Morphological Changes Of Particles Research Articles

The enzymatic modification of whey-proteins for spray drying encapsulation of Ginkgo-biloba extract

Ginkgo biloba extract (GBLE) contains many bioactives including flavonoids and terpene trilactones that play some pharmacological roles. These compounds are sensitive to operating conditions; so, encapsulation is a suitable approach to protect them. In this study, different carriers including maltodextrin (MD), and its combination with gum-Arabic (MD-GA), whey protein concentrate (MD-WPC), and whey-protein hydrolysate (MD-HWPC) were used to encapsulate GBLE. Powder production yield, physicochemical/functional characteristics, physical stability and flowability of particles were affected by the type and composition of carriers. FTIR results indicated the placement of phenolic compounds in the carrier matrix. The SEM images also showed the morphological changes of particles (especially the size, indentation and surface shrinkage) under the influence of various carriers. Microencapsulated powders formulated using MD-HWPC showed the highest values of TPC, DPPH, and ABTS and a lighter color which determined the suitability of this wall material (due to the improvement of surface activity and emulsifying properties of protein as a result of partial enzymatic hydrolysis) to protect the antioxidant properties of GBLE during spray-drying, improving the production yield and preserving physical and functional characteristics of the encapsulated powders.

How Does the CO2 in Supercritical State Affect the Properties of Drug-Polymer Systems, Dissolution Performance and Characteristics of Tablets Containing Bicalutamide?

The increasing demand for novel drug formulations has caused the introduction of the supercritical fluid technology, CO2 in particular, into pharmaceutical technology as a method enabling the reduction of particle size and the formation of inclusion complexes and solid dispersions. In this paper, we describe the application of scCO2 in the preparation of binary systems containing poorly soluble antiandrogenic drug bicalutamide and polymeric excipients, either Macrogol 6000 or Poloxamer®407. The changes in the particle size and morphology were followed using scanning electron microscopy and laser diffraction measurements. Differential scanning calorimetry was applied to assess thermal properties, while X-ray powder diffractometry was used to determine the changes in the crystal structure of the systems. The dissolution of bicalutamide was also considered. Binary solid dispersions were further compressed, and the attributes of tablets were assessed. Tablets were analyzed directly after manufacturing and storage in climate chambers. The obtained results indicate that the use of supercritical CO2 led to the morphological changes of particles and the improvement of drug dissolution. The flowability of blends containing processed binary systems was poor; however, they were successfully compressed into tablets exhibiting enhanced drug release.

A thermodynamically consistent phase‐field model for viscous sintering

AbstractA thermodynamically consistent phase‐field model for viscous sintering is proposed. It is based on an energetic variational formulation that allows the governing equations to be analytically derived from a defined energy law. The conservation of mass is satisfied through the incompressibility assumption and the assumption that mass density is uniform initially within the particle compact while the balance of linear momentum is formulated from an energy dissipation law. The morphological changes of particles are described by the temporal and spatial evolution of a phase‐field variable governed by a modified Cahn‐Hilliard equation, and the motion of viscous mass flow is controlled by the Stokes equation incorporating the surface tension effect. The application of the phase‐field model is illustrated by examining the effect of particle shape, initial contact angle and rearrangement effects on viscous sintering.

Investigation of Functional and Structural Properties of Insoluble Dietary Fiber From Sichuan Natural Fermented Pickles With Different Salting Treatments

In this study, the functional and structural properties of insoluble dietary fibers (IDFs) from Sichuan natural fermented pickle vegetables, subjected to different saline treatments are investigated. The IDF is extracted using an ultrasonic‐assisted enzyme method. The primary measurable indicators that are determined, include the water‐ and oil‐holding capacity, swelling capacity, heavy metal adsorption capacity, bile acid salts adsorption capacity, antioxidant activity, and polyphenol content. Additionally, a structural analysis is also performed using infrared spectroscopy, thermogravimetry (TG), and scanning electron microscopy. Experimental results demonstrate that both high and low salt saline fermentations have no significant effect on the techno‐functional properties of IDF in vegetables (p > 0.05); however, the physio‐functional properties, including bile acid salts adsorption capacity, heavy metal adsorption capacity (Pb, As), and the antioxidant capacity are shown to be significantly enhanced (p < 0.05). The low salt saline fermentation is shown to have an improvement effect as compared to the high salt fermentation, which is further supported by the structural characterizations including the structure and chemical groups differences, morphological changes of particles, and thermal stability differences. The findings from this work reveal the effects of saline treatments on the functional properties of IDFs, which are extracted from Sichuan pickle vegetables. In addition, they provide a potential manufacturing technique to improve the quality of the DF in Sichuan pickle vegetables.

Description of morphological changes of particles along spray drying

A description of morphological changes of particles along spray drying was carried out by means of scanning electron and light microscopy. Samples of atomized material (40% maltodextrin solution) were withdrawn during drying from a laboratory spray drier at various vertical distances from the atomizing nozzle, photographs of these materials were taken and images analyzed for detecting processes such as crust formation, inflation and shrinking. Final product was analyzed by SEM, mean size of particles determined and fractal dimension of projected perimeter was evaluated by means of the box counting method. This parameter of particles allowed for distinguishing between irregular and smooth contours of final powders. It was possible to explore qualitative relations of morphology and moisture content of particles with air drying temperatures along the actual drying operation, especially those related to breakage and inflation (intermediate and high drying temperatures) and with collapse (low-temperature drying).

Generation of Silica Nanoparticles from Tetraethylorthosilicate (TEOS) Vapor in a Diffusion Flame

Silica (SiO2) nanoparticles were synthesized by the gas phase thermal oxidation of tetraethylorthosilicate (TEOS) in a laminar diffusion flame reactor. Characteristics of the formation of silica nanoparticles along the axial distance above the burner outlet were investigated. Effects of maximum flame temperature, TEOS concentration, residence time, and water vapor on the particle size were also investigated. Silica nanoparticles less than 20 nm in average particle diameter were synthesized in all of the experiments. Morphological changes of particles were found along axial distance above the burner outlet; many small aggregates of particles (dp = ∼ 7 nm) were found up to 2 cm, isolated smaller particles ( dp = ∼ 5 nm) at 4 cm, and aggregates of bigger particles (dp = ∼ 10 nm) at 10 cm. Larger particles at higher TEOS concentrations are generated in the flame synthesis. As the maximum flame temperature increased, the average particle size of silica also increased. Smaller particles were produced with decre...

衝突，圧縮，粉砕に伴う三酸化二アンチモン粒子の性状変化

The morphological changes of particles through three different processes (impaction, compaction and grinding) were investigated experimentally. This was done using two types of antimony trioxide (Sb2O3)-fine particles which have almost the same particle size distributions but different surface properties. One has the sulfate group (-SO4) on the surface; the other does not.It is found that the diameter of the Sb2O3 particles having -SO4 begins to increase at lower impaction velocity or at lower compaction pressure than those having no -SO4 does. Estimation of the load applied on a single particle through these two processes reveals that the threshold of the load inducing the particle enlargement is almost the same for impaction and compaction.The tendency for the diameter to change through grinding is opposite to that through impaction or compaction. However, the Sb2O3 particles having -SO4 keep higher crystallinity than those having no -SO4 among these three processes.

Discharge Mechanism of MnO2 Electrodes as Influenced by the Solubility of the Reaction Products

An ultrathin electrolytic cell has been used to study by means of microscopic observation morphological changes of particles at magnification of 1500× in situ during discharge in various electrolytes. It is shown that the solubility of three‐valent manganese species plays an important role in certain electrolytes, depending on pH. The discharge mechanism is discussed in the light of the observed dissolution and on the basis of x‐ray data of the solid reaction products.

Experiments for the Partial Replacement of the Wall of the Urinary Bladder with Homotransplants

Experiments were made in 27 female dogs to investigate morphological changes of particles excised from the urinary bladder wall of an experimental animal and transplanted into the identic bladder-part of another. In the course of the experiments, the vertex of the bladder was removed with 50 per cent of the bladder, or the anterior wall of the bladder with the region of the internal orifice. The dissections of the experimental animals were performed during the first week and third month. Microscopic pictures obtained after one week showed the disappearance of the mucous membrane, which appeared again in the 4-5-week preparations. Endeavours to establish smooth muscle as a residue of the transplantate were unsuccessful, likewise proliferation of smooth muscles ensuing from the remaining wall of the bladder could not be observed. Intact smooth muscle elements were seen in one case, when the formation of a rich peritoneal vascular plexus extending towards the transplantate could be observed.