In-line estimation of the elastic module of milk gels with variation of temperature protein concentration

The cutting time of the curd is a relevant factor to improve the quality of the cheese. Only a few studies have focused on the prediction of objective rheological parameters, such as the elastic modulus of the gel (G′) instead of a subjective cut-off time. A complete randomized factorial design with three replicates was used to determine the effect of proteins and temperature in the prediction of G′ values, gelation time and cutting time in reconstituted skimmed milk gels. The coagulation process was monitored simultaneously using an in-line light backscatter sensor operated at 880 nm and a small amplitude oscillatory rheometer. Changes in the structure of the protein during milk coagulation correlated with the signal changes derived from both the optical sensor and the rheometer. The results showed that the backscatter sensor predicts well (R² = 0.99) the time when the gel reaches a value of G′ = 30 Pa.     

A Discretized Approach to Air Pollution Monitoring Using UAV-based Sensing

Mobile Networks and Applications - Recently, Unmanned Aerial Vehicles (UAVs) have become a cheap alternative to sense pollution values in a certain area due to their flexibility and ability to...     

A framework for conceptual characterization of ontologies and its application in the cybersecurity domain

Software and Systems Modeling - Organizations are actively seeking efficient solutions for the management and protection of their assets. However, Cybersecurity is a vast and complex domain,...     

Alteration of 3D Matrix Stiffness Regulates Viscoelasticity of Human Mesenchymal Stem Cells

Human mesenchymal stem cells (hMSCs) possess potential of bone formation and were proposed as ideal material against osteoporosis. Although interrogation of directing effect on lineage specification by physical cues has been proposed, how mechanical stimulation impacts intracellular viscoelasticity during osteogenesis remained enigmatic. Cyto-friendly 3D matrix was prepared with polyacrylamide and conjugated fibronectin. The hMSCs were injected with fluorescent beads and chemically-induced toward osteogenesis. The mechanical properties were assessed using video particle tracking microrheology. Inverted epifluorescence microscope was exploited to capture the Brownian trajectory of hMSCs. Mean square displacement was calculated and transformed into intracellular viscoelasticity. Two different stiffness of microspheres (12 kPa, 1 kPa) were established. A total of 45 cells were assessed. hMSCs possessed equivalent mechanical traits initially in the first week, while cells cultured in rigid matrix displayed significant elevation over elastic (G′) and viscous moduli (G″) on day 7 (p < 0.01) and 14 (p < 0.01). However, after two weeks, soft niches no longer stiffened hMSCs, whereas the effect by rigid substrates was consistently during the entire differentiation course. Stiffness of matrix impacted the viscoelasticity of hMSCs. Detailed recognition of how microenvironment impacts mechanical properties and differentiation of hMSCs will facilitate the advancement of tissue engineering and regenerative medicine.     

A comparative study of two polyelectrolyte complexes

This study reports on the synthesis and characterization of interpenetrating polymeric network (IPN) and polyelectrolyte complexes (PEC) produced by ion-complex formation between natural and synthetic polymer bearing opposed charge. PEC of sodium alginate (NaAlg) and poly(acryloxyethyl-trimethylammonium chloride-co-2-hydroxyethyl methacrylate) (poly(Q-co-H)) were formed by addition of 2.0 wt % sodium alginate solution to 1.5 wt % poly(Q-co-H) solution, and by adding the poly(Q-co-H) solution to the NaAlg solution under magnetic agitation. The IPN were prepared using the sequential method with three different compositions, in which Q and H monomers were mixed in the 95/5 proportions in presence of NaAlg. The mixture was polymerized at 60°C using potassium persulfate as initiator. The characterizations of scaffolds were investigated by Fourier-transform infrared spectroscopy and thermogravimetric analysis. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Evaluation of computer tools for idea generation and team formation in project-based learning

The main objective of this research was to validate the effectiveness of Wikideas and Creativity Connector tools to stimulate the generation of ideas and originality by university students organized into groups according to their indexes of creativity and affinity. Another goal of the study was to evaluate the classroom climate created by these tools and the method “Think Actively in a Social Context” (TASC) proposed by Wallace and Adams (1993) and framed within project-based learning (PBL). The research was conducted with a sample of 34 students in the third year of a Computer Engineering degree, which, during a period of 15 weeks, required them to design and implement an innovative distributed application project. The procedure consisted of the implementation of the eight phases of the TASC method integrated to the Wikideas and Creativity Connector tools. The information provided by the tools, interviews and questionnaires administered to students were used to analyze our hypothesis. The results show that the tools helped the students to generate, evaluate and select the most relevant ideas and to form teams for project execution. They also revealed that teams with high indexes of creativity and affinity (type α) achieved the best grades in academic performance and project originality. Furthermore, research data show that Wikideas and Creativity Connector along with the TASC approach created a positive classroom climate for students. Based on this work, several suggestions can be extracted on the use of the tools and the TASC method for project-based learning.