1,339 research outputs found

    Advanced materials research for long-haul aircraft turbine engines

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    The status of research efforts to apply low to intermediate temperature composite materials and advanced high temperature materials to engine components is reviewed. Emerging materials technologies and their potential benefits to aircraft gas turbines were emphasized. The problems were identified, and the general state of the technology for near term use was assessed

    ORIGIN OF LIGHT SCATTERING FROM DISORDERED SYSTEMS

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    Anelastic light scattering is computed numerically for model disordered systems (linear chains and 2-dimensional site and bond percolators), with and without electrical disorder. A detailed analysis of the vibrational modes and of their Raman activity evidences that two extreme mechanisms for scattering may be singled out. One of these resembles scattering from finite size systems, while the other mechanisms originates from spatial fluctuations of the polarizability and is such that modes in even small frequency intervals may have very different Raman activities. As a consequence, the average coupling coefficient C(ω)C(\omega) is the variance of a zero-average quantity. Our analysis shows that for both linear chains and 2-dimensional percolators the second mechanism dominates over the first, and therefore Raman scattering from disordered systems is essentially due to spatial fluctuations.Comment: 12 pages, Latex, 7 figures available on request

    Total Hemi-overgrowth in Pigmentary Mosaicism of the (Hypomelanosis of) Ito Type: Eight Case Reports.

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    Pigmentary mosaicism of the (hypomelanosis of) Ito type is an umbrella term, which includes phenotypes characterized by mosaic hypopigmentation in the form of streaks, whorls, patchy, or more bizarre skin configurations (running along the lines of Blaschko): these cutaneous patterns can manifest as an isolated skin disorder (pigmentary mosaicism of the Ito type) or as a complex malformation syndrome in association with extracutaneous anomalies (most often of the musculoskeletal and/or nervous systems) (hypomelanosis of Ito). Affected individuals are anecdotally reported to have also partial or total body hemi-overgrowth (HOG), which often causes moderate to severe complications.We studied the occurrence and features of HOG in the 114 children and adults with mosaic pigmentary disorders of the Ito type diagnosed and followed up (from 2 to 22 years; average follow-up 16 years) at our Institutions.Eight patients (5 M, 3 F; aged 4 to 25 years; median age 16 years) out of the 114 analyzed (7%) fulfilled the criteria for unilateral HOG, with differences in diameter ranging from 0.4 to 4.0 cm (upper limbs) and 1.0 to 9.0 cm (lower limbs). Moreover, among these 8 patients, 5/8 filled in the 75th to 90th percentile for height; 6/8 had associated kyphoscoliosis; and 5/8 showed cognitive delays. No tumour complications were recorded. Overall, 6/8 HOG patients presented with additional (extracutaneous) syndromic manifestations, apart from the HOG (ie, with a clinical phenotype of hypomelanosis of Ito).The present study, which includes children and adults with the longest follow-up so far recorded, confirms the association between pigmentary mosaicism of the Ito type and HOG lowering previous estimates (7% vs 16%) for HOG in the context of mosaic hypopigmentation. A careful examination, looking at subtle to moderate asymmetries and associated complications within the spectrum of these mosaic pigmentary disorders, is recommended

    Transcriptional control of the B3GALT5 gene by a retroviral promoter and methylation of distant regulatory elements

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    We focused on transcription factors and epigenetic marks that regulate the B3GALT5 gene through its retroviral long terminal repeat (LTR) promoter. We compared the expression levels of the B3GALT5 LTR transcript, quantitated by competitive RT-PCR, with those of the candidate transcription factors HNF1\u3b1/\u3b2 and Cdx1/2, determined by Western blot analysis, in colon cancer biopsies, various cell lines, and cell models serving as controls. We found that HNF1\u3b1/\u3b2 were easily detected, irrespective of the amount of LTR transcript expressed by the source, whereas Cdx1/2 were undetectable, and no sample lacking HNF1\u3b1/\u3b2 expressed the LTR transcript. On transfection in proper host cells, both HNF1\u3b1 and HNF1\u3b2 provided detectable LTR transcript, whereas shRNA-mediated silencing of HNF1\u3b2 impaired transcription. Treating cells with 5\u2032-aza-2\u2032-deoxycytidine (5AZA) strongly reduced expression, without affecting HNF1\u3b1/\u3b2, despite the lack of CpG islands in the LTR and proximal sequences. By electrophoresis mobility shift and luciferase reporter assays, the LTR promoter binding and activity did not correlate with the amounts of LTR transcript expressed in the cells and depended on the levels of the transcription factors. We conclude that HNF1\u3b1/\u3b2 are necessary but insufficient to activate and regulate B3GALT5 LTR transcription, which depends on unknown regulatory elements that are active when methylated and located outside of and far from the LTR promoter

    Learning to breathe: developmental phase transitions in oxygen status

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    Plants are developmentally disposed to considerable changes in oxygen availability, yet our understanding of the importance of hypoxia is almost entirely limited to stress biology. Differential patterns of the abundance of oxygen, nitric oxide (.NO) and reactive oxygen species (ROS), and redox potential occur in organs and meristems, and examples are emerging in the literature of mechanistic relationships of these to development. Here, we describe the convergence of these cues in meristematic and reproductive tissues, and discuss the evidence for regulated hypoxic niches, within which oxygen-, ROS-, .NO- and redox-dependent signalling curate developmental transitions in plants

    Pharyngeal airway dimensions: a cephalometric, growth-study-based analysis of physiological variations in children aged 6-17

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    SummaryOBJECTIVE: The aim was to assess pharyngeal airway dimensions and physiological changes based on lateral cephalometric radiographs from healthy untreated children aged 6-17 years. MATERIALS/METHODS: The sample consisted of 880 lateral cephalograms (412 females and 468 males) of the Zurich Craniofacial Growth Study. Statistical analyses on cephalometric measurements of airway dimensions (distances ‘p': shortest distance between soft palate and posterior pharyngeal wall and ‘t': shortest distance between tongue and posterior pharyngeal wall) and craniofacial parameters were performed. To disclose differences between different age groups, a Kruskal-Wallis test was applied. The influence of gender on ‘p' and ‘t' was analysed by a Mann-Whitney U-test for each age group separately. The Spearman correlation was computed in order to investigate associations between craniofacial parameters. Variables associated with ‘p' and ‘t' were chosen for multiple regression model investigation. RESULTS: The results demonstrated high interindividual variations. A slight influence of age on ‘p' (P = 0.034) could be attested (+1.03mm) but not on ‘t' (P = 0.208). With the exception of the 9-year age group, no significant differences between the genders were found. Correlation analysis revealed several statistically significant correlations between ‘t' or ‘p' and antero-posterior cephalometric variables. All correlation coefficients were, however, very low and the adjusted coefficient of determination also revealed the regression model to be very weak. CONCLUSIONS: The high interindividual variations of ‘p' and ‘t' render the use of reference values problematic. Contrary to other craniofacial structures, neither age-related changes nor sexual dimorphism were found for ‘p' and ‘t'. Any associations to antero-posterior cephalometric characteristics seem lo

    Reptilia, Squamata, Tropiduridae, <i>Stenocercus sinesaccus</i> Torres–Carvajal, 2005: Distribution extension

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    The present study reports the easternmost known record for the tropidurid lizard Stenocercussinesaccus Torres–Carvajal, 2005, at Floresta Nacional de Silvânia, state of Goiás, Brazil, in a transition areabetween cerrado sensu strictu and gallery fores

    Substance use and knowledge among Italian High School students.

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    This study was aimed for evaluation of Italian students' attitudes to addictive substances, their knowledge and personal experience, and their awareness about the risks. The research was realized among high school students from Marche region in the Central Italy in the year 2006; the study group was randomly chosen from all schools in the region. 4118 appropriately completed questionnaires returned. The statistic processing was carried out by using chi-square test for two qualitative variables. 29.9 % of the students have tried drugs; 36.4 % of the interviewed reckon alcohol, tobacco and antidepressants for drugs. A relationship between the use of licit and illicit addictive substances and a correlation between the use of illicit substances and the use of liquors and tobacco in family was found. The students, who drink frequently, smoke regularly and use drugs, believe that the drugs create dependence only if overused; only a quarter of them classify themselves as drug addicts. The study indicates a lack of information on the drugs among the young people. It emerges that the young people do not sufficiently know the risk of the dependence. A change of the preventive strategies should be considered

    Innovative Covid-19 diagnostics and testing strategies in Italy, Denmark, UK, Israel and Sweden: a comparative analysis including tests, incidence and mortality

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    Background and aim: Detecting SARS-CoV-2 remains a critical component in the global effort to control COVID-19, particularly with the emergence of variants. Since the outbreak, diagnostic techniques have evolved to meet different contexts and needs. Methods: In this study, we analyzed the use of these techniques in five countries (i.e. Italy, Denmark, the United Kingdom, Sweden, and Israel) based on their specific national testing and contact tracing strategies. We also examined the number of tests performed per week, the positivity rate of tests, and the mortality rate in these populations during the same time periods. These countries were chosen based on the directives of the consortium involved in the CORONADX project. Results: During the three-year period under review, Italy and Denmark adopted large-scale testing strategies over a long period of time, with different results: in Italy an average of 4.5% of the population adhered to diagnosis, in Denmark 21%, while Israel reached 6.5%. The UK prioritised mass testing for short periods, outperforming the other countries with 1,882,596,198 total swabs and an average adherence of 28.1% of the population. Despite this, it recorded the highest number of deaths related to COVID-19 (211,155), with a lethality rate of 0.87%, second only to Sweden with 0.88%, where the average adherence to diagnosis was 1.7% of the population. Significant are the data for Israel, where as deaths increased, so did testing (r = 0.62, p < 0.001). Conclusions: To control future outbreaks it’s fundamental satisfying the need for effective testing strategies and government communication, equitable healthcare access, and education in public health and hygiene principles. (www.actabiomedica.it)
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