On the homogenization of periodic beam-like structures

Abstract A homogenization method for periodic beam-like structures that is based on the unit cell force transmission modes is presented. Its main advantage is that to identify the principal vectors of the state transfer matrix corresponding to the transmission modes it operates directly on the sub-partitions of the unit cell stiffness matrix and allows to overcome the problems due to ill-conditioning of the transfer matrix. As case study, the Pratt girder is considered. Closed form solutions for the transmission modes of this girder are achieved and used into homogenization. Since the pure bending mode shows that the Pratt unit cell transmits two kinds of bending moments, one given by the axial forces and the other originated by nodal moments, the Timoshenko couple-stress beam is employed as substitute continuum. Finally, a validation of the proposed procedure is carried out comparing the predictions of the homogenized models with the results of a series of girder f.e. analyses

Visuo-spatial attention and reading abilities: an action game prototype for dyslexic children

The ability to play action videogames – not directly related to phonological or orthographic training – seems to be a teaching tool able to intervene specifically on spatial attention and drastically improve the reading skills of dyslexic children. The MADRIGALE project aims at the design and development of an action game, simultaneously involving both phonological and attention training in order to adapt educational game strategies for special needs. Within the MADRIGALE project, the design of the prototype was presented at the International Conference on Intelligent Networking and Collaborative Systems, while an experimentation about educational effectiveness of the prototype, conducted using ‘Prove MT2’ as a benchmarking tool for measuring accuracy and speed of reading, was published in the International Journal of Emerging Technologies in Learning (iJET). This paper is an extension of the work presented in SIREM – SIEL 2014 Conference, and presents the results of a Game Evaluation Sheet administered to 50 primary school teachers with experience of dyslexic student

Congenital Lung Malformations: Shifting from Open to Thoracoscopic Surgery.

Background Over the years the need for surgical treatment, timing of intervention, and the type of surgical approach have been discussed, but the treatment of congenital lung malformations remains controversial. The aim of this study was to compare the thoracotomy approach with the thoracoscopic technique by evaluating different surgical outcomes (duration of surgery, postoperative hospital stay, and complications). Methods All patients operated from January 2011 to March 2015 for suspected congenital cystic lung were included in the study. Patients treated for congenital lobar emphysema and tracheobronchial neoplasms were excluded from the study. Results In the analyzed period, 31 asymptomatic patients were treated: 18 lung resections were performed with thoracotomy (Group A) and 13 with the thoracoscopic approach (Group B). No significant differences were observed between the age and weight at surgery, length of the procedures, complications, and the need for postoperative intensive care between the two groups. The postoperative hospital stay in Group A was twice that for Group 2 ( p = 0.0009). Conclusion Comparing thoracoscopic surgery with the traditional open approach, we confirmed the superiority of minimally invasive treatment in terms of postoperative hospital stay. Common technical recommendations can help pediatric centers to develop the thoracoscopic approach for the treatment of congenital pulmonary malformations

Melanoma Brain Metastases in the Era of Target Therapies: An Overview

Malignant melanoma is the third most common type of tumor that causes brain metastases. Patients with cerebral involvement have a dismal prognosis and their treatment is an unmet medical need. Brain involvement is a multistep process involving several signaling pathways such as Janus kinase/signal Transducer and Activator of Transcription (JAK/STAT), Phosphoinositide 3-kinase/Protein Kinase B (PI3K/AKT), Vascular Endothelial Growth Factor and Phosphatase and Tensin Homolog (PTEN). Recently therapy that targets the MAPK signaling (BRAF/MEK inhibitors) and immunotherapy (anti-CTLA4 and anti-PD1 agents) have changed the therapeutic approaches to stage IV melanoma. In contrast, there are no solid data about patients with brain metastases, who are usually excluded from clinical trials. Retrospective data showed that BRAF-inhibitors, alone or in combination with MEK-inhibitors have interesting clinical activity in this setting. Prospective data about the combinations of BRAF/MEK inhibitors have been recently published, showing an improved overall response rate. Short intracranial disease control is still a challenge. Several attempts have been made in order to improve it with combinations between local and systemic therapies. Immunotherapy approaches seem to retain promising activity in the treatment of melanoma brain metastasis as showed by the results of clinical trials investigating the combination of anti-CTL4 (Ipilimumab) and anti-PD1(Nivolumab). Studies about the combination or the sequential approach of target therapy and immunotherapy are ongoing, with immature results. Several clinical trials are ongoing trying to explore new approaches in order to overcome tumor resistance. At this moment the correct therapeutic choices for melanoma with intracranial involvement is still a challenge and new strategies are needed

Successful treatment of Neuroblastoma in an adolescent with intra-arterial embolization before surgery

Abstract Introduction Neuroblastoma in the adolescent is characterized by indolent growth and poor outcome. Surgical resection of the tumor is an essential part of the multimodality treatment. Surgical complications depend on the presence of Image Defined Risk Factors (IDRFs). Methods We present an adolescent with pelvic neuroblastoma and epidural compression. To facilitate tumor resection, the patient underwent preoperative selective embolization. Results After selective embolization a subsequent complete resection etraspinal localisation was performed without complication with complete remission after 2 years. Conclusions Preoperative embolization is a safe and feasible technique that can help pediatric surgical oncologist to reduce complications IDRFs-related

Regional stratigraphy of the south polar layered deposits (Promethei Lingula, Mars): “Discontinuity-bounded” units in images and radargrams

The Mars South Polar Layered Deposits (SPLD) are the result of depositional and erosional events, which are marked by different stratigraphic sequences and erosional surfaces. To unambiguously define the stratigraphic units at regional scale, we mapped the SPLD on the basis of observed discontinuities (i.e., unconformities, correlative discontinuities and conformities), as commonly done in terrestrial modern stratigraphy. This methodology is defined as “Discontinuity-Bounded Units” or allostratigraphy, and is complemented by geomorphological mapping. Our study focuses on Promethei Lingula (PL) and uses both high-resolution images (CTX, HiRISE) and radargrams (SHARAD) to combine surface and sub-surface observations and obtain a 3D geological reconstruction of the SPLD. One regional discontinuity (named AUR1) was defined within the studied stratigraphic succession and is exposed in several non-contiguous outcrops around PL as well as observed at depth within the ice sheet. This is the primary contact between two major depositional sequences, showing a different texture at CTX resolution. The lower sequence is characterized mainly by a “ridge and trough” morphology (Ridge and Trough Sequence; RTS) and the upper sequence shows mainly by a “stair-stepped” morphology (Stair-Stepped Sequence; SSS). On the basis of the observations, we defined two regional “discontinuity-bounded” units in PL, respectively coinciding with RTS and SSS sequences. Our stratigraphic reconstruction provides new hints on the major scale events that shaped this region. Oscillations in Martian axial obliquity could have controlled local climate conditions in the past, affecting the PL geological record

Ischaemic and bleeding complications with new, compared to standard, ADP-antagonist regimens in acute coronary syndromes: a meta-analysis of randomized trials

Background: Platelets play a pivotal role in the pathogenesis of acute coronary syndromes (ACS) and their inhibition remains a mainstay therapy in this setting. We aimed to perform a meta-analysis of randomized trials to evaluate the benefits of new oral antiplatelet regimens to block platelet ADPreceptors compared to standard-dose clopidogrel (300 mg loading dose followed by 75 mg/daily). Methods: We obtained results from all randomized trials enrolling patients with ACS. Primary endpoint was mortality. Secondary endpoints were myocardial infarction and definite in-stent thrombosis. Safety endpoint was the risk of major bleeding complications. We prespecified subanalyses according to new antiplatelet drugs (prasugrel/ticagrelor), high-dose clopidogrel (600 mg) and patients undergoing percutaneous coronary intervention. Results: A total of seven randomized trials were finally included in the meta-analysis (n = 58 591). We observed a significant reduction in mortality (2.9% vs. 3.4%, OR= 0.87, 95% CI 0.79–0.95, P = 0.002), recurrent myocardial infarction (4.2% vs. 5.2%, OR= 0.80, 95% CI 0.74–0.87, P < 0.0001), definite in-stent thrombosis (0.9% vs. 1.7%, OR= 0.52, 95% CI 0.43–0.63, P < 0.0001). The benefits in mortality and reinfarction were driven by the treatment with prasugrel or ticagrelor, without a significant difference in terms of major bleeding complications as compared to standarddose clopidogrel (5% vs. 4.7%, OR= 1.06 95% CI 0.96–1.17, P = 0.25). Conclusions: This meta-analysis showed that new oral antiplatelet regimens are associated with a significant reduction in mortality, reinfarction and in-stent thrombosis in ACS patients without an overall increase of major bleeding when treated with new antiplatelet drugs

Study of N2O formation over Rh- and Pt-based LNT catalysts

In this paper, mechanistic aspects involved in the formation of N2O over Pt-BaO/Al2O3 and Rh-BaO/Al2O3 model NOx Storage-Reduction (NSR) catalysts are discussed. The reactivity of both gas-phase NO and stored nitrates was investigated by using H2 and NH3 as reductants. It was found that N2O formation involves the presence of gas-phase NO, since no N2O is observed upon the reduction of nitrates stored over both Pt- and Rh-BaO/Al2O3 catalyst samples. In particular, N2O formation involves the coupling of undissociated NO molecules with N-adspecies formed upon NO dissociation onto reduced Platinum-Group-Metal (PGM) sites. Accordingly, N2O formation is observed at low temperatures, when PGM sites start to be reduced, and disappears at high temperatures where PGM sites are fully reduced and complete NO dissociation takes place. Besides, N2O formation is observed at lower temperatures with H2 than with NH3 in view of the higher reactivity of hydrogen in the reduction of the PGM sites and onto Pt-containing catalyst due to the higher reducibility of Pt vs. Rh