Elastic Bioresorbable Polymeric Capsules for Osmosis-Driven Delayed Burst Delivery of Vaccines

Single-administration vaccine delivery systems are intended to improve the efficiency and efficacy of immunisation programs in both human and veterinary medicine. In this work, an osmotically triggered delayed delivery device was developed that was able to release a payload after a delay of approximately 21 days, in a consistent and reproducible manner. The device was constructed out of a flexible poly(ε-caprolactone) photo-cured network fabricated into a hollow tubular shape, which expelled approximately 10% of its total payload within 2 days after bursting. Characterisation of the factors that control the delay of release demonstrated that it was advantageous to adjust material permeability and device wall thickness over manipulation of the osmogent concentration in order to maintain reproducibility in burst delay times. The photo-cured poly(ε-caprolactone) network was shown to be fully degradable in vitro, and there was no evidence of cytotoxicity after 11 days of direct contact with primary dermal fibroblasts. This study provides strong evidence to support further development of flexible biomaterials with the aim of continuing improvement of the device burst characteristics in order to provide the greatest chance of the devices succeeding with in vivo vaccine booster delivery.

Determining structural and technological parameters of the polymer films winding process for pipelines

The paper considers issues related to technology of manufacturing pipelines by winding polymer film materials and assessing their tightness with respect to gaseous and liquid fuel components. The shell is made by winding the required number of layers of continuous film tape with a given width, thickness and overlap on a rigid removable mandrel. The multilayer film structure of the shell made by winding a narrow polymer tape is considered as a computational model of the sealing shell of the pipeline. The tightness of the polymer pipeline shell is determined both by the physical and chemical parameters of the film material (permeability and diffusion coefficients) and by the structural and technological parameters of the wound shell. The simulation results allowed determining the main structural and technological parameters of the winding process as applied to the polyimide-fluoroplastic film PMF-352, which provide the total leakage of the film fuel lines within the requirements.

Aerodynamic performance of the supersonic parachute with material permeability

A new flow field model was established to simulate compressible flow around porous canopy. The compressible Ergun equation was introduced into the source term of momentum equations for the first time to study the influence of material permeability on aerodynamic performance of supersonic parachutes. By using this method, the dynamic variations of related flow field results such as flow structure, drag performance and shock wave standoff distance were obtained. Numerical results including shock wave shape and the average value of drag coefficient are in accordance with the wind tunnel test results. The numerical results show that the velocity-penetrating fabric makes the wake vortex area become narrower and move backward. With the increase of material permeability, the oscillation amplitude and the average value of drag coefficient decrease. This new method can be a good supplement in parachute design and research. It also instructs how to choose fabric for supersonic parachutes.

Penentuan Permeabilitas Magnet Melalui Percobaan Induksi Magnet dengan Logger Lite

In magnet world learning, the discussion of the µ magnetic permeability concept has not yet been addressed specifically. The magnetic permeability often discussed is the µ0 vacuum permeability whose value is 4p x 10-7 Tm/A. In fact, the permeability value of objects is not the same as the vacuum permeability. Therefore, it is necessary to conduct experiments on this in order to obtain an adequate understanding of its concepts. The experimental devices include Logger Lite devices, solenoids, computer, power supply, and two types of ferromagnetic materials i.e. steel and white metal which are precisely similar in both lengths. The deciding of the material permeability is done by placing the materials on the solenoid varying electric current (i) which flows in the solenoid and records the induction field produced (B). Then, based on the data set of I towards B, it’s done a linear regression. The material permeability is determined from the slope of the graph.Based on the experiment, the permeability value of vacuum results mo = (4p ± 0,34) x 10-7 Tm/A. Whereas, for each experimented material it shows that the steel is is m = (8.24 ± 0,008) x 10-6 Tm/A and the white metal is m = (1.85 ± 0,002) x 10-5 Tm/A. Based on the experiment, it’s obvious that the permeability concept seems more and more tangible.