Radical photoinduced cationic frontal polymerization in porous media

Two different interpenetrating phase composites were produced using a radical photoinduced cationic frontal polymerization process. The composites were based on polyurethane (PU) and aluminium open-cell foams impregnated with a formulation of a cycloaliphatic epoxy with different concentrations of a cationic photoinitiator and a thermal initiator. The influence of both types of initiators on the frontal polymerization features was systematically evaluated for the PU foam. It was found to occur only when the concentration of both initiators was greater than 0.5 wt%, leading to full conversion of the epoxy in the whole volume of the 15 mm thick composite samples within less than 100 s. The maximum temperature reached by the propagation front was in the range 275–305 °C depending on the type of formulation, leading to pores in the epoxy phase and extensive degradation of the PU phase. In the case of the opaque aluminium foam, an additional layer of pure resin was required on the UV-exposed surface, which corresponded to a critical mass of a few grams to ensure sufficient heat generation and trigger the front propagation. © 2020 Society of Chemical Industry

Experimental, Theoretical and Numerical Evaluation of the Stiffness of a Soil-Foundation Model by Shaking-Table Test

A well-controlled test was carried out on a Leighton Buzzard sand-shallow foundation system by means of the six-degree-of-freedom shaking table available at the University of Bristol. The foundation consists of a concrete block located into a flexible shear-stack (Taylor et al., 1994) filled up to 1.00 m with the sand. During the test the block was subjected to a centered vertical load and to one direction sine dwell-type acceleration applied at the base of the shear stack. The static and dynamic sand properties were evaluated through different laboratory tests, among them resonant column tests, cyclic and monotonic loading torsional shear tests were performed (Mazzarella, 1999). A comprehensive network of accelerometers and displacement transducers was used to check the static and dynamic soil-foundation interaction (Maugeri et al., 1999a). The impedance functions (Gazetas, 1991) were evaluated and then compared with the experimental results. Finally, the experimental results were compared with the numerical ones obtained by means of a FEM code (Massimino, 1999) developed at the University of Catania

Aulogous fibrin sealant (Vivostat®) in the neurosurgical practice: Part II: Vertebro-spinal procedures

Background: Epidural hematomas, cerebrospinal fluid fistula, and spinal infections are challenging postoperative complications following vertebro-spinal procedures. We report our preliminary results using autologous fibrin sealant as both fibrin glue and a hemostatic during these operations. Methods: Prospectively, between January 2013 and March 2015, 68 patients received an autologous fibrin sealant prepared with the Vivostat®system applied epidurally to provide hemostasis and to seal the dura. The surgical technique, time to bleeding control, and associated complications were recorded. Results: Spinal procedures were performed in 68 patients utilizing autologous fibrin glue/Vivostat®to provide rapid hemostasis and/or to seal the dura. Only 2 patients developed postoperative dural fistulas while none exhibited hemorrhages, allergic reactions, systemic complications, or infections. Conclusions: In this preliminary study, the application of autologous fibrin sealant with Vivostat®resulted in rapid hemostasis and/or acted as an effective dural sealant. Although this product appears to be safe and effective, further investigations are warranted

Impasse in the management of recurrent basal cell carcinoma of the skull with sagittal sinus erosion1

Abstract Basal cell carcinoma (BCC) is a non melanocytic skin cancer that arises from basal cells, affecting commonly fair-skinned human beings. Although the tumor is well known for local recurrences, extension into the intracranial space is reported. A case of a giant BCC of the scalp invading the middle and posterior third of the superior sagittal sinus (SSS) is reported. A 70-year-old male with a basal cell carcinoma history presented with a massive bleeding from the SSS invaded by the tumor. Since the patient refused surgery the bleeding was managed through direct compression by applying a thrombin-based hemostatic agents and sterile dressings. This procedure was performed daily in order to stimulate the spontaneous thrombosis of the dural sinus and development of collateral circle. BCC invading the SSS is rarely reported. A technical description of this case is provided. This case underscores the importance of early and appropriate treatment for high risk BCC, and whenever surgical procedure is not suitable appropriate conservative treatment may be efficacious

The reconstructive role of TachoSil in neurosurgery

Hemorrhages, cerebrospinal fluid (CSF) fistula and infections are the most challenging post-operative complications in Neurosurgery [1–5]. Fibrin sealant agents have been developed with the aim to provide efficient hemostasis and safe dural closure [3,6–14]. In this study we report our initial experience using TachoSil® (haemostatic surgical patch; Nycomed, Linz, Austria) in achieving hemostasis and CSF leakage repair during cranio-cerebral procedures [15–18]. We describe and show the unique features of this fibrin sealant, pioneered with stunning success in many surgical procedures known to be at high risk of peri- and postoperative bleeding (i.e. nephrectomies, pulmonary lobectomies, ballistic injuries, arthroplasties, coronary bypass graftings), but still not widely exploited at its best in the field of Neurosurgery

Delayed chronic intracranial subdural hematoma complicating resection of a tanycytic thoracic ependymoma

Background: To demonstrate that the diagnosis of an intracranial subdural hematoma should be considered for patients presenting with acute or delayed symptoms of intracranial pathology following resection of a spinal tumor. Case Description: We present a case of a 57-year-old woman found to have a chronic subdural hematoma 1 month following resection of a thoracic extramedullary ependymoma. Evacuation of the hematoma through a burr hole relieved the presenting symptoms and signs. Resolution of the hematoma was confirmed with a computed tomography (CT) scan. Conclusion: Headache and other symptoms not referable to spinal pathology should be regarded as a warning sign of an intracranial subdural hematoma, and a CT scan of the head should be obtained. The mechanism of the development of the hematoma may be related to the leakage of cerebrospinal fluid with subsequent intracranial hypotension leading to an expanding subdural space and hemorrhage

A rare case of extra-intramedullary dorsal tanycitic ependymoma, radically removed with intraoperative neurophysiological monitoring

Introduction: Tanycitic dorsal extra and intramedullary ependymoma is a rare form of tumor. From the histological point of view, these tumors show several aspects that make difficult the differential diagnosis from schwannomas and pilocytic astrocytomas. Tanycytic variant, often occurs in the thoracic tract of the spinal cord, and it is constituted by tanycites, that are typical elongated and bipolar cells that give to the tumor fibrillary aspects. Tanycitic variant has been recently characterized as a variant of ependymoma, since the 2000 World Health Organization (WHO) system. Case presentation: A 57 years old woman presented with intractable back pain often radiating to the left leg. Neurological exam revealed mild weakness in left tight flexion. No sensory or sphincterial disturbances were present. A dorso-lumbar Magnetic Resonance Imaging (MRI)with contrast medium showed a well-demarked T12 intradural extramedullary lesion, suggestive for schwannoma. The tumor was radically removed, with an excellent neurological outcome, and was then characterized as a grade II tanycitic ependymoma. Conclusion: To differentiate the diagnosis between extramedullary ependymomas and schwannomas, meningiomas or astrocytomas is necessary a histopathological examination and a close follow up period is recommended since the tumor could evolve into higher grade. Neurophysiological monitoring is necessary for a satisfactory neurological outcome

A rare case of extra-intramedullary dorsal tanycitic ependymoma, radically removed with intraoperative neurophysiological monitoring

Introduction: Tanycitic dorsal extra and intramedullary ependymoma is a rare form of tumor. From the histological point of view, these tumors show several aspects that make difficult the differential diagnosis from schwannomas and pilocytic astrocytomas. Tanycytic variant, often occurs in the thoracic tract of the spinal cord, and it is constituted by tanycites, that are typical elongated and bipolar cells that give to the tumor fibrillary aspects. Tanycitic variant has been recently characterized as a variant of ependymoma, since the 2000 World Health Organization (WHO) system. Case presentation: A 57 years old woman presented with intractable back pain often radiating to the left leg. Neurological exam revealed mild weakness in left tight flexion. No sensory or sphincterial disturbances were present. A dorso-lumbar Magnetic Resonance Imaging (MRI)with contrast medium showed a well-demarked T12 intradural extramedullary lesion, suggestive for schwannoma. The tumor was radically removed, with an excellent neurological outcome, and was then characterized as a grade II tanycitic ependymoma. Conclusion: To differentiate the diagnosis between extramedullary ependymomas and schwannomas, meningiomas or astrocytomas is necessary a histopathological examination and a close follow up period is recommended since the tumor could evolve into higher grade. Neurophysiological monitoring is necessary for a satisfactory neurological outcome

Fiber-reinforced lightweight foamed concrete panels suitable for 3D printing applications

This contribution presents a set of experimental results on fiber-reinforced innovative lightweight panels (FRIL-panels) having thickness of 12mm. These panels are prepared with a peculiar foamed concrete that has a high viscosity and cohesion in the fresh state, which makes it particularly suitable for 3D printing applications. The FRIL-panels can be used for internal partitions, external infills, and suspended ceilings of buildings as more effective solutions than conventional plasterboard ones, with better thermal insulation and acoustic absorption properties due to the internal air-void microstructure. The aim of this work is to investigate the out-of-plane resistance of FRIL-panels, prepared with a density of 800kg/m3, under displacement-controlled three-point bending tests. In view of potential use in the precast industry, the FRIL-panels were placed into an accelerated concrete curing tank so as to speed up the overall production process. Modulus of rupture, ultimate deflection and collapse mode of FRIL-panels are critically analysed and discussed