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

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

From EIT photon correlations to Raman anti-correlations in coherently prepared Rb vapor

We have experimentally observed switching between photon-photon correlations (bunching) and anti-correlations (anti-bunching) between two orthogonally polarized laser beams in an EIT configuration in Rb vapor. The bunching and anti-bunching sswitching occurs at a specific magnetic field strength.Comment: 4 pages and 3 figure

The Pion Light-Cone Wave Function Phi_pi on the lattice: a partonic signal?

We determine the conditions required to study the pion light-cone wave function Phi_pi with a new method: a direct display of the partons constituting the pion. We present the preliminary results of a lattice computation of Phi_pi following this direction. An auxiliary scalar-quark is introduced. The spectroscopy of its bound states is studied. We observe some indications of a partonic behavior of the system of this scalar-quark and the anti-quark.Comment: 3 pages, 4 figures, Lattice2001(matrixelement

Cutoff for the East process

The East process is a 1D kinetically constrained interacting particle system, introduced in the physics literature in the early 90's to model liquid-glass transitions. Spectral gap estimates of Aldous and Diaconis in 2002 imply that its mixing time on $L$ sites has order $L$. We complement that result and show cutoff with an $O(\sqrt{L})$-window. The main ingredient is an analysis of the front of the process (its rightmost zero in the setup where zeros facilitate updates to their right). One expects the front to advance as a biased random walk, whose normal fluctuations would imply cutoff with an $O(\sqrt{L})$-window. The law of the process behind the front plays a crucial role: Blondel showed that it converges to an invariant measure $\nu$, on which very little is known. Here we obtain quantitative bounds on the speed of convergence to $\nu$, finding that it is exponentially fast. We then derive that the increments of the front behave as a stationary mixing sequence of random variables, and a Stein-method based argument of Bolthausen ('82) implies a CLT for the location of the front, yielding the cutoff result. Finally, we supplement these results by a study of analogous kinetically constrained models on trees, again establishing cutoff, yet this time with an $O(1)$-window.Comment: 33 pages, 2 figure

Quark propagator and vertex: systematic corrections of hypercubic artifacts from lattice simulations

This is the first part of a study of the quark propagator and the vertex function of the vector current on the lattice in the Landau gauge and using both Wilson-clover and overlap actions. In order to be able to identify lattice artifacts and to reach large momenta we use a range of lattice spacings. The lattice artifacts turn out to be exceedingly large in this study. We present a new and very efficient method to eliminate the hypercubic (anisotropy) artifacts based on a systematic expansion on hypercubic invariants which are not SO(4) invariant. A simpler version of this method has been used in previous works. This method is shown to be significantly more efficient than the popular ``democratic'' methods. It can of course be applied to the lattice simulations of many other physical quantities. The analysis indicates a hierarchy in the size of hypercubic artifacts: overlap larger than clover and propagator larger than vertex function. This pleads for the combined study of propagators and vertex functions via Ward identities.Comment: 14 pags., 9 fig

Orbital angular momentum exchange in an optical parametric oscillator

We present a study of orbital angular momentum transfer from pump to down-converted beams in a type-II Optical Parametric Oscillator. Cavity and anisotropy effects are investigated and demostrated to play a central role in the transverse mode dynamics. While the idler beam can oscillate in a Laguerre-Gauss mode, the crystal birefringence induces an astigmatic effect in the signal beam that prevents the resonance of such mode.Comment: 10 pages, 8 figures, regular articl

Experimental and theoretical study on bond behavior of GFRP bars in steel fiber reinforced self compacting concrete

To estimate the cracking and the deformational behavior of steel fiber reinforced selfcompacting concrete (SFRSCC) beams reinforced with glass fiber reinforced polymer (GFRP) bars, it is fundamental to understand the interfacial bond behavior of embedded bars. Hence, the evaluation of the bond behavior between GFRP and (SFRSCC) was investigated in this study. A closed-form formulation was derived, adopting a new local bond stress-slip relationship. Furthermore, an experimental program composed of pullout bending tests was carried out in order to assess the influence of the following parameters on the bond behavior: bar diameter, bar surface treatment, embedment length and SFRSCC cover thickness. Finally, a numerical simulation was performed with a FEM-based computer program in order to simulate the bond behavior between GFRP bar and SFRSCC by means of a non-linear bond-slip relationship assigned to the interface finite element. The predictive performance of the theoretical models was appraised by comparing experimental and numerical results

Experimental study on bond performance of GFRP bars in self-compacting steel fiber reinforced concrete

Reinforcing bars made of Glass-Fiber-Reinforced Polymers (GFRP) are more and more common as internal reinforcement of concrete structures and infrastructures. Since the design of GFRP reinforced concrete members is often controlled by serviceability limit state criteria (i.e., deflection or crack width control), an accurate knowledge of the GFRP-concrete bond behavior is needed to formulate sound design equations. Furthermore, bond laws currently available and widely accepted for conventional steel rebars cannot be straightforwardly applied for GFRP ones. Hence, an experimental program consisting of 36 pullout bending tests was carried out to evaluate the bond performance between GFRP bars and steel fiber reinforced self-compacting concrete (SFRSCC) by analyzing the influence of the following parameters: GFRP bar diameter, surface characteristics of the GFRP bars, bond length, and SFRSCC cover thickness. Based on the results obtained in this study, pullout failure was occurred for almost all the specimens. SFRSCC cover thickness and bond length plaid important role on the ultimate value of bond stress of GFRP bars. Moreover, the GFRP bars with ribbed and sand-coated surface treatment showed different interfacial bond behaviors.Fundação para a Ciência e a Tecnologia (FCT