Drug Release from Lipogels According to Gelling Conditions and Mechanical Treatment

The release rate of a drug dissolved in the liquid phase of lipogels may be greatly affected by the type and concentration of gelling agent and by processing conditions and mechanical treatment of the ointment. These differences in release rate are reduced after application of mechanical stress comparable with the strain exerted on the ointment during application to the skin. Therefore, changes in the concentration of gelling agents used to achieve suitable consistency and manufacturing and packing processes that meet industrial and marketing requirements do not appear to exert a practical influence on drug availability after application to the skin.     

Implementation of a real option in a sustainable supply chain: an empirical study of alkaline battery recycling

Green supply chain management (GSCM) has emerged as a key approach for enterprises seeking to become environmentally sustainable. This paper aims to evaluate and describe the advantages of a GSCM approach by analysing practices and performance consequences in the battery recycling sector. It seeks to integrate works in supply chain management (SCM), environmental management, performance management and real option (RO) theory into one framework. In particular, life cycle assessment (LCA) is applied to evaluate the environmental impact of a battery recycling plant project, and life cycle costing (LCC) is applied to evaluate its economic impact. Firms, also understanding the relevance of GSCM, have often avoided applying the green principles because of the elevated costs that such management involved. Such costs could also seem superior to the potential advantages since standard performance measurement systems are internally and business focused; for these reasons, we consider all the possible value deriving also by uncertainty associated to a green project using the RO theory. This work is one of the few and pioneering efforts to investigate GSCM practices in the battery recycling sector.     

Polymer biomaterials (polyphosphazenes) in the repair of peripheral nervous system

Biodegradable polymers gives interesting perspectives of use in making artificial conduits for peripheral nerve reconstruction. Poliphosphazenes are materials highly biocompatible and have a controllable reabsorption rate. According to the substitutes that are introduced in the molecule, they can also be used as a framework for drug release. Conduits obtained with poli [bis(etilalanate) phosphazene] were evaluated as guides for nerve regeneration in an experimental animal model. In six Wistar rats, under general anesthesia and with microsurgical technique, the ischiatic nerve was isolated. On the right side a segment of the nerve was removed in order to create a 10 mm gap. The defect was then repaired using the conduit. On the controlateral limb the nerve continuity was restored using as an autograft the segment removed from the right. Control were performed at 30, 90, 180 days and consisted in histological and electron microscopy investigations. They showed the gradual degradation of the conduit without signs of local and general toxicity. The regeneration of the nerve fibers in the lumen of the conduit was not significantly different from the one obtained with the autologous grafts. So poliphosphazene conduits may be considered effective as a guide for nerve regeneration, above all for the possibility of use the polymer as a carrier for neurite-promoting factors.     

Na-feldspar (F) and kaolinite (K) system at high temperature: Resulting phase composition,micro-structural features and mullite-glass Gibbs energy of formation,as a function of F/K ratio and kaolinite crystallinity

The system Na-feldspar (F) and kaolinite (K) was investigated at temperatures of interest in ceramic applications (1200–1280 °C) to study the effects of F/K ratios by weight and crystallinity degree of kaolinite on the final product, micro-structural features and mullite-glass Gibbs energy of formation (ΔG^eff). Mullite and glass are the dominant phases; in general, the higher the temperature, the larger the former. An F/K increase promotes the formation of glass and secondary mullite, appearing along with the primary one. ΔG^eff was modelled by α(T) × (F/K)² + β(T) × F/K + γ(T), α, β and γ being linear functions of temperature whose coefficients were determined by fitting the ΔG^eff-theoretical to the ΔG^eff-obtained from the measured phase compositions. ΔG^eff is less affected by temperature than by F/K, whose increase shifts equilibrium towards glass phases. The ΔG^eff-curves for ordered and disordered kaolinite intersect one another at F/K ～0.5, a ratio close to that used in industrial practice.     

Accumulation of polarization-mode dispersion in cascades ofcompensated optical fibers

First-order compensation of polarization-mode dispersion (PMD) leaves residual, higher order PMD. We analyze the accumulation of residual distortion in cascades of compensated fibers. Total distortion is calculated and limitations on the total propagation length are given. While compensation can greatly extend the total propagation distance, its effectiveness diminishes rapidly as the bandwidth is increased     

Hydroxy- and fluorapatite films on Ti alloy substrates: Sol-gel preparation and characterization

In this paper we describe the preparation of hydroxyfluorapatite (HFA) and fluorapatite (FA) films deposited on titanium alloys by means of the dip-coating method starting from a sol-gel prepared colloidal solution. These materials are compared with hydroxyapatite (HA) films prepared via sol gel and commercial films prepared by means of plasma spray. The film characterization from the point of view of the composition and crystallinity, performed by means of XRD, FTIR and Raman Spectroscopies, has shown a good purity degree, and compositional homogeneity for the sol-gel materials, though traces of carboxy-hydroxy apatite were found. Also, the samples exhibit a good crystallinity. SEM pictures, taken on HA coating deposited via sol-gel, revealed a homogeneous surface structure and optimum features to set up a good prosthesis-tissue interface.     

Influence of membrane oxygenators on the pulsatile flow in extracorporeal circuits: an experimental analysis

An experimental analysis was carried out to evaluate the effects induced by two typical extracorporeal circuits on the pressure and flow generated by a roller pump with a pulsatile module. The hydraulic behaviour of the patient was simulated by means of a mechanical mock-up system consisting of a few lumped parameters reproducing the physiologic vascular impedance. Pressure and flow tracings were acquired at different locations along the circuit using an automatic data acquisition system. Nine lest conditions with different pulse frequency and systolic time values were examined using a mean volumetric flow rate of approximately 4 l/min. A complete analysis of the results obtained in terms of pressure drops and inflow-outflow differences across the components of the arterial line, as well as the calculation of the hydraulic pulsatile power along the circuit, allowed us to assess the influence of the various components upon the pulsatility. The results indicated that the membrane oxygenators tested slightly affect the pulsatility of the flow and the pressure; on the contrary the arterial pipe line is responsible for large damping and head losses. To optimize the use of pulsatile flow for cardiopulmonary bypass it is necessary to reduce the length of the arterial pipe lines thus integrating the circuit as much as possible.