Collagen/polyester-polyurethane porous scaffolds for use in meniscal repair.

Focusing on the regeneration of damaged knee meniscus, we propose a hybrid scaffold made of poly(ester-urethane) (PEU) and collagen that combines suitable mechanical properties with enhanced biological integration. To ensure biocompatibility and degradability, the degradable PEU was prepared from a poly(ε-caprolactone), L-lysine diisocyanate prepolymer (PCL di-NCO) and poly(lactic-co-glycolic acid) diol (PLGA). The resulting PEU (Mn = 52 000 g mol-1) was used to prepare porous scaffolds using the solvent casting (SC)/particle leaching (PL) method at an optimized salt/PEU weight ratio of 5 : 1. The morphology, pore size and porosity of the scaffolds were evaluated by SEM showing interconnected pores with a uniform size of around 170 µm. Mechanical properties were found to be close to those of the human meniscus (Ey ∼ 0.6 MPa at 37 °C). To enhance the biological properties, incorporation of collagen type 1 (Col) was then performed via soaking, injection or forced infiltration. The latter yielded the best results as shown by SEM-EDX and X-ray tomography analyses that confirmed the morphology and highlighted the efficient pore Col-coating with an average of 0.3 wt% Col in the scaffolds. Finally, in vitro L929 cell assays confirmed higher cell proliferation and an improved cellular affinity towards the proposed scaffolds compared to culture plates and a gold standard commercial meniscal implant.

New insights into the rapid germination process of lentil and cowpea seeds: High thiamine and folate, and low α-galactoside content.

During germination sensu-stricto in pulses, an increase in the content of thiamine (B1) and folate (B9) vitamins is expected, along with a reduction in α-galactoside levels. The aim of our study was to optimize germination to increase the nutritional quality of lentils and cowpeas. An experimental design was carried out at 12 h and 24 h of imbibition to analyze the effects of temperature, light, and water content on thiamine, folate, and α-galactoside content. Germination increased thiamine content by 152% in lentils, while in cowpeas, the increase was only 10%. Folate content in cowpea increased by 33%, while α-galactoside content decreased by 99% in cowpeas and by 48% in lentils. Germination sensu-stricto can be safely implemented by any food company worldwide as it is simple and involves less sanitary risk than sprouting. This opens up opportunities for enhancing food nutrient content and new ways of processing pulses.

Mechanical approach for the evaluation of the crispiness of food granular products.

Crispiness of food products is a key parameter for consumer acceptance. Available methods to evaluate this attribute are subjective and have limitations. They are particularly difficult to implement when granular products are considered. The present study aims to provide a physical characterization of the crispiness of food granular products (gari and grinded corn flakes) based on the compression cycle modeling and the determination of the Py (yield pressure) parameter of the Heckel model. High Py values attributed to the brittle behavior, are indicative of product crispiness. Furthermore, Py parameter showed sensitivity to the plasticizing effect of water. This developed physical method was validated through sensory analysis and acoustic measurements which are both considered as reference methods for crispiness evaluation. The brittle/plastic behavior attributed to crispy/non crispy products respectively was confirmed through image analysis using X-ray microcomputed tomography. The latter made it possible to distinguish the brittle from the plastic behavior through the particle size distribution evolution. This work suggests that the Py value is a relevant indicator for the crispiness evaluation of granular products. This physical characterization is expected to contribute in food engineering as an alternative method for granular products crispiness in a simpler and a more objective way.

Role of dewatering and roasting parameters in the quality of handmade gari.

Gari is a common cassava precooked dried semolina in sub-Saharan Africa. Our study investigated the role of process parameters and mash water content on gari quality during traditional roasting stage. The statistical analysis for eight quality criteria revealed that gari quality is highly influenced by the process parameters adopted by the operators. To emphasise the twin impact of roasting parameters and mash water content, different mashes with varying water content were roasted leading to different adjustments of the roasting conditions according to the operators. When the variability of the water content becomes greater, a greater variability in the final quality of the obtained garis was observed between operators (lightness, swelling capacity, starch content, texture and colour). These results suggest that technological improvements to the gari process could be achieved by appropriate management of the roasting and dewatering parameters.

Identification of critical versus robust processing unit operations determining the physical and biochemical properties of cassava-based semolina (gari).

The gari-making process involves several unit operations (U.O.), some of which strongly influence the quality of the end product. Two contrasting process scales (laboratory-scale vs conventional) were compared in order to identify which U.O. were affected by the change of scale. U.O. that changed end-product characteristics depending on process scale were deemed critical; whereas U.O. that resulted in similar characteristics were deemed robust. The classification depended on quality attributes considered: rasping and roasting were critical for physical properties, in particular particle size which ranged from 0.44 to 0.89 mm between the two process scales; and robust for biochemical properties. In contrast, fermentation and pressing were critical for biochemical properties such as lactic acid content (0.93-1.88 g/100 g dry matter after pressing), which influences the perception of flavour, and robust for physical properties. This classification between critical and robust operations help quality control of gari, by pinpointing which U.O. control specific quality characteristics.

Left ventricle function assessment using gated first-pass 18F-FDG PET: Validation against equilibrium radionuclide angiography.

PURPOSE: We appraised the feasibility of left ventricle (LV) function assessment using gated first-pass 18F-FDG PET, and assessed the concordance of the produced measurements with equilibrium radionuclide angiography (ERNA). MATERIALS AND METHODS: Twenty-four oncologic patients benefited from 99mTc-labeled red-blood-cell ERNA, in planar mode (all patients) and using SPECT (22 patients). All patients underwent gated first-pass 18F-FDG cardiac PET. Gated dynamic PET images were reconstructed over 1 minute during tracer first-pass inside the LV and post-processed using in-house software (TomPool). After re-orientation into cardiac canonical axes and adjustment of the valves plane using a phase image, pseudo-planar PET images obtained by re-projection were automatically segmented using thresholded region growing and gradient-based delineation to produce an LV ejection fraction (EF) estimate. PET images were also post-processed in fully-tomographic mode to produce LV end diastole volume (EDV), end systole volume (ESV), and EF estimates. Concordance was assessed using Lin's concordance (ccc) and Bland-Altman analysis. Reproducibility was assessed using the coefficient of variation (CoV) and intra-class correlation (ICC). RESULTS: Pseudo-planar PET EF estimates were concordant with planar ERNA (ccc = 0.81, P < .001) with a bias of 0% (95% CI [- 2%; 3%], limits of agreement [- 11%; 12%]). Reproducibility was excellent and similar for both methods (CoV = 2 ± 1% and 3 ± 2%, P = NS; ICC = 0.97 and 0.92, for PET and ERNA, respectively). Measurements obtained in fully-tomographic mode were concordant with SPECT ERNA: ccc = 0.83 and bias = - 3 mL for LV EDV, ccc = 0.92 and bias = 0 mL for LV ESV, ccc = 0.89 and bias = - 1% for LV EF (all P values < .001 for ccc, all biases not significant). CONCLUSIONS: Gated first-pass 18F-FDG PET might stand as a relevant alternative to ERNA for LV function assessment, enabling a joint evaluation of both therapeutic response and cardiac toxicity in oncologic patients receiving cardiotoxic chemotherapy.

A contribution to the understanding of micro-pollutant sorption mechanisms in wastewater biological processes: case of the tributyltin.

Micro-pollutant fluxes distribution throughout the physical separation and biological units of wastewater treatment plants (WWTPs) are very dependent ofsorption phenomena. The understanding and the control of the sorption stage is thus essential for the optimization of micro-pollutant removal in WWTPs, and particularly in biological treatments where these mechanisms influence the bioavailability towards micro-organisms. If the influence of the micro-pollutant physicochemical characteristics (e.g. Kow, pKa) on their ability to sorb on biological media (i.e. sludge) has been demonstrated, it appears that some other parameters, like the biosorbent characteristics, have to been taken into account. The aim of this study is thus to correlate the capacities of sorption of an environmentally relevant substance (tributyltin), with a thorough characterization of different types of sludge. The characterization of three biological media (raw, sonicated and flocculated activated sludges) is proposed according to various characterization parameters related to biochemical composition, aggregate size, rheological behaviour etc. The results show first that, whatever the sludge characteristics may be, the sorption mechanisms are very rapid and that an equilibrium state is reached after a few minutes. The influence of the sludge characteristics, notably the floc size and the chemical oxygen demand partition between solid and colloidal fraction, on sorption efficiency is demonstrated. A Langmuir modelling allows giving the maximum sorption capacity, as well as the binding energy for the three studied sludges, according to their physicochemical characteristics.

Psychrometry as a methodological tool for optimizing the spray drying process.

Because psychrometry takes into account a great number of variables reflecting the quality of the drying air, it is an interesting tool to improve the control and the optimization of the spray drying process. In this article the authors study the evolution of the psychrometric variables according to the values taken by four inlet parameters (inlet air temperature, liquid flow rate, solid concentration of the spray dried liquid, and nature of the product). The results highlighted the existence of mathematical models making it possible to optimize the process, but also to underline the influence of the nature of the product on the drying mechanism.