578 research outputs found

    The Team Orienteering Problem with Overlaps : An Application in Cash Logistics

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    The team orienteering problem (TOP) aims at finding a set of routes subject to maximum route duration constraints that maximize the total collected profit from a set of customers. Motivated by a real-life automated teller machine cash replenishment problem that seeks for routes maximizing the number of bank account holders having access to cash withdrawal, we investigate a generalization of the TOP that we call the team orienteering problem with overlaps (TOPO). For this problem, the sum of individual profits may overestimate the real profit. We present exact solution methods based on column generation and a metaheuristic based on large neighborhood search to solve the TOPO. An extensive computational analysis shows that the proposed solution methods can efficiently solve synthetic and real-life TOPO instances. Moreover, the proposed methods are competitive with the best algorithms from the literature for the TOP. In particular, the exact methods can find the optimal solution of 371 of the 387 benchmark TOP instances, 33 of which are closed for the first time

    Improving Rigid 3-D Calibration for Robotic Surgery

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    Autonomy is the next frontier of research in robotic surgery and its aim is to improve the quality of surgical procedures in the next future. One fundamental requirement for autonomy is advanced perception capability through vision sensors. In this article, we propose a novel calibration technique for a surgical scenario with a da Vinci Research Kit (dVRK) robot. Camera and robotic arms calibration are necessary to precise position and emulate expert surgeon. The novel calibration technique is tailored for RGB-D cameras. Different tests performed on relevant use cases prove that we significantly improve precision and accuracy with respect to state of the art solutions for similar devices on a surgical-size setups. Moreover, our calibration method can be easily extended to standard surgical endoscope used in real surgical scenario

    Proteostasis Regulators in Cystic Fibrosis: Current Development and Future Perspectives

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    In cystic fibrosis (CF), the deletion of phenylalanine 508 (F508del) in the CF transmembrane conductance regulator (CFTR) leads to misfolding and premature degradation of the mutant protein. These defects can be targeted with pharmacological agents named potentiators and correctors. During the past years, several efforts have been devoted to develop and approve new effective molecules. However, their clinical use remains limited, as they fail to fully restore F508del-CFTR biological function. Indeed, the search for CFTR correctors with different and additive mechanisms has recently increased. Among them, drugs that modulate the CFTR proteostasis environment are particularly attractive to enhance therapy effectiveness further. This Perspective focuses on reviewing the recent progress in discovering CFTR proteostasis regulators, mainly describing the design, chemical structure, and structure-activity relationships. The opportunities, challenges, and future directions in this emerging and promising field of research are discussed, as well

    Response to measles, mumps and rubella (Mmr) vaccine in transfusion-dependent patients

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    Measles, mumps and rubella (MMR) still determine significant morbidity and mortality, although a highly effective vaccine is available. Postponing the MMR vaccination until 6 months after the last red blood cell (RBC) transfusion is recommended, but this delay is incompatible with chronic transfusions. The present study aimed at investigating the impact of blood transfusions on the immunogenicity of the MMR vaccine. In this observational study, a group of 45 transfusion-dependent (TD) patients was compared to 24 non-transfusion-dependent (NTD) patients. Immunity to measles was achieved in 35 (78%) TD and 21 (88%) NTD subjects (p = 0.7), to mumps in 36 (80%) TD and 21 (88%) NTD subjects (p = 0.99), and to rubella in 40 (89%) TD and 23 (96%) NTD subjects (p = 0.99). No significant difference was observed in the number of non-immune individuals or those with doubtful protection between the two groups (p > 0.05). The mean IgG value, assayed in 50 pre-storage leukoreduced RBC units, was 0.075 ± 0.064 mg/mL, ten times lower than the level assumed in blood units and considered detrimental to the immune response in TD patients. This work shows a favorable response to MMR vaccination in TD and NTDT patients and paves the way for further larger studies assessing the impact of chronic transfusions on vaccine response

    Amelioration of renal damage by administration of anti-thymocyte globulin to potential donors in a brain death rat model

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    Brain death (BD), a non-immunological factor of renal injury, triggers an inflammatory process causing pathological signs of cell death in the kidney, such as necrosis and apoptosis. Kidneys from brain dead donors show lower success rates than kidneys from living donors and one strategy to improve transplantation outcome is to precondition the donors. For the first time, anti-rat thymoglobulin (rATG) was administered in an experimental brain death animal model to evaluate if it could ameliorate histopathological damage and improve organ function. Animals were divided into three groups: V (n = 5) ventilated for 2 h; BD (n = 5) brain death and ventilated for 2 h; and BD+rATG (n = 5) brain death, ventilated for 2 h, rATG was administered during brain death (10 mg/kg). We observed lower creatinine levels in treatment groups (means): V, 0·88 ± 0·22 mg/dl; BD, 1·37 ± 0·07 mg/dl; and BD+rATG, 0·64 ± 0·02 mg/dl (BD versus BD+rATG, P < 0·001). In the BD group there appeared to be a marked increase of ATN, whereas ATN was decreased significantly in the rATG group (V, 2·25 ± 0·5 versus BD, 4·75 ± 0·5, P < 0·01; BD+rATG, 2·75 ± 0·5 versus BD 4·75 ± 0·5 P < 0·01). Gene expression was evaluated with reverse transcription–polymerase chain reaction; tumour necrosis factor (TNF)-α, interleukin (IL)-6, C3, CD86 showed no significant difference between groups. Increased IL-10 and decreased CCL2 in BD+rATG compared to BD (both cases P < 0·01). Myeloperoxidase was increased significantly after the brain death setting (V: 32 ± 7·5 versus BD: 129 ± 18). Findings suggest that rATG administered to potential donors may ameliorate renal damage caused by BD. These findings could contribute in the search for specific cytoprotective interventions to improve the quality and viability of transplanted organs.Facultad de Ciencias Médica

    Caratterizzazione geofisica dell'acquifero idrotermale dell'area di Panza (Ischia)

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    Gli obiettivi di questo lavoro sono quelli di ricostruire, con metodologie geofisiche integrate, le principali geometrie tettoniche ed idrogeologiche del territorio di Panza nell’isola di Ischia. La zona è stata scelta in quanto caratterizzata da un’intensa attività idrotermale e deformativa connessa con la presenza di un reservoir geotermico

    Preconditioning donor with a combination of tacrolimus and rapamacyn to decrease ischaemia-reperfusion injury in a rat syngenic kidney transplantation model

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    Reperfusion injury remains one of the major problems in transplantation. Repair from ischaemic acute renal failure (ARF) involves stimulation of tubular epithelial cell proliferation. The aim of this exploratory study was to evaluate the effects of preconditioning donor animals with rapamycin and tacrolimus to prevent ischaemia–reperfusion (I/R) injury. Twelve hours before nephrectomy, the donor animals received immunosuppressive drugs. The animals were divided into four groups, as follows: group 1 control: no treatment; group 2: rapamycin (2 mg/kg); group 3 FK506 (0, 3 mg/kg); and group 4: FK506 (0, 3 mg/kg) plus rapamycin (2 mg/kg). The left kidney was removed and after 3 h of cold ischaemia, the graft was transplanted. Twenty-four hours after transplant, the kidney was recovered for histological analysis and cytokine expression. Preconditioning treatment with rapamycin or tacrolimus significantly reduced blood urea nitrogen and creatinine compared with control [blood urea nitrogen (BUN): P < 0·001 versus control and creatinine: P < 0·001 versus control]. A further decrease was observed when rapamycin was combined with tacrolimus. Acute tubular necrosis was decreased significantly in donors treated with immunosuppressants compared with the control group (P < 0·001 versus control). Moreover, the number of apoptotic nuclei in the control group was higher compared with the treated groups (P < 0·001 versus control). Surprisingly, only rapamycin preconditioning treatment increased anti-apoptotic Bcl2 levels (P < 0·001). Finally, inflammatory cytokines, such as tumour necrosis factor (TNF)-α and interleukin (IL)-6, showed lower levels in the graft of those animals that had been pretreated with rapamycin or tacrolimus. This exploratory study demonstrates that preconditioning donor animals with rapamycin or tacrolimus improves clinical outcomes and reduce necrosis and apoptosis in kidney I/R injury.Facultad de Ciencias MédicasComisión de Investigaciones Científicas de la provincia de Buenos Aire
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