5,146 research outputs found
Analysis of the mass and deformation variation rates over time and their influence on long-term durability for specimens of porous material
In an environment subjected to continuous climatic evolution, the study of the long-term behavior of building materials subject to environmental aggressions becomes an extremely important factor in evaluating the sustainability of these materials over time. The damage due to the aggression of external agents does not only affect the surface of the building but can cause a loss of performance in the mechanical qualities of the material with the worsening of the safety conditions of the entire structure. The velocity of the damage evolution is an interesting item. Here the variation velocity of some parameters characterizing the porous materials subjected to aggressive actions is dealt with. Starting from standard material characterization tests, extending the test times, the rate of variation of the mass and the deformation induced by the absorption of saline solutions in the porous medium and the variation of these speeds over time were evaluated. Hypotheses are formulated on the influence that this speed on the degradation of the material in the short and long time. The results obtained show how long-term aggressive action can cause internal damage with a consequent critical increase in absorption, mass and deformation, phenomena that can induce even severe damage to structural element
Multiple guests in a single host: interactions across symbiotic and phytopathogenic bacteria in phloem-feeding vectors – a review
Using System Dynamics Modelling Approach to Develop Management Tools for Animal Production with Emphasis on Small Ruminants
Small ruminants are important assets in several regions of the world. They account for more than half of the domesticated ruminants. Despite the growth in goat production in the world (more than 2% per year), research related to goat production is less than desired. One underused but potentially valuable approach for research on small ruminants is simulation modelling. Models of the components of small ruminant systems can enhance the financial returns and reduce negative environmental impacts. These models can be used to assess many dimensions of small ruminant production, from rumen dynamics to economic policies designed to support small ruminant production. Understanding the nutrition, production, and economic policy feedback signals and planning ahead is crucial to build a robust and integrated production activity that can be managed under different production scenarios. System Dynamics (SD) is a computer-aided modelling methodology that can be used to perform policy analysis and decision support system (DSS) applied to dynamic problems arising in complex social, managerial, economic, or ecological dynamic systems characterized by interdependence, mutual interaction, information feedback, and circular causality. SD can be used as a modelling tool to aggregate knowledge to solve different types of problems that have a limited scope to a specific location or have broad trends of applications across locations and areas of science. Important issues of broad application include the bearings of animal production in the climate change and the impacts of climate change in animal production, alternative production scenarios of animal and crop integration, associations between animal production and business (economics, marketing). The trend of increasing small ruminants in tropical and subtropical regions and an increasing pressure on tropical and subtropical livestock systems to produce food, to feed livestock, and to produce energy crops warrants the development of DSS to address issues such as what is the “real” benefits of livestock, the negative impacts livestock can have on greenhouse-gas emissions and the environment, and the effects of climate change on livestock systems
DNA waves and water
Some bacterial and viral DNA sequences have been found to induce low
frequency electromagnetic waves in high aqueous dilutions. This phenomenon
appears to be triggered by the ambient electromagnetic background of very low
frequency. We discuss this phenomenon in the framework of quantum field theory.
A scheme able to account for the observations is proposed. The reported
phenomenon could allow to develop highly sensitive detection systems for
chronic bacterial and viral infections.Comment: Invited talk at the DICE2010 Conference, Castiglioncello, Italy
September 201
Expression analysis of HLA-E and NKG2A and NKG2C receptors points at a role for natural killer function in ankylosing spondylitis
Background. Ankylosing Spondylitis (AS) is a complex chronic inflammatory disease strongly associated with the majority of HLA-B27 alleles. HLA-E are non-classical MHC class I molecules that specifically interact with the natural killer receptors NKG2A (inhibitory) and NKG2C (activating), and have been recently proposed to be involved in AS pathogenesis. Objectives: To analyze the expression of HLA-E and the CD94/NKG2 pair of receptors in HLA-B27 positive AS patients and healthy controls (HC) bearing the AS-associated, B*2705 and the non-AS-associated, B*2709 allele. Methods: The level of surface expression of HLA-E molecules on CD14 positive peripheral blood mononuclear cell was evaluated in 21 HLA-B*2705 patients with AS, 12 HLA-B*2705 HC, 12 HLA-B*2709 HC and 6 HLA-B27 negative HC, using the monoclonal antibody MEM-E/08 by quantitative cytofluorimetric analysis. The percentage and density of expression of HLA-E ligands NKG2A and NKG2C were also measured on CD3-CD56+ NK cells. Results. HLA-E expression in CD14 positive cells was significantly higher in AS patients (587.0 IQR 424-830) compared to B*2705 HC (389 IQR 251.3-440.5, p=0.0007), B*2709 HC (294.5 IQR 209.5-422, p=0.0004) and HLA-B27 negative HC (380 IQR 197.3-515.0, p=0.01). A higher number of NK cells expressing NKG2A compared to NKG2C was found in all cohort analysed as well as a higher cell surface density. Conclusion: The higher surface level of HLA-E molecules in AS patients compared to HC, concurrently with a prevalent expression of NKG2A, suggests that the crosstalk between these two molecules might play a role in AS pathogenesis accounting for the previously reported association between HLA-E and AS
Plasma Cortisol in Men – Relationship With Atherosclerosis of Retinal Arteries
The production of cortisol increases in acute stress but the effects of chronic stress on
plasma cortisol are still controversial. Stress on the other hand plays a role in coronary
artery disease (CAD) and carotid atherosclerosis. Since there is no data about plasma
cortisol and atherosclerosis of the retinal arteries, the purpose of this study was to explore
the relationship between plasma cortisol in 101 adult males with the degree of
their retinal vessels atherosclerosis. The results were compared with those in 47
matched apparently healthy men with no retinal vessels changes. The atherosclerotic
changes of retinal vessels were determined by direct ophthalmoscopy and graded (1–4)
according to Scheie. Morning plasma cortisol levels were determined by radioimmunoassay
using commercial kits. The results were compared by using chi-square test. No association
between morning plasma cortisol concentrations and retinal vessels atherosclerosis
could be found. The results of this study do not support a role for physiological
levels of plasma cortisol in the development of atherosclerosis, at least of the retinal arteries,
in men
Diffuse functional brain disconnection syndrome in critically ill patients with COVID-19
The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is most closely related to severe respiratory syndrome; however, recent reports showed that it is capable of causing neurological disease. Here we report a case-series of 4 critically ill COVID-19 patients who recovered from pneumonia but showed serious neurological symptoms and eventually died
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The helicase Ded1p controls use of near-cognate translation initiation codons in 5' UTRs.
The conserved and essential DEAD-box RNA helicase Ded1p from yeast and its mammalian orthologue DDX3 are critical for the initiation of translation1. Mutations in DDX3 are linked to tumorigenesis2-4 and intellectual disability5, and the enzyme is targeted by a range of viruses6. How Ded1p and its orthologues engage RNAs during the initiation of translation is unknown. Here we show, by integrating transcriptome-wide analyses of translation, RNA structure and Ded1p-RNA binding, that the effects of Ded1p on the initiation of translation are connected to near-cognate initiation codons in 5' untranslated regions. Ded1p associates with the translation pre-initiation complex at the mRNA entry channel and repressing the activity of Ded1p leads to the accumulation of RNA structure in 5' untranslated regions, the initiation of translation from near-cognate start codons immediately upstream of these structures and decreased protein synthesis from the corresponding main open reading frames. The data reveal a program for the regulation of translation that links Ded1p, the activation of near-cognate start codons and mRNA structure. This program has a role in meiosis, in which a marked decrease in the levels of Ded1p is accompanied by the activation of the alternative translation initiation sites that are seen when the activity of Ded1p is repressed. Our observations indicate that Ded1p affects translation initiation by controlling the use of near-cognate initiation codons that are proximal to mRNA structure in 5' untranslated regions
Errors in neuroradiology
Approximately 4Â % of radiologic interpretation in daily practice contains errors and discrepancies that should occur in 2-20Â % of reports. Fortunately, most of them are minor degree errors, or if serious, are found and corrected with sufficient promptness; obviously, diagnostic errors become critical when misinterpretation or misidentification should significantly delay medical or surgical treatments. Errors can be summarized into four main categories: observer errors, errors in interpretation, failure to suggest the next appropriate procedure, failure to communicate in a timely and a clinically appropriate manner. Misdiagnosis/misinterpretation percentage should rise up in emergency setting and in the first moments of the learning curve, as in residency. Para-physiological and pathological pitfalls in neuroradiology include calcification and brain stones, pseudofractures, and enlargement of subarachnoid or epidural spaces, ventricular system abnormalities, vascular system abnormalities, intracranial lesions or pseudolesions, and finally neuroradiological emergencies. In order to minimize the possibility of error, it is important to be aware of various presentations of pathology, obtain clinical information, know current practice guidelines, review after interpreting a diagnostic study, suggest follow-up studies when appropriate, communicate significant abnormal findings appropriately and in a timely fashion directly with the treatment team
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