Economic-efficient design of residential net zero energy buildings with respect to local context

Tese de doutoramento. Sistemas Sustentáveis de Energia. Faculdade de Engenharia. Universidade do Porto. 201

The Role of 3 Tesla MRA in the Detection of Intracranial Aneurysms

Intracranial aneurysms constitute a common pathological entity, affecting approximately 1–8% of the general population. Their early detection is essential for their prompt treatment. Digital subtraction angiography is considered the imaging method of choice. However, other noninvasive methodologies such as CTA and MRA have been employed in the investigation of patients with suspected aneurysms. MRA is a noninvasive angiographic modality requiring no radiation exposure. However, its sensitivity and diagnostic accuracy were initially inadequate. Several MRA techniques have been developed for overcoming all these drawbacks and for improving its sensitivity. 3D TOF MRA and contrast-enhanced MRA are the most commonly employed techniques. The introduction of 3 T magnetic field further increased MRA's sensitivity, allowing detection of aneurysms smaller than 3 mm. The development of newer MRA techniques may provide valuable information regarding the flow characteristics of an aneurysm. Meticulous knowledge of MRA's limitations and pitfalls is of paramount importance for avoiding any erroneous interpretation of its findings

Towards compliant building airtightness and ventilation systems. AIVC Contributed Report 16

Because buildings are responsible for 40% of energy use and 36% of Greenhouse Gas (GHG) emissions in the EU, energy efficiency in buildings has become a priority to drastically reduce the energy use in buildings. Consequently, a number of policy measures have been implemented in European Member States to drive the market towards Nearly Zero-Energy Buildings, including the Energy Performance of Buildings Certificates (EPCs), which are the most visible instrument of the Energy Performance of Buildings Directive (EPBD). Nevertheless, the boundary conditions that are necessary for these measures to be effective have rarely been carefully addressed. In this respect, two specific concerns lie in the compliance of Energy Performance of Buildings Certificates (EPCs) and in the quality of building works.The IEE QUALICHeCK project\u27s goal was to raise awareness and trigger initiatives to improve the compliance of Energy Performance Certificates and the quality of buildings works in order to decrease the actual energy use of buildings. In other words, QUALICHeCK urges building professionals to "do what they declare" since otherwise, it discredits the overall approach already engaged since a number of years in European countries with energy conservation regulations and incentives in the building sector.This goal entailed 3 specific objectives:1. To confirm the concern for non-compliant EPCs and quality of buildings works. Although there were some unstructured market feedback and studies pointing out this problem, further understanding of the status on the ground and the extent to which non-compliance could jeopardize the effectiveness of policies was necessary.2. To show the benefits of existing approaches. There exist several voluntary or regulatory schemes that have been developed in many European countries to contain non-compliance of EPCs and of the quality of building works. QUALICHeCK\u27s objective was to disseminate information on these schemes to inspire other bodies facing similar challenges.3. To give the key steps to set up compliance frameworks. Because the development of a compliance framework can appear somewhat chaotic for an external observer—for instance because of feedback loops with stakeholders—the consortium came up with a summary of key issues that should be addressed for a sound foundation of the framework.Based on a literature review and 10 specific field studies in 9 countries, each on samples of 25+ buildings, the EU QUALICHeCK project has confirmed this concern for non-compliant EPCs and quality of buildings works by showing that insufficient quality assurance measures increase the risk of discrepancies between claimed or expected and actual performance. Speaking about ventilation and airtightness, this could consist in the absence of controls of the building or ductwork airtightness values reported in the EPCs; this could also be the ambiguity left for the EPC expert to choose the appropriate input data for a specific ventilation system.The good news is that there are also interesting approaches that have been developed to contain some of the issues reported in the field campaigns. In the area of ventilation and airtightness, these approaches include competent tester schemes for building airtightness or ventilation system performance checks, or databases developed to ease unambiguous EPC input data selection and control.QUALICHeCK ended in February 2017. The consortium has archived its key findings in several reports and 59 factsheets which are short 2- to 10-page documents highlighting specific results. All public deliverables are available on the QUALICHeCK website (http://qualicheck-platform.eu/).To ease the dissemination of these results in the ventilation and infiltration community, this report collates 23 factsheets specifically related to ventilation and airtightness issues, field data, and solutions. We hope you will find this information useful. Buildings are responsible for a major share of energy use and have been a special target in the global actions for climate change mitigation, with measures that aim at improving their energy efficiency, reduce carbon emissions and increase renewable energy use

Intradural extramedullary Ewing's sarcoma: A case report and review of the literature

Introduction Extra-skeletal Ewing's sarcomas are very rare lesions to the spine surgeon, with the intradural, extramedullary lesions being even rarer. Herein we present a patient with an intradural, extramedullary form of Ewing's sarcoma and review the relevant literature. The medical records, operative reports, radiographical studies and histological examinations of a single patient are retrospectively reviewed. Case report A 31-year old male presented with back-pain, right-leg progressive paraparesis, and inability to walk. Both motor and sensory disturbances were revealed on the right leg at the clinical examination. Lumbar MRI showed two lesions. The first one was an intradural, extramedullary lesion at the L2-L3 level, while the second was smaller, located at the bottom of the dural sac. The patient underwent gross total resection of the L2-L3 lesion after a bilateral laminectomy. Histological examination was compatible with Ewing's sarcoma, and was verified by molecular analysis. No other extra-skeletal or skeletal lesion was found. A chemotherapy scheme was tailored to the patients’ histological diagnosis. The patient presented with local recurrence and bone metastasis 2 years after his initial diagnosis. A second operation was performed and the follow up of the patient showed no disease progression 18 months after revision surgery. Conclusion The spine surgeon should be aware of the existence of such rare entities, in order to timely fulfill the staging process and institute the proper therapy. The management of patients with extra-skeletal Ewing's sarcomas involves professionals as members of a multidisciplinary team, all of which should co-operate for the patient's optimal outcome

Signal-to-noise per unit time optimization for in vivo single-voxel proton magnetic resonance spectroscopy of the brain: Theoretical formulation and experimental verification at two field strengths

Signal-to-noise ratio optimization, regarding repetition time selection, was explored mathematically and experimentally for single-voxel proton magnetic resonance spectroscopy. Theoretical findings were benchmarked against phantom measurements at 1.5 Tesla and localized in vivo proton brain spectra acquired at both 1.5 Tesla/3.0 Tesla. A detailed mathematical description of signal-to-noise ratio per unit time was derived, yielding an optimal repetition time of 1.256 times the metabolite longitudinal relaxation time. While long-repetition-time acquisitions minimize longitudinal relaxation time contributions, a repetition time of ~1.5s results in maximum signal-to-noise ratio per unit time, which can in turn be invested into smaller voxel sizes. The latter is of utmost importance in brain oncology, allowing accurate spectroscopic characterization of small lesions.Comment: 26 pages, 4 figures, submitted to Spectroscopy Letter