosts. H. megidis dispersed well in both media, but only showed taxis towards hosts in sand. In outdoor mesocosms in which both species were applied, S. carpocapsae outcompeted H. megidis in terms of host finding in peat, whereas the opposite was true in sand. Our data suggest that these 2 EPN may be habitat specialists and highlight the difficulties of studying soil-transmitted parasites in non-soil media

    Epigenetics as an Evolutionary Tool for Centromere Flexibility

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    Centromeres are the complex structures responsible for the proper segregation of chromosomes during cell division. Structural or functional alterations of the centromere cause aneuploidies and other chromosomal aberrations that can induce cell death with consequences on health and survival of the organism as a whole. Because of their essential function in the cell, centromeres have evolved high flexibility and mechanisms of tolerance to preserve their function following stress, whether it is originating from within or outside the cell. Here, we review the main epigenetic mechanisms of centromeres’ adaptability to preserve their functional stability, with particular reference to neocentromeres and holocentromeres. The centromere position can shift in response to altered chromosome structures, but how and why neocentromeres appear in a given chromosome region are still open questions. Models of neocentromere formation developed during the last few years will be hereby discussed. Moreover, we will discuss the evolutionary significance of diffuse centromeres (holocentromeres) in organisms such as nematodes. Despite the differences in DNA sequences, protein composition and centromere size, all of these diverse centromere structures promote efficient chromosome segregation, balancing genome stability and adaptability, and ensuring faithful genome inheritance at each cellular generation

    Early Arrival of New World Species Enriching the Biological Assemblage of the Santi Quattro Coronati Complex (Rome, Italy)

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    This paper reports the archaeobotanical and archaeozoological data from a disposal pit, whose use started after the partial closure of a staircase, and from a mortar surface within a former porch in the Santi Quattro Coronati complex in Rome, Italy. The two contexts were in use in the Early Modern Age, when the complex served as a cardinal seat. The element that distinguishes the Santi Quattro Coronati from other contemporaneous contexts is the presence of New World species, until now only hypothesized based on a letter sent by the first resident bishop in Santo Domingo to Lorenzo Pucci, then cardinal with the titulus of the Santi Quattro Coronati. Pumpkin seeds (Cucurbita pepo and C. maxima/moschata) were found in the pit, while a pelvis of guinea pig (Cavia porcellus) was found in a former porch. Numerous archaeobotanical remains preserved by mummification, identified mostly as food, and many archaeozoological specimens were found in the pit. Based on the data, it is hypothesized that the pit was used mainly as a deposit for table waste. The results as a whole help towards the investigation of the eating customs and daily habits of a Renaissance high-status clerical community

    Quality of the online delivery in the European Master in Adult Education

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    AbstractThe students from European Master in Adult Education were attending offers on Moodle platform, and also interacting with professors and peers from abroad. The students’ satisfaction about the quality of online delivery, and their preferences for a fully online offer/a blended one, or a F2F one were investigated, trying also to find out if there are differences in students’ perceptions if they are from different countries. Results showed that, in spite of being very favorable to the online offer, they were more content with F2F delivery, suggesting that like this they met professors from abroad, an highly appreciated opportunity

    R&D and market size: who benefits from orphan drug legislation?

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    Since the early 80s, incentives have been introduced to stimulate R&D for rare diseases. We develop a theoretical model to study the impact of push and pull incentives on the intensive and extensive margin of optimal R&D investments. The model describes the mechanisms by which the type of incentives provided may favor R&D for orphan diseases with comparatively high prevalence. In our empirical analysis, we merge data on orphan drug designations by the Food and Drug Administration with Orphanet data on disease characteristics. In line with the theoretical results, we find evidence supporting the idea that the incentives adopted may have contributed substantially to widening the gap between more and less rare diseases classified as orphan. Our theoretical and empirical findings together suggest that, if providing some therapeutic option to patients with very rare diseases is a priority, a revision of the current system of incentives should be considered
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