19 research outputs found

    Microzonation Study of Duzce, Turkey

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    Duzce in Turkey was severely damaged during the November 12th, 1999 earthquake (Mw 7.2). The paper presents different surveys and studies performed after the earthquake, which resulted in the microzonation study of the city. At first we collected and analyzed all available geophysical and geological data. Then we performed a well focused geophysical and geotechnical campaign comprising a sufficient number of shallow and deep boreholes, seismic down-hole tests, array measurements of microtremors and ambient noise measurements. The synthesis of all these data resulted in the construction of the seismic geotechnical map and the geometry of the “seismic bedrock” of the city, adequate for site effect analysis. At a second stage we performed a thorough analysis of all available strong ground motion records and we carried out a detailed seismic hazard analysis, which provided the necessary input motion characteristics for the spatial analysis of the seismic ground response. Finally, we conducted a specific site effect analysis for the seismic scenario of the 1999 earthquake with a series of conventional 1D EQL analysis. The processing of the theoretical analysis results led to the estimation and the spatial distribution of the mean acceleration, velocity and displacement response spectra. As a result, Duzce was divided in seismic zones and for each one we proposed the corresponding mean design acceleration response spectra and all other characteristics of the expected ground response

    The Role of Soil and Site Conditions in the Vulnerability and Risk Assessment of Lifelines and Infrastructures. The Case of Thessaloniki (Greece).

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    Soil conditions and site effects play an important role in the vulnerability assessment of lifelines and infrastructures under strong seismic excitation. Due to the spatial extent of these networks, they are subjected to non-uniform and incoherent ground motion as a result of the variability of soil and geological conditions; consequently their vulnerability assessment depends entirely on the variability of soil conditions and ground motion, known as site effects, for a given seismic scenario. Fragility functions for the exposed elements at risk, composing the different lifelines and infrastructure systems, play an equally important role. The paper presents some selected results of a recent application of a comprehensive methodology assessing the vulnerability of several lifeline systems in Thessaloniki in Greece. The work is part of a large research program, aiming to the development of a general methodology for the assessment of the seismic risk for the building stock, lifeline systems and infrastructures at urban scale. Key factors of the methodology are the inventory, the typology, the specific characteristics and the importance (global value) of the elements at risk, the development of seismic scenarios (seismic hazard) and the geotechnical characterization, with the detailed site response analysis. The methodology and the role of soil and site conditions are highlighted with representative examples of the application in Thessaloniki

    Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study

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    PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19–free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19–free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19–free surgical pathways. Patients who underwent surgery within COVID-19–free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19–free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score–matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19–free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19–free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

    Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study.

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    PURPOSE: As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS: This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS: Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION: Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

    SEISMIC PERFORMANCE OF A SYSTEM OF INTERDEPENDENT LIFELINE AND INFRASTRUCTURE COMPONENTS

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    The aim of this research is to develop a generic procedure for the assessment of the serviceability of a system (single system or system of systems) if one or more interacting components of the system are damaged by an earthquake. The system serviceability (functionality) is evaluated starting from the expected degree of damage of the single components (direct physical damage estimated using appropriate fragility functions) and accounting for their functional interaction (functional system architecture and single or by-directional interactions among components). Through the evaluation of the components’ non-functionality, the overall serviceability of the system is assessed, possibly in the form of a “system serviceability curve”, for different levels of seismic input intensity. Aleatory and epistemic uncertainties are treated using a Bayesian inference. The applicability of the proposed approach is established through an illustrative example. It is shown that the methodology is quite general and applicable to real systems with diverse degrees of complexity and knowledge of system and components details

    Fabrication of high-contrast waveguide amplifiers in erbium doped potassium double tungstates

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    High-contrast waveguides in crystalline potassium double tungstates pave the road towards compact and efficient on-chip amplifiers. In this work, the design and fabrication of erbium doped high contrast potassium double tungstates waveguides will be described

    Long-Term Neuropsychological Outcomes Following Temporal Lobe Epilepsy Surgery: An Update of the Literature

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    We present an update of the literature concerning long-term neuropsychological outcomes following surgery for refractory temporal lobe epilepsy (TLE). A thorough search was conducted through the PubMed and Medline electronic databases for studies investigating neuropsychological function in adult patients undergoing resective TLE surgery and followed for a mean/median > five years period. Two independent reviewers screened citations for eligibility and assessed relevant studies for the risk of bias. We found eleven studies fulfilling the above requirements. Cognitive function remained stable through long-term follow up despite immediate post-surgery decline; a negative relation between seizure control and memory impairment has emerged and a possible role of more selective surgery procedures is highlighted

    Combined Invasive Peripheral Nerve Stimulation in the Management of Chronic Post-Intracranial Disorder Headache: A Case Report

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    The introduction of ventricular shunts dramatically changed the outcome and quality of life of hydrocephalic patients. However, shunt surgery continues to be associated with numerous adverse events. Headache is one of the most common complications after shunt operation. It is often of prolonged duration, the symptoms resemble those of migraine, and pain does not respond to medication. We propose invasive peripheral nerve stimulation as a potential solution in the treatment of patients suffering from chronic headache associated with shunted hydrocephalus. A young woman presented with daily holocephalic headache with diffuse pain exacerbated by lying down. Imaging revealed panventricular enlargement and possible aqueduct stenosis. When a ventriculoperitoneal shunt was placed, clinical symptoms resolved. Nevertheless, she gradually exacerbated after a second valve replacement due to wound infection. Imaging revealed decompressed ventricles and appropriate shunt placement. The diagnosis of chronic post-intracranial disorder headache was set. Therefore, occipital nerve stimulation was applied and, considering that the patient did not have a total response, bilateral parietal stimulation was added. Three months after the combined PNS, she experienced total remission of headache. Combined PNS eases refractory headaches much more than occipital nerve stimulation alone and could be considered as a solution for shunted hydrocephalus-associated headache
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