259 research outputs found

    A stochastic model for financiers

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    In this work, two models for legal and illegal financiers are presented. The aim of the financiers are different: a bank try to minimize the defalt probabilityof the funded company, while the illegal financier aims to bring the company to bankruptcy and, at the same time, to obtain the maximum level of the firm's guarantee wealth. A couple of stochastic dynamic optimization problems are solved. The illegal case let intervene a numerical analysis of the microeconomic situation of the firm, strating fromreal data and writing new simulation�procedure in Matlab and GAMS. The legal case has been solved in closed-form, by using stochastic control theory.

    Cadmium in cephalopod molluscs: implications for public health.

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    Cadmium concentrations were measured in the flesh and hepatopancreas (digestive gland) of 1,392 specimens of different species of cephalopod molluscs (broadtail squid, spider octopus, curled octopus, horned octopus, elegant cuttlefish, and pink cuttlefish) to determine whether maximum levels fixed by the European Commission were exceeded. In all species, mean cadmium concentrations were higher in hepatopancreas than in flesh. Large differences among the different species were also observed. Pink cuttlefish and spider octopus had the highest concentrations for both flesh (spider octopus, 0.77 microg g(-1); pink cuttlefish, 0.87 microg g(-1)) and hepatopancreas (spider octopus, 9.65 microg g(-1); pink cuttlefish, 18.03 microg g(-1)), and the lowest concentrations were encountered in broadtail squid (flesh, 0.13 microg g(-1); hepatopancreas, 2.48 microg g(-1)). The other species had intermediate concentrations of 0.20 to 0.30 microg g(-1) in flesh and 5.46 to 8.01 microg g(-1) in hepatopancreas. Concentrations exceeding the limit proposed by the European Commission (1.00 microg g(-1)) were observed in 44.4 and 40.0% of flesh samples of spider octopus and pink cuttlefish, respectively. The estimated weekly intake, 0.09 to 0.66 microg/kg body weigh, was below the provisional tolerable weekly intake set by the World Health Organization

    Update of Indicator PCB Levels in Food in Southern Italy: Assessment of the Dietary Exposure for Adult and Elderly Population

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    The levels of non-dioxin-like PCB indicators (iPCBs 28, 52, 101, 138, 153, and 180) were determined in food samples (seafood, meat and processed meat, milk and dairy products, hen eggs, olive oil, and other fats) to evaluate the exposure of adult and elderly population. iPCB levels in samples were in the following order: fishery products > meat and processed meat > milk and dairy products > olive oil and other fats. None of the samples had concentrations above the maximum permissible limits for human consumption established by the European Union legislation, except for salami samples. The dietary intake for the total population was 12.33 ng·kg−1 bw·d−1, while depending on the sex/age groups, exposure was estimated between 9.60 and 12.11 ng·kg−1 bw·d−1, with seafood being the major contributor. The exposure scenario indicates that further efforts must still be carried out to protect the consumer from these harmful chemicals

    Polychlorinated dioxins, furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) in food from Italy: Estimates of dietaryintake and assessment

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    Dietary intake of polychlorinated dioxins and furans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) from various foods (fish and seafood, meat and meat-based products, milk and dairy products, hen eggs, olive oil and fats) was investigated for various sex/age groups of the Italian population. The concentrations of PCDD/Fs and dl-PCBs and their contribution to total TEQ values varied depending on food matrix. Fish (0.50 pg WHO-TEQ/g wet weight) and seafood (0.16 pg WHO-TEQ/g wet weight) showed the highest mean concentrations of PCDD/Fs plus dl-PCBs, followed by meat (1.70 pg WHO-TEQ/g lipid weight), meat based products (1.03 pg WHO-TEQ/g lipid weight), milk and dairy products (0.78 pg WHO-TEQ/g lipid weight), hen eggs (0.71 pg WHO-TEQ/g lipid weight), fats (0.27 pg WHO-TEQ/g lipid weight) and olive oil (0.09 pg WHO-TEQ/g lipid weight). In all samples WHO-TEQ PCDD/F plus dl-PCB concentrations fulfilled the European Union food law, except in pork loin samples (1.39 pg WHO-TEQ/g lipid weight). Differences in exposure depending on the sex/age groups (children > teenagers > adults > elders) and hypotheses considered (lower bound and upper bound) were encountered. Non-cancer risk values showed a low exposure. Carcinogenicity risk results revealed that highly exposed individuals were distributed over all sex/age groups, even though the proportion of individuals exceeding the safe limit was higher in children. These data once again underline the importance of trying to control the levels of these contaminants in fishery products, particularly in fish, who represents one of the main exposure sources for consumers. PRACTICAL APPLICATION: This paper may help the consumer in making food choices to minimize the exposure risk to dioxins, furans and PCBs

    Antimicrobial and Antibiofilm Activity of a Recombinant Fragment of β-Thymosin of Sea Urchin Paracentrotus lividus

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    With the aim to obtain new antimicrobials against important pathogens such as Staphylococcus aureus and Pseudomonas aeruginosa, we focused on antimicrobial peptides (AMPs) from Echinoderms. An example of such peptides is Paracentrin 1 (SP1), a chemically synthesised peptide fragment of a sea urchin thymosin. In the present paper, we report on the biological activity of a Paracentrin 1 derivative obtained by recombination. The recombinant paracentrin RP1, in comparison to the synthetic SP1, is 22 amino acids longer and it was considerably more active against the planktonic forms of S. aureus ATCC 25923 and P. aeruginosa ATCC 15442 at concentrations of 50 µg/mL. Moreover, it was able to inhibit biofilm formation of staphylococcal and P. aeruginosa strains at concentrations equal to 5.0 and 10.7 µg/mL, respectively. Molecular dynamics (MD) simulations allowed to rationalise the results of the experimental investigations, providing atomistic insights on the binding of RP1 toward models of mammalian and bacterial cell membranes. Overall, the results obtained point out that RP1 shows a remarkable preference for bacterial membranes, in excellent agreement with the antibacterial activity, highlighting the promising potential of using the tested peptide as a template for the development of novel antimicrobial agents

    Muscle synergies for the control of single-limb stance with and without visual information in young individuals

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    Purpose: Single-limb stance is a demanding postural task featuring a high number of daily living and sporting activities. Thus, it is widely used for training and rehabilitation, as well as for balance assessment. Muscle activations around single joints have been previously described, however, it is not known which are the muscle synergies used to control posture and how they change between conditions of normal and lack of visual information. Methods: Twenty-two healthy young participants were asked to perform a 30 s single-limb stance task in open-eyes and closed-eyes condition while standing on a force platform with the dominant limb. Muscle synergies were extracted from the electromyographical recordings of 13 muscles of the lower limb, hip, and back. The optimal number of synergies, together with the average recruitment level and balance control strategies were analyzed and compared between the open- and the closed-eyes condition. Results: Four major muscle synergies, two ankle-dominant synergies, one knee-dominant synergy, and one hip/back-dominant synergy were found. No differences between open- and closed-eyes conditions were found for the recruitment level, except for the hip/back synergy, which significantly decreased (p = 0.02) in the closed-eyes compared to the open-eyes condition. A significant increase (p = 0.03) of the ankle balance strategy was found in the closed-eyes compared to the open-eyes condition. Conclusion: In healthy young individuals, single-limb stance is featured by four major synergies, both in open- and closed-eyes condition. Future studies should investigate muscle synergies in participants with other age groups, as well as pathological conditions

    Levels of Mercury, Methylmercury and Selenium in Fish: Insights into Children Food Safety

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    Total mercury (THg), methylmercury (MeHg), and selenium (Se) concentrations were measured in various commercially important fish species. The benefit–risk binomial associated with these chemicals was assessed in children through the probability of exceeding the provisional tolerable weekly intakes (PTWIs) of the contaminants and the Se recommended dietary allowance (RDA). The Se:Hg molar ratios, selenium health benefit values (HBVSe), and monthly consumption rate limits (CRmm) for each species were also calculated. THg and Se were analyzed by atomic absorption spectrophotometer (Shimadzu, Milan, Italy), while MeHg was determined by Trace Ultra gas chromatograph connected with a PolarisQ MS (Thermo Fisher Scientific,Waltham, MA, USA). None of the analyzed fish had Hg levels above the European Community regulatory limits, while most large predators had MeHg levels over the threshold concentration set by US EPA. The estimated weekly intakes of THg and MeHg exceeded in many cases the PTWIs and the Se estimated daily intakes were provided from 0.71% to 2.75% of the RDA. Se:Hg molar ratios above 1 and positive HBVSe index suggested that Se in fish could be enough to alleviate the potential toxic effect of Hg. However, high-risk groups as children should consume fish in moderation because a large consumption pattern, especially of swordfish and tunas, might be of concern for health

    Paracentrin 1, a synthetic antimicrobial peptide from the sea-urchin Paracentrotus lividus, interferes with staphylococcal and Pseudomonas aeruginosa biofilm formation

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    The rise of antibiotic-resistance as well as the reduction of investments by pharmaceutical companies in the development of new antibiotics have stimulated the investigation for alternative strategies to conventional antibiotics. Many antimicrobial peptides show a high specificity for prokaryotes and a low toxicity for eukaryotic cells and, due to their mode of action the development of resistance is considered unlikely. We recently characterised an antimicrobial peptide that was called Paracentrin 1 from the 5-kDa peptide fraction from the coelomocyte cytosol of the Paracentrotus lividus. In this study, the chemically synthesised Paracentrin 1, was tested for its antimicrobial and antibiofilm properties against reference strains of Gram positive and Gram negative. The Paracentrin 1 was active against planktonic form of staphylococcal strains (reference and isolates) and Pseudomonas aeruginosa ATCC 15442 at concentrations ranging from 12.5 to 6.2 mg/ml. The Paracentrin 1 was able to inhibit biofilm formation of staphylococcal and Pseudomonas aeruginosa strains at concentrations ranging from 3.1 to 0.75 mg/ml. We consider the tested peptide as a good starting molecule for novel synthetic derivatives with improved pharmaceutical potentia

    Diffuse panbronchiolitis in a patient with common variable immunodeficiency: a casual association or a pathogenetic correlation?

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    Diffuse panbronchiolitis (DPB) is an idiopathic inflammatory disease that seems to have an immunological pathogenesis and that causes a severe progressive suppurative and obstructive respiratory disorder. Common variable immunodeficiency (CVID) is the most common serious primary immunodeficiency and it is often associated with respiratory diseases. Herein, we describe a case of DPB in a 41-year-old man affected by CVID. We examined the patient's lungs, focusing on the characteristics of the inflammatory cells and of the foamy macrophagic nodules typical of DPB. Immunohistochemical typing of the lymphocytic infiltrate showed that B-cells were almost absent, matching the immunological profile of CVID. The case described is the first case reported in the literature of DPB in a patient affected by CVID. Moreover it seems to confirm the correlation between an immunodeficiency status and the development of DPB and provides more information on the accumulation of nodules of foamy macrophages in DPB

    Novel Sortase A Inhibitors to Counteract Gram-Positive Bacterial Biofilms

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    Sortase A (SrtA) is a membrane enzyme responsible for the covalent anchoring of surface proteins on the cell wall of Gram-positive bacteria. Nowadays it is considered an interesting target for the development of new anti-infective drugs which aim to interfere with important Gram-positive virulence mechanisms. Along the years, we studied the anti-staphylococcal and anti-biofilm activity of some natural and synthetic polyhalogenated pyrrolic compounds, called pyrrolomycins. Some of them were active on Gram-positive pathogens at a μg/mL range of concentration (1.5-0.045 μg/mL) and showed a biofilm inhibition in the range of 50-80%. [1-3] In light of these encouraging results, herein we present our efforts in the design and synthesis of novel pyrrolomycins. To dispose of sufficient amount for the in-depth in vitro investigation, we developed an efficient and easy-to-use microwave synthetic methodology. All compounds showed a good inhibitory activity toward SrtA, in accordance with the molecular modelling studies, having IC50 values ranging from 130 to 300 µM comparable to berberine hydrochloride, our reference compound. Particularly, the pentabromo-derivative exhibited the highest capability to interfere with biofilm formation of S. aureus with an IC50 of 3.4 nM. This compound was also effective in altering S. aureus murein hydrolase activity, responsible for degradation, turnover, and maturation of bacterial peptidoglycan and involved in the initial stages of S. aureus biofilm formation. [4
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