1,659 research outputs found

    Outcomes in the emergency endovascular repair of blunt thoracic aortic injuries

    Get PDF
    Abstract Thoracic aorta blunt injury (BAI) is a highly lethal lesion. A large number of victims die before obtaining emergency care. Thoracic endovascular aneurysm repair (TEVAR) is a less invasive method compared with open surgery and may change protocols for BAI treatment. This retrospective study was developed to evaluate the potential issues about thoracic endografting in the management of these patients. Twenty-seven patients with a BAI underwent aortic stent grafting. Intervention was preceded by the treatment of more urgent associated lesions in nine cases. In-hospital mortality was 7.4%. No paraplegia or ischemic complications developed because of the coverage of the left subclavian artery. In one case (3.2%), a type I endoleak was detected, proximal endograft infolding in two cases (7.4%) and endograft distal migration in further two cases were detected during follow-up (6-110 months). Thoracic endovascular aneurysm repair of BAI showed encouraging results in terms of perioperative mortality and morbidity. Concerns still remain about the potential mid- and long-term complications in younger patients

    Single-center experience in the treatment of visceral artery aneurysms

    Get PDF
    Background: Visceral artery aneurysms (VAAs), although rare, represent a life-threatening disease with high mortality rates. With the more frequent use of diagnostic tests, there has been an incidental detection of these lesions which are mostly asymptomatic. It follows that surgeons are increasingly called to decide on the most appropriate management of VAAs between an open surgical or endovascular approach and among the different endovascular options currently available. The aim of this retrospective study was to evaluate the results of open surgery and interventional endovascular strategies of visceral artery aneurysms with respect to technical success, therapy-associated complications, and postinterventional follow-up in the elective and emergency situation. Methods: From January 1992 to January 2017, 125 open surgical or endovascular interventions for VAA were performed at our institution. Once the VAA was diagnosed and the indication for treatment was assessed, the preoperative diagnostic work-up consisted of contrast computed tomography (CT) or magnetic resonance imaging (MRI) and, in some patients, digital subtraction angiography. Follow-up included clinical and duplex ultrasound scan (DUS) and contrast-enhanced ultrasound to assess the treated vessel patency and organ perfusion after 1, 6, and 12 months, and yearly thereafter. CT or MRI controls were also performed at 1 year of follow-up and only when DUS was not diagnostic or showed a complication thereafter. After the first 5 years of follow-up, the status of the patient was obtained by a structured telephone survey. Results: The treatment option was endovascular in 56 of 125 cases (44.8%). Technical success was 98.3%. In one case, the procedure was interrupted for the extensive dissection of the afferent vessel. Twenty-six patients were treated by coil embolization while 29 with covered stenting. The endovascular approach was in emergency in two cases (3.6%). In the endovascular group, mortality was nil. Complications occurred in 5 cases (8.9%): 1 subacute intestinal ischemia caused by superior mesenteric artery dissection, 2 aneurysm reperfusion, 1 stent thrombosis, and 1 massive splenic hematoma. In 69 (55.2%) cases, surgical treatment was preferred, with 24 VAA resections and 45 arterial reconstructions. In 20 cases (29%), open surgery was performed in emergency conditions. In the surgical group, 8 emergency patients (40%) died intraoperatively. The mortality after elective surgical interventions was nil. Complications after surgery were 4 graft late thrombosis (5.8%): asymptomatic in three cases and requiring splenectomy in one. Conclusions: There is no overall consensus regarding the indications for treatment of VAA. Currently in emergent setting, the endovascular approach should be considered as the first choice because of its reduced invasiveness, faster way to access and bleeding control; this accounts for the lower morality of the interventional therapy than open surgery. Endovascular approach is effective for elective repair of VAAs, but procedure-related complications may occur in a not negligible number of patients. Given comparable mortality rates and low procedure-related complication rate, surgical approach still has space in the elective management of VAAs, especially for aneurysms unsuitable or challenging for the endovascular option in patients with low surgical risk. The size, location, and morphology of VAAs, systemic or local comorbidities, and specific anatomical situations such as previous abdominal surgery should dictate treatment choice

    Solar Heating in Commercial Buildings

    Get PDF
    Heating, ventilation, and air conditioning (HVAC) equipment accounts for 40% to 50% of a commercial building’s energy usage. This energy is supplied using either electricity or natural gas. Combustion products from natural gas pollute the environment and the burning of fossil fuels to produce electricity also pollutes the environment. The world must turn to clean, renewable energy resources to stop pollution. Solar energy has the potential to play a huge role in the renewable energy movement. Solar energy can be harnessed through active or passive solar techniques. Active solar uses solar collectors to harness the sun’s energy and passive solar uses heat transfer through architectural features to transfer the sun’s energy as heat. The exterior walls of commercial buildings are typically bare, plain walls. Why not use this space to harness solar energy for space heating? This report will analyze two identical commercial buildings, one in St. Louis, MO and one in Phoenix, AZ. Both buildings will have flat plate solar collectors installed on the south facing wall and the peaking heating demand will be compared to the amount of solar energy that can be harnessed at that time. The peak heating demands are calculated using Trace 700. It was found that on January 17th at 1:00 pm, the St. Louis system could harness 104.2kW of solar energy (33.2% of the heating demand) and the Phoenix system could harness 465.8 kW of energy (290.8% of the heating demand.) This proves that solar energy has the potential to play a huge role in the world of renewable energy, but the size of its impact is dependent upon location

    optical measurement techniques of recombination lifetime based on the free carriers absorption effect

    Get PDF
    We review successful measurement techniques for the evaluation of the recombination properties in semiconductor materials based on the optically induced free carrier absorption. All the methodologies presented share the common feature of exploiting a laser beam to excite electron-hole pairs within the volume of the sample under investigation, while the probing methods can vary according to the different methodology analyzed. As recombination properties are of paramount importance in determining the properties of semiconductor devices (i.e, bipolar transistor gain, power devices switching features, and solar cells efficiency), their knowledge allows for better understanding of experimental results and robust TCAD simulator calibration. Being contactless and applicable without any particular preparation of the sample under investigation, they have been considered attractive to monitor these parameters inline or just after production of many different semiconductor devices

    Role of Glycation in Amyloid: Effect on the Aggregation Process and Cytotoxicity

    Get PDF
    Although the aggregation process of amyloidogenic proteins has been widely studied in vitro and many physiological factors have been identified, the molecular mechanisms underlying the formation of aggregates in vivo and under pathological conditions are still poorly understood. Post‐translational modifications are known to affect protein structure and function. Some of these modifications might affect proteins in detrimental ways and lead to their misfolding and accumulation. Reducing sugars play an important role in modifying proteins, forming advanced glycation end‐products (AGEs) in a nonenzymatic process, called glycation. Recently, much attention has been devoted to the role played by glycation in stimulating amyloid aggregation and cellular toxicity. Proteins in amyloid deposits are often found glycated, suggesting a direct correlation between protein glycation and amyloidosis

    Mid- and Long-Term Results of Endovascular Treatment in Thoracic Aorta Blunt Trauma

    Get PDF
    Study Aim. Evaluation of results in blunt injury of the thoracic aorta (BAI) endovascular treatment. Materials and Methods. Sixteen patients were treated for BAI. Thirteen patients had associated polytrauma, 4 of these had a serious hypotensive status and 4 had an hemothorax. In the remaining 3, two had a post-traumatic false aneurysm of the isthmus and 1 had a segmental dissection. In those 13 patients a periaortic hematoma was associated to hemothorax in 4. All patients were submitted to an endovascular treatment, in two cases the subclavian artery ostium was intentionally covered. Results. One patient died for disseminated intravascular coagulation. No paraplegia was recorded. No ischemic complications were observed. A type I endoleak was treated by an adjunctive cuff. During the followup (1–9 years) 3 patients were lost. A good patency and no endoleaks were observed in all cases. One infolding and 1 migration of the endografts were corrected by an adjunctive cuff. Conclusion. The medium and long term results of the endovascular treatment of BAI are encouraging with a low incidence rate of mortality and complications. More suitable endo-suite and endografts could be a crucial point for the further improvement of these results

    Electrically induced Bragg Reflectors in In/InGaAsP waveguides as ultrafast optoelectronic modulators

    Get PDF
    In this paper, with the help of numerical simulations, we show how it is possible to create a Distributed Bragg Reflector by electrically inducing periodical refractive index variations in unperturbed III-V rib-waveguides to design different kind of devices. This approach allows to induce the optoelectronic devices by a suitable reconfiguration of the potential applied to the electrode matrix, i.e. to have a defined routing/switching matrix, or, for dynamic applications, realize intensity modulators, capable of reaching a theoretical 40 GHz switching speed
    • 

    corecore