294 research outputs found
Analysis and Verification of Robustness Properties in Becker-Döring Model
No full textMany biochemical processes in living cells involve clusters of particles. Such processes include protein aggregation and the development of intracellular concentration gradients. To study these mechanisms, we can apply coagulation-fragmentation models describing populations of interacting components. In this context, the Becker-Döring equations - theorized in 1935 - provide the simplest kinetic model to describe condensations phenomena. Experimental works on this model reveal that it exhibits robustness, defined as the system’s capability to preserve its features despite noise and fluctuations. Here, we verify the robustness of the BD model, applying our notions of initial concentration robustness (α -robustness and β -robustness), which are related to the influence of the perturbation of the initial concentration of one species (i.e., the input) on the concentration of another species (i.e., the output) at the steady state. Then, we conclude that a new definition of robustness, namely the asymptotic robustness, is necessary to describe more accurately the model’s behavior
Introduzione e propagazione del Campylobacter jejuni in allevamenti di broilers. Presenza del germe su cute e piumaggio prima della macellazione e possibile influenza sulla contaminazione delle carni
No full textFormal characterization and efficient verification of a biological robustness property
No full textRobustness is an observable property for which a chemical reaction network (CRN) can maintain its functionalities despite the influence of different perturbations. In general, to verify whether a network is robust, it is necessary to consider all the possible parameter configurations. This is a process that can entail a massive computational effort. In the work of Rizk et al., the authors propose a definition of robustness in linear temporal logic (LTL) through which, on the basis of multiple numerical timed traces obtained by considering different parameter configurations, they verify the robustness of a reaction network. In this paper, we focus on a notion of initial concentration robustness (alpha -robustness), that is related to the influence of the perturbation of the initial concentration of one species (i.e., the input) on the concentration of another species (i.e., the output) at the steady state. We characterize this notion of robustness in the framework proposed by Rizk et al., and we show that, for monotonic reaction networks, this allows us to drastically reduce the number of traces necessary to verify robustness of the CRN
Ricerche sulla presenza di Campylobacter jejuni nell'apparato riproduttore di ovaiole in deposizione
No full textComparative study and quality evaluation of Italian focaccias seasoned with extra virgin olive oil
No full textAn extra virgin olive oil was used as seasoning for three different types of focaccia produced on an industrial scale. This oil and samples of the oil extracted from the focaccias after baking were submitted to routine analyses and to silica gel column chromatography to separate polar compounds. These were then subjected to high performance size-exclusion chromatographic (HPSEC) analysis and it allowed to determine oxidative and hydrolytic degradation products. The results were compared with those obtained from artisan focaccias, seasoned with the same oil and toppings, by statistical analyses. The different technologies and the toppings employed directed in different ways the oxidative and hydrolytic processes in the oil. Copyright © Taylor & Francis Group, LLC
Changes in the oxidative state of extravirgin olive oil used in baked Italian focaccia topped with different ingredients
No full textFour different types of "focaccia" (Italian flat bread) prepared with the same dough and the same extra virgin olive oil but with different seasonings, were analyzed. Lipids were extracted from each sample using the Folch method. The indices commonly used to assess oil quality, the amounts of trans fatty acids and compounds of triglyceride polymerization, oxidation and hydrolysis, were determined in all the samples to better assess the degree of oxidation and hydrolysis of the oils. The findings showed that, once baked, the oil sampled from the different types of focaccias could not be included in the virgin category. The level of oxidation of the baked samples was greater than that in the uncooked oil. However the results obtained showed that the level of degradation of the extracted oils was lower than that found in edible refined oils and it seemed to be influenced by the topping used to flavour the focaccias. © 2007 Elsevier Ltd. All rights reserved
Glucose metabolism and coronary heart disease in patients with normal glucose tolerance.
No full textContext Several investigations as well as prospective studies have shown a significant
correlation between glucose metabolism and atherosclerosis in patients without
diabetes, but differences in parameters of glucose metabolism among the various degrees
of coronary disease in such patients have not been specifically evaluated.
Objective To investigate glucose metabolism in patients with normal glucose tolerance
(NGT) and coronary heart disease (CHD).
Design, Setting, and Participants Cross-sectional study of 234 men (mean [SD]
age, 56.2 [6.1] years) with NGT and suspected CHD who were admitted from January
1 through June 30, 2001, to an academic medical center in Italy for coronary angiography.
Main Outcome Measures Correlation of glucose metabolic factors and extent of
atherosclerosis determined by coronary angiography. Factors included levels of fasting
and postload glucose and insulin, glycosylated hemoglobin (HbA1c), and lipids, as
well as insulin resistance measured by homeostasis model assessment (HOMA-IR).
Results Patients were divided into 4 groups based on coronary angiography: no significant
stenosis (n=42), 1-vessel disease (n=72), 2-vessel disease (n=64), and 3-vessel
disease (n=56). Simple correlation analysis showed that the factors correlated with
the extent of atherosclerosis were levels of postload glucose (r=0.667), HbA1c (r=0.561),
postload insulin (r=0.221), and fasting insulin (r=0.297), as well as HOMA-IR (r=0.278)
(P*.001 for all). Multiple stepwise regression analysis suggested that the factors independently
associated with the number of stenosed coronary arteries were levels of
postload plasma glucose (r=0.572), HbA1c (r=0.413), postload insulin (r=0.267), and
fasting insulin (r=0.174), as well as HOMA-IR (r=0.250) (P*.001 for all). Similar results
were obtained after grouping patients by Duke Myocardial Jeopardy Score.
Conclusions For patients with NGT and different extents of atherosclerotic disease,
postload glycemia and HbA1c level are not equally distributed but are significantly higher
in those with more severe disease. This suggests that the glycemic milieu correlates
with the cardiovascular risk according to a linear model
Valorization of agro-industrial fermentation residues: biotransformation of ginger active molecules
No full textThe ginger rhizome is a primary ingredient of oriental food, beverage, and herbal medicine catching on Western Countries meals. In 2016 the food sector processed 3.3 million tonnes of ginger generating a pulp waste that was mostly destined to agricultural field, biorefinery, papermaking etc.1 The ginger pulp waste still contains an oleoresin rich in gingerol-like compounds, such as gingerols and shogaols, bioactive components with recognized anti-inflammatory and anticancer properties.2,3
As an alternative valorisation strategy, the recovery of the main ginger waste components and their biotransformation to generate a small library of optically enriched derivatives was herein investigated. The oleoresin was first extracted from a fermented ginger biomass originating from a local farm. The conventional extraction confirmed the presence of still 30% gingerol-like compounds with unaltered chemical profile as characterized and quantified by UPLC-TUV and GC-MS. Then the enantioselective reduction of prochiral carbonyl moiety of pure isolated 6-gingerol (1), 8-gingerol (2), 6-shogaol (3), 8-shogaol (4), 6-paradol (5), 8-paradol (6) and zingerone (7) by different alcohol dehydrogenases (ADHs)4 was investigated. From our preliminary results, no ketone reduction was observed for 3 and 4. As far as the other substrates concern, only the ADH from Micrococcus luteus and engineered ADHs from Evoxx led to chiral alcohols in low yield, but with good diastereo- and enantiomeric excess (d.e and e.e) (Figure 1)
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