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In this paper, the robust digital stabilization problem of nonlinear systems is investigated. In particular, a methodology for the design of robust quantized sampled-data stabilizers updated via an event-triggered mechanism is provided for time-varying control-affine nonlinear systems affected by actuation disturbances and measurement noises. The notion of time-varying steepest descent feedback (TSDF), continuous or not, and the Input-to-State Stability (ISS) redesign methodology are used for the development of the proposed robust event-based digital controller. Under the assumption that the actuation disturbances and measurement noises are bounded with a-priori known bounds and that the amplitude of the measurement noises satisfies a certain condition related to the new added robustification term, the following result is proved: there exist a suitably fast sampling and an accurate quantization of the input/output channels such that the digital implementation of robustified TSDF controllers, updated through a proposed event-triggered mechanism, ensures semi-global practical stability of the related closed-loop system regardless of the above uncertainties. In the methodology here proposed, time-varying sampling periods and the non-uniform quantization of the input/output channels are allowed. Moreover, the theory here developed includes the analysis of the intersampling system behaviour. Possible discontinuities in the function describing the TSDF at hand are also managed. The provided results are validated through a numerical example. [ABSTRACT FROM AUTHOR]

The diffusion of COVID-19 represents a real threat for the health and economic system of a country. Therefore the governments have to adopt fast containment measures in order to stop its spread and to prevent the related devastating consequences. In this paper, a technique is proposed to optimally design the lock-down and reopening policies so as to minimize an aggregate cost function accounting for the number of individuals that decease due to the spread of COVID-19. A constraint on the maximal number of concomitant infected patients is also taken into account in order to prevent the collapse of the health system. The optimal procedure is built on the basis of a simple SIR model that describes the outbreak of a generic disease, without attempting to accurately reproduce all the COVID-19 epidemic features. This modeling choice is motivated by the fact that the containing measurements are actuated during the very first period of the outbreak, when the characteristics of the new emergent disease are not known but timely containment actions are required. In fact, as a consequence of dealing with poor preliminary data, the simplest modeling choice is able to reduce unidentifiability problems. Further, the relative simplicity of this model allows to compute explicitly its solutions and to derive closed-form expressions for the maximum number of infected and for the steady-state value of deceased individuals. These expressions can be then used to design static optimization problems so to determine the (open-loop) optimal lock-down and reopening policies for early-stage epidemics accounting for both the health and economic costs. [ABSTRACT FROM AUTHOR]

The current coronavirus pandemic has produced severe consequences on economic and health systems all over the world, with the governments being challenged in searching for containment solutions balancing virus diffusion and limitations to social and work activities. In this paper, we propose a framework for the real-time optimization of restrictions in epidemics, based on the use of a time-varying SIRD model. Despite their simplicity, this class of models is able to capture the essential features of the epidemic spread, with the inherent parameter variation allowing accurate adaptation to real data. An optimization problem is formulated, properly balancing health and economic costs, and is solved parametrically by following a receding-horizon approach, resulting in an optimal sequence of social contact restrictions, which are assumed to be actuated via governmental containment measures. Numerical simulations based on the real data of the Italian COVID-19 emergency highlight the potential of the proposed approach and can be possibly helpful for the decision makers in present and future pandemics. [ABSTRACT FROM AUTHOR]

We focus on Taylor Series Methods (TSM) and Automatic Differentiation (AD) for the numerical solution of Ordinary Differential Equations (ODE) characterized by a vector field given by a finite composition of elementary and standard functions. We show that computational advantages are achieved if a kind of pre-processing said Exact Quadratization (EQ) is applied to the ODE before applying the TSM and the AD. In particular, when the ODE function is given by a formal polynomial (i.e. with real powers) of n variables and m monomials, the computational complexity required by our EQ based method for the calculation of the k -th order Taylor coefficient is O (k) whereas by using the existing AD methods it amounts to O (k 2). • The paper describes the QTSM method, and proves that it outperforms in terms of execution time the classic TSM method. • The capability of QTSM for more general nonlinear ODEs than formally polynomal ones, is discussed. • The paper illustrates, in a simulation example, that TSM correctly calculates the solution whereas lower order methods fails. • The paper illustrates the performance of QTSM vs TSM for the Kepler, and the Van der Pol ODEs. [ABSTRACT FROM AUTHOR]

This paper considers the smoothing problem for inhomogeneous Gauss–Markov Random Fields on a spherical lattice. Various observation models are considered, such as the case of noisy, possibly correlated, observations available only on a subset of sites, or a variable number of process components being measured. A 2D recursive optimal smoothing algorithm is derived, with computational complexity of O ( N 2 ) where N is the number of sites, in line with known more common algorithms for inhomogeneous fields on rectangular lattices. An application of the method in weather forecasting using real data is presented, showing the capability of the proposed method. [ABSTRACT FROM AUTHOR]

Background The Glasgow prognostic score (GPS) is an inflammation-based score based on albuminemia and C-reactive protein concentration proved to be associated with cancer-specific survival in several neoplasms. The present study explored the immediate postoperative value of the GPS for patients undergoing pneumonectomy for lung cancer. Methods The value of the GPS preoperatively was studied in 250 patients undergoing pneumonectomy for non-small cell lung cancer (NSCLC). We analyzed overall postoperative complications, pulmonary and cardiac complications, 30-day postoperative death, reoperation for early complications, intensive care unit (ICU) length of stay and total length of hospital stay. Results Patients with a GPS of 0 and 1 had a mean ICU length of stay of 0.8 days, whereas patients with a GPS of 2 had a mean ICU stay of 5.0 days ( p = 0.004). The postoperative mortality rate in patients with a GPS of 2 was much higher than in patients with a GPS of 1 and 2, although it was not statistically significant ( p = 0.083). Conclusions A preoperative GPS of 2 effectively predicts a prolonged ICU stay in patients who undergo pneumonectomy for cancer. The score may be proposed as an easy-to-determine, economical, and fast preoperative tool to plan and optimize ICU admissions after elective pneumonectomy. [ABSTRACT FROM AUTHOR]

Background Pulmonary artery (PA) reconstruction for lung cancer is technically feasible with low morbidity and mortality. We assessed our experience with partial or circumferential resection of the PA during lung resection. Methods Between 1998 and 2013, we performed PA angioplasty in 150 patients with lung cancer. Partial PA resection was performed in 146 patients. PA reconstruction was performed by running suture in 113 patients and by using a pericardial patch in 33. A circumferential PA resection was performed in 4 patients, and reconstruction was made with polytetrafluoroethylene and by a custom-made bovine pericardial conduit. Bronchial sleeve resection was associated in 56 patients. Stage I disease was present in 32 patients, stage II in 43, stage IIIA in 51, and stage IIIB in 17. Seventy-five patients received induction chemotherapy, and 7 patients had a complete response. Results Thirty-day mortality was 3.3% (n = 5); two of these patients died of a massive hemoptysis. Pulmonary complications occurred in 33 patients, cardiac in 28, and air leaks in 17. Overall 5-year and 10-year survival was 50% and 39%, respectively. Survival at 5 and 10 years for stages I and II vs stage III was, respectively, 66% vs 32% and 56% vs 20% ( p < 0.0001). Five-year survival was 61% for N0 and N1 nodal involvement vs 28% for N2, and the respective 10-year survival was 45% vs 28% ( p = 0.001). Induction chemotherapy did not influence survival. Multivariate analysis yielded advanced stage, N2 status, and squamous cell carcinoma as negative prognostic factors. Conclusions PA reconstruction is safe, with excellent long-term survival. Our results support this technique as an effective option to pneumonectomy for patients with lung cancer. [ABSTRACT FROM AUTHOR]

Abstract: This paper addresses the solution of large zero-sum matrix games using randomized methods. We formalize a procedure, termed as the sampled security policy (SSP) algorithm, by which a player can compute policies that, with a high confidence, are security policies against an adversary using randomized methods to explore the possible outcomes of the game. The SSP algorithm essentially consists of solving a stochastically sampled subgame that is much smaller than the original game. We also propose a randomized algorithm, termed as the sampled security value (SSV) algorithm, which computes a high-confidence security-level (i.e., worst-case outcome) for a given policy, which may or may not have been obtained using the SSP algorithm. For both the SSP and the SSV algorithms we provide results to determine how many samples are needed to guarantee a desired level of confidence. We start by providing results when the two players sample policies with the same distribution and subsequently extend these results to the case of mismatched distributions. We demonstrate the usefulness of these results in a hide-and-seek game that exhibits exponential complexity. [Copyright &y& Elsevier]

Background: Extended resections (ER) for lung cancer may improve survival in selected patients. However, analysis on large series is still lacking. We reviewed our experience to identify prognostic factors useful for patient selection. Methods: Between 1998 and 2010, 167 patients with involvement of one or more mediastinal organs underwent operations with the intent to perform ER. At thoracotomy, 42 patients (25%) were considered unresectable (explorative thoracotomy [ET]), and 125 (75%) underwent ER. The types of ER were superior vena cava in 43 patients (34.4%), carina in 33 (26.4%), combined with superior vena cava in 18 (14.4%), with the left atrium in 35 (28%), and with the aorta in 14 (11.2%). We excluded Pancoast tumors and vertebral resections. The minimum follow-up was 6 months. Kaplan-Meier method and log-rank test were used for statistical analysis of survival. Results: There were 136 men (81.4%), with mean age of 63 years (range, 36 to 81 years). Of the 167 patients, induction chemotherapy was administered in 119 (71.3%), including 34 ET patients (81%) and 85 ER patients (68%). Complete resection was achieved in 106 patients (84.8%). The overall 5-year survival was 23% (27% in ER and 13% in ET, p = 0.41). Overall 30-day mortality was 4.8% and morbidity was 34.1%. Factors affecting survival were complete resection (p < 0.01), pStage 0-I-II disease (p < 0.0007), and age younger than 60 years (p < 0.01). Conclusions: ER for lung cancer invading mediastinal organs could improve long-term survival (46% at 5-years in pN0). The best surgical candidates are young patients without lymph nodes involvement who undergo radical resection. Multimodality treatment is suggested in case of mediastinal lymph node involvement. [ABSTRACT FROM AUTHOR]

Background: Bronchoangioplastic interventions (BAIs) for lung cancer are challenging procedures associated with a high risk of postoperative morbidity and mortality. The role of induction chemotherapy (IC) in these patients is debated. Methods: We reviewed clinical records of patients who underwent a BAI between 1998 and 2009 using a prospective clinical and operative database. Results: Among 47 patients (39 men; mean age, 66 years) who underwent BAI, 26 (55.3%) received IC for N2 disease or for locally advanced lung cancer. We performed 35 pulmonary artery (PA) sleeve resections (31 partial and 4 circumferential), 10 PA reconstructions with a pericardial patch (8 autologous, and 2 heterologous), and 2 PA reconstructions using heterologous conduit. The 30-day mortality rate was 4.2% (n = 2). Morbidity occurred in 19 (40.4%) patients; 5 patients (10.6%) had major complications (3 [6.4%] patients with fatal bronchovascular fistulas and 1 patient each with cardiac dislocation and acute respiratory distress syndrome) (2.2%). Fourteen patients (29.8%) had minor complications: 6 (12.7%) cardiac, 7 (14.9%) pulmonary, and 1 (2.2%) stroke. IC did not influence the complication rate. Overall 5-year survival and disease-free survival was 39.2% and 36.9%, respectively. Early pathologic stage and the absence of nodal involvement significantly influenced survival (p = 0.005 and p = 0.002, respectively). Patients receiving IC had a better prognosis (62.7% versus 10.7%; p = 0.0003). At multivariate analysis, IC influenced long-term survival (p = 0.003 [95% CI, 2.92–8.56]). Conclusions: BAIs are feasible and effective surgical procedures with acceptable morbidity and mortality. IC does not influence morbidity and allows good long-term outcomes. [Copyright &y& Elsevier]

Background: Robotic lobectomy with radical lymph node dissection is a new frontier of minimally invasive thoracic surgery. Series of sublobar anatomic resection for primary initial lung cancers or for metastasis using video-assisted thoracic surgery have been reported but no cases have been so far reported using the robot-assisted approach. We present the technique and surgical outcome of our initial experience. Methods: Clinical data of patients undergoing robotic lung anatomic segmentectomy were retrospectively reviewed. All cases were done using the DaVinci System. A 3- or 4-incision strategy with a 3-cm utility incision in the anterior fourth or fifth intercostal space was performed. Individual ligation and division of the hilar structures was performed using Hem-o-Lok (Teleflex Medical, Research Triangle Park, NC) or endoscopic staplers. The parenchyma was transected with endovascular staplers introduced by the bedside assistant mainly through the utility incision. Systematic mediastinal lymph node dissection or sampling was performed. Results: From 2008 to 2010, 17 patients underwent a robot-assisted lung anatomic segmentectomy in two centers. There were 10 women and 7 men with a mean age of 68.2 years (range, 32 to 82). Mean duration of surgery was 189 minutes. There were no major intraoperative complications. Conversion to open procedure was never required. Postoperative morbidity rate was 17.6% with pneumonia in 1 case and prolonged air leaks in 2 patients. Median postoperative stay was 5 days (range, 2 to 14), and postoperative mortality was 0%. Final pathology was non-small cell lung cancer in 8 patient, typical carcinoids in 2, and lung metastases in 7. Conclusions: Robotic anatomic lung segmentectomy is feasible and safe procedure. Robotic system, by improving ergonomic, surgeon view and precise movements, may make minimally invasive segmentectomy easier to adopt and perform. [Copyright &y& Elsevier]

Background: Bilobectomy for lung cancer is considered a high-risk procedure for the increased postoperative complication rate and the negative impact on survival. We analyzed the safety and the oncologic results of this procedure. Methods: We retrospectively reviewed patients who underwent bilobectomy for lung cancer between October 1998 and August 2009. Age, gender, bilobectomy type and indication, complications, pathology, stage, and survival were analyzed. Results: Bilobectomy was performed on 146 patients (101 men; mean age, 62 years). There were 77 upper-middle and 69 middle-lower bilobectomies. Indications were tumor extending across the fissure in 27 (18.5%) patients, endobronchial tumor in 39 (26.7%), extrinsic tumor or nodal invasion of bronchus intermedius in 66 (45.2%), and vascular invasion in 14 (9.6%). An extended resection was performed in 24 patients (16.4%). Induction therapy was performed in 43 patients (29.4%). Thirty-day mortality was 1.4% (n = 2). Overall morbidity was 47.2%. Mean chest tube persistence was 7 days (range, 6 to 46 days). Overall 5-year survival was 58%. Significance differences in survival were observed among different stages (stage I, 70%; stage II, 55%; stage III, 40%; p = 0.0003) and the N status (N0, 69%; N1, 56%; N2, 40%; p = 0.0005). Extended procedure (p = 0.0003) and superior bilobectomy (p = 0.0008) adversely influenced survival. Multivariate analysis demonstrated that an extended resection (p = 0.01), an advanced N disease (p = 0.02), and an upper-mild lobectomy (p = 0.02) adversely affected prognosis. Conclusions: Bilobectomy is associated with a low mortality and an increased morbidity. Survival relates to disease stage and N factor. Optimal prognosis is obtained in patients with lower-middle lobectomy without extension of the resection. [ABSTRACT FROM AUTHOR]

Background: We describe preoperative computed tomography (CT)–guided injection of radiotracer technetium 99m macroaggregates (99mTc-MAA) in challenging small lung nodules, intraoperative localization, and resection. Methods: Between November 2007 and February 2010, 44 patients with 47 lung nodules which were detected incidentally or at screening and that were 18F-fluorodeoxyglucose positron emission tomography (18F FDG-PET) positive or increasing in size at subsequent CT scans were candidates for surgical biopsy. Inclusion criteria for preoperative percutaneous CT-guided (low-dose technique) 99mTc-MAA localization included having at least one of the following characteristics: nodule size less than 1 cm, subsolid morphology, or distance from the pleura greater than 1 cm. Results: Mean nodule size was 11 mm (range, 5 to 24 mm); 24 nodules were nonsolid, 15 nodules were partially solid, and 8 nodules had a solid morphology. Mean distance from the pleura was 11 mm (range, 0 to 35 mm). Localization complications included 13 minor asymptomatic pneumothoraces, 9 parenchymal hemorrhage suffusions, 1 mild allergic reaction to contrast medium, and 2 patients with chest pain after the procedure. Nine patients had mild extravasation of radiotracer into the pleura. In 2 cases, there was an extravasation of a significant quantity of radiotracer into the pleural cavity. Thoracoscopic biopsy was performed in 30 cases, 2 cases were converted to thoracotomy, and 12 patients underwent intentional thoracotomy. Conclusions: Asymptomatic subjects with suspicious nodules detected by screening or incidental CT are best candidates due to small lesion size and high percentage of nonsolid morphology, making thoracoscopic biopsy potentially difficult. Radiotracer localization is a safe, versatile, simple technique to help perform diagnosis with a minimally invasive approach in nonpalpable lung lesions. [ABSTRACT FROM AUTHOR]

Objectives: We investigated the feasibility and safety of four-arm robotic lung lobectomy in patients with lung cancer and described the robotic lobectomy technique with mediastinal lymph node dissection. Methods: Over 21 months, 54 patients underwent robotic lobectomy for early-stage lung cancer at our institute. We used a da Vinci Robotic System (Intuitive Surgical, Inc, Mountain View, Calif) with three ports plus one utility incision to isolate hilum elements and perform vascular and bronchial resection using standard endoscopic staplers. Standard mediastinal lymph node dissection was performed subsequently. Surgical outcomes were compared with those in 54 patients who underwent open surgery over the same period and were matched to the robotic group using propensity scores for a series of preoperative variables. Results: Conversion to open surgery was necessary in 7 (13%) cases. Postoperative complications (11/54, 20%, in each group) and median number of lymph nodes removed (17.5 robotic vs 17 open) were similar in the 2 groups. Median robotic operating time decreased by 43 minutes (P = .02) from first tertile (18 patients) to the second-plus-third tertile (36 patients). Median postoperative hospitalization was significantly shorter after robotic (excluding first tertile) than after open operations (4.5 days vs 6 days; P = .002). Conclusions: Robotic lobectomy with lymph node dissection is practicable, safe, and associated with shorter postoperative hospitalization than open surgery. From the number of lymph nodes removed it also appears oncologically acceptable for early lung cancer. Benefits in terms of postoperative pain, respiratory function, and quality of life still require evaluation. We expect that technologic developments will further simplify the robotic procedure. [Copyright &y& Elsevier]

Objective: Pneumonectomy is not always sufficient for the radical resection of cancer. In the present study, pneumonectomy may be associated with an extended resection of mediastinal or parietal structures. The postoperative risk and the oncologic benefits of such an extended procedure have not been sufficiently demonstrated. Methods: We have defined “extended” pneumonectomy (EP) as the removal of the entire lung, associated with one or more of the following structures: superior vena cava, tracheal carina, left atrium, aorta, chest wall, or diaphragm. Our clinical database was retrospectively reviewed to identify patients who underwent EP to assess their postoperative morbidity, mortality, and long-term survival. Results: Between 1998 and 2005, 47 EPs were performed. The “extended” procedure included left atrium resection in 15 patients, combined SVC and carinal resection in 9 patients, aortic resection in 8 patients (in 3 patients with prosthetic replacement), chest wall or diaphragmatic resection in 6 patients, SVC resection in 4 patients, and carinal resection in 4 patients. A partial esophageal muscular resection was performed in 1 patient. Overall 60-day mortality was 8.5%. Major postoperative complications occurred in 8 patients (17%). The 2- and 5-year survival rates for the overall population were 42% and 22.8%, respectively. Interestingly, long-term survivors were recorded only in the group of patients who received induction treatment. Conclusions: Extended pneumonectomy is a feasible procedure with an acceptable risk factor. To improve the selection of patients, all candidates should undergo preoperative mediastinoscopy and induction chemotherapy. In patients with positive response to chemotherapy or stable disease, extended pneumonectomy may afford a radical resection in more than 80% of cases and may result in a permanent cure in some instances. [Copyright &y& Elsevier]

Summary: Occasionally, breast cancer relapses in the subclavicular region. In patients with failed multimodal treatment, or in those who develop an isolated recurrence, surgical resection may be useful to remove all macroscopically evident diseases. However, the procedure may be technically demanding and there are no published data regarding its benefits. The aim of the present study was to evaluate the feasibility and safety of subclavicular resection in breast cancer and provide indications as to whether it can contribute to disease control. We used a transpectoral approach to surgically remove isolated breast cancer recurrence in the subclavicular region in seven consecutive patients presenting over 2 years; in the eighth case a transmanubrial approach was necessary. We found that the surgical approach proposed is feasible and safe, with a 75% rate of complete resection; however, the series was characterised by a high rate of local and distant relapse. We conclude that the technique may be useful, in selected cases, for palliation only. [Copyright &y& Elsevier]

Objective: The impact of induction chemotherapy on postoperative complications after pneumonectomy remains unclear. The aim of the study was to test the hypothesis that chemotherapy may increase the risk of postoperative respiratory complications. Methods: Data from 202 consecutive standard pneumonectomies performed for lung cancer were collected and analyzed. Postoperative and 90-day mortality, overall morbidity, and respiratory complication rates were evaluated in patients who had no induction treatment (group A, n = 103) as well as in those who received it (n = 99, group B). Preoperative chemotherapy was inserted as a variable together with 12 other variables (age, sex, smoking status, body mass index, previous cardiac event, American Society of Anesthesiologists score, preoperative forced expiratory volume in 1 second [percent], diffusion capacity for carbon monoxide adjusted for alveolar volume [percent], side of pneumonectomy, perfusion of the removed lung, operating time, and blood transfusion) into univariate and multivariate logistic regression. Results: No difference in terms of mortality was recorded between group A (4.9%) and group B (3%, P > .05). Respiratory complications were more frequent in group B than in group A (19 cases, 19.2%, vs 7 cases, 6.8%, P = .008). Univariate logistic regression has demonstrated that pulmonary complications were more frequent in patients over the age of 70 than in those aged 70 or less (25.7% vs 10.2, P = .02), in those with a lower diffusion capacity adjusted for alveolar volume (18.3% vs 5.95%, P = .06), and in patients who received preoperative chemotherapy (19.2% vs 6.8, P = .008). Logistic regression confirmed the role of age (odds ratio = 6.3), preoperative chemotherapy (odds ratio = 4.4), and diffusion capacity adjusted for alveolar volume (odds ratio = 0.33) as risk factors of respiratory complications. Conclusions: Standard pneumonectomy is a safe procedure even after induction chemotherapy, with a mortality rate in the order of 5%, but this increases in patients over the age of 70 years. In the case of induction chemotherapy, the risk of respiratory complications is significantly increased, apparently not affecting the overall mortality rate. [Copyright &y& Elsevier]

Background: The objective of the present study was to assess whether placing chest tubes on water seal after pulmonary lobectomy reduced the duration of air leak compared with suction.Methods: One hundred forty-five patients who underwent pulmonary lobectomy for lung cancer and with an air leak on the first postoperative day were prospectively randomly assigned to two groups: in group 1 (72 patients), chest tubes were placed on water seal on the morning of the first postoperative day; in group 2 (73 patients), chest tubes were on continuous suction (-20 cm H2O). Eighty percent of the patients who underwent upper lobectomy had also a pleural tent procedure. Preoperative, operative, and postoperative variables were compared between the groups.Results: The two groups were evenly matched for preoperative and operative characteristics. No statistically significant differences were found between group 1 and group 2 in terms of air leak duration (6.5 versus 6.3, respectively; p = 0.9) and the incidence of prolonged air leak cases (27.8% versus 30.1%, respectively; p = 0.8). Similar results were obtained when the analysis was corrected for the length of the stapled parenchyma and the site of resection (upper and lower resections) or restricted to patients with a forced expiratory volume in 1 second less than 80% of predicted. Water seal patients had increased postoperative complications compared with suction patients (31.9% versus 17.8%, respectively; p = 0.056).Conclusions: Chest tubes placed on water seal after pulmonary lobectomy were generally well tolerated and safe; however, they did not reduce the duration of air leak or the incidence of prolonged air leak compared with suction. [Copyright &y& Elsevier]

: BackgroundThe objective of this study was to identify the predictors of prolonged air leak (air leak longer than 7 days) in patients submitted to pulmonary lobectomy for lung cancer.: MethodsA retrospective analysis on 588 patients operated on of pulmonary lobectomy from January 1995 through June 2003 was performed. Univariate and logistic regression analyses were performed to generate a model predicting the risk of prolonged air leak. Bootstrap resampling technique was used to validate the regression model.: ResultsA prolonged leak was exhibited by 15.6% of patients. Logistic regression analysis demonstrated that significant independent predictors of prolonged air leak were a reduced predicted postoperative forced expiratory volume in 1 second (p < 0.0001), the presence of pleural adhesions (p = 0.003), and upper resections (p = 0.006). Bootstrap resampling analysis confirmed the reliability of these variables. A regression equation was generated for the prediction of the risk of prolonged air leak.: ConclusionsWe report that a low predicted postoperative forced expiratory volume in 1 second, the presence of pleural adhesions, and the upper lobectomy or bilobectomy increased the risk of air leak persisting for more than 7 days. A model was generated to calculate this risk and assist the surgeon in taking extra measures to prevent such complication (ie, optimizing bronchodilator treatment, pleural tent, sealants, buttressed staple lines, water seal, and chest tube drainage). [Copyright &y& Elsevier]

: BackgroundThe objective of this study was to identify the predictors of underestimation and overestimation of postoperative maximum oxygen consumption (V˙o2max).: MethodsA prospective analysis was performed on 229 patients who had 38 pneumonectomies, 171 lobectomies, and 20 segmentectomies. All patients performed a preoperative and postoperative (on average 9.2 days after surgery) maximal stair-climbing test. Predicted postoperative V˙o2max (ppoV˙o2max) was calculated on the basis of the number of functioning segments removed during operation. The patients were divided into three groups: group A (158 cases), patients with a ppoV˙o2max within 1 standard deviation of the observed postoperative V˙o2max; group B (56 cases), patients with a difference between the observed postoperative V˙o2max and ppoV˙o2max greater than 1 standard deviation (underestimation); and group C (15 cases), patients with a difference between ppoV˙o2max and the observed postoperative V˙o2max greater than 1 standard deviation (overestimation). Univariate and multivariate analyses were performed.: ResultsThe only significant predictor of underestimation was a high percentage of functional parenchyma removed during operation (p < 0.0001). The significant predictors of overestimation were a low percentage of functional parenchyma removed during operation (p = 0.01) and a high preoperative V˙o2max (p = 0.002).: ConclusionsThe prediction of postoperative V˙o2max was not accurate in all patients. Those with a large amount of functional lung tissue removed during operation tended to have a postoperative V˙o2max greater than expected. Conversely, those patients with a small amount of functional lung tissue resected tended to have a postoperative V˙o2max lower than predicted. [Copyright &y& Elsevier]

: BackgroundThe object of this study was to assess the efficay and maximum duration of effect of the pleural tent in reducing the incidence of air leak after upper lobectomy.: MethodsTwo hundred patients who underwent upper lobectomy were prospectively randomized into two groups: 100 patients who underwent an upper lobectomy and a pleural tent procedure (group 1; tented patients) and 100 patients who underwent only an upper lobectomy and not a pleural tent procedure (group 2; untented patients). The preoperative, operative, and postoperative characteristics of both groups were compared. Then multivariate analyses were used to identify factors predictive of prolonged air leaks and their duration. The reduction of incidences of air leak in the two groups was subsequently compared during successive postoperative periods.: ResultsNo differences were detected between the two groups in terms of preoperative and operative characteristics. A significant reduction occurred in group 1 patients for the mean duration of air leak in days (2.5 vs 7.2 days; p < 0001), the number of days a chest tube was required (7.0 vs 11.2 days; p < 0.0001), the length of postoperative hospital stay in days (8.2 vs 11.6 days; p < 0.0001), and the hospital stay cost per patient ($4,110 vs $5,805; p < 0.0001). Logistic regression analyses showed that not having undergone a pleural tent procedure was the most significant predictive factor of the occurrence and duration of prolonged air leaks. A greater reduction in the duration of air leaks was observed before postoperative day 4 in group 1, and logistic regression analysis showed that having undergone a pleural tent procedure was the most significant predictive factor of air leaks that persisted for less than 4 days.: ConclusionsPleural tenting after upper lobectomy was a safe procedure that reduced the duration of air leaks and the hospital stay costs. The benefit from that procedure was achieved before postoperative day 4. [Copyright &y& Elsevier]

In this paper, the stabilization problem of nonlinear time-delay systems in presence of known exogenous disturbances and by means of quantized sampled-data event-based controllers is investigated. In particular, nonlinear systems with state delays are studied. Known exogenous disturbances affecting the plant dynamics are considered in order to address, for instance, tracking control problems commonly studied by considering the stabilization problem of the corresponding tracking error system in which the chosen reference signal appears as a known exogenous signal. The stabilization in the sample-and-hold sense theory is used as a tool to provide sufficient conditions for the existence of a suitably fast sampling and of an accurate quantization of the input/output channels such that: the quantized sampled-data implementation of continuous-time controllers, updated through a proposed event-based mechanism, guarantees the semi-global practical stability property, with arbitrarily small final target ball of the origin, of the related closed-loop system. A spline approximation methodology is used in order to: (i) cope with the problem of the possible non-availability in the buffer of suitable past values of the system variables needed for the digital implementation of the controller; (ii) consider approximations related to the hardware implementation of the signal describing the known exogenous disturbance (e.g., the chosen reference signal). The provided results include the case of non-uniform quantization of the input/output channels and the case of aperiodic sampling. Applications are presented in order to validate the results, one of which concerning a single-link flexible joint robot arm with time delays. [ABSTRACT FROM AUTHOR]

Introduction: Breast cancer is the leading cause of cancer death among women in the industrialized countries. The incidence of local recurrences after mastectomy and breast-conserving therapy varies between 5% and 40% depending on risk factors and primary therapy.Methods: From April 1999 to April 2011, 40 patients underwent chest wall resection and reconstruction for locally recurrent breast carcinoma with chest wall invasion. The main goal of surgery was local disease control to palliate clinical symptoms.Results: Local radical resection was achieved in 26 patients (65%). One, 2 and 5 year overall survival rates were 94.4%, 82.0% and 68.5%; 1, 2 and 5 year disease-free survival rates were 94.4%, 73.6% and 45.5% respectively. Univariate analysis indicated age (p = 0.002) and synchronous distant metastases (p = 0.020) as factors having a negative impact on overall survival; multivariate analysis disclosed age (p = 0.052) and synchronous metastases (p = 0.059) as factors with a slight negative impact on overall survival. Older age was associated with improved overall survival. Univariate analysis indicated synchronous distant metastases (p = 0.029) and the need of post resectional additional treatments (p = 0.022) as factors adversely conditioning disease-free survival or time to progression; multivariate analysis disclosed the need of post resectional additional treatments (p = 0.036) as the only factor adversely conditioning disease-free survival or time to progression.Conclusions: Chest wall resection and reconstruction for locally recurrent breast cancer is a feasible and safe procedure providing adequate local disease control and an excellent palliation of very disabling symptoms in a selected group of patients. [ABSTRACT FROM AUTHOR]

Formal methods have been recently used as the basis of a systematic framework to address control design of continuous or hybrid systems with specifications expressed in a logic form. However, results available in the literature assume full information of the state, or of its quantization. This information may not be available in relevant applications. In this paper, we consider the more realistic scenario where the controller cannot access the state of the plant but can only access a quantized measurement of its outputs where nonidealities of the sensing devices can be modeled. We focus on a control problem where the plant is described by a possibly unstable continuous-time nonlinear control system, the controller is dynamic, digital and quantized, and takes as input a (quantized) measurement of the output of the plant, and the specification is expressed in terms of regular languages. The solution to the control problem is based on formal methods. A finite-state system, also called symbolic model approximating the plant is first derived and then used to find the solution to the control problem. An illustrative example is provided and the symbolic control of a car-like robot is presented. [ABSTRACT FROM AUTHOR]

Background: Prolonged air leak after pulmonary lobectomy is a common time- and cost-consuming complication. Its prevention may significantly reduce hospitalization length and costs offering patients a standard uneventful postoperative course. The aim of the present study is to identify predictors of prolonged postoperative air leak and to stratify preoperative risk factors. Methods: From July 2004 to December 2007 241 consecutive standard lobectomies were performed with curative intent for lung cancer. After excluding patients not fulfilling the inclusion criterion, 58 patients were enrolled in the "prolonged air leak" group and 63 patients were enrolled in the "standard outcome" group. Results: Total lung capacity (p=0.0038) and percentage emphysema (p=0.0050) calculated by computed tomography were both significantly related to prolonged postoperative air leak; the values of 4773cc and 0.4% showed the highest predictive value in terms of sensitivity (84.5% and 75.9% respectively). Multivariate logistic regression disclosed that male sex (p=0.0006), right side of operation (p=0.0010) and age (p=0.0082) were significantly related to prolonged postoperative air leak. Preoperative chemotherapy (p=0.0940) did not affect air leak status. Conclusions: Computed tomography quantification of emphysema is the best predictor of prolonged air leak. Age, male sex and right side lobectomy are correlated to this complication. Preoperative chemotherapy is not an additional risk factor. [ABSTRACT FROM AUTHOR]