AN INNOVATIVE STRATEGY BASED ON UNCERTAINTY PROFILE FOR THE VALIDATION OF MICROBIOLOGICAL METHODS FOR COUNTING ENTEROBACTERIACEAE IN FOODS

Objective: A new and powerful statistical approach known as the uncertainty profile concept has been suggested for both testing the validity and making easy and straightforward interpretation of results obtained during the validation of an analytical method. The main goal of this paper is to confirm the applicability of this new strategy for the validation of a commercial kit, microbiological method, for the enumeration of the Enterobacteriaceae in foods and the estimate of the measurement uncertainty by using the newly provided formula and without referring to any additional experiments.Methods: An innovative formula to assess the uncertainty by using validation data and without recourse to other additional experiments was proposed. The uncertainty was evaluated through the two-sided β-content, γ-confidence tolerance interval, which is computed with three manners: the Mee's approach, the Generalized Pivotal Confidence, and the Modified Large Simple procedureResults: After the use of the three chemometric method of calculation of tolerance intervals, the obtained results with uncertainty profile show without doubt that the enumeration method is valid over the range of target values given that the upper and the lower 66.7 %-content, 90 %-confidence tolerance limits have fallen within the two acceptance limits of±0.25 Log unit. If the β is stretched to 80 %-content, 90 %-confidence, the three computed tolerance intervals lead to different decisions.Conclusion: we have demonstrated the ability of the uncertainty profile to be used for testing the validity of enumeration method which represents the first application of an uncertainty profile to food microbiological methods, and provides good estimations of the uncertainty measurements for each concentration level.Keywords: Validation, Uncertainty profile, β-content-γ-confidence tolerance interval, Uncertainty measurement, Microbiological metho

Study of natural degradation effect on lignocellulose fibers of archaeological cedar wood: monitoring by Fourier Transform Infrared (FTIR) spectroscopy

The present work aims at elucidating the changes in the chemical composition of Moroccan cedar wood during exposure time to the natural degradation process. Correlation of these changes with certain physical properties and performance of this polymeric material were proposed. Four archaeological Cedrus atlantica wood samples dating from the 16th, 17th, 19th and 21st centuries were analyzed using Fourier Transform Infrared spectroscopy. The infrared spectroscopic analyses demonstrated in detail the significant changes that occurred in different molecular groups of lignocelluloses fibers, as evidenced by the decrease of band intensities related to the carbohydrates and lignin. The influence of the natural degradation process on these fibers was enhanced by the gradual decline in fingerprint (1800-800cm-1) related to the cellulose amount accompanied by the detection of new carbonyl band at 1650cm-1 attributed to the C=O quinone suggesting the lignin’s oxidation

Scanning Electron Microscopy examination of the surface of softwood attacked by fungus

The morphological structure of the surface of four Cedrus atlantica softwood samples was monitored by scanning electron microscope. The obtained results have shown formation of cracks on the surface of samples with deterioration of the majority of cellulosic fibers. The alteration of wood structure and decomposition of carbohydrates exploited by scanning electron microscopy images could act as a confidential sign of an advanced stage of wood decay by biological attacks, leading upon time to the extinction of this natural wealth. It appeared that the studied samples were attacked by brown-rot fungus selectively decaying the cell wall of softwood materials. The scanning electron microscope morphological observation revealed that microfibril distribution was heterogeneous and dynamic contact angles increase significantly during exposure to the non-controlled environmental conditions

MiR-155 Dysregulation Is Associated with the Augmentation of ROS/p53 Axis of Fibrosis in Thioacetamide-Induced Hepatotoxicity and Is Protected by Resveratrol

Liver fibrosis is a hallmark of thioacetamide (TAA) intoxications. MicroRNAs (miRs), such as miR-155, have been implied in the pathogenesis of liver disease, and regulated by the antioxidant and anti-inflammatory compound resveratrol (RES). The link between reactive oxygen species (ROS), tumour suppressor p53 (p53), and liver fibrosis-during the pathogenesis of TAA-induced liver injury-associated with miR-155 dysregulation with and without RES incorporation has not been previously studied. Therefore, one group of rats received TAA injections of 200 mg/kg; twice a week at the beginning of week 3 for 8 weeks (TAA group; or model group), whereas the protective group was pretreated daily with RES suspension (20 mg/kg; orally) for the first two weeks and subsequently sustained on receiving both RES and TAA until being sacrificed at the 10th week. Liver injuries developed in the model group were confirmed by a significant (p < 0.0001) elevation of hepatic tissue levels of miR-155, ROS, p53, and the profibrogenic biomarkers: tissue inhibitor of metalloproteinases-1 and α-smooth muscle actin, as well as collagen deposition (fibrosis). All these parameters were significantly (p ≤ 0.0234) protected by resveratrol (RES + TAA). In addition, we observed a significant (p < 0.0001) correlation between ROS/p53 axis mediated liver fibrosis and miR-155. Thus, TAA intoxication induced miR-155 imbalance and ROS/p53-mediated liver fibrosis, with resveratrol, conversely displaying beneficial hepatic pleiotropic effects for a period of 10 weeks