Development and Application of a Process Window for Achieving High-Quality Coating in a Fluidized Bed Coating Process

Next to the coating formulation, process conditions play important roles in determining coating quality. This study aims to develop an operational window that separates layering from agglomeration regimes and, furthermore, the one that leads to the best coating quality in a fluidized bed coater. The bed relative humidity and the droplet size of the coating aerosol were predicted using a set of engineering models. The coating quality was characterized using a quantitative image analysis method, which measures the coating thickness distribution, the total porosity, and the pore size in the coating. The layering regime can be achieved by performing the coating process at a certain excess of the viscous Stokes number (ΔSt _v). This excess is dependent on the given bed relative humidity and droplet size. The higher the bed relative humidity, the higher is the ΔSt _v required to keep the process in the layering regime. Further, it is shown that using bed relative humidity and droplet size alone is not enough to obtain constant coating quality. The changes in bed relative humidity and droplet size have been identified to correlate to the fractional area of particles sprayed per unit of time. This parameter can effectively serve as an additional parameter to be considered for a better control on the coating quality. High coating quality is shown to be achieved by performing the process close to saturation and spraying droplets small enough to obtain high spraying rate, but not too small to cause incomplete coverage of the core particles.     

Polystomatidae (Monogenea) of southern African Anura: Polystoma claudecombesi n. sp. parasitic in Rana angolensis Bocage

Polystoma claudecombesi is described as a new species of the Polystomatidae (Monogenea) parasitic in the urinary bladder of the anuran host Rana angolensis. This parasite was collected at three localities in South Africa, namely Vernon Crookes Nature Reserve in Natal province, Witsieshoek Mountain Resort in the north-eastern Orange Free State and Bovenste Oog in the province of Transvaal. It is the largest African polystome described to date. Prevalence at Vernon Crookes Nature Reserve was 4.0% and 2.7% in two successive years, with a mean intensity of 1.0 (n=25 and 36, respectively). One of the two R. angolensis from Witsieshoek was infected with 5 parasites. The diversity and distribution of southern African polystomes is also discussed.     

Lactobacillus plantarum USM8613 Aids in Wound Healing and Suppresses Staphylococcus aureus Infection at Wound Sites

Probiotics and Antimicrobial Proteins - This study aimed to elucidate the targets and mechanisms of anti-staphylococcal effects from bioactive metabolites produced by lactic acid bacteria. We aimed...     

Reduction of cyclic AMP phosphodiesterase activity of several subcellular fractions of rat brain after pretreatment with phospholipase C

Cyclic AMP phosphodiesterase (PDE) activity was assayed in the plasma membrane, mitochondrial and microsomal fractions of rat brain. The specific activity of the enzyme was highest in the plasma membrane fraction followed by mitochondrial and then the microsomal fraction. Phosphodiesterase activity of all three fractions was reduced after pretreatment with lecithinase C (PCase) from Clostridium perfringens but less markedly affected by the pretreatment with sphingomyelinase (SMase) from human placenta. The PDE activity of the plasma membrane fraction was more sensitive to PCase treatment compared with the other two particulate fractions, which showed only a slight loss of activity. Temperature seemed to affect PDE activity of the plasma membrane. The enzyme was quite stable at 30 degrees C but its activity dropped by approximately 46% at 37 degrees C after 90 min of incubation. Pretreatment of the plasma membrane at 30 degrees C with PCase at a concentration of more than 5 U caused a marked loss of PDE activity and the decrease in activity reached a plateau at concentrations above 10 U.     

A caterpillar (Callopistria floridensis G. (Lepidoptera: Noctuidae)) accumulates arsenic from an arsenic‐hyperaccumulating fern (Pteris vittata L.).

1. The consumption of arsenic is toxic to most biota. However, a noctuid caterpillar was recently reported feeding on a plant known to hyperaccumulate arsenic. 2. The aim of this study was to investigate the effects of arsenic‐rich Pteris vittata L. consumption by Callopistria floridensis G., and measure differences in arsenic concentrations at various stages of development (larval and adult), and associated with exuviae and frass. 3. Callopistria floridensis accumulated extraordinary concentrations of arsenic. The relative accumulation of arsenic was highest in exuviae and larvae. Larvae invariably preferred P. vittata grown on low arsenic soil to P. vittata grown on higher soil arsenic concentrations, and appeared able to selectively forage on lower arsenic concentrations within each treatment. 4. These findings show that C. floridensis is tolerant of arsenic, and successfully develops to adulthood containing elevated concentrations of arsenic. Callopistria floridensis represents the only known terrestrial animal capable of accumulating arsenic, and may have developed novel physiological and behavioural adaptations to regulate the negative effects of arsenic.