108 research outputs found
Stochastic modelling and simulation of PTEN regulatory networks with miRNAs and ceRNAs
In this work, three genetic regulatory networks are considered, that model the post–transcriptional regulation of the PTEN onco suppressor gene, mediated by microRNAs and competitive endogenous RNAs, in glioblastoma multiforme, the most severe of brain tumours. We simulate solutions of the resulting stochastic differential systems and discuss the effects of this miRNA-fashioned regulation on PTEN expression
Generalized patterns from local and non local reactions
A class of systems is considered, where immobile species associated to
distinct patches, the nodes of a network, interact both locally and at a
long-range, as specified by an (interaction) adjacency matrix. Non local
interactions are treated in a mean-field setting which enables the system to
reach a homogeneous consensus state, either constant or time dependent. We
provide analytical evidence that such homogeneous solution can turn unstable
under externally imposed disturbances, following a symmetry breaking mechanism
which anticipates the subsequent outbreak of the patterns. The onset of the
instability can be traced back, via a linear stability analysis, to a
dispersion relation that is shaped by the spectrum of an unconventional
reactive Laplacian. The proposed mechanism prescinds from the classical Local
Activation and Lateral Inhibition scheme, which sits at the core of the Turing
recipe for diffusion driven instabilities. Examples of systems displaying a
fixed-point or a limit cycle, in their uncoupled versions, are discussed. Taken
together, our results pave the way for alternative mechanisms of pattern
formation, opening new possibilities for modeling ecological, chemical and
physical interacting systems
Myocardial infarction in major noncardiac surgery: Epidemiology, pathophysiology and prevention
The number of subjects undergoing major noncardiac surgery who are at risk for perioperative myocardial infarction (MI) is growing worldwide. It has been estimated that 500,000 to 900,000 patients suffer major perioperative cardiovascular complications every year, with consequent heavy, long-term prognostic implications and costs. It is well known that perioperative MIs don't share the same pathophysiology as nonsurgical MIs but the relative role of the different, potential triggers has not been completely clarified. Many aspects of the perioperative management, including risk-stratification and prophylactic or postoperative interventions have also not been completely defined. Throughout recent years many resources have been invested to clarify these aspects and experts have developed indices and algorithm-based strategies to better assess the cardiac risk and to guide the perioperative management. The scope of the present review is to discuss the main aspects of perioperative MI in noncardiac surgery, with particular regard to epidemiology, pathophysiology, preoperative risk stratification, prophylaxis and therapy
Random walks on hypergraphs
In the last twenty years network science has proven its strength in modelling
many real-world interacting systems as generic agents, the nodes, connected by
pairwise edges. Yet, in many relevant cases, interactions are not pairwise but
involve larger sets of nodes, at a time. These systems are thus better
described in the framework of hypergraphs, whose hyperedges effectively account
for multi-body interactions. We hereby propose a new class of random walks
defined on such higher-order structures, and grounded on a microscopic physical
model where multi-body proximity is associated to highly probable exchanges
among agents belonging to the same hyperedge. We provide an analytical
characterisation of the process, deriving a general solution for the stationary
distribution of the walkers. The dynamics is ultimately driven by a generalised
random walk Laplace operator that reduces to the standard random walk Laplacian
when all the hyperedges have size 2 and are thus meant to describe pairwise
couplings. We illustrate our results on synthetic models for which we have a
full control of the high-order structures, and real-world networks where
higher-order interactions are at play. As a first application of the method, we
compare the behaviour of random walkers on hypergraphs to that of traditional
random walkers on the corresponding projected networks, drawing interesting
conclusions on node rankings in collaboration networks. As a second
application, we show how information derived from the random walk on
hypergraphs can be successfully used for classification tasks involving objects
with several features, each one represented by a hyperedge. Taken together, our
work contributes to unveiling the effect of higher-order interactions on
diffusive processes in higher-order networks, shading light on mechanisms at
the hearth of biased information spreading in complex networked systems
Molecular diagnosis of Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle (Nematoda Aphelenchida Parasitaphelenchidae) in presence of polyphenols and other inhibitory compounds.
The pine wood nematode Bursaphelenchus xylophilus (Aphelenchida Parasitaphelenchidae) infects conifers, in particular pines, causing pine wilt disease. This nematode is considered a quarantine organism according to the EPPO and AQISQ guidelines. For this reason, several procedures for an affordable diagnostic test have been developed based on LAMP technique. In this work we shown how this technique behaved in presence of compounds that exert an inhibitory effect on DNA polymerases, a common problem that could be found in DNA preparations obtained from samples included in plant matrixes  LAMP technique was found able to detect presence of its specific DNA target in almost all cases studied but we found that the addiction of polyphenolic compounds present in some woody matrixes to DNA preparations could affect significantly on the sensibility of diagnostic test, while resinous material had a lesser influence on amplification
A PETase enzyme synthesised in the chloroplast of the microalga Chlamydomonas reinhardtii is active against post-consumer plastics
Polyethylene terephthalate hydrolases (PETases) are a newly discovered and industrially important class of enzymes that catalyze the enzymatic degradation of polyethylene terephatalate (PET), one of the most abundant plastics in the world. The greater enzymatic efficiencies of PETases compared to close relatives from the cutinase and lipase families have resulted in increasing research interest. Despite this, further characterization of PETases is essential, particularly regarding their possible activity against other kinds of plastic. In this study, we exploited for the first time the use of the microalgal chloroplast for more sustainable synthesis of a PETase enzyme. A photosynthetic-restoration strategy was used to generate a marker-free transformant line of the green microalga Chlamydomonas reinhardtii in which the PETase from Ideonella sakaiensis was constitutively expressed in the chloroplast. Subsequently, the activity of the PETase against both PET and post-consumer plastics was investigated via atomic force microscopy, revealing evidence of degradation of the plastics
Appendectomy and women’s reproductive outcomes: a review of the literature
Background The most frequent abdominal surgery performed for benign disease in females of fertile age is appendectomy, which remains among the most common surgeries and is a possible cause of peritoneal adhesions. The fact that appendectomy can cause adhesions may lead one to think that this may
be a relevant risk factor for infertility; however, there is no universal agreement regarding the association between appendectomy and fertility. The aim of this
review is to evaluate weather appendectomy may have a relevant impact on female fertility.Methods The search was conducted in PubMed and there was no limitation set on the date of publication. All studies regarding populations of female patients who had undergone appendectomy for inflamed appendix, perforated appendix, or negative appendix between childhood and the end of the reproductive period were included.
Results Some authors believe that pelvic surgery can cause adhesions which can potentially lead to tubal infertility by causing tubal obstruction or by altering
motility of fimbriae, tubal fluid secretion, and embryo transport. On the other hand, the most recent evidence reported that removal of the appendix seems to be associated with an increased pregnancy rate in large population studies.
Conclusion Despite the existence of contrasting opinions concerning fertility after appendectomy, the most recent evidence suggests that appendectomy may actually lead to improved fertility and decreased time to pregnancy. Appendectomy seems to be correlated with improved fertility and higher pregnancy rates
Nutrient intakes in an Italian population of infants during the complementary feeding period
Objective: To describe the nutrient intakes of an Italian cohort of infants at 6, 9 and 12 months of age.
Design: Dietary data were collected using a food diary at three follow-ups (6, 9 and 12 months of age of infants). The infants' dietary data were used to estimate nutrient intakes using the Italian food composition database integrated with data from nutritional labels and the literature. The mean and standard deviation, median and interquartile range, minimum and maximum, and 5th, 25th, 75th and 95th percentiles were calculated for the daily intake of twenty-eight nutrients, with sex differences evaluated using parametric/non-parametric statistical methods.
Setting: A prospective population-based birth cohort.SubjectInfants (n 400) living in the urban area of Trieste (Italy).
Results: The sex distribution was fairly balanced at each follow-up. The mean daily intakes of energy and the other twenty-seven nutrients considered were greater in males at all follow-ups. In particular, a significant statistical difference was observed in higher male consumption of cholesterol at 9 months and in energy and carbohydrate intakes at 12 months (P < 0·05). The mean daily intake of proteins was greater than that recommended by the Italian Dietary Reference Values at all follow-ups.
Conclusions: These preliminary results provide a useful basis for understanding the nutrient intake patterns of infants in this area of Italy during the first year of life
Performance of rapid tests in the management of dengue fever imported cases in Lazio, Italy 2014-2019
Abstract Background In Italy, dengue virus is the most frequent agent of imported viral infections. The use of rapid diagnostic tests (RDTs) may be of help as a preliminary user-friendly quick assay to facilitate dengue diagnosis, as ordinary laboratory diagnosis of dengue fever may require special efforts in terms of tools availability, interpretation of results, and skilled personnel. The performance of RDTs, however, may vary according to different epidemiological and laboratory background. Methods We reviewed five years of laboratory records of two dengue RDT results (Colorimetric SD-Bioline Dengue-Duo-RDT and Fluorimetric SD-Biosensor-STANDARD-F-Dengue-RDT), able to detect viral NS1 antigen and specific IgM and IgG. Diagnostic parameters were calculated using as reference the results of molecular (RT-PCR) and serological (immunofluorescence, IFA) tests. Overall performance, calculated considering the final case definition, was included in the accuracy assessment of RDTs. Results The combined use of NS1 and IgM/IgG RDT for the detection of acute dengue cases resulted in an overall sensitivity and specificity of 87.2% and 97.9% for Colorimetric RDT, 96.2% and 96.2% for Fluorimetric RDT. NS1 was the most reliable marker of acute infection, while IgM resulted falsely positive in nine samples, including sera derived from 2 Zika and 4 non-arbovirus infected patients. Conclusions The inclusion of RDT in the diagnostic algorithm is of undeniable help in the prompt management and surveillance of dengue infection in non-endemic areas. Confirmatory tests are, however, necessary to rule in or rule out dengue fever diagnosis
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