RHEOLOGICAL BEHAVIOR OF CONCENTRATED INULIN SOLUTION: INFLUENCE OF SOLUBLE SOLIDS CONCENTRATION AND TEMPERATURE

Inulin is a storage polysaccharide present in more than 30,000 vegetable products, including chicory roots, that are considered suitable for industrial application. The objective of this work was to evaluate the influence of temperature and the soluble solids concentration on the rheological behavior of a concentrated inulin solution obtained from a centrifugation process from chicory roots, after freezing at − 24C. For all the evaluated soluble solids concentrations, inulin solutions showed a rheological behavior of a highly pseudoplastic fluid, with high resistance to flow at low strain rates followed by a breakdown of the structure when the shear rate increased. The effect of temperature on the apparent viscosity of inulin solutions can be represented by the Arrhenius equation. The rheological behavior of inulin solutions can be represented by the Herschel–Bulkley, Casson, Cross and Power Law equations, where the consistency index increases as temperature rises and the soluble solids concentration as well.

PRACTICAL APPLICATIONS

The main objective of this work was to analyze the rheological behavior of a concentrated inulin solution obtained from chicory roots, to check the possibility of its application to obtain powder inulin.
The concentrated inulin solution was obtained by diffusion in hot water, followed by concentration by evaporation and phase separation conducted by lowering the temperature (−24C) and centrifugation at a velocity of 10,000 rpm for a time interval of 15 min. However, this solution is still going to be processed. Therefore, it is important to know its rheological behavior.
The influence of temperature and the soluble solids concentration on the rheological behavior of the concentrated inulin solution was also studied.     

Diffusion of 51Cr in MgO Crystals

An arc fusion technique was used to grow single crystals of MgO with an aliovalent impurity level of ∼ 250 ppm. Diffusion coefficients for Cr³⁺ in single-crystal MgO were measured from 1353° to 1553°C using a high-specific-activity isotope,⁵¹ Cr. The diffusion coefficient of ⁵¹Cr for both arc-grown and vapor-deposited MgO crystals can be characterized by an activation energy of 70.0±2.1 kcal/mol. These results are comparable with the interdiffusion coefficients in Cr₂O₃-MgO when the interdif-fusion D is extrapolated to low Cr concentrations.     

Design of a robust estimator for nonlinear kinetic modelling

A biased estimator for nonlinear kinetic modelling is studied. The proposed estimator contains two easily tuned parameters that enable the estimator to possess robustness in dealing with the problem of a nearly singular design matrix. The robustness of the estimator is discussed in detail, and the asymptotic normality of the estimator is proved concisely but rigorously. The regularity conditions imposed to obtain the results are fairly weak in engineering applications. Three examples presented demonstrate that the estimator is significantly better than the least-squares (LS) estimator and the ridge estimator in both estimate accuracy and convergence speed     

Impact of SARS-CoV-2 infection during pregnancy on postnatal brain development: The potential role of glial cells

Glial cells are crucial for maintaining central nervous system (CNS) homeostasis. They actively participate in immune responses, as well as form functional barriers, such as blood-brain barrier (BBB), which restrict the entry of pathogens and inflammatory mediators into the CNS. In general, viral infections during the gestational period can alter the embryonic and fetal environment, and the related inflammatory response may affect neurodevelopment and lead to behavioral dysfunction during later stage of life, as highlighted by our group for Zika virus infection. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) induces a cytokine storm and, during pregnancy, may be related to a more severe form of the coronavirus disease-19 (COVID-19) and also to higher preterm birth rates. SARS-CoV-2 can also affect the CNS by inducing neurochemical remodeling in neural cells, which can compromise neuronal plasticity and synaptic function. However, the impact of SARS-CoV-2 infection during pregnancy on postnatal CNS, including brain development during childhood and adulthood, remains undetermined. Our group has recently highlighted the impact of COVID-19 on the expression of molecular markers associated with neuropsychiatric disorders, which are strongly related to the inflammatory response. Thus, based on these relationships, we discussed the impact of SARS-CoV-2 infection either during pregnancy or in critical periods of neurodevelopment as a risk factor for neurological consequences in the offspring later in life, focusing on the potential role of glial cells. Thus, it is important to consider future and long-term public health concerns associated with SARS-CoV-2 infection during pregnancy.     

Further Studies on the Formation of Nitrosamines in Cured Pork Products Packaged in Elastic Rubber Nettings

Traces of N-nitrosodi-n-butylamine (NDBA) and N-nitrosodiethylamine (NDEA) can form in cured pork products packaged in elastic rubber nettings due to the interaction of nitrite in meat and amines in the rubber. Studies were carried out to determine whether taking nettings off immediately after processing or placing a layer of collagen as a barrier between nettings and meat could prevent or minimize formation of the above nitrosamines. None was effective. However, cured pork products packaged in a reformulated rubber netting, made with different amine additives, contained either none or only negligible levels of NDBA or NDEA, but, instead, contained 8–104 ppb levels of a new nitrosamine, N-nitrosodibenzylamine which is reported to be noncarcinogenic.     

A Pictorial Query Language for Geographic Features in an Object-Oriented Environment

In this paper, a visual algebra and the relative pictorial query language (PQL) for geographic information systems (GIS) are proposed and discussed. The base data structure of the object oriented model for geographical data is defined and the symbolic features used in the PQL are described. The algebra operators are formally defined, besides their properties and applicability. The use of the symbolic features to express the queries is illustrated, as well as the possible pictorial operations are considered. The used interface is part of the Scenario GIS, developed using an object-oriented environment. This PQL makes easier the formulation of a complex query and simplifies user approach to the system, maintaining a strong expressive power. Finally, an example of query and its pictorial composition on the screen is shown.     

Microbiological and physicochemical characteristics and aminopeptidase activities during ripening of Serrano cheese

The physicochemical and microbiological characteristics and the aminopeptidase activity variation of Serrano cheese during winter and summer were investigated. Samples from different producers varied significantly, showing nonstandardized procedures for the manufacturing and ripening of this product. There were no significant changes in aminopeptidase activity during maturation and most of the enzyme activity found in the water extracts of cheese would have their origin in lactobacillus and enterococci, suggesting autolysis of these micro-organisms. Results show an increase in free amino acids during maturation, with higher amounts in the summer product.