1,593 research outputs found
Realizzazione di un sistema qualitativo in Real-Time PCR per l'identificazione di Escherichia Coli patogeni
No full textShiga toxin-producing E. coli (STEC-VTEC) are foodborne pathogens that have been associated with gastroenteric diseases in humans. Infections are often caused by ingestion of contaminated food. For this purpose, the report ‘Technical specifications for the monitoring and reporting of verotoxigenic Escherichia coli (VTEC o STEC) on animals and food (VTEC surveys on animals and food)’ was proposed by EFSA (European Food Safety Authority) in order to harmonize STEC research methods in EU Member States. Moreover, the reference method ISO 13136:2012 describes the molecular identification of Shiga toxin-producing E. coli through the detection of stx and eae virulence genes and serogroup assignment through the detection of the genes associated with O157, O111, O26, O103, O145 serogroups. The genes aggR and aaiC, distinctive for Enteroaggregative E. coli (EAEC) strains, should be also taken into account considering that the large outbreak occurred in Germany in 2011 (750 cases of HUS of which 44 deaths) was due to the consumption of sprouts contaminated by a O104 strain, which was found both STEC and EAEC (stx2, aggR and aaiC) positive.
The aim of this study was to develop a multiplex real-time PCR assay for the rapid detection of pathogenic E.coli strains in food, in particular an assay for the detection of stx1, stx2, and eae genes, which identifies STEC; other three assays specifically formulated for the identification of the six main pathogenic serogroups (O157, O111, O26, O103, O145, and O104), and , lastly, another assay for the detection of aggR and aaiC genes, specific for EAEC. Furthermore, the assays were compared with official methods used in USA (USDA-FSIS, FDA/BAM) for the identification of E.coli in foodstuffs.
The results obtained show that the assays for the sensitive, specific and rapid detection of STEC (stx-eae) and serogroups (O26-O103-O111-O145-O157-O104) were developed, in compliance with the reference method ISO 13136:2012. These assays were able to identify pathogenic E. coli in the main foodstuff implicated in epidemic outbreaks. Moreover, this work demonstrates that the performance of the assays is reliant on the enrichment process that remain a critical step in assay development. Since the contamination level of STEC in food is usually low, the selection of an appropriate medium is a key element of STEC detection protocol, to reduce the risk of false negative results. Therefore, alternative enrichment condition, like mBPWp + CV at 42°C, should be taken into consideration.
Furthermore, colony tests carried out with EAEC E.coli detection assay showed optimal results, with 100% of exclusivity and efficiency.
The comparison between molecular assays developed in this study and USDA-FSIS and FDA/BAM official methods showed equivalent results of performance and sensitivity, providing in some cases better results with our method
Size Dependence of Protein Diffusion in the Cytoplasm of Escherichia coli
No full textDiffusion in the bacterial cytoplasm is regarded as the primary method of intracellular protein movement and must play a major role in controlling the rates of cell processes. A number of recent studies have used green fluorescent protein (GFP) tagging and fluorescence microscopy to probe the movement and distribution of proteins in the bacterial cytoplasm. However, the dynamic behavior of indigenous proteins must be controlled by a complex mixture of specific interactions, combined with the basic physical constraints imposed by the viscosity and macromolecular crowding of the cytoplasm. These factors are difficult to unravel in studies with indigenous proteins. To what extent the addition of a GFP tag might affect the movement of a protein through the cytoplasm has also remained unknown. To resolve these problems, we have carried out a systematic study of the size dependence of protein diffusion coefficients in the Escherichia coli cytoplasm, using engineered GFP multimers (from 2 to 6 covalently linked GFP molecules). Diffusion coefficients were measured using confocal fluorescence recovery after photobleaching (FRAP). At least up to 110 kDa (four linked GFP molecules), the diffusion coefficient varies with size roughly as would be predicted from the Einstein-Stokes equation for a classical (Newtonian) fluid. Thus, protein diffusion coefficients are predictable over this range. GFP tagging of proteins has little impact on the diffusion coefficient over this size range and therefore need not significantly perturb protein movement. Two indigenous E. coli proteins were used to show that their specifi
Giulia Veronica Varisco
No full textThe headword explains the biography and the contribution of the author Giulia Varisco to the children's literatur
Photobiomodulation and Orthodontic Treatment with Clear Aligners: A Case Report of Severe Crowding and Agenesis
No full textThis paper aims to demonstrate the effectiveness of photobiomodulation in accelerating orthodontic treatment with clear aligners in correcting an orthodontic malocclusion characterized by severe crowding and agenesis in an adult subject. An adult male patient with Class I malocclusion, a mild Class III skeletal base and severe crowding was treated with 88 Invisalign® (Align Technology, Santa Clara, CA, USA) pairs of aligners replaced every 5 days in combination with an Orthopulse™ (Biolux Research, Vancouver, BC, Canada) photobiomodulation device for home use by the patient. The total orthodontic treatment time was 440 days. Orthopulse™ is a photobiomodulation device that generates continuous beams of near-infrared light (NIR—near-infrared) with a wavelength of 850 nm and a power of 42 mW/cm2 to produce an average energy density on the surface of the silicone impression of 9.3 J/cm2. The combined use of clear aligners and the Orthopulse™ device allowed the patient to replace the aligners according to an experimental 5-day protocol to speed up the orthodontic therapy and, thus, resolve the malocclusion in less time than the manufacturer’s standard
Ytterbium Disilicate/Monosilicate Multilayer Environmental Barrier Coatings: Influence of Atmospheric Plasma Spray Parameters on Composition and Microstructure
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Ytterbium Disilicate/Monosilicate Multilayer Environmental Barrier Coatings: Influence of Atmospheric Plasma Spray Parameters on Composition and Microstructure
by Giulia Di Iorio,Laura Paglia *ORCID,Giulia PedrizzettiORCID,Virgilio GenovaORCID,Francesco MarraORCID,Cecilia BartuliORCID andGiovanni PulciORCID
INSTM Reference Laboratory for Materials and Surface Engineering, Sapienza University of Rome, Eudossiana 18, 00184 Rome, Italy
*
Author to whom correspondence should be addressed.
Coatings 2023, 13(9), 1602; https://doi.org/10.3390/coatings13091602
Original submission received: 10 August 2023 / Revised: 31 August 2023 / Accepted: 11 September 2023 / Published: 13 September 2023
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Abstract
SiC/SiC ceramic matrix composites (SiCf/SiC CMCs) are regarded as the new materials for the hot-section components of aircraft gas turbine engines, since they have one-third of the density of metallic superalloys, a higher temperature capability, good mechanical strength, and excellent thermal shock resistance. However, high-temperature water-vapor-rich combustion gases can induce severe surface recession phenomena in SiC/SiC leading to component failure. For this reason, it is necessary to design protective coatings, i.e., environmental barrier coatings (EBCs), able to protect the SiC/SiC surface in combustion environments. In the present work, ytterbium monosilicate (Yb2SiO5), stable when exposed to water vapor at high temperatures, and ytterbium disilicate (Yb2Si2O7), characterized by a thermal expansion coefficient closer to that of the substrate, were selected for a multilayer EBC system. EBCs were processed using the atmospheric plasma spray (APS) technique. A set of deposition parameters were tested, varying the power of the torch, and the composition and microstructure of the deposited coatings were studied in terms of porosity, crack density, and post-deposition phase retention by performing SEM, EDS, and XRD analysis. The results allow for the definition of the influence of deposition parameters on the final properties of multilayer EBC coatings
Correction to: Safety and Psychological Outcomes of Tandem t:Slim X2 Insulin Pump with Control-IQ Technology in Children, Adolescents, and Young Adults with Type 1 Diabetes: A Systematic Review
No full textThe second author name was incorrectly published as Giula Maria Smylie. The correct name is Giulia Marie Smylie. The original article has been corrected
Virulence Genes of Pathogenic Escherichia coli in Wild Red Foxes (Vulpes vulpes)
No full textSIMPLE SUMMARY: Escherichia coli is a commensal of the intestinal tract of humans and animals, but some pathotypes can cause severe infections. Enteropathogenic E. coli (EPEC), Shiga toxin-producing E. coli (STEC), and enterohemorrhagic E. coli (EHEC) are the pathotypes most frequently involved in enteric disorders observed in people and domestic animals. Wildlife may harbor and excrete these pathotypes too, therefore, they may be source of infections for humans and domestic animals. Vulpes vulpes seem to be involved in the epidemiology of pathogenic E. coli strains, and thus they could be a relevant threat mainly when they invade human settlements in rural and urban areas. ABSTRACT: Different pathotypes of Escherichia coli can cause severe diseases in animals and humans. Wildlife may contribute to the circulation of pathogenic pathotypes, including enteropathogenic E. coli (EPEC), Shiga toxin-producing E. coli (STEC), and enterohemorrhagic E. coli (EHEC). This study analyzed 109 DNA samples previously extracted from fecal specimens collected from red foxes (Vulpes vulpes) to detect E. coli virulence genes eaeA, hlyA, stx1, and stx2, that characterize the EPEC, STEC, and EHEC strains. Thirty-one (28.4%) samples were positive for at least one investigated virulence gene: eaeA gene was detected in 21 (19.2%) samples, hlyA in 10 (9.1%), stx1 in 6 (5.5%), and stx2 in 4 (3.6%). Nine DNA samples resulted positive for two or three virulence genes: five (4.6%) samples were positive for eaeA and hlyA genes, two (1.8%) for eaeA and stx1, one (0.9%) for hlyA and stx1, one (0.9%) for eaeA, hlyA and stx2. Red foxes seem to be involved in the epidemiology of these infections and their role could be relevant because they may be source of pathogenic E. coli for other wild animals, as well as domestic animals and humans
Photobiomodulation to Reduce Orthodontic Treatment Time in Adults: A Historical Prospective Study
No full textBackground: Orthodontic treatment in adult patients is hindered by several problems, such as little time for regular dental visits and financial costs. In recent years, photobiomodulation (PBM) has been shown to significantly reduce the duration of orthodontic treatment and significantly increase patient compliance. Objective: This study aimed to investigate the efficacy of PBM in shortening the orthodontic treatment duration in adult patients while ensuring optimal patient compliance. Methods: A total of 170 orthodontic patients with a Little’s irregularity index (LII) ≥ 3 mm treated with Invisalign clear aligners (Align Technology, Santa Clara, CA, USA) were included. The treatment group (PBM) (n = 90 patients) was trained in the use of the OrthopulseTM device (Biolux Research, Vancouver, Canada) according to an application protocol of 5 min per day. The control group (n = 80 patients) was treated with transparent Invisalign® without PBM applications. The LII was measured at a baseline and each aligner change until the end of the treatment when the LII was less than 1 mm. The crowding resolution rate (CRR), expressed in mm/week, and the total treatment time were measured. Results: The alignment rate of the PBM group was significantly higher than that of the control group (0.33 mm/week vs. 0.21 mm/week) with a reduction in the treatment time of 57.5 weeks in the PBM group compared with the control group. Conclusion: The PBM performed with the Orthopulse™ is shown to be an effective and noninvasive technique for accelerating teeth movements and can contribute in a relevant way to increase access to orthodontic treatment by the adult population as well as increase its compliance
Scrivere senza anestesia. La chiarezza di Giulia Niccolai
No full textIl saggio colloca storicamente la narratrice e poetessa Giulia Niccolai nel canone del Novecento letterario italiano discutendone poetica e cifre stilistiche. L'ampia analisi proposta tocca tutte le opere dell'autrice evidenziandone i legami intertestuali, anche tra poesia e narrativa, e i progressivi sviluppi in un arco cronologico esteso, tra anni Sessanta e primi anni Duemila. Lo studio coglie anche l'importanza dei riferimenti alle arti visive, in particolare alla fotografia, che Giulia Niccolai ha praticato in prima persona negli anni della Neoavanguardia, e alla pittura americana.The essay places the narrator and poet Giulia Niccolai in the canonical twentieth century Italian literary discussing her poetics and stylistic figures. The wide analysis proposed touches all the works of the author highlighting the intertextual links, also between poetry and narrative, and the progressive developments in an extended chronological period, between the Sixties and early Twenties. The study also captures the importance of references to the visual arts, especially photography, which Giulia Niccolai has practiced in the years of the Neo-avant-garde, and to American painting
Growth control of adherent-invasive Escherichia coli (AIEC) by the Predator Bacteria Bdellovibrio bacteriovorus: a new therapeutic approach for Crohn’s disease patients
No full textIn Crohn’s disease (CD) patients, intestinal dysbiosis with an overgrowth of Proteobacteria, mainly Escherichia coli, has been reported. A new pathotype of E. coli, the adherent-invasive Escherichia coli strain (AIEC), has been isolated from the mucosae of CD patients. AIEC strains play an important role in CD pathogenesis, increasing intestinal mucosa damage and inflammation. Several studies have been undertaken to find possible strategies/treatments aimed at AIEC strain reduction/elimination from CD patients’ intestinal mucosae. To date, a truly e↵ective strategy against AIEC overgrowth is not yet available, and as such, further investigations are warranted. Bdellovibrio bacteriovorus is a predator bacterium which lives by invading Gram-negative bacteria, and is usually present both in natural and human ecosystems. The aim of this study was to evaluate a novel possible strategy to treat CD patients’ mucosae when colonized by AIEC strains, based on the utilization of the Gram-negative predatory bacteria, B. bacteriovorus. The overall results indicate that B. bacteriovorus is able to interfere with important steps in the dynamics of pathogenicity of AIEC strains by its predatory activity. We indicate, for the first time, the possibility of counteracting AIEC strain overgrowth by exploiting what naturally occurs in microbial ecosystems (i.e., predation)
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