209 research outputs found

    Quantitative flood hazard assessment methods: A review

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    Flood hazard assessment is a fundamental step in flood risk mapping. Quantitative assessment requires hydrodynamic modelling of the flooding process in order to calculate the spatial distribution of suitable flood hazard indicators representative of flooding intensity and frequency, hence its potential to result in harm. Flood hazard indicators are usually defined by combining relevant flooding parameters, mainly flood depth and flow velocity, but also flooding arrival time, flooding duration, sediment or contamination load, and so forth. A flood hazard classification is commonly introduced to assign a hazard level to areas potentially subject to flooding. This article presents a systematic review of quantitative methods proposed in the scientific literature or prescribed by government authorities to assess the hazard associated with natural or anthropic flooding. Flood hazard classification methods are listed and compared by specifying their underlying approach (heuristic, conceptual, empirical), the exposed element which they were designed for (people, buildings, vehicles, etc.), and their fields of application (river overflow, dam-break, levee breach, debris flow). Perspectives and future challenges in quantitative flood hazard analysis are also discussed. This review aims to help modellers and practitioners to select the most suitable flood hazard assessment method for the case study of interest

    Data Fusion Techniques for Processing Aerospace Remote Sensing Electro-Optical Data

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    This paper deals with data fusion between different resolution multispectral (MS) and panchromatic (Pan) images in order to obtain high spatial resolution MS images. A survey is provided about the state-of-the-art data fusion techniques and synthesized product's quality assessment criteria. Several fusion algorithms and quality indexes were implemented in a Toolbox with a graphical user interface developed in MATLAB environment, namely Fusion Tool Box (FTB), developed to obtain experimental results. The analysis performed through FTB on two different data sets was oriented to validate the theoretical analysis and to perform a quantitative comparison among fusion algorithms for several applications. Results allow a first level evaluation of advantages and drawbacks of the various techniques for specific applications

    Frequency and type of interval adverse events during the waiting period to complex aortic endovascular repair

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    Objective: The aim of the present study was to evaluate the frequency and type of adverse events that can occur during the waiting period to complex aortic endovascular repair. Methods: We performed a retrospective study of all elective patients with complex aortic aneurysms (including pararenal, suprarenal, thoracoabdominal, and aortic arch aneurysms) that had required a custom-made device (CMD) from Cook Medical (Bloomington, Ind) at a tertiary referral vascular center (November 2010 to May 2020). The waiting period was defined as the interval between the date of the stent-graft order and the date of the procedure or cancellation. Interval adverse events were defined as any event that had occurred during the waiting period and led to either mortality, aneurysm rupture, or cancellation of the planned procedure. Results: A total of 235 patients (mean age, 72 years; 25% female) had had a CMD graft ordered (201 planned as a single-stage procedure). The median waiting time until surgery was 106 days (interquartile range [IQR], 77-146 days) in the whole cohort and 101 days (IQR, 77-140 days) for the single-stage cohort. The planned procedure was performed electively in 219 patients (93%), with an overall 30-day elective mortality of 2% (n = 5). A total of 16 interval adverse events occurred during the waiting period. Of these 16 events, 10 were aneurysm ruptures and 6 were cancellations of the procedure owing to non–aneurysm-related deaths (3% of the entire cohort). A total of 10 interval deaths were registered (4.2%), 4 of which were aneurysm related. The risk of rupture during the waiting period (Kaplan-Meier) was 6.1% ± 2.3% at 180 days. The median interval from the stent-graft order to aneurysm rupture was 101 days (IQR, 54-200 days). Of the 10 aneurysm ruptures that had occurred, 6 had undergone emergent repair, with 0% mortality at 30 days (one open repair, one t-Branch, one physician-modified endograft, two cases for which the CMD was already available, one case for which a different CMD was available). Conclusions: The median waiting time from the stent-graft order to implantation was ∼15 weeks. During this waiting period, a substantial proportion of patients could experience adverse events, either related to aneurysm rupture or underlying comorbidities. The risk of rupture during the waiting period exceeded the risk of perioperative mortality. Thus, efforts to decrease this risk could significantly improve the outcomes. A combination of different techniques might play a vital role in reducing the mortality after cases of interval rupture

    Emergent endovascular treatment options for thoracoabdominal aortic aneurysm

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    For a long time, parallel grafting, physician-modified endografts, and, more recently, in situ fenestration were the only go-to endovascular options for ruptured thoracoabdominal aortic aneurysm, offered mixed results, and depended mainly on the operator's and center's experience. As custom-made devices have become an established endovascular treatment option for elective thoracoabdominal aortic aneurysm, they are not a viable option in the emergency setting, as endograft production can take up to 4 months. The development of off-the-shelf (OTS) multibranched devices with a standardized configuration has allowed the treatment of ruptured thoracoabdominal aortic aneurysm with emergent branched endovascular procedures. The Zenith t-Branch device (Cook Medical) was the first readily available graft outside the United States to receive the CE mark (in 2012) and is currently the most studied device for those indications. A new device, the E-nside thoracoabdominal branch endoprosthesis OTS multibranched endograft (Artivion), has been made commercially available, and the GORE EXCLUDER thoracoabdominal branch endoprosthesis OTS multibranched endograft (W. L. Gore and Associates) is expected to be released in 2023. Due to the lack of guidelines on ruptured thoracoabdominal aortic aneurysm, this review summarizes the available treatment options (ie, parallel grafts, physician-modified endografts, in situ fenestrations, and OTS multibranched devices), compares the indications and contraindications, and points out the evidence gaps that should be filled in the next decade

    A scoping review on the approaches for cannulation of reno-visceral target vessels during complex endovascular aortic repair

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    OBJECTIVES: The aim of this study was to assess the approaches to reno-visceral target vessels (TVs) cannulation during branched-fenestrated endovascular aortic repair, determine the evidence base that links these approaches to clinical outcomes and identify literature gaps. METHODS: A scoping review following the PRISMA Protocols Extension for Scoping Reviews was performed. Available full-text studies published in English (PubMed, Cochrane and EMBASE databases; last queried, 31 June 2022) were systematically reviewed and analysed. Data were reported as descriptive narrative or tables, without any statistical analysis nor quality assessment. RESULTS: Fourteen retrospective articles were included. Seven articles studied the use of upper extremity access (UEA) during branched-fenestrated endovascular aortic repair, 3 studied the use of steerable sheaths and 4 included both approaches. A left UEA was used in 757 patients (technical success: 99%, stroke rate: 1-3%) and a right UEA in 215 patients (technical success: 92-98%, stroke rate: 0-13%). Seven studies (1066 patients) described a surgical access only (technical success: 80-99%, stroke rate: 0-13%), while 3 studies (146 patients) described a percutaneous access only (technical success: 83-90%, stroke rate: 3%) and lastly 4 studies compared UEA versus use of steerable sheaths from the transfemoral approach (TFA) (UEA: 563 patients, technical success: 95-98%, stroke rate: 1-8%; TFA: 209 patients, technical success: 98-100%, stroke rate: 0-1%). CONCLUSIONS: Both UEA and TFA as cannulation approaches were associated with high technical success and low perioperative complications. Currently, there is a paucity of high-quality data to provide definitive indication. Optimal UEA in terms of side (left versus right) and approach (surgical versus percutaneous) needs further study

    Early Experience With a Novel Dissection-Specific Stent-Graft to Prevent Distal Stent-Graft-Induced New Entry Tears After Thoracic Endovascular Repair of Chronic Type B Aortic Dissections

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    Background: The aim was to report short and mid-term outcomes of a novel, investigational, dissection-specific stent-graft (DSSG), specifically designed to address the features of chronic type B aortic dissection (CTBAD) and reduce the risk of distal stent-graft-induced new entry tears (dSINE). Materials and Methods: A retrospective single center cohort study of all patients undergoing TEVAR with the DSSG for CTBAD from January 1, 2017 to January 31, 2020. The DSSG, which is a modified stent-graft based on the Cook Zenith Alpha Thoracic platform, has no proximal barbs, and a customized longer body length with substantial taper. The second and third distal Z-stents are sited internally to avoid any contact of the metal skeleton with the dissection membrane and have reduced radial force, while the most distal stent was removed creating a distal 30 mm unsupported Dacron graft. Results: Sixteen patients (13 males, 3 females) with a median age of 66 years (range 31–79 years) underwent elective TEVAR of CTBAD using the DSSG. Six patients (38%) had an underlying connective tissue disorder. The median tapering was 10 mm (range 4 mm–21 mm) and median length 270 mm (range 210–380 mm). Technical success was achieved in all but one case (96%). One patient died within 30 days, due to retrograde type A dissection with cardiac tamponade. The 30-day rate of stroke, spinal cord ischemia, and re-interventions was 0%. After median imaging follow-up time of 17 months (range 1–31 months), one patient developed a dSINE 4 months after the index procedure. After median survival follow-up of 23 months (range 2–35 months), one late death occurred due to traumatic brain injury, while no aortic-related death occurred during follow-up. Complete false lumen (FL) thrombosis was achieved in 9 patients while the remaining 6 showed partial FL thrombosis. No instances of diameter increase at the level oftreated aortic segment were noted with serial measurements showing either stable (n = 7) or decreased (n = 8) maximal transverse diameter. Conclusions: Use of a novel DSSG with low radial force for TEVAR in the setting of CTBAD is safe and feasible. This early real-world experience shows promising mid-term effectiveness with low rates of dSINE or unplanned re-interventions and satisfactory aortic remodeling during follow-up. Longer follow-up is needed, however, before any firm conclusions can be drawn

    Hepatobiliary disease resection in patients with advanced epithelial ovarian cancer: prognostic role and optimal cytoreduction

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    Objective: The purpose of this study was to evaluate the feasibility and safety in terms of prognostic significance and perioperative morbidity and mortality of cytoreduction in patients affected by advance ovarian cancer and hepato-biliary metastasis. Methods: Patients with a least one hepatobiliary metastasis who have undergone surgical treatment with curative intent of were considered for the study. Perioperative complications were evaluated and graded with Accordion severity Classification. Five-year PFS and OS were estimated using the Kaplan–Meier curve. Results: Sixty-seven (20.9%) patients had at least one metastasis to the liver, biliary tract, or porta hepatis. Forty-four (65.7%) and 23 (34.3%) patients underwent respectively high and intermediate complexity surgery according. Complete cytoreduction was achieved in 48 (71.6%) patients with hepato-biliary disease. In two patients (2.9%) severe complications related to hepatobiliary surgery were reported. The median PFS for the patients with hepato-biliary involvement (RT = 0 vs. RT > 0) was 19 months [95% confidence interval (CI) 16.2–21.8] and 8 months (95% CI 6.1–9.9). The median OS for the patients with hepato-biliary involvement (RT = 0 vs. RT > 0) 45 months (95% CI 21.2–68.8 months) and 23 months (95% CI 13.9–32.03). Conclusions: Hepatobiliary involvement is often associated with high tumor load and could require high complex multivisceral surgery. In selected patients complete cytoreduction could offer survival benefits. Morbidity related to hepatobiliary procedures is acceptable. Careful evaluation of patients and multidisciplinary approach in referral centers is mandatory

    HDL cholesterol protects from liver injury in mice with intestinal specific LXRα activation

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    Background and aims: Liver X receptors (LXRs) exert anti-inflammatory effects even though their hepatic activation is associated with hypertriglyceridemia and hepatic steatosis. Selective induction of LXRs in the gut might provide protective signal(s) in the aberrant wound healing response that induces fibrosis during chronic liver injury, without hypertriglyceridemic and steatogenic effects. Methods: Mice with intestinal constitutive LXRα activation (iVP16-LXRα) were exposed to intraperitoneal injection of carbon tetrachloride (CCl4) for 8 weeks, and in vitro cell models were used to evaluate the beneficial effect of high-density lipoproteins (HDL). Results: After CCl4 treatment, the iVP16-LXRα phenotype showed reduced M1 macrophage infiltration, increased expression M2 macrophage markers, and lower expression of hepatic pro-inflammatory genes. This anti-inflammatory effect in the liver was also associated with decreased expression of hepatic oxidative stress genes and reduced expression of fibrosis markers. iVP16-LXRα exhibited increased reverse cholesterol transport in the gut by ABCA1 expression and consequent enhancement of the levels of circulating HDL and their receptor SRB1 in the liver. No hepatic steatosis development was observed in iVP16-LXRα. In vitro, HDL induced a shift from M1 to M2 phenotype of LPS-stimulated Kupffer cells, decreased TNFα-induced oxidative stress in hepatocytes and reduced NF-kB activity in both cells. SRB1 silencing reduced TNFα gene expression in LPS-stimulated KCs, and NOX-1 and IL-6 in HepG2. Conclusions: Intestinal activation of LXRα modulates hepatic response to injury by increasing circulating HDL levels and SRB1 expression in the liver, thus suggesting this circuit as potential actionable pathway for therapy

    Covid-19 infection in children, infants and pregnant subjects: An overview of recent insights and therapies

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    Background: The SARS-CoV-2 pandemic has involved a severe increase of cases worldwide in a wide range of populations. The aim of the present investigation was to evaluate recent insights about COVID-19 infection in children, infants and pregnant subjects. Methods: a literature overview was performed including clinical trials, in vitro studies, reviews and published guidelines regarding the present paper topic. A descriptive synthesis was performed to evaluate recent insights and the effectiveness of therapies for SARS-CoV-2 infection in children, infants and pregnant subjects. Results: Insufficient data are available regarding the relationship between COVID-19 and the clinical risk of spontaneous abortion and premature foetus death. A decrease in the incidence of COVID-19 could be correlated to a minor expression of ACE2 in childrens’ lungs. At present, a modulation of the dose-effect posology for children and infants is necessary. Conclusions: Pregnant vertical transmission has been hypothesised for SARS-CoV-2 infection. Vaccines are necessary to achieve mass immunity for children and also pregnant subjects
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