100 research outputs found

    Lithobiontic recolonization following cleaning and preservative treatments on the rock engravings of Valle Camonica, Italy: A 54-months monitoring

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    : Both the indirect control of microclimate conditions and the direct application of preservative products to contrast stone bioreceptivity may contribute to limit lithobiontic recolonization of cultural heritage surfaces after cleaning interventions. However, the priority deserved by these different preventive approaches has still been poorly evaluated, particularly in outdoor environments. This work dealt with the engraved sandstone surfaces of the National Park of Rock Engravings of Naquane (Italy, UNESCO WHS), widely colonized by lichens, mosses and a dark cyanobacterial biofilm, and thus requiring frequent cleaning interventions to preserve their legibility for visitors and scholars. In particular, post-cleaning recolonization by the different lithobionts was seasonally monitored along 54 months in different zones of an engraved outcrop, primarily differing in levels of shading, on parcels exposed to nine different conservative treatments. These included (or not) a pre-cleaning devitalization of lithobionts and the post-cleaning application of biocidal (benzalkonium chloride, plant essential oils, usnic acid) and other restoration products (nanocrystalline anatase, polysiloxane-based water repellent, ethyl-silicate-based consolidant). The combination of surface image analyses, fluorimetric and colorimetric measurements showed that mosses and the cyanobacterial biofilm rapidly recolonized all the parcels in the more shaded zone, irrespective of conservative treatments. In the other areas, recolonization significantly differed depending on the treatment. The post-cleaning application of biocides determined the best results through two vegetative seasons, but only nanocrystalline anatase and the polysiloxane-based water repellent maintained the surfaces lighter than uncleaned controls along the whole monitoring period. Recolonization primarily proceeded by the uncleaned surfaces surrounding the parcels and, at least in the examined case of lichens, did not show substantial shifts in community composition, although some nitrophytic species increased their frequency. In conclusion, the effectiveness of preservative treatments to prevent a rapid recolonization of heritage stone surfaces appeared subordinate to the presence of microenvironmental conditions less favourable to lithobionts

    Use of larvae of the wax moth Galleria mellonella as an in vivo model to study the virulence of Helicobacter pylori

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    BACKGROUND: Helicobacter pylori is the first bacterium formally recognized as a carcinogen and is one of the most successful human pathogens, as over half of the world’s population is colonized by the bacterium. H. pylori-induced gastroduodenal disease depends on the inflammatory response of the host and on the production of specific bacterial virulence factors. The study of Helicobacter pylori pathogenic action would greatly benefit by easy-to-use models of infection. RESULTS: In the present study, we examined the effectiveness of the larvae of the wax moth Galleria mellonella as a new model for H. pylori infection. G. mellonella larvae were inoculated with bacterial suspensions or broth culture filtrates from either different wild-type H. pylori strains or their mutants defective in specific virulence determinants, such as VacA, CagA, CagE, the whole pathogenicity island (PAI) cag, urease, and gamma-glutamyl transpeptidase (GGT). We also tested purified VacA cytotoxin. Survival curves were plotted using the Kaplan-Meier method and LD(50) lethal doses were calculated. Viable bacteria in the hemocoel were counted at different time points post-infection, while apoptosis in larval hemocytes was evaluated by annexin V staining. We found that wild-type and mutant H. pylori strains were able to survive and replicate in G. mellonella larvae which underwent death rapidly after infection. H. pylori mutant strains defective in either VacA, or CagA, or CagE, or cag PAI, or urease, but not GGT-defective mutants, were less virulent than the respective parental strain. Broth culture filtrates from wild-type strains G27 and 60190 and their mutants replicated the effects observed using their respective bacterial suspension. Also, purified VacA cytotoxin was able to kill the larvae. The killing of larvae always correlated with the induction of apoptosis in hemocytes. CONCLUSIONS: G. mellonella larvae are susceptible to H. pylori infection and may represent an easy to use in vivo model to identify virulence factors and pathogenic mechanisms of H. pylori. The experimental model described can be useful to screen a large number of clinical H. pylori strain and to correlate virulence of H. pylori strains with patients’ disease status

    Litobionti e arte rupestre: strategie per la conservazione

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    Prova a guardare da vicino la superficie di una roccia esposta in ambiente esterno, che sia in un bosco o al bordo di una strada, in alta montagna, in prossimità del mare o anche in città: vedrai che è colonizzata da organismi viventi! Sono tanti e diversi fra loro per dimensioni e strategie di vita, nel loro complesso sono chiamati litobionti. I più grandi, ad esempio i muschi e i licheni, hanno per lo più dimensioni centimetriche e si vedono bene ad occhio nudo o con l’aiuto di una lente d’ingrandimento, mentre i più piccoli possono essere distinti solo con l'aiuto di un microscopio: sono cianobatteri, alghe verdi unicellulari e funghi neri a sviluppo microcoloniale. Questi microrganismi spesso si organizzano in biofilm ossia patine di vari colori spesso visibili sulle rocce; avvolti da una matrice gelatinosa che li protegge dagli agenti esterni, convivono tanti organismi diversi sia autotrofi che eterotrofi. Continua a leggere..

    Litobionti e arte rupestre: strategie per la conservazione

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    Prova a guardare da vicino la superficie di una roccia esposta in ambiente esterno, che sia in un bosco o al bordo di una strada, in alta montagna, in prossimità del mare o anche in città: vedrai che è colonizzata da organismi viventi! Sono tanti e diversi fra loro per dimensioni e strategie di vita, nel loro complesso sono chiamati litobionti. I più grandi, ad esempio i muschi e i licheni, hanno per lo più dimensioni centimetriche e si vedono bene ad occhio nudo o con l’aiuto di una lente d’ingrandimento, mentre i più piccoli possono essere distinti solo con l'aiuto di un microscopio: sono cianobatteri, alghe verdi unicellulari e funghi neri a sviluppo microcoloniale. Questi microrganismi spesso si organizzano in biofilm ossia patine di vari colori spesso visibili sulle rocce; avvolti da una matrice gelatinosa che li protegge dagli agenti esterni, convivono tanti organismi diversi sia autotrofi che eterotrofi. Continua a leggere..

    Aplastic anaemia in childhood. Description of two cases and review of the literature

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    AbstractChildhood aplastic anaemia (AA) is an uncommon but potentially fatal haematological disorder. Patients with AA receive supportive care based on transfusions and timely treatment of opportunistic infections, along with specific therapies, which may be bone marrow transplantation and immunosuppressive therapy. Early diagnosis and supportive therapy are required to prevent fatal complications like overwhelming sepsis or life threatening haemorrhages. We report two cases of aplastic anaemia having a different aetiology. The diagnostic work-up and the therapeutic management for each case are described below

    Armida disvelata. L’immagine del velo nella "Gerusalemme liberata"

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    The essay takes into account the different occurrences of the term ‘veil’ in the Gerusalemme liberata. After an analysis of the metaphorical meanings of the term, the focus moves towards the veils that hide or embellish some of the female characters, in particular Sofronia, Erminia and Armida, bringing to light the different functions – even symbolic – that appear to be connected to this garment.The essay takes into account the different occurrences of the term ‘veil’ in the Gerusalemme liberata. After an analysis of the metaphorical meanings of the term, the focus moves towards the veils that hide or embellish some of the female characters, in particular Sofronia, Erminia and Armida, bringing to light the different functions – even symbolic – that appear to be connected to this garment

    The association of indwelling urinary catheter with delirium in hospitalized patients and nursing home residents: an explorative analysis from the "Delirium Day 2015"

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    Backround: Use of indwelling urinary catheter (IUC) in older adults has negative consequences, including delirium. Aim: This analysis, from the "Delirium Day 2015", a nationwide multicenter prevalence study, aim to evaluate the association of IUC with delirium in hospitalized and Nursing Homes (NHs) patients. Methods: Patients underwent a comprehensive geriatric assessment, including the presence of IUC; inclusion criteria were age > 65 years, being Italian speaker and providing informed consent; exclusion criteria were coma, aphasia, end-of-life status. Delirium was assessed using the 4AT test (score ≥ 4: possible delirium; scores 1-3: possible cognitive impairment). Results: Among 1867 hospitalized patients (mean age 82.0 ± 7.5 years, 58% female), 539 (28.9%) had IUC, 429 (22.9%) delirium and 675 (36.1%) cognitive impairment. IUC was significantly associated with cognitive impairment (OR 1.60, 95% CI 1.19-2.16) and delirium (2.45, 95% CI 1.73-3.47), this latter being significant also in the subset of patients without dementia (OR 2.28, 95% CI 1.52-3.43). Inattention and impaired alertness were also independently associated with IUC. Among 1454 NHs residents (mean age 84.4 ± 7.4 years, 70.% female), 63 (4.3%) had IUC, 535 (36.8%) a 4AT score ≥ 4, and 653 (44.9%) a 4AT score 1-3. The multivariate logistic regression analysis did not show a significant association between 4AT test or its specific items with IUC, neither in the subset of patients without dementia. Discussion: We confirmed a significant association between IUC and delirium in hospitalized patients but not in NHs residents. Conclusion: Environmental and clinical factors of acute setting might contribute to IUC-associated delirium occurrence

    New high statistics measurement of Ke4K_{e4} decay form factors and ππ\pi\pi scattering phase shifts

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    We report results from a new measurement of the Ke4K_{e4} decay K±→π+π−e±νK^{\pm} \rightarrow \pi^{+}\pi^{-}e^{\pm}\nu by the NA48/2 collaboration at the CERN SPS, based on a partial sample of more than 670000 Ke4K_{e4} decays in both charged modes collected in 2003. The form factors of the hadronic current (F, G, H) and ππ\pi\pi phase difference (δ=δs−δp\delta=\delta_{s}-\delta_{p}) have been measured in ten independent bins of the ππ\pi\pi mass spectrum to investigate the variation. A sizeable acceptance at large ππ\pi\pi mass, a low background and a very good resolution contribute to an improved experimental accuracy, a factor two better than in the previous measurement, when extracting the ππ\pi\pi scattering lengths a00a^{0}_{0} and a02a^{2}_{0}. Under the assumption of isospin symmetry and using numerical solutions of the Roy equations, the following values are obtained in the plane (a00,a02):a00=0.233±0.016stat±0.007syst,a02=−0.0471±0.011stat±0.004systa^{0}_{0}, a^{2}_{0}): a^{0}_{0}=0.233 \pm 0.016_{stat} \pm 0.007_{syst}, a^{2}_{0}=-0.0471 \pm 0.011_{stat} \pm 0.004_{syst}. The presence of potentially large isospin effects is also considered and will allow comparison with precise predictions from Chiral Perturbation Theory

    Search for direct CP violating charge asymmetries in K±→π±π+π−K^\pm\to\pi^\pm\pi^+\pi^- and K±→π±π0π0K^\pm\to\pi^\pm\pi^0\pi^0 decays

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    A measurement of the direct CP violating charge asymmetries of the Dalitz plot linear slopes Ag=(g+−g−)/(g++g−)A_g=(g^+-g^-)/(g^++g^-) in K±→π±π+π−K^\pm\to\pi^\pm\pi^+\pi^- and K±→π±π0π0K^\pm\to\pi^\pm\pi^0\pi^0 decays by the NA48/2 experiment at CERN SPS is presented. A new technique of asymmetry measurement involving simultaneous K+K^+ and K−K^- beams and a large data sample collected allowed a result of an unprecedented precision. The charge asymmetries were measured to be Agc=(−1.5±2.2)×10−4A^c_g=(-1.5\pm2.2)\times10^{-4} with 3.11×1093.11\times 10^9 K±→π±π+π−K^{\pm}\to\pi^\pm\pi^+\pi^- decays, and Agn=(1.8±1.8)×10−4A^n_g=(1.8\pm1.8)\times10^{-4} with 9.13×1079.13\times 10^7 K±→π±π0π0K^{\pm}\to\pi^\pm\pi^0\pi^0 decays. The precision of the results is limited mainly by the size of the data sample.Comment: 29 pages, 9 figures. An updated version accepted by the EPJ
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