Performance Assessment of Different Roof Integrated Photovoltaic Modules under Mediterranean Climate

AbstractMany countries, for aesthetic purposes, offer economic advantages (tax deductions, incentives, etc..) for the installation of building integrated photovoltaic modules (BIPV), with water-tightness capability and adequate mechanical resistance in order to substitute tile covering or part of it. Nevertheless, poor or absent ventilation under BIPV panels could cause them to overheat and reduce their efficiency.It is well established that the presence of an air gap between a photovoltaic (PV) module and roof covering facilitates ventilation cooling under the device and consequently reduces cell temperature and improves its performance.In this study, we investigated the thermal performance of PV modules installed in a real scale experimental building over a traditional clay tile pitched roof in Italy for almost one year (from August 2009 to June 2010). One PV module was rack-mounted over the roof covering with a 0.2 m air gap; the others were fully integrated and installed at the same level of the roof covering (one with an air gap of 0.04 m, the other mounted directly in contact with the insulation). Temperature and heat flux measurements for each panel, and environmental parameters were recorded.Experimental results demonstrate that even though the rack-mounted PV module constantly maintains cell temperature below that of the other full-building integrated modules, due to the presence of a higher air gap, the difference in the energy produced by the PV modules estimated for the entire monitoring period is less than 4%

Radiofrequency Ablation in Vertebral Body Metastasis with and without Percutaneous Cement Augmentation: A Systematic Review Addressing the Need for SPINE Stability Evaluation

Vertebral body metastases (VBM) are one of the most frequent sites of bone metastasis, and their adequate therapeutic management still represents an insidious challenge for both oncologists and surgeons. A possible alternative treatment for VBM is radiofrequency ablation (RFA), a percutaneous technique in which an alternating current is delivered to the tumor lesion producing local heating and consequent necrosis. However, RFA alone could alter the biomechanics and microanatomy of the vertebral body, thus increasing the risk of post-procedure vertebral fractures and spine instability, and indeed the aim of the present study is to investigate the effects of RFA on spine stability. A systematic review according to PRISMA-P guidelines was performed, and 17 papers were selected for the systematic review. The results show how RFA is an effective, safe, and feasible alternative to conventional radiotherapy for the treatment of VBM without indication for surgery, but spine stability is a major issue in this context. Although exerting undeniable benefits on pain control and local tumor recurrence, RFA alone increases the risk of spine instability and consequent vertebral body fractures and collapses. Concomitant safe and feasible therapeutic strategies such as percutaneous vertebroplasty and kyphoplasty have shown synergic positive effects on back pain and improvement in spine stability

Evaluation of the Siemens HIV Antigen-Antibody Immunoassay

Fourth-generation assays for the simultaneous detection of human immunodeficiency virus (HIV) antigen and antibodies are available on the international market and are currently used for blood donor screening and for HIV diagnosis. In this study we evaluated the performance of the novel automated fourth-generation ADVIA Centaur® HIV Ag/Ab Combo assay. The assay detected seroconversion at the same bleed or at least one bleed earlier in panels with respect to other assays and showed a detection efficacy equal to those of other assays in a low-titer panel. Samples obtained from blood donors (n = 2,778) or from HIV-positive patients (HIV-1 B subtype, n = 82; non-B subtype, n = 71) were also tested, showing a good correlation with other fourth-generation assays. We assessed the performance of 3 fourth-generation assays for detecting in utero transmitted anti-HIV antibodies and found a more specific detection efficiency with the ADVIA Centaur HIV Ag/Ab Combo assay compared to the other fourth-generation assays