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Power Factor Correction (PFC) converters are essential in designing any charging architecture, regardless of the battery's capacity and the application. Nevertheless, power converters, having continuous output current features, are widely used for battery charging applications. In contrast, converters with continuous input current characteristics exhibit better PFC performance. The Cuk converter c
What are the heaviest elements that can exist in Nature or be created on Earth? Does an ‘Island of Stability’ exist beyond uranium? Questions like these are often asked in connection with Long Range Plans of nuclear physics communities or large-scale accelerator facilities. Information on the chemical and physical properties of superheavy elements (Z>103) or nuclei is notoriously difficult to coll
The mechanisms of glass transitions and the behavior of small solute molecules in a glassy matrix are some of the most important topics of modern thermodynamics. Water plays an important role in the physical and chemical stability of lyophilized biologics formulations, in which glassy carbohydrates act as cryoprotectants and stabilizers. In this study, sorption calorimetry was used for simultaneou
To evaluate an atomic force microscopy (AFM) approach for effective density analysis of single spray dried carbohydrate particles in order to investigate the internal structure of the particles. In addition, the AFM method was compared to an established technique, that is gas pycnometry. Resonant frequency AFM analysis was employed for determination of the mass of individual particles of spray-dri
Powders are essential ingredients of chocolate. In particular for milk chocolate milk and whey powders are important, together with sucrose, lactose and cocoa solids. During processing to maintain a good flow of the molten chocolate mass, particles with hydrophilic surfaces, such as dairy powders and sugars, are coated with a surface-active compound. Only lecithin and polyglycerol polyricinoleate
In this paper, we present a method for in situ coating of individual protein particles in a respirable size. The aim of the coating was to influence the particle/powder properties, and to reduce or prevent surface-induced conformational changes of the protein, during spray-drying, which was the method used for simultaneously preparing and coating particles. The investigated formulations included b
Solid insulin formulations obtained by different methods of preparation were compared with respect to chemical stability and morphology. Spray- and freeze-drying, solution enhanced dispersion by supercritical fluids (SEDS) and precipitation into starch microspheres were the methods used for preparation of solid powders. The excipients applied were melezitose, starch, and sodium taurocholate. The s
The purpose of this study was to examine some fundamental aspects of the particle formation during spray drying, related to particle size and density. Particles were prepared in a laboratory spray dryer from carbohydrates with different solubility and crystallization propensity, such as lactose, mannitol, and sucrose/dextran 4:1. The feed concentrations ranged from 1% w/w to saturated and the size
This study investigates to what extent an aqueous two-phase system (ATPS) can encapsulate and protect the secondary structure of a protein during spray drying. The ATPSs contained polyvinyl alcohol (PVA) and dextran solutions, in different proportions. A model protein, bovine serum albumin (BSA) and, in some experiments, trehalose were added to the ATPS prior to spray drying. Electron spectroscopy
Fat encapsulation in spray-dried protein-stabilised emulsions is known to depend on the choice of protein, the emulsion droplet size, and the melting point of the fat. However, the fat encapsulation may also depend on the fat crystal habit. Fats may crystallise in three different forms α, β′ and β, of which the β-form is thermodynamically stable. The α-form is obtained in rapidly cooled fats, and
To find means of controlling the size and density of particles intended for inhalation the relationship between droplet and particle size during spray drying was investigated. Lactose solutions were atomized with a two-fluid nozzle and dried in a laboratory spray drier. The effects of nozzle orifice diameter, atomization airflow and feed concentration on droplet and particle size were examined. Ma
Microencapsulation of fish oil was achieved by spray-drying homogenized emulsions of fish oil using 3 different types of casein as emulsifier and lactose as filler. As the degree of aggregation of the casein emulsifier increased, the vacuole volume of the microencapsulated powders decreased. The shelf life of the powders increased as the degree of aggregation of the casein emulsifier increased at
Several important technical properties of spray-dried food powders depend on particle-liquid interactions (e.g. wettability, dispersability) and particle-particle interactions (e.g. flowability). It can be assumed that the chemical composition of the surface layer of the particles to a large extent determine these properties. The present study has been aimed to investigate the relation between the
Spray-drying has been investigated as a method for preparation of dry formulations of live bacteria with high viability and high cell density. The concept used in this study has been to disperse the bacteria in an aqueous polymer containing two-phase system (ATPS), compatible with the micro-organisms. The cells partition to one phase, which is separated from the other phase in a droplet dispersion
This investigation describes a novel concept in the formulation of carrier systems for the spray-drying of biological materials. As carrier material a system composed of poly(vinyl pyrrolidone) (PVP) and dextran was used. This system yields an aqueous two-phase system in which each phase is enriched in one of the polymers. By varying the composition of the system, the effective structure of a 'sti
In the present study trypsin mixed with various carbohydrates, i.e. lactose, sucrose, mannitol, α-cyclodextrin and dextrin, was spray-dried in order to investigate the effects of spray-drying on this enzyme, with particular emphasis on the effects of interactions between trypsin and the surface formed during spray-drying. The protein was strongly over-represented at the surface of the powder parti
In the present investigation freeze-drying of proteins (BSA or trypsin) together with various carbohydrates, i.e. lactose, sucrose, mannitol, α-cyclodextrin and dextrin, has been studied with particular emphasis on the surface composition of the freeze-dried powders. The proteins were found to be over-represented on the powder surface as compared to the bulk concentration of protein. The mechanism
A simple and flexible chemoenzymatic route for the preparation of a wide range of dimeric (gemini) and trimeric mono- and disaccharide-based surfactants was developed. The synthesis relies on the use of enzymes for regioselective introduction of fatty acids into carbohydrate moieties. Several structures were prepared containing xylose, glucose, galactose, and lactose, connected via different hydro
Enzymatic transglycosylation in supersaturated solutions of substrates was investigated using crude glycosidase preparations from barley, snail, and coffee beans. It was shown that the use of supersaturated glycoside solutions as media for transglycosylation reactions offers considerable advantages over conventional aqueous systems. These advantages include higher yields, more efficient use of the
The results of an initial study of enzymatic catalysis in metastable supersaturated solutions of carbohydrates are presented. It has been shown that such solutions, formed in the presence of small amounts of water and alcohol as plasticizers, are sufficiently stable under ambient conditions to enable enzymatic transformations of substrates. A partial phase diagram for a system consisting of glucos
