1,932 research outputs found

    Pressure induced magnetic phase separation in La0.75_{0.75}Ca0.25_{0.25}MnO3_{3} manganite

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    The pressure dependence of the Curie temperature TC(P)_{C}(P) in La0.75_{0.75}Ca0.25_{0.25}MnO3_{3} was determined by neutron diffraction up to 8 GPa, and compared with the metallization temperature TIM(P)_{IM}(P) \cite{irprl}. The behavior of the two temperatures appears similar over the whole pressure range suggesting a key role of magnetic double exchange also in the pressure regime where the superexchange interaction is dominant. Coexistence of antiferromagnetic and ferromagnetic peaks at high pressure and low temperature indicates a phase separated regime which is well reproduced with a dynamical mean-field calculation for a simplified model. A new P-T phase diagram has been proposed on the basis of the whole set of experimental data.Comment: 5 pages, 4 figure

    Evidence of a pressure-induced metallization process in monoclinic VO2_2

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    Raman and combined trasmission and reflectivity mid infrared measurements have been carried out on monoclinic VO2_2 at room temperature over the 0-19 GPa and 0-14 GPa pressure ranges, respectively. The pressure dependence obtained for both lattice dynamics and optical gap shows a remarkable stability of the system up to P*‚ąľ\sim10 GPa. Evidence of subtle modifications of V ion arrangements within the monoclinic lattice together with the onset of a metallization process via band gap filling are observed for P>>P*. Differently from ambient pressure, where the VO2_2 metal phase is found only in conjunction with the rutile structure above 340 K, a new room temperature metallic phase coupled to a monoclinic structure appears accessible in the high pressure regime, thus opening to new important queries on the physics of VO2_2.Comment: 5 pages, 3 figure

    Detection of potential enteric pathogens in children with severe acute gastroenteritis using the filmarray: Results from a three - years hospital-based survey in Northern Italy

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    Acute gastroenteritis (AGE) are leading causes of morbidity and mortality in children. Therefore, rapid pathogens identification is needed. The AGE aetiology was investigated from 2018 to 2020 in 2,066 children in Parma (Italy) by FilmArray Gastrointestinal Panel and Enterovirus-targeting RT-PCR. Pathogens were detected in 1,162 (56.2%) stool samples from as many children; 798 (68.7%) were single and 364 (31.3%) mixed infections (68.7% vs 31.3%, P < 0.0001). Children aged 0‚Äď5 years showed the highest infection incidence (66.1%). The most frequent pathogens were Enteropathogenic Escherichia coli (EPEC; 19.14%), Clostridioides difficile (10.42%), Norovirus (10.36%), Enterovirus (9.44%), and Campylobacter (9.21%). EPEC, Campylobacter, enteroaggregative E. coli, Norovirus, and Rotavirus showed seasonality. The incidence of pathogens detected decreased between 2018 and 2020 (42.7% vs 20.8%, P < 0.0001), seemingly for the preventive measures imposed by the severe acute respiratory syndrome coronavirus-2 pandemic. A putative aetiology in half the children examined and an estimate of enteric pathogens epidemiology were assessed

    Impact of human cytomegalovirus and human herpesvirus 6 infection on the expression of factors associated with cell fibrosis and apoptosis: Clues for implication in systemic sclerosis development

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    Systemic sclerosis (SSc) is a severe autoimmune disorder characterized by vasculopathy and multi-organ fibrosis; its etiology and pathogenesis are still largely unknown. Herpesvirus infections, particularly by human cytomegalovirus (HCMV) and human herpesvirus 6 (HHV-6), have been suggested among triggers of the disease based on virological and immunological observations. However, the direct impact of HCMV and/or HHV-6 infection on cell fibrosis and apoptosis at the cell microenvironment level has not yet been clarified. Thus, this study aimed to investigate the effects of HCMV and HHV-6 infection on the induction of pro-fibrosis or pro-apoptosis conditions in primary human dermal fibroblasts, one of the relevant SSc target cells. The analysis, performed by microarray in in vitro HCMV-or HHV-6-infected vs. uninfected cells, using specific panels for the detection of the main cellular factors associated with fibrosis or apoptosis, showed that both viruses significantly modified the expression of at least 30 pro-fibrotic and 20 pro-apoptotic factors. Notably, several recognized pro-fibrotic factors were highly induced, and most of them were reported to be involved in vivo in the multifactorial and multistep pathogenic process of SSc, thus suggesting a potential role of both HCMV and HHV-6

    Host-cell dependent role of phosphorylated keratin 8 during influenza A/NWS/33 virus (H1N1) infection in mammalian cells

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    In this study, we investigated the involvement of keratin 8 during human influenza A/NWS/33 virus (H1N1) infection in semi-permissive rhesus monkey-kidney (LLC-MK2) and permissive human type II alveolar epithelial (A549) cells. In A549 cells, keratin 8 showed major expression and phosphorylation levels. Influenza A/NWS/33 virus was able to subvert keratin 8 structural organization at late stages of infection in both cell models, promoting keratin 8 phosphorylation in A549 cells at early phases of infection. Accordingly, partial colocalizations of the viral nucleoprotein with keratin 8 and its phosphorylated form were assessed by confocal microscopy at early stages of infection in A549 cells. The employment of chemical activators of phosphorylation resulted in structural changes as well as increased phosphorylation of keratin 8 in both cell models, favoring the influenza A/NWS/33 virus's replicative efficiency in A549 but not in LLC-MK2 cells. In A549 and human larynx epidermoid carcinoma (HEp-2) cells inoculated with respiratory secretions from pediatric patients positive for, respectively, influenza A virus or respiratory syncytial virus, the keratin 8 phosphorylation level had increased only in the case of influenza A virus infection. The results obtained suggest that in A549 cells the influenza virus is able to induce keratin 8 phosphorylation thereby enhancing its replicative efficiency

    Prevalence of Intestinal Parasitoses in a Non-Endemic Setting during a 10-Year Period (2011‚Äď2020): A Focus on Dientamoeba fragilis

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    Dientamoeba fragilis is a cosmopolitan and neglected protozoan. Although little is known concerning its pathogenicity and its true prevalence worldwide, its role as enteric pathogen is emerging, as the occurrence of dientamoebiasis has increased also in industrialised countries. This study investigated the occurrence and prevalence of intestinal parasites, focusing on D. fragilis in a 10-year period (2011‚Äď2020) in a single tertiary-care hospital located in Northern Italy. A statistical evaluation of the correlation between dientamoebiasis and specific signs other than gastrointestinal-related ones was performed. The laboratory diagnosis was performed on 16,275 cases of suspected intestinal parasitoses. Intestinal parasites were detected in 3254 cases, 606 of which were associated to D. fragilis, which represented 18.6% (606/3254) of all the intestinal parasitoses with a 3.7% (606/16,275) prevalence and an increasing trend during the last five years (2011‚Äď2015: 2.8% vs. 2016‚Äď2020: 4.8%). D. fragilis was commonly detected in foreigners, especially those from developing countries, as well as in children; prevalence was equal in males and females. With regard to the clinical aspect, the only putative sign statistically related to dientamoebiasis was anal pruritus. Despite the controversial epidemiological knowledges on dientamoebiasis, the prevalence of D. fragilis found in this study highlights the need to consider this parasite in any differential diagnosis of gastrointestinal disease

    Modulation of micrornome by human cytomegalovirus and human herpesvirus 6 infection in human dermal fibroblasts: Possible significance in the induction of fibrosis in systemic sclerosis

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    Human cytomegalovirus (HCMV) and Human herpesvirus 6 (HHV‚Äź6) have been report-edly suggested as triggers of the onset and/or progression of systemic sclerosis (SSc), a severe autoimmune disorder characterized by multi‚Äźorgan fibrosis. The etiology and pathogenesis of SSc are still largely unknown but virological and immunological observations support a role for these beta-herpesviruses, and we recently observed a direct impact of HCMV and HHV‚Äź6 infection on the expression of cell factors associated with fibrosis at the cell level. Since miRNA expression has been found profoundly deregulated at the tissue level, here we aimed to investigate the impact on cell microRNome (miRNome) of HCMV and HHV‚Äź6 infection in in vitro infected primary human dermal fibroblasts, which represent one of the main SSc target cells. The analysis, performed by Taq-man arrays detecting and quantifying 754 microRNAs (miRNAs), showed that both herpesviruses significantly modulated miRNA expression in infected cells, with evident early and late effects and deep modulation (>10 fold) of >40 miRNAs at each time post infection, including those previously recognized for their key function in fibrosis. The correlation between these in vitro results with in vivo observations is strongly suggestive of a role of HCMV and/or HHV‚Äź6 in the multistep patho-genesis of fibrosis in SSc and in the induction of fibrosis‚Äźsignaling pathways finally leading to tissue fibrosis. The identification of specific miRNAs may open the way to their use as biomarkers for SSc diagnosis, assessment of disease progression and possible antifibrotic therapies

    Rapid classification of clostridioides difficile strains using maldi-tof ms peak-based assay in comparison with pcr-ribotyping

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    Typing methods are needed for epidemiological tracking of new emerging and hyperviru-lent strains because of the growing incidence, severity and mortality of Clostridioides difficile infections (CDI). The aim of this study was the evaluation of a typing Matrix-Assisted Desorption/Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS (T-MALDI)) method for the rapid classification of the circulating C. difficile strains in comparison with polymerase chain reaction (PCR)-ribotyping results. Among 95 C. difficile strains, 10 ribotypes (PR1‚ÄďPR10) were identified by PCR-ribotyping. In particular, 93.7% of the isolates (89/95) were grouped in five ribotypes (PR1‚ÄďPR5). For T-MALDI, two classifying algorithm models (CAM) were tested: the first CAM involved all 10 ribotypes whereas the second one only the PR1‚ÄďPR5 ribotypes. Better performance was obtained using the second CAM: recognition capability of 100%, cross-validation of 96.6% and agreement of 98.4% (60 correctly typed strains, limited to PR1‚ÄďPR5 classification, out of 61 examined strains) with PCR-ribotyping results. T-MALDI seems to represent an alternative to PCR-ribotyping in terms of reproducibility, set up time and costs, as well as a useful tool in epidemiological investigation for the detection of C. difficile clusters (either among CAM included ribotypes or out-of-CAM ribotypes) involved in outbreaks

    Rapid identification of escherichia coli colistin-resistant strains by maldi-tof mass spectrometry

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    Colistin resistance is one of the major threats for global public health, requiring reliable and rapid susceptibility testing methods. The aim of this study was the evaluation of a MALDI-TOF mass spectrometry (MS) peak-based assay to distinguish colistin resistant (colR) from susceptible (colS) Escherichia coli strains. To this end, a classifying algorithm model (CAM) was developed, testing three different algorithms: Genetic Algorithm (GA), Supervised Neural Network (SNN) and Quick Classifier (QC). Among them, the SNN-and GA-based CAMs showed the best performances: recognition capability (RC) of 100% each one, and cross validation (CV) of 97.62% and 100%, respec-tively. Even if both algorithms shared similar RC and CV values, the SNN-based CAM was the best performing one, correctly identifying 67/71 (94.4%) of the E. coli strains collected: in point of fact, it correctly identified the greatest number of colS strains (42/43; 97.7%), despite its lower ability in identifying the colR strains (15/18; 83.3%). In conclusion, although broth microdilution remains the gold standard method for testing colistin susceptibility, the CAM represents a useful tool to rapidly screen colR and colS strains in clinical practice

    SARS-CoV-2 infection diagnosed only by cell culture isolation before the local outbreak in an Italian seven-week-old suckling baby

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    SARS-CoV-2 emerged in China in December 2019 and has now been declared a pandemic by the World Health Organization. This paper described the case of a 7-week-old suckling baby from Italy who was SARS-CoV-2-positive only by the cell culture method, with no clinical suspicion of and/or risk factors for SARS-CoV-2 infection. The baby was referred to hospital, with signs and symptoms of upper respiratory tract infection, before the virus had spread to the province. Nasal and pharyngeal swabs and a nasopharyngeal aspirate were used for conventional and molecular diagnostic assays not including the SARS-CoV-2 virus. Bacteria referred to the resident population were revealed in nasal and pharyngeal swabs. No viruses were detected using both immunofluorescence assay and nucleic acid amplification assays in the nasopharyngeal aspirate. The baby was discharged in good condition after 3 days of hospitalisation. Later, a cytopathic effect on the cell monolayers currently used for respiratory viruses was observed and the viral particles were identified as Coronaviridae by transmission electron microscopy. SARS-CoV-2 was identified by RT-PCR performed both on cell culture and on the stored aliquot of the original sample. The virus isolate was named SARS-Cov-2/human/Parma/1/2020. Cell culture still remains the only reference diagnostic method also for emerging viruses, allowing it to reveal cytopathogenic viruses and demonstrate their infectivity
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