37 research outputs found

    A Parametric Approach for Conceptual Integration and Performance Studies of Liquid Hydrogen Short–Medium Range Aircraft

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    The present paper deals with the investigation, at conceptual level, of the performance of short–medium-range aircraft with hydrogen propulsion. The attention is focused on the relationship between figures of merit related to transport capability, such as passenger capacity and flight range, and the parameters which drive the design of liquid hydrogen tanks and their integration with a given aircraft geometry. The reference aircraft chosen for such purpose is a box-wing short–medium-range airplane, the object of study within a previous European research project called PARSIFAL, capable of cutting the fuel consumption per passenger-kilometre up to 22%. By adopting a retrofitting approach, non-integral pressure vessels are sized to fit into the fuselage of the reference aircraft, under the assumption that the main aerodynamic, flight mechanic, and structural characteristics are not affected. A parametric model is introduced to generate a wide variety of fuselage-tank cross-section layouts, from a single tank with the maximum diameter compatible with a catwalk corridor to multiple tanks located in the cargo deck, and an assessment workflow is implemented to perform the structural sizing of the tanks and analyse their thermodynamic behaviour during the mission. This latter is simulated with a time-marching approach that couples the fuel request from engines with the thermodynamics of the hydrogen in the tanks, which is constantly subject to evaporation and, depending on the internal pressure, vented-out in gas form. Each model is presented in detail in the paper and results are provided through sensitivity analyses to both the technologic parameters of the tanks and the geometric parameters influencing their integration. The guidelines resulting from the analyses indicate that light materials, such as the aluminium alloy AA2219 for tanks’ structures and polystyrene foam for the insulation, should be selected. Preferred values are also indicted for the aspect ratios of the vessel components, i.e., central tube and endcaps, as well as suggestions for the integration layout to be adopted depending on the desired trade-off between passenger capacity, as for the case of multiple tanks in the cargo deck, and achievable flight ranges, as for the single tank in the section

    Weekly versus three weeks chemotherapy for advanced ovarian cancer. A meta-analysis

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    Aim: Three weeks paclitaxel and carboplatin has been considered the standard of care for primary treatment of ovarian cancer (OC). Whether weekly therapy will further improve the clinical outcomes or not is still unclear. We conducted a meta-analysis to compare the two regimens. Method: Articles were selected with a systematic approach, using PubMed databases. Trials concerning comparison between carboplatin plus weekly paclitaxel (dose-dense regimen) and carboplatin plus paclitaxel every 3 weeks were considered. Outcomes included overall survival (OS), progression free survival (PFS) and severe acute toxicity. Results: Dose-dense regimen was associated with significant improvement of PFS compared with standard schedule, with HR of 0.73 (95% CI 0.61-0.88, p = 0.001). There was no difference in OS between treatment regimens (HR 0.95, 95% CI 0.77-1.16, p=0.06), as well as in term of severe acute toxicity. Conclusion: Dose-dense regimen is superior to standard schedule in terms of PFS. Further studies are necessary to firmly confirm this evidence in advanced OC treatment

    Prediction of Maximum Lift Coefficient of Box-Wing Aircraft through the Combination of an Analytical Adaptation of the DATCOM Method and Vortex-Lattice Simulations

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    The present paper concerns the introduction of a mixed analytical-numerical method for the estimation of the maximum lift coefficient of box-wing aircraft in unflapped configuration. The analytical aspect is related to the adaptation of the method included in the United States Air Force Stability and Control Data Compendium (USAF DATCOM) by means of an approach built on the characteristics of the optimal lift distribution of the box-wing and implemented through simplifying assumptions. Since the formulation depends on parameters proper of the considered aircraft, numerical simulations are performed through a Vortex-Lattice Method to complete the input dataset. The method is first presented and then validated for the case of the 2-seater amphibious PrandtlPlane from the project “IDINTOS”, for which wind tunnel data are available. The method is then applied to two test cases for which CFD data are available: a 300 passengers mid-range PrandtlPlane, developed within the European research project “PARSIFAL”, and a regional hybrid-electric PrandtlPlane, object of study in the Italian research project “PROSIB”. Results are presented and discussed, also analyzing the links between the proposed method and relevant parameters of the box-wing design, such as taper ratios and wing loading repartition among the two wings

    A Conceptual Design Methodology for e-VTOL Aircraft for Urban Air Mobility

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    Recent progress of electric systems has raised attention towards hybrid‐electric and fullelectric aircraft. Nevertheless, the current low battery energy density limits the application of these propulsive architectures to large transport aircraft. In the context of the general aviation category, full‐electric aircraft for the so‐called Urban Air Mobility scenario are gaining increasing interest. These air taxis, also called e‐VTOL, are conceived to exploit vertical take‐off and landing capabilities, to carry people from one point to another, typically within the same city. In this paper, a new conceptual design methodology for urban air vehicles is presented and applied to an innovative convertiplane, called TiltOne, based on a box‐wing architecture coupled with tilt‐wing mechanisms. Several TiltOne configurations have been designed according to the current regulations imposed by European Union Aviation Safety Agency, and sensitivity analyses have been carried out on the varying main design parameters, such as wing loading and propellers’ disk loading, as well as main top‐level aircraft requirements. The results provide an overview for today’s operational capabilities of such aircraft and, in addition, depict possible scenarios for a near‐future horizon, based on the assumption of increased performance levels for the electric powertrain components. In such scenario, two different concepts of operations are analysed and discussed: the first is based on a given design range, long enough to cover the urban distances; the second is conceived to exploit the capability of flying multiple shorter missions with a single battery charge. The designed TiltOne configurations derived from thes

    Efficacy and toxicity of bevacizumab in recurrent ovarian disease: an update meta-analysis on phase III trials

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    Background: To analyze the efficacy and toxicity of bevacizumab on survival outcomes in recurrent ovarian cancer. Results: Bevacizumab was associated with significant improvement of PFS and OS compared with standard treatment with HRs of 0.53 (95% CI 0.44 - 0.63; p < 0.00001) and 0.87 (95% CI, 0.77 to 0.99; p = 0.03), respectively. Bevacizumab increased the incidence of G3/G4 hypertension (RR 19.01, 95% CI 7.77 - 46.55; p < 0.00001), proteinuria (RR 17.31, 95% CI 5.42 - 55.25; p < 0.00001), arterial thromboembolic events (ATE) (RR 4.99, 95% CI 1.29 - 19.27; p = 0.02) and bleeding (RR 3.14, 95% CI 1.35 - 7.32; p = 0.008). Materials and Methods: Three randomized phase III trials representing 1502 patients were identified. Pooled hazard ratio (HR), odd ratio (OR), risk ratio (RR) with 95% confidence interval (CI) were calculated using fixed or random effects model. Conclusions: Adding bevacizumab to standard chemotherapy improved ORR, PFS and OS, and it had a higher, but manageable, incidence of toxicities graded 3 to 4

    Fertility preservation in gynaecologic cancers

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    Due to substantial improvement in the diagnosis and treatment of gynaecologic cancers, a better understanding of patient care needs to be revised. We reviewed the literature related to fertility preservation strategies in gynaecological cancer and discussed current general management approaches. New technical modalities and patients’ own desire for motherhood should be integral and paramount in the clinical evaluation to significantly contribute to preserving fertility in those women diagnosed with gynaecologic cancers during the reproductive years

    Synchronous anal canal cancer and cervical cancer: report of a case and management implication

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    Background: This is the case report of a synchronous anal canal cancer and cervical cancer in a patient who underwent definitive chemoradiotherapy (CRT) and radical surgery for anal canal and cervical carcinoma, respectively. Case Report: A 55-year-old woman was diagnosed with cT4a cN1 Mx anal canal squamous cell carcinoma and stage IA2 cervical squamous cell carcinoma, based on biopsy and imaging. Definitive CRT consisted of radiotherapy (total dose of 59.4 Gy) and concomitant mitomycin (10 mg/m(2)) and 5-fluorouracil (750 mg/m(2)/5 daily continuous infusion) during the first and last week of radiation. The patient exhibited a complete clinical and radiological response. A radical hysterectomy with pelvic lymphadenectomy was then performed. At the last follow-up (30 months), the patient is still disease-free without any treatment-associated complications. Conclusion: There is limited information in the literature regarding treatment strategy and outcome of patients with synchronous anal canal and cervical cancer. A two-step treatment, including CRT and radical hysterectomy, is likely to be accepted as valid option

    Development of a Nomogram Predicting the Risk of Persistence/Recurrence of Cervical Dysplasia

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    Background: Cervical dysplasia persistence/recurrence has a great impact on women's health and quality of life. In this study, we investigated whether a prognostic nomogram may improve risk assessment after primary conization. Methods: This is a retrospective multi-institutional study based on charts of consecutive patients undergoing conization between 1 January 2010 and 31 December 2014. A nomogram assessing the importance of different variables was built. A cohort of patients treated between 1 January 2015 and 30 June 2016 was used to validate the nomogram. Results: A total of 2966 patients undergoing primary conization were analyzed. The median (range) patient age was 40 (18-89) years. At 5-year of follow-up, 6% of patients (175/2966) had developed a persistent/recurrent cervical dysplasia. Median (range) recurrence-free survival was 18 (5-52) months. Diagnosis of CIN3, presence of HR-HPV types, positive endocervical margins, HPV persistence, and the omission of HPV vaccination after conization increased significantly and independently of the risk of developing cervical dysplasia persistence/recurrence. A nomogram weighting the impact of all variables was built with a C-Index of 0.809. A dataset of 549 patients was used to validate the nomogram, with a C-index of 0.809. Conclusions: The present nomogram represents a useful tool for counseling women about their risk of persistence/recurrence after primary conization. HPV vaccination after conization is associated with a reduced risk of CIN2+

    Complex movement disorders at disease onset in childhood narcolepsy with cataplexy

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    Narcolepsy with cataplexy is characterized by daytime sleepiness, cataplexy (sudden loss of bilateral muscle tone triggered by emotions), sleep paralysis, hypnagogic hallucinations and disturbed nocturnal sleep. Narcolepsy with cataplexy is most often associated with human leucocyte antigen-DQB1*0602 and is caused by the loss of hypocretin-producing neurons in the hypothalamus of likely autoimmune aetiology. Noting that children with narcolepsy often display complex abnormal motor behaviours close to disease onset that do not meet the classical definition of cataplexy, we systematically analysed motor features in 39 children with narcolepsy with cataplexy in comparison with 25 age- and sex-matched healthy controls. We found that patients with narcolepsy with cataplexy displayed a complex array of ‘negative’ (hypotonia) and ‘active’ (ranging from perioral movements to dyskinetic–dystonic movements or stereotypies) motor disturbances. ‘Active’ and ‘negative’ motor scores correlated positively with the presence of hypotonic features at neurological examination and negatively with disease duration, whereas ‘negative’ motor scores also correlated negatively with age at disease onset. These observations suggest that paediatric narcolepsy with cataplexy often co-occurs with a complex movement disorder at disease onset, a phenomenon that may vanish later in the course of the disease. Further studies are warranted to assess clinical course and whether the associated movement disorder is also caused by hypocretin deficiency or by additional neurochemical abnormalities
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