Particle formation from droplet containing nanoparticles: Internal bubble growth

ABSTRACT

Modeling spray drying is based on the behavior of individual droplets involved in the process. The drying history of single droplets is generalized to the entire spray by incorporating drying kinetics equations into Euler–Lagrange models of spray drying process. The morphological evolution of single droplet is determined by parameters of the drying agent and properties of solid material in the droplet. In this study, the possible causes for bubble inception are discussed and different morphological evolutions and deformations are examined. A novel mathematical model of single droplet containing insoluble nanoscale particles and internal bubble has been developed and parametrically studied.     

Intersubband terahertz transitions in Landau level system of cascade GaAs/AlGaAs quantum well structures in strong tilted magnetic field

ABSTRACT: The tunable terahertz intersubband Landau level transitions in resonant tunneling cascade quantum well structures are considered. The way of lifting the selection rule forbidding the inter-Landau level terahertz transitions of interest by applying a magnetic field tilted with respect to the structure layers is proposed. The importance of asymmetric structure design to achieve considerable values of transition dipole matrix elements is demonstrated.     

Simultaneous separate and group determination of tylosin and tilmicosin in foodstuffs using single antibody-based immunoassay

An approach to modify the specificity of competitive indirect ELISA for determination of veterinary macrolides tylosin (TYL) and tilmicosin (TMN) using different structural design of coating antigen is described. The homologous and heterologous assay formats using rabbit antiserum against BSA-TYL conjugate were developed. The first format allowed selective determination of TYL (cross-reactivity for TMN was negligible). Heterologous hapten desmycosin (DMN) based conjugate being immobilised on the plates changed the specificity to group recognition (cross-reactivity for TMN was 103.4%). Using two coating antigens but single antibody and the same TYL standard solutions the described tandem test was capable for simultaneous determination of the respective analytes with their possible differentiation. The detection limit of assay that was far below the current MRLs and achieved 0.07 ng mL⁻¹ for TYL and 0.14 ng mL⁻¹ for TMN allowed to minimise matrix effect by sample dilution. The ELISAs of antibiotics in milk, eggs, honey and chicken muscle were optimised and showed acceptable recovery rate. A range of foodstuff samples was analysed using the developed tandem test.     

Fabrication of all‐polymeric photonic bandgap Bragg fibers using rolling of coextruded PS/PMMA multilayer films

Photonic bandgap Bragg fibers feature periodic sequence of layers of different materials. In those particular waveguides, the wave path is controlled by a periodical spatial modification of the refractive index. Depending on the periodicity of the structure and on the refractive index contrast, a specific wavelength range is propagated along the fiber axis. In this work, we developed all‐polymeric photonic bandgap Bragg fibers based on polystyrene (PS)/polymethyl methacrylate (PMMA) alternating layers. We describe a novel and efficient method for the preparation of the fibers preforms, and we present the fibers drawing process and the transmission properties of the resulting Bragg fibers. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers     

Toward an interoperable dynamic network analysis toolkit

To facilitate the analysis of real and simulated data on groups, organizations and societies, tools and measures are needed that can handle relational or network data that is multi-mode, multi-link and multi-time period in which nodes and edges have attributes with possible data errors and missing data. The integrated CASOS dynamic network analysis toolkit described in this paper is an interoperable set of scalable software tools. These tools form a toolchain that facilitate the dynamic extraction, analysis, visualization and reasoning about key actors, hidden groups, vulnerabilities and changes in such data at varying levels of fidelity. We present these tools and illustrate their capabilities using data collected from a series of 368 texts on an organizational system interfaced with covert networks in the Middle East.     

Combining Coarse-Grained Protein Models with Replica-Exchange All-Atom Molecular Dynamics

We describe a combination of all-atom simulations with CABS, a well-established coarse-grained protein modeling tool, into a single multiscale protocol. The simulation method has been tested on the C-terminal beta hairpin of protein G, a model system of protein folding. After reconstructing atomistic details, conformations derived from the CABS simulation were subjected to replica-exchange molecular dynamics simulations with OPLS-AA and AMBER99sb force fields in explicit solvent. Such a combination accelerates system convergence several times in comparison with all-atom simulations starting from the extended chain conformation, demonstrated by the analysis of melting curves, the number of native-like conformations as a function of time and secondary structure propagation. The results strongly suggest that the proposed multiscale method could be an efficient and accurate tool for high-resolution studies of protein folding dynamics in larger systems.     

Preparation and characterization of methanol selective membranes based on polyheteroarylene − Cu(I) complexes for purification of methyl tertiary butyl ether

A comparative study of metal ? polymer complexes of Cu(I) with polybenzoxazinoneimide (PBOI) and its prepolymer imide‐containing polyamic acid (PAA) as novel membrane materials for methyl tertiary butyl ether (MTBE) purification was undertaken. The structure, physical parameters and transport properties were characterized in detail to analyse the separation performance of the membranes and obtain new knowledge on the interdependence of the chemical structure and physical data with transport parameters. Thermally initiated conversion of PAA ? Cu(I) to PBOI ? Cu(I) was studied by TGA and DSC. The thermal conversion increases the polymer glass transition temperature and membrane density. Both polymers were applied to pervaporation separation of MTBE from methanol impurities. Membranes based on PAA are highly effective in MTBE purification and preferably permeate methanol. The transport properties of PAA ? Cu(I) membrane are compared with those of known membranes. © 2017 Society of Chemical Industry     

Microbial and Genetic Resources for Cobalamin (Vitamin B12) Biosynthesis: From Ecosystems to Industrial Biotechnology

Many microbial producers of coenzyme B12 family cofactors together with their metabolically interdependent pathways are comprehensively studied and successfully used both in natural ecosystems dominated by auxotrophs, including bacteria and mammals, and in the safe industrial production of vitamin B12. Metabolic reconstruction for genomic and metagenomic data and functional genomics continue to mine the microbial and genetic resources for biosynthesis of the vital vitamin B12. Availability of metabolic engineering techniques and usage of affordable and renewable sources allowed improving bioprocess of vitamins, providing a positive impact on both economics and environment. The commercial production of vitamin B12 is mainly achieved through the use of the two major industrial strains, Propionobacterium shermanii and Pseudomonas denitrificans, that involves about 30 enzymatic steps in the biosynthesis of cobalamin and completely replaces chemical synthesis. However, there are still unresolved issues in cobalamin biosynthesis that need to be elucidated for future bioprocess improvements. In the present work, we review the current state of development and challenges for cobalamin (vitamin B12) biosynthesis, describing the major and novel prospective strains, and the studies of environmental factors and genetic tools effecting on the fermentation process are reported.