Wing structure of the next-generation civil tiltrotor: From concept to preliminary design

The main objective of this paper is to describe a methodology to be applied in the preliminary design of a tiltrotor wing based on previously developed conceptual design methods. The reference vehicle is the Next-Generation Civil Tiltrotor Technology Demonstrator (NGCTR-TD) developed by Leonardo Helicopters within the Clean Sky research program framework. In a previous work by the authors, based on the specific requirements (i.e., dynamics, strength, buckling, functional), the first iteration of design was aimed at finding a wing structure with a minimized structural weight but at the same time strong and stiff enough to comply with sizing loads and aeroelastic stability in the flight envelope. Now, the outcome from the first design loop is used to build a global Finite Element Model (FEM), to be used for a multi-objective optimization performed by using a commercial software environment. In other words, the design strategy, aimed at finding a first optimal solution in terms of the thickness of composite components, is based on a two-level optimization. The first-level optimization is performed with engineering models (non-FEA-based), and the second-level optimization, discussed in this paper, within an FEA environment. The latter is shown to provide satisfactory results in terms of overall wing weight, and a zonal optimization of the composite parts, which is the starting point of an engineered model and a detailed FEM (beyond the scope of the present work), which will also take into account manufacturing, assembly, installation, accessibility and maintenance constraints

Prospective, observational, multicenter study on minimally invasive gastrectomy for gastric cancer: robotic, laparoscopic and open surgery compared on operative and follow-up outcomes - IMIGASTRIC II study protocol: IMIGASTRIC II

Background:Several meta-analyses have tried to defi ne the role of minimally invasive approaches. However, further evidence to get a wider spread of these methods is necessary. Current studies describe minimally invasive surgery as a possible alternative to open surgery but deserving further clarifi cation. However, despite the increasing interest, the difficulty of planning prospective studies of adequate size accounts for the low level of evidence, which is mostly based on retrospective experiences.A multi-institutional prospective study allows the collection of an impressive amount of data to investigate various aspects of minimally invasive procedures with the opportunity of developing several subgroup analyses.A prospective data collection with high methodological quality on minimally invasive and open gastrectomies can clarify the role of diff erent procedures with the aim to develop specifi c guidelines.Methods and analysis:a multi-institutional prospective database will be established including information on surgical, clinical and oncological features of patients treated for gastric cancer with robotic, laparoscopic or open approaches and subsequent follow-up.The study has been shared by the members of the International study group on Minimally Invasive surgery for GASTRIc Cancer (IMIGASTRIC)The database is designed to be an international electronic submission system and a HIPPA protected real time data repository from high volume gastric cancer centers.Ethics:This study is conducted in compliance with ethical principles originating from the Helsinki Declaration, within the guidelines of Good Clinical Practice and relevantlaws/regulations.Trial registration number:NCT0275108

Coronary artery calcium score and coronary computed tomography angiography for patients with asymptomatic polyvascular (non-coronary) atherosclerosis

The primary endpoint of this study was to determine the prevalence of coronary artery disease (CAD) and coronary artery calcium score (CACS) using coronary computed tomography angiography (CCTA) among patients with polyvascular atherosclerosis (PVA). Secondary endpoints were to evaluate the prevalence of cardiovascular risk factors and determine the predictors of PVA

Oncologic Effectiveness and Safety of Splenectomy in Total Gastrectomy for Proximal Gastric Carcinoma: Meta-analysis of Randomized Controlled Trials

Background/Aim: The role of splenectomy as an essential component of radical surgery for proximal gastric cancer, from an oncological point of view, is still debated, and no consistent recommendations have been proposed. The aim of this systematic review with meta-analysis was to provide a more robust answer regarding the oncological effectiveness and safety of splenectomy in total gastrectomy for proximal gastric carcinoma. Materials and Methods: A systematic review and meta-analysis of randomized controlled trials was planned and performed in accordance with Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement and Cochrane Handbook for Systematic Reviews of Intervention. Patients with a histological diagnosis of gastric adenocarcinoma located in the upper third of the stomach who underwent D2 total gastrectomy with or without splenectomy were selected. The primary outcome was to analyze the influence of splenectomy on the overall survival of patients. Additionally, the mean difference in procedure time, length of hospital stay, number of retrieved lymph nodes, as well as the odds ratio of postoperative complications comparing splenectomy to spleen preservation were investigated in a secondary analysis Results: Overall, four studies with a total of 978 patients met the inclusion criteria. The pooled analysis showed no difference in overall survival rates between those who underwent spleen preservation compared to the splenectomy-treated group (risk ratio=0.92, 95% confidence interval=0.79 to 1.06, p=0.277). Interestingly, all studies reporting overall morbidity data highlighted statistically significant differences in favor of spleen-preservation group (odds ratio=2.11, 95% confidence interval=1.44 to 3.09, p<0.001). Conclusion: In total, gastrectomy for proximal gastric cancer, splenectomy should not be recommended as it increases operative morbidity without improving survival when compared to spleen preservation. Furthermore, our results may help in planning the updated versions of Gastric Cancer Treatment Guidelines. This meta-analysis, however, points to the urgent need for high-quality, well-designed, large-scale, clinical trials, with short-as well as long-term evaluation comparing splenectomy with spleen-preserving procedures, in a controlled randomized manner to help future research and to establish an evidence-based approach to gastric cancer treatment

Intersatellite link for Earth Observation Satellites constellation

This paper is devoted to investigate the possibility to implement a data Intersatellite Link between satellites of an Earth Observation constellation and a dedicated TLC GEO satellite. An EO system is mainly composed of two segments (space and ground) connected by a complex network of communications that permits to manage the operations of the constellation. Due to the high performances in terms of imaging capabilities of the radar/optical payloads a corresponding high capacity to download data to ground is needed. To guarantee that the system is able to download to the ground station, in a proper time, all the images taken from the radar during the mission, external ground stations, located in a polar zone, have to be foreseen. Polar stations offer a service needed to provide the requested images to the users in a near real-time manner. In this paper an alternative approach, using an Intersatellite link system (ISLs) instead of polar stations, is presented. The most relevant trade-offs from technical point of view have been addressed. The purposes of this activities is to demonstrate the capability of a high speed two way optical link, between LEO and GEO terminals, with a bit rate in the order to 2.5 Gbps in the frame of satellites constellation. This implementation should permit to avoid the use of polar stations ensuring in the same time the achievement of high system time performances, in an operational cost-saving approach

Wing Structure of the Next-Generation Civil Tiltrotor: From Concept to Preliminary Design

The main objective of this paper is to describe a methodology to be applied in the preliminary design of a tiltrotor wing based on previously developed conceptual design methods. The reference vehicle is the Next-Generation Civil Tiltrotor Technology Demonstrator (NGCTR-TD) developed by Leonardo Helicopters within the Clean Sky research program framework. In a previous work by the authors, based on the specific requirements (i.e., dynamics, strength, buckling, functional), the first iteration of design was aimed at finding a wing structure with a minimized structural weight but at the same time strong and stiff enough to comply with sizing loads and aeroelastic stability in the flight envelope. Now, the outcome from the first design loop is used to build a global Finite Element Model (FEM), to be used for a multi-objective optimization performed by using a commercial software environment. In other words, the design strategy, aimed at finding a first optimal solution in terms of the thickness of composite components, is based on a two-level optimization. The first-level optimization is performed with engineering models (non-FEA-based), and the second-level optimization, discussed in this paper, within an FEA environment. The latter is shown to provide satisfactory results in terms of overall wing weight, and a zonal optimization of the composite parts, which is the starting point of an engineered model and a detailed FEM (beyond the scope of the present work), which will also take into account manufacturing, assembly, installation, accessibility and maintenance constraints

Unrepaired Tetralogy of Fallot in a 73 year old woman

Among cyanotic congenital heart diseases (CHD) Tetralogy of Fallot (TOF) is the most common, with an incidence of 0.28 cases every 1000 live-births. Despite the excellent prognosis related to early surgical correction, usually performed before the sixth month of age, life expectancy without surgery is dramatically reduced [1] and [2]. According to large observational series, 24% of individuals with an uncorrected TOF die before the age of 10 and only 4% survive above thirties [3] and [4]. Survival to advanced age is extremely rare. In the present manuscript we describe the case of a seventy-three year old woman with uncorrected TOF

Laparoscopic Compared with Open D2 Gastrectomy on Perioperative and Long-Term, Stage-Stratified Oncological Outcomes for Gastric Cancer: A Propensity Score-Matched Analysis of the IMIGASTRIC Database.

The laparoscopic approach in gastric cancer surgery is being increasingly adopted worldwide. However, studies focusing specifically on laparoscopic gastrectomy with D2 lymphadenectomy are still lacking in the literature. This retrospective study aimed to compare the short-term and long-term outcomes of laparoscopic versus open gastrectomy with D2 lymphadenectomy for gastric cancer. The protocol-based, international IMIGASTRIC (International study group on Minimally Invasive surgery for Gastric Cancer) registry was queried to retrieve data on patients undergoing laparoscopic or open gastrectomy with D2 lymphadenectomy for gastric cancer with curative intent from January 2000 to December 2014. Eleven predefined, demographical, clinical, and pathological variables were used to conduct a 1:1 propensity score matching (PSM) analysis to investigate intraoperative and recovery outcomes, complications, pathological findings, and survival data between the two groups. Predictive factors of long-term survival were also assessed. A total of 3033 patients from 14 participating institutions were selected from the IMIGASTRIC database. After 1:1 PSM, a total of 1248 patients, 624 in the laparoscopic group and 624 in the open group, were matched and included in the final analysis. The total operative time (median 180 versus 240 min, p &lt; 0.0001) and the length of the postoperative hospital stay (median 10 versus 14.8 days, p &lt; 0.0001) were longer in the open group than in the laparoscopic group. The conversion to open rate was 1.9%. The proportion of patients with in-hospital complications was higher in the open group (21.3% versus 15.1%, p = 0.004). The median number of harvested lymph nodes was higher in the laparoscopic approach (median 32 versus 28, p &lt; 0.0001), and the proportion of positive resection margins was higher (p = 0.021) in the open group (5.9%) than in the laparoscopic group (3.2%). There was no significant difference between the groups in five-year overall survival rates (77.4% laparoscopic versus 75.2% open, p = 0.229). The adoption of the laparoscopic approach for gastric resection with D2 lymphadenectomy shortened the length of hospital stay and reduced postoperative complications with respect to the open approach. The five-year overall survival rate after laparoscopy was comparable to that for patients who underwent open D2 resection. The types of surgical approaches are not independent predictive factors for five-year overall survival

Minimally invasive surgery for gastric cancer: A comparison between robotic, laparoscopic and open surgery

IF 3.365International audienceAIMTo investigate the role of minimally invasive surgery for gastric cancer and determine surgical, clinical, and oncological outcomes.METHODSThis is a propensity score-matched case-control study, comparing three treatment arms: robotic gastrectomy (RG), laparoscopic gastrectomy (LG), open gastrectomy (OG). Data collection started after sharing a specific study protocol. Data were recorded through a tailored and protected web-based system. Primary outcomes: harvested lymph nodes, estimated blood loss, hospital stay, complications rate. Among the secondary outcomes, there are: operative time, R0 resections, POD of mobilization, POD of starting liquid diet and soft solid diet. The analysis includes the evaluation of type and grade of postoperative complications. Detailed information of anastomotic leakages is also provided.RESULTSThe present analysis was carried out of 1026 gastrectomies. To guarantee homogenous distribution of cases, patients in the RG, LG and OG groups were 1: 1: 2 matched using a propensity score analysis with a caliper = 0.2. The successful matching resulted in a total sample of 604 patients (RG = 151; LG = 151; OG = 302). The three groups showed no differences in all baseline patients characteristics, type of surgery (P = 0.42) and stage of the disease (P = 0.16). Intraoperative blood loss was significantly lower in the LG (95.93 +/- 119.22) and RG (117.91 +/- 68.11) groups compared to the OG (127.26 +/- 79.50, P = 0.002). The mean number of retrieved lymph nodes was similar between the RG (27.78 +/- 11.45), LG (24.58 +/- 13.56) and OG (25.82 +/- 12.07) approach. A benefit in favor of the minimally invasive approaches was found in the length of hospital stay (P < 0.0001). A similar complications rate was found (P = 0.13). The leakage rate was not different (P = 0.78) between groups.CONCLUSIONLaparoscopic and robotic surgery can be safely performed and proposed as possible alternative to open surgery. The main highlighted benefit is a faster postoperative functional recovery