Effect of Acetylation, Hydroxypropylation and Dual Acetylation-Hydroxypropylation on Physicochemical and Digestive Properties of Rice Starches with Different Amylose Content

Four rice (Oryza sativa L.) starches widely differing in amylose content were subjected to acetylation, hydroxypropylation, and dual modification involving acetylation followed by hydroxypropylation. The starches showed a higher affinity to hydroxypropyl substitution. However, acetylation caused a significant alteration in the glycosidic matrices. The changes in physicochemical properties were most prominent in the dual-modified samples. Hydroxypropylated and dual-modified granules showed greater swelling power with structural retention. Degrees of acetylation were high in the amorphous regions of waxy and low amylose starches (0.04 and 0.05). Minor granular swelling was observed under SEM. Substitution partially dissociated side-chain superhelices, lowering crystallinity values by 3.12-4.58%, however retaining the native A-type XRD patterns. Glycosidic dissociation and enhanced hydrophilicity caused a significant lowering of gelatinization temperature (To, Tp, Tc), enthalpy (H), and cooking time as observed from DSC and RVA results. Low setback viscosity and low syneresis during freeze-thaw cycles indicated the decreased tendency of modified starch chains to realign. Dual modified starches could be cooked to thinner and more precise pastes, which are highly resilient to retrogradation. Significant increases in enzyme-resistant RS and SDS (up to 20% of each) were recorded. The dual modification method could suitably alter the properties of starches for food use.

The effects of silk layer-by-layer surface modification on the mechanical and structural retention of extracellular matrix scaffolds

The SF layer-by-layer surface functionalized SIS membrane exhibits tunable mechanical properties and degradation rate, satisfactory biocompatibility and good bioactivity.

Needle-Free Dermal Delivery of a Diphtheria Toxin CRM197Mutant on Potassium-Doped Hydroxyapatite Microparticles

ABSTRACTInjections with a hypodermic needle and syringe (HNS) are the current standard of care globally, but the use of needles is not without limitation. While a plethora of needle-free injection devices exist, vaccine reformulation is costly and presents a barrier to their widespread clinical application. To provide a simple, needle-free, and broad-spectrum protein antigen delivery platform, we developed novel potassium-doped hydroxyapatite (K-Hap) microparticles with improved protein loading capabilities that can provide sustained local antigen presentation and release. K-Hap showed increased protein adsorption over regular hydroxyapatite (P< 0.001), good structural retention of the model antigen (CRM197) with 1% decrease in α-helix content and no change in β-sheet content upon adsorption, and sustained releasein vitro. Needle-free intradermal powder inoculation with K-Hap–CRM197induced significantly higher IgG1 geometric mean titers (GMTs) than IgG2a GMTs in a BALB/c mouse model (P< 0.001) and induced IgG titer levels that were not different from the current clinical standard (P> 0.05), namely, alum-adsorbed CRM197by intramuscular (i.m.) delivery. The presented results suggest that K-Hap microparticles may be used as a novel needle-free delivery vehicle for some protein antigens.

Effectiveness monitoring for biodiversity: comparing 15 year old structural retention harvest areas to fires in boreal aspen

Convergence of species composition in regenerating harvested areas and naturally disturbed forest is a critical component of forest management modeled after natural disturbances. We assessed convergence of birds, plants, and habitat structures in aspen (Populus tremuloides) stands harvested with structural retention by Alberta-Pacific Forest Industries Inc. (Al-Pac) 15 years ago with similar aged fire area, and examined a chronosequence of younger and older burned aspen stands from Alberta Biodiversity Monitoring Institute (ABMI) sites. Most habitat structures and many bird and plant species in the 15 year harvest areas were at levels similar to 20–40 year or >40 year fire areas. Snags, moss, and lichen cover, and a few groups of species were at lower levels in the harvest areas than comparable aged fire areas or older stands. Agglomerative clustering showed the plant community to be most similar to >40 year burned stands, with the bird community intermediate between >20 year and <20 year fire areas. A novel likelihood-based analysis of species estimated the 15 year harvest areas to have a community similar to forest sites with 36.8% human footprint, indicating substantial recovery of the harvest areas. Harvesting aspen stands with structural retention appears to be effective at allowing most biodiversity components to recover rapidly.