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Background: Major postoperative morbidity after laparoscopic sleeve gastrectomy (LSG) is often related to staple line leaks (SLL). Of note, a recent study suggested a central role of the absolute numbers of stapler firings as a predictive factor for postoperative morbidity due to SLL. In addition, a larger gastric remnant volume could be responsible for lower weight loss after LSG, and nevertheless, the gastric resection volume (GRV) is strictly related to the residual volume. Methods: Prospectively, collected data of 384 consecutive patients with complete follow-up at 12 months after LSG at our institution were retrospectively analyzed. Patients were stratified according to three different variables (i.e., number of stapler firings, GRV, and GRV/stapler firings-ratio), and respective impact on postoperative complications and weight loss was analyzed. Results: High absolute number of stapler firings was linked to increased intraoperative and postoperative bleeding and prolonged hospitalization, but was not associated with SLL, transfusion rate or revisional procedures. Absolute GRV showed no impact on both complications and outcome after LSG. Interestingly, higher ratio of GRV/stapler firings was not only linked to decreased intraoperative bleeding and shorter hospital stay but also to higher Excess Body Mass Index Loss (EBMIL) at 12 months after LSG. Conclusions: Here, we introduce GRV/stapler firings-ratio as a simple predictive factor for identifying patients at risk for postoperative complications and impaired weight loss that is superior compared with absolute number of stapler firings or GRV alone. [ABSTRACT FROM AUTHOR]

Structural design of unreinforced masonry buildings in The Netherlands, recently exposed to low-intensity ground motions induced by gas extraction, was not originally conceived for earthquake-resistance. Indeed, the presence of both large openings and flexible diaphragms, and the lack of any specific seismic consideration or detailing significantly increase their vulnerability towards horizontal loading. In this paper, the Applied Element Method (AEM), which explicitly represents the discrete nature of masonry, is used to simulate the shake-table response of a full-scale building specimen representative of a typical Dutch detached house made of unreinforced solid clay-brick masonry. Using this modelling strategy, the damage evolution, as well as both global failure mode and hysteretic behaviour, are described. The results show a good agreement with the experimentally observed response, confirming the capabilities of the AEM in reproducing effectively the behaviour of masonry structures, whilst simultaneously keeping computational costs within acceptable limits for this type of detailed modelling. [ABSTRACT FROM AUTHOR]

Based on the outcomes of a recent experimental project addressing unreinforced stone masonry undertaken at the European Centre for Training and Research in Earthquake Engineering, the seismic response exhibited by two full-scale building prototypes during shaking table tests was simulated according to an existing equivalent frame modeling approach involving nonlinear macroelements. Given the use of different strengthening solutions, the two building specimens strongly differed in the in-plane stiffness of their timber floors and roof diaphragms. This article addresses several issues concerning numerical modeling of the seismic response of this type of masonry construction, particularly its effect upon assessing the global response of the discretization and geometry of the equivalent frame model and upon definition of model parameters based on tests of material characteristics and lateral response of structural members. Even in the case of flexible diaphragms, the results of pushover analysis of the calibrated models provided a fair approximation in terms of both envelope curve and damage pattern. The results of time history analysis accounting for cumulative damage indicate good simulation in terms of hysteretic response as well. [ABSTRACT FROM PUBLISHER]

Masonry walls constructed with lightweight AAC blocks and thinlayer mortar meet the increasingly strict requirements of energy efficiency and sustainability. In this sense, they represent an excellent solution for modern buildings, not only for external cladding but also as loadbearing elements. Despite the possible advantages of using lightweight AAC masonry, a specific assessment of its seismic performance is mandatory in order to set design recommendations allowing to reach safety levels consistent with those required for other masonry types complying with EN 1998 standard requirements. A comprehensive study on the seismic performance of unreinforced masonry buildings made of lightweight AAC was carried out in an integrated experimental-numerical approach. The experimental campaign provided the necessary information to setup a reliable numerical model to be extensively used to assess the seismic performance of a number of prototype AAC masonry buildings with different characteristics, by means of both linear and nonlinear static (pushover) analysis. The results of this systematic numerical assessment were eventually used to draft design recommendations, to set parameters (behaviour factors) to be used in linear analysis and to calibrate rules for simple buildings. [ABSTRACT FROM AUTHOR]

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An extensive experimental campaign has been conducted at EUCENTRE to understand the dynamic behavior of historic stone masonry structures and evaluate the seismic performance of selected strengthening strategies, aimed at improving wall-to-floor connections and in-plane diaphragm stiffness. Shaking table tests were performed of full-scale two-storey buildings in undressed double-leaf stone masonry with timber floor and roof. A first prototype (Building 1), representing a vulnerable building without antiseismic detailing and devices, was tested showing a response characterized by in-plane distortion of the flexible diaphragms and local out-of-plane failure mechanisms. In Building 2 the wall-to-diaphragm connections were improved, providing only a moderate in-plane stiffening of the wooden diaphragms. When subjected to shake-table testing, the strengthened building showed a global type of structural response without the occurrence of out-of-plane mechanisms. In the present paper the strengthening interventions on Building 2 are described, and the results obtained during the dynamic tests are illustrated, focusing on the response of the structure, the evolution of damage mechanisms during the tests, in comparison to the seismic performance of the first unstrengthened reference prototype response. The improvement of the connections proved to be very effective, increasing significantly the seismic capacity of Building 2 with respect to Building 1. [ABSTRACT FROM PUBLISHER]