3,486 research outputs found
Laparoscopic peritoneal lavage. Our experience and review of the literature
NTRODUCTION:
Over the years various therapeutic techniques for diverticulitis have been developed. Laparoscopic peritoneal lavage (LPL) appears to be a safe and useful treatment, and it could be an effective alternative to colonic resection in emergency surgery.
AIM:
This prospective observational study aims to assess the safety and benefits of laparoscopic peritoneal lavage in perforated sigmoid diverticulitis.
MATERIAL AND METHODS:
We surgically treated 70 patients urgently for complicated sigmoid diverticulitis. Thirty-two (45.7%) patients underwent resection of the sigmoid colon and creation of a colostomy (Hartmann technique); 21 (30%) patients underwent peritoneal laparoscopic lavage; 4 (5.7%) patients underwent colostomy by the Mikulicz technique; and the remaining 13 (18.6%) patients underwent resection of the sigmoid colon and creation of a colorectal anastomosis with a protective ileostomy.
RESULTS:
The 66 patients examined were divided into 3 groups: 32 patients were treated with urgent surgery according to the Hartmann procedure; 13 patients were treated with resection and colorectal anastomosis; 21 patients were treated urgently with laparoscopic peritoneal lavage. We had no intraoperative complications. The overall mortality was 4.3% (3 patients). In the LPL group the morbidity rate was 33.3%.
CONCLUSIONS:
Currently it cannot be said that LPL is better in terms of mortality and morbidity than colonic resection. These data may, however, be proven wrong by greater attention in the selection of patients to undergo laparoscopic peritoneal lavage
Instance segmentation of standing dead trees in dense forest from aerial imagery using deep learning
"© 2022 The Author(s). Published by Elsevier B.V. on behalf of International Society of Photogrammetry and Remote Sensing (isprs). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)"Mapping standing dead trees, especially, in natural forests is very important for evaluation of the forest's health status, and its capability for storing Carbon, and the conservation of biodiversity. Apparently, natural forests have larger areas which renders the classical field surveying method very challenging, time-consuming, labor-intensive, and unsustainable. Thus, for effective forest management, there is the need for an automated approach that would be cost-effective. With the advent of Machine Learning, Deep Learning has proven to successfully achieve excellent results. This study presents an adjusted Mask R-CNN Deep Learning approach for detecting and segmenting standing dead trees in a mixed dense forest from CIR aerial imagery using a limited (195 images) training dataset. First, transfer learning is considered coupled with the image augmentation technique to leverage the limitation of training datasets. Then, we strategically selected hyperparameters to suit appropriately our model's architecture that fits well with our type of data (dead trees in images). Finally, to assess the generalization capability of our model's performance, a test dataset that was not confronted to the deep neural network was used for comprehensive evaluation. Our model recorded promising results reaching a mean average precision, average recall, and average F1-Score of 0.85, 0.88, and 0.87 respectively, despite our relatively low resolution (20 cm) dataset. Consequently, our model could be used for automation in standing dead tree detection and segmentation for enhanced forest management. This is equally significant for biodiversity conservation, and forest Carbon storage estimation.publishedVersio
A semi-anaytical model for the analysis of a Permanent Magnet Tubular Linear Generator
In this paper the authors introduce a semi-analytical model for the analysis and the design of a Permanent Magnet (PM) tubular linear generator intended for electrical energy generation from sea waves. The translator of the analyzed machine is constituted by axially magnetized ferrite PMs with alternating polarity and soft-magnetic pole-pieces in between; a two poles, double layer three-phase winding is located in the slots of the stator. The presented model, based on use of the Carter coefficient and of the Fourier transform in the direction of the motion, is able to take into account the end effects due to the finite length of the stator. The presence of slots and teeth is subsequently considered by some post processing calculation carried on the results of the semi-analytical model. Comparison with a Finite Element analysis and with measurements taken on a prototype has been performed to validate the presented model. The model can be easily extended to other translator typologies, e.g. to air core translator with Halbach array of NdFeB PMs
Mechanical Ventricular Assistance as Destination Therapy for End-Stage Heart Failure: Has it Become a First Line Therapy?
Patients with end-stage heart failure have poor quality of life and prognosis.Therapeutic options are scarce and not available for all:only few patients can be transplanted and several medical and surgical strategies have shown limited ability to influence prognosis and quality of life. In the past years, technological progress has realized devices capable of providing appropriate hemodynamic stabilization and recovery of secondary organ failure.In the recent years,these devices are assessed and discussed as definitive treatment for patients who do not qualify for transplantation or/and instead to transplantation (destination therapy).This indication is increasingly considered following the results of newest clinical study reporting long-term survival without device correlated adverse events using last generation devices, and acceptable quality of life.The current knowledge about Destination Therapy and some original data from the DAVID Study (an Italian multicenter prospective study designed to evaluate the patient’s survival rate and quality of life of patients implanted with these new devices as long-term support or destination therapy) are summarized
EMALS optimal design
A semi-analytical model of the Double Sided Tubular Linear Induction Motor (DSTLIM) is adopted for the optimization of the thrust force of the stages of an ElectroMagnetic Aircraft Launch System (EMALS). The model allows a fast and accurate prediction of all the electromagnetic quantities in the device, including the thrust force, the back-electromotive force, the distribution of the induced current and the average magnetic flux density in the teeth. This provides a basis for the design which has been performed by a novel evolutionary optimization algorithm. By using the semi-analytical formulation, the characterization of the machine is greatly facilitated so allowing a fast evaluation of the cost function and of the design constraints
KEMTUB012-NI2, a novel potent tubulysin analog that selectively targets hypoxic cancer cells and is potentiated by cytochrome p450 reductase downregulation
Peer reviewedPublisher PD
Electromechanical Numerical Analysis of an Air-Core Pulsed Alternator via Equivalent Network Formulation
In this paper, the numerical analysis on an air-core pulsed alternator is presented. Since compulsators are characterized by very fast electromechanical transients, their accurate analysis requires strong coupling between the equations governing the electrical and the mechanical behaviors. The device is investigated by using a dedicated numerical code capable to take into account eddy currents, compensating windings, as well as the excitation/control circuits. Furthermore, the code is capable of modeling centrifugal forces and vibrations acting on the shaft due to electric and mechanical unbalances or to misalignments of the shaft from its centered position. This makes the code a very powerful tool during the design phase. Examples of application of the code to machines with nonuniform compensating shield and with shorted compensating windings are shown
CFD MODELING OF SOLAR COLLECTOR WITH NANO-FLUID DIRECT ABSORPTION FOR CIVIL APPLICATION
Direct solar absorption has been considered often in the past as a possible configuration of solar thermal collectors for residential and small commercial applications. Of course, a direct absorption could improve the performance of solar collectors by skipping one step of the heat transfer mechanism of standard devices and by modifying the temperature distribution inside the collector. In fact, classical solar thermal collectors have a metal sheet as absorber, designed such that water has the minimum temperature in each transversal section, in order to collect as much as possible the solar thermal energy. On the other hand, in a direct configuration, the hottest part of the system is the operating fluid and this allows to have a more efficient conversion. Nanofluids, i.e. fluids with a suspension of nano-particles, as carbon nano-horns, could be a good and innovative family of absorbing fluids, for their higher absorption coefficient with respect to the base fluid and stability under moderate temperature gradients. Moreover, carbon nanohorns offer the significant advantage to be non-toxic unlike other carbon nanoparticles (e.g. carbon nanotubes). In this work, an original 3D model of the absorption phenomena in nano-fluids flowing in a cylindrical tube is coupled with a CFD analysis of the flow and temperature field. Recent measurements of the optical properties of nano-fluids with different concentrations have been used for the radiation heat transfer modeling and included in the fluid dynamic modeling as well. Heat losses due to conduction, convection and radiation at the boundaries are included in the model. The results are compared with the typical performance of flat solar collectors present on the marke
DINSAR ANALYSIS REVEALS BULGING OF AZERBAIJAN MUD VOLCANO EDIFICES BEFORE AN ERUPTION
Mud volcanism consists in the surface extrusion of gases, saline waters and mud breccias, which produce conical edifices of various sizes with morphology similar to that of magmatic volcanoes. In this work, DInSAR technique has been used to investigate the ground deformation related to the activity of Azerbaijan mud volcanoes during the period October 2003-November 2005. This work focuses on two important deformation events at the Ayaz-Akhtarma and Khara-Zira mud volcanoes. The ground deformations at mud volcanoes are generally originated by fluid pressure and volume variations in the reservoir. The observed deformation pattern is characterized by pre-eruptive inflation that reaches a cumulative value of up to 20 cm at Ayaz-Akhtarma in about two years. Similar pre-eruptive bulging has been observed at magmatic volcanoes, where uplift is typically associated with magma intrusion. We conclude that mud and magmatic volcanoes display some similarities in the behavior of ground deformation during pre-eruptive stages
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