Preparation of polycaprolactone nanoparticles via supercritical carbon dioxide extraction of emulsions

Polycaprolactone (PCL) nanoparticles were produced via supercritical fluid extraction of emulsions (SFEE) using supercritical carbon dioxide (scCO2). The efficiency of the scCO2 extraction was investigated and compared to that of solvent extraction at atmospheric pressure. The effects of process parameters including polymer concentration (0.6–10% w/w in acetone), surfactant concentration (0.07 and 0.14% w/w) and polymer-to-surfactant weight ratio (1:1–16:1 w/w) on the particle size and surface morphology were also investigated. Spherical PCL nanoparticles with mean particle sizes between 190 and 350 nm were obtained depending on the polymer concentration, which was the most important factor where increase in the particle size was directly related to total polymer content in the formulation. Nanoparticles produced were analysed using dynamic light scattering and scanning electron microscopy. The results indicated that SFEE can be applied for the preparation of PCL nanoparticles without agglomeration and in a comparatively short duration of only 1 h

Advantage of the go/no-go task over the yes/no lexical decision task: ERP indexes of parameters in the diffusion model.

Previous research findings supporting the advantages of the go/no-go choice over the yes/no choice in lexical decision task (LDT) have suggested that the go/no-go choice might require less cognitive resources in the non-decisional processes. This study aims to test such an idea using the event-related potential method. In this study, the tasks (yes/no LDT and go/no-go LDT) and word frequency (high and low) were manipulated, and the difference between the go/no-go choice and yes/no choice were examined with BP, pN, pN1, P200, N400, and P3 components that were assumed to be closely related with the various parameters in the diffusion model. The results showed that BP, pN and pN1 amplitudes reflecting the preparation stage were not differently affected by word frequency and the task type. However, ERPs after stimulus onset showed differences. The P200 amplitudes were smaller in the go/no-go task than in the yes/no task only for low-frequency words. N400 and P3 amplitudes were only affected by word frequency. The results suggest that the go/no-go task and the yes/no task differ in sub-lexical processes, which is indicated in the Tencoding parameter in the diffusion model. This study is important as it offers the first electrophysiological evidence supporting the assumption in the diffusion model that explains the advantage of the go/no-go choice over the yes/no choice

Ocular syphilis masquerading as refractory retinal diseases

Abstract Purpose To report two cases of syphilis masquerading as chronic refractory macular diseases. Case descriptions Two patients had been diagnosed with neovascular age-related macular degeneration (neovascular AMD) and diabetic macular edema (DME), respectively. The disease worsened despite repeated intravitreal injections of anti-vascular endothelial growth factor (VEGF) and also surgical treatment (in suspected case of DME). Systemic evaluations were positive for syphilis. Intravenous penicillin was started, and the macular diseases improved. The lesions were well controlled afterward. Conclusions The current two cases demonstrated that ocular syphilis can masquerade as refractory chronic retinal diseases such as DME and neovascular AMD. Laboratory evaluations for syphilis may be needed, not only for uveitis but also for refractory retinal diseases. Indocyanine green angiography may be helpful to reveal occult syphilis

An electrospun polycaprolactone-collagen membrane for the resurfacing of cartilage defects

A polycaprolactone (PCL)–collagen electrospun mesh is proposed as a novel alternative to the conventional periosteal graft in autologous chondrocyte implantation. This is the first known attempt in designing a cartilage resurfacing membrane using a mechanically resilient PCL mesh with a weight-average molecular weight of 139 300 that is enhanced with bioactive collagen. PCL–collagen 10, 20 and 40% electrospun meshes (Coll-10, Coll-20 and Coll-40) were evaluated and it was discovered that the retention of surface collagen could only be achieved in Coll-20 and Coll-40. Furthermore Coll-20 was stiffer and stronger than Coll-40 and it satisfied the mechanical demands at the cartilage implant site. When seeded with mesenchymal stem cells (MSCs), the cells adhered on the surface of the Coll-20 mesh and they remained viable over a period of 28 days; however, they were unable to infiltrate through the dense meshwork. Cell compatibility was also noted in the chondrogenic environment as the MSCs differentiated into chondrocytes with the expression of Sox9, aggrecan and collagen II. More importantly, the mesh did not induce a hypertrophic response from the cells. The current findings support the use of Coll-20 as a cartilage patch, and future implantation studies are anticipated

Production of menthol-loaded polymeric nanoparticles by solvent displacement

The production of producing menthol-loaded poly--caprolactone nanoparticles (NPs) for dermal application was investigated. The nanoparticles were produced in three different mixers: a confined impinging jet mixer (CIJM), a two-inlet vortex mixer (VM) and a four-inlet vortex mixer (MIVM), testing their performances in the same operating conditions. The effects of various process parameters such as polymer and menthol concentration, flow rate, solvent type (acetone, acetonitrile, or THF), and quench ratio, on mean nanoparticle size, menthol loading and encapsulation efficiency were compared and discussed. The amount of menthol encapsulated inside the nanoparticles was quantified by GC analysis and the structure and shape of the NPs were analyzed by TEM. Nanoparticles of size between 200 nm to 800 nm were obtained using the CIJM, the VM and the MIVM with different feeding sequence. It was observed that mixer geometry had a strong effect on particle size (at the same operating conditions the size decreased from MIVM with two inlets to VM and to CIJM) and the smallest particles were obtained using the MIVM using one solvent and three antisolvent streams. By using acetonitrile, the mean nanoparticle size was larger. Incorporation efficiency and menthol loading values up to 80 % and 60 % respectively were obtained depending on the inlet menthol and polymer concentrations