Kefir Immobilized on Corn Grains as Biocatalyst for Lactic Acid Fermentation and Sourdough Bread Making

Abstract: The natural mixed culture kefir was immobilized on boiled corn grains to produce an efficient biocatalyst for lactic acid fermentation with direct applications in food production, such as sourdough bread making. The immobilized biocatalyst was initially evaluated for its efficiency for lactic acid production by fermentation of cheese whey at various temperatures. The immobilized cells increased the fermentation rate and enhanced lactic acid production compared to free kefir cells. Maximum lactic acid yield (68.8 g/100 g) and lactic acid productivity (12.6 g/L per day) were obtained during fermentation by immobilized cells at 37 °C. The immobilized biocatalyst was then assessed as culture for sourdough bread making. The produced sourdough breads had satisfactory specific loaf volumes and good sensory characteristics. Specifically, bread made by addition of 60% w/w sourdough containing kefir immobilized on corn was more resistant regarding mould spoilage (appearance during the 11^th day), probably due to higher lactic acid produced (2.86 g/Kg of bread) compared to the control samples. The sourdough breads made with the immobilized biocatalyst had aroma profiles similar to that of the control samples as shown by headspace SPME GC‐MS analysis.     

Finding all roots of 2?×?2 nonlinear algebraic systems using back-propagation neural networks

The objective of this research is the numerical estimation of the roots of a complete 2?×?2 nonlinear algebraic system of polynomial equations using a feed forward back-propagation neural network. The main advantage of this approach is the simple solution of the system, by building a structure—including product units—that simulates exactly the nonlinear system under consideration and find its roots via the classical back-propagation approach. Examples of systems with four or multiple roots were used, in order to test the speed of convergence and the accuracy of the training algorithm. Experimental results produced by the network were compared with their theoretical values.     

Practical benefits for the separation process of drying that can be realized from novel multiscale modeling procedures that utilize the scientific information and results obtained from molecular dynamics modeling and simulation studies

Novel multiscale modeling procedures are constructed and presented that use the scientific information and results determined from microscopic molecular dynamics (MD) modeling and simulation studies to calculate local effective values for the parameters that characterize the heat and mass transfer mechanisms of dynamic macroscopic continuum models (Euler physics of continua) that are used in practice to describe and predict the dynamic behavior of large scale in time and space (e.g., industrial scale), separation (e.g., drying; adsorption), and chemical and biochemical reaction engineering (e.g., chemical catalysis; biocatalysis; immobilized cell bioreactor systems) processes involving porous media whose pore structure is formed either by a solid rigid matter or by a solid soft matter. Furthermore, the results determined from MD modeling and simulation studies with regard to the energies of interaction between the molecules of the different species of the porous media during the time evolution (time varying) of the drying process can be used to design a time optimally controlled heat input system that could appropriately and accurately supply at any time during drying the amount of heat necessary to provide a desired drying rate with respect to both free and bound water and to satisfy the constraints that safeguard the quality properties of the product.     

Mobile social networking: reconnect virtual community with physical space

Online social networks (OSNs) such as Facebook and MySpace, etc., greatly improve our social connectivity and collaboration. However, those applications lead to a shift from physical communities to virtual communities. The recent availability of mobile broadband connections and location technologies, their increasing affordability, and the usability of new mobile devices (e.g. smartphones) have led to the emergence of mobile social networks (MSNs), which re-connect the virtual community to the physical region, and move users between them in a way that enhances both. Currently, MSN applications are mushrooming and racing to replicate the success of social computing in the mobile domain. We argue that the potential success of MSNs lies in active collaboration among users, which naturally arises many interdisciplinary challenges. However, there exists no systematical survey about MSNs. This paper thoroughly characterizes the basic design principles, research architecture, typical techniques, and fundamental issues in MSNs from cross-discipline and application viewpoints. Our contributions lie in the following aspects: First, we summarized the basic design principles and fundamental issues that run through MSN researches and applications; then, from multidisciplinary viewpoint, the research architecture is divided into multi-dimensional structural characteristics and evolution of users’ rational behaviors. Finally, from application perspective, MSNs are categorized into two areas: Socially inspired mobile networking technologies, and enhanced real social life with mobile computing (people-centric tasks and place centric tasks). Briefly, this paper organizes the isolated topics and systems in existing work into meaningful categories, and structures the design space for identifying social-technical challenges, inspiring potentially interesting social networking applications, and suggesting important research opportunities.     

Synthesis and Biopharmaceutical Evaluation of Imatinib Analogues Featuring Unusual Structural Motifs

A convenient synthesis of imatinib, a potent inhibitor of ABL1 kinase and widely prescribed drug for the treatment of a variety of leukemias, was devised and applied to the construction of a series of novel imatinib analogues featuring a number of non‐aromatic structural motifs in place of the parent molecule's phenyl moiety. These analogues were subsequently evaluated for their biopharmaceutical properties (e.g., ABL1 kinase inhibitory activity, cytotoxicity). The bicyclo[1.1.1]pentane‐ and cubane‐containing analogues were found to possess higher themodynamic solubility, whereas cubane‐ and cyclohexyl‐containing analogues exhibited the highest inhibitory activity against ABL1 kinase and the most potent cytotoxicity values against cancer cell lines K562 and SUP‐B15. Molecular modeling was employed to rationalize the weak activity of the compounds against ABL1 kinase, and it is likely that the observed cytotoxicity of these agents arises through off‐target effects.     

Methodology to quantify the ratio of multiple-to single-charged fractions acquired in aerosol neutralizers

A methodology for the quantification of the ratio of multiple- to single-charged fractions acquired in aerosol neutralizers is presented. These quantities are necessary for an accurate monodisperse calibration of aerosol instrumentation. A tandem Differential Mobility Analyzer (DMA) setup is required, with the second DMA scanning the electrical mobility spectra classified in the first DMA. In contrast to previous studies on the quantification of bipolar charge distribution utilizing tandem DMA schemes, the methodology targets at the direct determination of the multiple- to single-charge fractions and does so through the analysis of the raw signal instead of the inverted size distributions, thus circumventing errors associated with the assumptions in the DMA data inversion. The proposed methodology is employed for the characterization of different types of aerosols commonly employed for instrument calibration. Spherical liquid particles (emery oil and dioctyl sebacate) were found to acquire lower multiple charge fractions than those suggested by the commonly employed regression fits of Wiedensohler, which was published in the year 1988 in the Journal of Aerosol Science (vol. 19, pp. 387–389), but still within the range of values reported in the literature. Diffusion flame soot and spark generated graphite particles, produced by a miniCAST 6203C burner and a PALAS DNP 3000, respectively, exhibited higher fraction of multiple charges, in good agreement with previous work on agglomerates. The use of a soft X-ray bipolar charger (TSI 3088) yielded systematically higher multiple fractions of positive charges compared to a ⁸⁵Kr neutralizer (TSI 3077A), confirming the importance of direct photoionization charging on the former.

Copyright © 2016 American Association for Aerosol Research     

Generation of spatio-temporal concentration profiles for cell culture systems: A case study in ammonia

Cellular behavior is influenced by micro-concentration gradients existing in their immediate spatio-environment. A practical real-time measurement system, composed of miniaturized long-lasting sensors placed within a two-dimensional bioreactor and a 32-channel data acquisition system for ammonia, is presented in this paper aiming to generate the spatio-temporal ammonia concentration profiles for the whole culture process. Our results demonstrate the feasibility of the system and its applicability in elucidating the cell growth micro-environment within a bioreactor, which can potentially facilitate the intelligent control of ammonia levels in cell culture systems. The presented system is flexible enough to interface other sensors for generating their spatio-temporal profiles of the sensed cell culture parameters.     

Long‐Aliphatic‐Segment Polyamides: Salt Preparation and Subsequent Anhydrous Polymerization

Long‐aliphatic‐segment polyamides were prepared based on hexamethylenediamine and α,ω‐(CH₂)_x biosynthetic diacids (x = 10, 11, 12). The pertinent monomers (salts) were isolated as solids, thoroughly characterized for the first time, and then submitted to an anhydrous melt prepolymerization technique. The obtained prepolymers exhibited in the range of 5 100–11 800 g · mol^?1, and the molecular weight was further increased by up to 55% through solid‐state finishing. The suggested overall polyamidation cycle was conducted at short melt‐reaction times, so as to avoid any thermal degradation, and was proved efficient, indicating similar reactants polymerizability independently of the methylene content.

     

Cloud-assisted body area networks: state-of-the-art and future challenges

Body area networks (BANs) are emerging as enabling technology for many human-centered application domains such as health-care, sport, fitness, wellness, ergonomics, emergency, safety, security, and sociality. A BAN, which basically consists of wireless wearable sensor nodes usually coordinated by a static or mobile device, is mainly exploited to monitor single assisted livings. Data generated by a BAN can be processed in real-time by the BAN coordinator and/or transmitted to a server-side for online/offline processing and long-term storing. A network of BANs worn by a community of people produces large amount of contextual data that require a scalable and efficient approach for elaboration and storage. Cloud computing can provide a flexible storage and processing infrastructure to perform both online and offline analysis of body sensor data streams. In this paper, we motivate the introduction of Cloud-assisted BANs along with the main challenges that need to be addressed for their development and management. The current state-of-the-art is overviewed and framed according to the main requirements for effective Cloud-assisted BAN architectures. Finally, relevant open research issues in terms of efficiency, scalability, security, interoperability, prototyping, dynamic deployment and management, are discussed.