Template synthesis of ordered macroporous hydroxyapatite bioceramics

Hydroxyapatite has found wide application in bone tissue engineering. Here we use a macroporous carbon template to generate highly ordered macroporous hydroxyapatite bioceramics composed of close-packed hollow spherical pores with interconnected channels. The template has advantages for the preparation of ordered materials.     

Deformation and breakup of micro- and nanoparticle stabilized droplets in microfluidic extensional flows

Using a microfluidic flow-focusing device, monodisperse water droplets in oil were generated and their interface populated by either 1 μm or 500 nm amine modified silica particles suspended in the water phase. The deformation and breakup of these Pickering droplets were studied in both pure extensional flow and combined extensional and shear flow at various capillary numbers using a microfluidic hyperbolic contraction. The shear resulted from droplet confinement and increased with droplet size and position along the hyperbolic contraction. Droplet deformation was found to increase with increasing confinement and capillary number. At low confinements and low capillary numbers, the droplet deformation followed the predictions of theory. For fully confined droplets, where the interface was populated by 1 μm silica particles, the droplet deformation increased precipitously and two tails were observed to form at the rear of the droplet. These tails were similar to those seen for surfactant covered droplets. At a critical capillary number, daughter droplets were observed to stream from these tails. Due to the elasticity of the particle-laden interface, these drops did not return to a spherical shape, but were observed to buckle. Although increases in droplet deformation were observed, no tail streaming occurred for the 500 nm silica particle covered droplets over the range of capillary numbers studied.     

Basic characteristics of interference image obtained using spatially phase-modulated mirror array

Single-shot full-field optical coherence tomography (OCT) using spatially phase-modulated reference light has been proposed to achieve a higher sensitivity.16) The reference light can be generated by a spatially phase-modulated mirror array (SPMA). The basic characteristics of an interference image using SPMA have been demonstrated using a superluminescent diode (SLD) with a center wavelength of 840 nm as a popular low-coherence light source. SPMA consisted of a small mirror of 10 × 10 mm² and had a full area of 5 × 5mm². The magnifications in the reference arm were 3, 2, and 1. The corresponding magnifications in the signal arm were 18.1, 12.2, and 5.2. The ratios of the interference area to the full CCD area were 0.68, 0.32, and 0.13. Visibilities and ratios for calculations were measured at 0.38 (54%), 0.19 (28%), and 0.062 (8.2%). The periodical background noise was high owing to interferences with scattered lights from SPMA. From the spectra of signal intensity profiles in the subtracted image between two interference images, it was confirmed that the optical phase in the reference light was spatially and periodically modulated by SPMA.     

Cost-effective interrogation of single nucleotide polymorphisms using the mismatch amplification mutation assay and capillary electrophoresis

The ability to characterize SNPs is an important aspect of many clinical diagnostic, genetic and evolutionary studies. Here, we designed a multiplexed SNP genotyping method to survey a large number of phylogenetically informative SNPs within the genome of the bacterium Bacillus anthracis. This novel method, CE universal tail mismatch amplification mutation assay (CUMA), allows for PCR multiplexing and automatic scoring of SNP genotypes, thus providing a rapid, economical and higher throughput alternative to more expensive SNP genotyping techniques. CUMA delivered accurate B. anthracis SNP genotyping results and, when multiplexed, saved reagent costs by more than 80% compared with TaqMan real-time PCR. When real-time PCR technology and instrumentation is unavailable or the reagents are cost-prohibitive, CUMA is a powerful alternative for SNP genotyping.