Size Controlled Preparation of Starch Nanoparticles from Wheat through Precipitation at Low Temperature

This study developed an energy efficient procedure to produce size-controlled starch nanoparticles (SNPs) via precipitation. A 0.06 g/ml aqueous starch suspension was solubilized in a solvents system including NaOH and urea at temperature of 35 °C. Applying only 3 minutes ultrasonic treatment leads to formation of SNPs in a narrow size range of 50-70 nm with production yield of 92±5%. TEM and FESEM revealed formation of uniform short nanofibers. Unlike starch/water suspension, the nanoparticles/water suspension remained stable for 48 hours.

Small females prefer small males: size assortative mating in Aedes aegypti mosquitoes

With Aedes aegypti mosquitoes now being released in field programs aimed at disease suppression, there is interest in identifying factors influencing the mating and invasion success of released mosquitoes. One factor that can increase release success is size: released males may benefit competitively from being larger than their field counterparts. However, there could be a risk in releasing only large males if small field females avoid these males and instead prefer small males. Here we investigate this risk by evaluating mating success for mosquitoes differing in size. We measured mating success indirectly by coupling size with Wolbachia-infected or uninfected mosquitoes and scoring cytoplasmic incompatibility as a way of estimating relative mating success. Large females showed no evidence of a mating preference, whereas small males were relatively more successful than large males when mating with small females, exhibiting an advantage of around 20-25%. Because field females typically encompass a wide range of sizes while laboratory reared (and released) males typically fall into a narrow size range of large mosquitoes, these patterns can influence the success of release programs which rely on cytoplasmic incompatibility to suppress populations and initiate replacement invasions. Releases could include some small males generated under low food or crowded conditions to counter this issue, although this would need to be weighed against issues associated with costs of producing males of various size classes.

Separation of Particles for Drug Delivery Using a Microfluidic Device With Actuation

The purpose of this study is to demonstrate particle separation through a novel mechanism termed as “time series alternate flow” using a microdevice as it is a real challenge to separate particles with a narrow size range (i.e., 1–10 μm or smaller), especially achieving particles separation through the hydrodynamic method without the help from additional flow or force fields. High fidelity computational fluid dynamics with particle trajectory approach was employed for simulations. Particle separation of different sizes in the range 2–10 μm size was achieved by operating the microdevice at various actuating frequencies. The results obtained indicated that the proposed mechanism is feasible for particle separation of multiple sizes. Our novel mechanism proposed potentially represents a viable microtechnological approach for particle separation in many drug delivery applications.