Spiral formation at the microscale by µ-pyro-electrospinning.

Spiral shapes occur frequently in nature as in the case of snail shells or the cochlea - the auditory portion of the inner ear. They also inspire many technological devices that take advantage of this geometry. Here we show that µ-pyro-electrospinning is able to control whipping instabilities in order to form spiralling fibres (down to 300 nm thick) directly on a support with true microscale regularity. The results show that polymer concentration plays a key role in producing reliable and long spirals. We investigate the cell response to these spiral templates that, thanks to their true regularity, would be useful for developing innovative cochlea regeneration scaffolds.

Spontaneous assembly of carbon-based chains in polymer matrixes through surface charge templates.

Stable chains of carbon-based nanoparticles were formed directly in polymer matrixes through an electrode-free approach. Spontaneous surface charges were generated pyroelectrically onto functionalized ferroelectric crystals, enabling the formation of electric field gradients that triggered the dipole-dipole interactions responsible for the alignment of the particles, while embedded in the polymer solution. The phenomenon is similar to the dielectrophoretic alignment of carbon nanotubes reported in the literature. However, here the electric fields are generated spontaneously by a simple heat treatment that, simultaneously, aligns the particles and provides the energy necessary for curing the host polymer. The result is a polymer sheet reinforced with well-aligned chains of carbon-based particles, avoiding the invasive implementation of appropriate electrodes and circuits. Because polymers with anisotropic features are of great interest for enhancing the thermal and/or the electrical conductivity, the electrode-free nature of this technique would improve the scaling down and the versatility of those interconnections that find applications in many fields, such as electronics, sensors, and biomedicine. Theoretical simulations of the interactions between the particles and the charge templates were implemented and appear in good agreement with the experimental results. The chain formation was characterized by controlling different parameters, including surface charge configuration, particle concentration, and polymer viscosity, thus demonstrating the reliability of the technique. Moreover, micro-Raman spectroscopy and scanning electron microscopy were used for a thorough inspection of the assembled chains.

[The role of necrosectomy and continuous peritoneal lavage in the treatment of acute necrotic-hemorrhagic pancreatitis]. / Il ruolo della necrosectomia e del lavaggio peritoneale continuo nel trattamento della pancreatite acuta necrotico-emorragica.

Acute necrotizing pancreatitis involves high mortality. When diagnosed, the disease implies a choice of suitable timing and proper technique of surgical approach. The experience on 16 patients with acute necrotizing pancreatitis, 9 males and 7 females, mean age of 54.7 +/- 3.3 years, is presented in this study. Necrosectomy and continuous local lavage of abdominal collections and pancreatic necrotic surfaces was the most appropriate surgical treatment. The method seems able to remove necrosis and active biological compounds and would appear to achieve a limited mortality and morbidity. Necrosectomy and postoperative local lavage represent a therapeutic effective procedure.