Thiol-terminated polyethylene glycol (PEG) is commonly used to functionalize the surface of gold nanoparticles (AuNPs) in order to improve their in vivo stability and to avoid uptake by the reticular endothelial system. Although it has been reported that AuNPs functionalized with tethered PEG are stable in biological media, the influence of chain density remains unclear. This study investigates the influence of PEG capping density on the stability of washed and dried AuNPs in: water, phosphate-buffered saline solution (PBS), phosphate-buffered saline solution containing bovine serum albumin (PBS/BSA), and dichloromethane (DCM). PEG coating had a dramatic effect on stability enabling stable suspensions to be produced in all the media studied. A linear relationship was observed between capping density and stability in water and DCM with a somewhat lower stability observed in PBS and PBS/BSA. A maximum PEG loading level of ∼14 wt.% was achieved, equivalent to a PEG surface density of ∼1.13 chains/nm 2 .

Global rating scores provide a reliable, valid method for assessing technical skills between specialties when performing a small bowel anastomosis. We provide reasons why general surgeons may be more proficient at this task than urologists. These findings have possible application to identifying trainees who need additional training and may also provide a mechanism to ensure competence in this task.

Solvent-based methods are commonly employed for the production of polyester-based samples and coatings in both medical device production and research. The influence of solvent casting and subsequent drying time was studied using thermal analysis, spectroscopy and weight measurement for four grades of 50 : 50 poly(lactic-co-glycolic acid) (PLGA) produced by using chloroform, dichloromethane, and acetone. The results demonstrate that solvent choice and PLGA molecular weight are critical factors in terms of solvent removal rate and maintaining sample integrity, respectively. The protocols widely employed result in high levels of residual solvent and a new protocol is presented together with solutions to commonly encountered problems.

ABSTRACT:The potential of pulp fiber-reinforced thermoplastics is currently not fully explored in composites. One of the main reasons is that pulp fibers are extracted for the use in papermaking and are thus not optimized for use as reinforcements in thermoplastics. Furthermore, currently used processing methods constitute several severe thermomechanical steps inducing premature degradation of the fibers. A systematic development of these composite materials requires the study of both these aspects. The goal of this work was to optimize fiber extraction against properties relevant to the reinforcement of thermoplastics. To this end, thick-walled Miscanthus x giganteus pulp fibers were selected. The fibers were pulped by the alkaline-methanolanthraquinone process. An unreplicated factorial design was applied to determine the effect of key operating variables on fiber thermal stability and mechanical properties. The thermomechanical properties of pulp fibers depend primarily on the morphology and chemical composition of the fiber resource in terms of the respective amounts of lignin, hemicellulose, and cellulose, all strongly influenced by the choice of pulping conditions. Optimal pulping parameters were identified, allowing production of fibers thermally stable up to 255°C with an aspect ratio of 40, a straightness of 95%, and tensile strength as high as 890 MPa. , respectively.

Abstract