7,329 research outputs found
Single-center experience in the treatment of visceral artery aneurysms
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
Effects of ambient temperature, humidity, and other meteorological variables on hospital admissions for angina pectoris.
BACKGROUND:
Seasonal peaks in cardiovascular disease incidence have been widely reported, suggesting weather has a role.
DESIGN:
The aim of our study was to determine the influence of climatic variables on angina pectoris hospital admissions.
METHODS:
We correlated the daily number of angina cases admitted to a western Sicilian hospital over a period of 12 years and local weather conditions (temperature, humidity, wind force and direction, precipitation, sunny hours and atmospheric pressure) on a day-to-day basis. A total of 2459 consecutive patients were admitted over the period 1987-1998 (1562 men, 867 women; M/F - 1:8).
RESULTS:
A seasonal variation was found with a noticeable winter peak. The results of Multivariate Poisson analysis showed a significant association between the daily number of angina hospital admission, temperature, and humidity. Significant incidence relative ratios (95% confidence intervals/measure unit) were, in males, 0.988 (0.980-0.996) (p = 0.004) for minimal temperature, 0.990 (0.984-0.996) (p = 0.001) for maximal humidity, and 1.002 (1.000-1.004) (p = 0.045) for minimal humidity. The corresponding values in females were 0.973 (0.951-0.995) (p < 0.017) for maximal temperature and 1.024 (1.001-1.048) (p = 0.037) for minimal temperature.
CONCLUSIONS:
Environmental temperature and humidity may play an important role in the pathogenesis of angina, although it seems different according to the gender. These data may help to understand the mechanisms that trigger ischemic events and to better organize hospital assistance throughout the year
Nellix endovascular aortic sealing endoprosthesis late explantation for concomitant type I endoleak and stent frames proximal caudal migration
Endovascular aneurysm sealing (EVAS) using the Nellix™ System was introduced in clinical practice with the aim of reducing the incidence of complications such as migration, endoleaks, and reinterventions after conventional endovascular aneurysm repair (EVAR). Although, initial efficacy data on this device have been encouraging, EVAS has also demonstrated to undergo adverse events. Herein, we report a case of Nellix graft explant due to endobags shrinkage after air bubble reabsorption leading to proximal type I A endoleak and stent migration. The focus of this article is on the importance of a more assiduous surveillance of this new device, in particular in those cases with air into the endobags immediately after the procedure; this surveillance should be aimed to timely identify complications which can otherwise lead to consequences that require open conversion
Sistema de alerta da ferrugem do cafeeiro.
RESUMO: Este trabalho apresenta um sistema de alerta Web para a ferrugem do cafeeiro, demonstrando suas funcionalidades e características. O sistema incorpora modelos para predizer se a taxa de progresso da ferrugem será maior ou igual a 5 ou 10 pontos percentuais em relação ao mês anterior. A modelagem utilizou dados meteorológicos e de cultura fornecidos pela Fundação Procafé e coletados nas cidades de Boa Esperança, Carmo de Minas e Varginha, em Minas Gerais. Dados similares são utilizados para a predição. A emissão de alerta positivo ou negativo é obtida através de um sistema de votação entre as saídas dos modelos. Caso a maioria indique aumento na taxa de progresso superior ao valor estipulado, o alerta é positivo; caso contrário, é negativo. O intuito do sistema é auxiliar na elaboração de boletins mensais de avisos fitossanitários distribuídos aos cafeicultores e demais interessados na cultura do café, com informações úteis para o controle da ferrugem, procurando indicar os momentos oportunos para a aplicação de fungicidas
Sistema de alerta da ferrugem do cafeeiro: resultado de um processo de mineração de dados.
Resumo. Este artigo apresenta o sistema de alerta de doença de plantas desenvolvido para realizar a predição da taxa de progresso da ferrugem do cafeeiro, que utiliza modelos preditivos criados a partir de dados meteorológicos e da cultura, fornecidos pela Fundação Procafé. O sistema de alerta desenvolvido visa auxiliar, através do resultado da predição, o técnico da Fundação Procafé a elaborar boletins mensais de recomendação de tomada de decisão no controle da ferrugem do cafeeiro.SBIAgro 2013
Single-Crystal Organic Charge-Transfer Interfaces probed using Schottky-Gated Heterostructures
Organic semiconductors based on small conjugated molecules generally behave
as insulators when undoped, but the hetero-interfaces of two such materials can
show electrical conductivity as large as in a metal. Although charge transfer
is commonly invoked to explain the phenomenon, the details of the process and
the nature of the interfacial charge carriers remain largely unexplored. Here
we use Schottky-gated heterostructures to probe the conducting layer at the
interface between rubrene and PDIF-CN2 single crystals. Gate-modulated
conductivity measurements demonstrate that interfacial transport is due to
electrons, whose mobility exhibits band-like behavior from room temperature to
~ 150 K, and remains as high as ~ 1 cm2V-1s-1 at 30 K for the best devices. The
electron density decreases linearly with decreasing temperature, an observation
that can be explained quantitatively based on the heterostructure band diagram.
These results elucidate the electronic structure of rubrene-PDIF-CN2 interfaces
and show the potential of Schottky-gated organic heterostructures for the
investigation of transport in molecular semiconductors.Comment: 37 pages, 9 Figures (including supplementary information
Very low bias stress in n-type organic single crystal transistors
Bias stress effects in n-channel organic field-effect transistors (OFETs) are
investigated using PDIF-CN2 single-crystal devices with Cytop gate dielectric,
both under vacuum and in ambient. We find that the amount of bias stress is
very small as compared to all (p-channel) OFETs reported in the literature.
Stressing the PDIF-CN2 devices by applying 80 V to the gate for up to a week
results in a decrease of the source drain current of only ~1% under vacuum and
~10% in air. This remarkable stability of the devices leads to characteristic
time constants, extracted by fitting the data with a stretched exponential -
that are \tau ~ 2\cdot10^9 s in air and \tau ~ 5\cdot10^9 s in vacuum -
approximately two orders of magnitude larger than the best values reported
previously for p-channel OFETs.Comment: Submitted to Applied Physics Letters; 14 pages, 3 figure
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