2,793 research outputs found
Definizione e analisi delle mappe di prestazione di un turboalbero aeronautico
Nel presente lavoro di tesi, in seguito ad acquisizioni di dati effettuate nella sala prove del "Laboratorio di Macchine e Propulsione" della Scuola di Ingegneria e Architettura di Forlì sul turboshaft Allison 250 C18, in una prima fase sono state ricavate le mappe prestazionali dei singoli componenti del motore, elaborando i dati sperimentali in ambiente MatLab. Le acquisizioni sono state effettuate mediante l'utilizzo di sensori di pressione, temperatura e velocità installati in precedenza sul motore e opportunamente calibrati. In seguito alla realizzazione delle mappe prestazionali, si è passati all'allestimento completo di un modello dinamico in ambiente Simulink, del motore Allison 250 C18. Tale modello riproduce, in opportuni blocchi, ciascun componente facente parte della motorizzazione. Ogni blocco riceve in ingresso le caratteristiche fisiche di interesse del flusso (temperatura, pressione, calore specifico a pressione costante e gamma) provenienti dal blocco precedente tramite un "filo", le rielabora al suo interno risolvendo le equazioni tipiche di ciascun componente e interpolando le mappe di prestazione ricavate precedentemente in MatLab, e le invia come input al blocco successivo o in retroazione ai blocchi precedenti. In ogni blocco è stato realizzato un sistema di dinamica di pressione che, ad ogni istante, risolve un'equazione differenziale dipendente dalla differenza di portata a monte e a valle di un componente e dal volume di controllo, che restituisce il valore di pressione in uscita proporzionale alla variazione di portata stessa. Nel presente lavoro di tesi si è cercato di stabilizzare questo complesso sistema in una condizione di progetto, fissata a 30000 rpm del gruppo gas generator. Un sistema di controllo del numero di giri tramite variazione di portata di combustibile è stato realizzato al fine di poter, in futuro, far funzionare il modello anche fuori dalla condizione di progetto e riuscire a simulare l'andamento delle prove sperimentali reali
Obesity in patients with acute lymphoblastic leukemia in childhood
Acute lymphoblastic leukemia is the most common malignancy in childhood. Continuous progress in risk-adapted treatment for childhood acute lymphoblastic leukemia has secured 5-year event-free survival rates of approximately 80% and 8-year survival rates approaching 90%. Almost 75% of survivors, however, have a chronic health condition negatively impacting on cardiovascular morbidity and mortality. Obesity can be considered one of the most important health chronic conditions in the general population, with an increasing incidence in patients treated for childhood cancers and especially in acute lymphoblastic leukemia survivors who are, at the same time, more at risk of experiencing precocious cardiovascular and metabolic co-morbidities. The hypothalamic-pituitary axis damage secondary to cancer therapies (cranial irradiation and chemotherapy) or to primary tumor together with lifestyle modifications and genetic factors could affect long-term outcomes. Nevertheless, the etiology of obesity in acute lymphoblastic leukemia is not yet fully understood. The present review has the aim of summarizing the published data and examining the most accepted mechanisms and main predisposing factors related to weight gain in this particular population
Unusual osseous presentation of blastomycosis in an immigrant child: a challenge for European pediatricians.
Blastomycosis, caused by the thermally dimorphic fungus Blastomyces dermatitidis is a systemic pyogranulomatous infection, endemic in United States and Canada, with few reported cases in Africa and Asia. It is uncommon among children and adolescents, ranging from 3% to 10%. Clinical features vary from asymptomatic spontaneously healing pneumonia, through acute or chronic pneumonia, to a malignant appearing lung mass. Blastomycosis can originate a "metastatic disease" in the skin, bones, genitourinary tract and central nervous system. Bone is the third most common site of blastomycotic lesions, after lung and skin. Bones may be involved in 14-60% of cases of blastomycosis. Direct visualization of single broadbased budding yeast with specific stains in sputum or tissue samples at microscopy is the primary method for diagnosis, while culture is timeconsuming and other methods are unreliable.
CASE PRESENTATION: We report a case of severe osteoarticular Blastomycosis occurring in a 3-years-old presented to our Emergency Department with pain and swelling of the left knee, successfully treated with surgical curettage and antifungal therapy. To our knowledge this is the first case reported in Europe.
CONCLUSIONS: Blastomycosis represents a challenge for European physicians, and it should be included in the differential diagnosis of unexplained infections in patients coming from endemic areas
In vitro differentiation of human amniotic epithelial cells into insulin-producing 3D spheroids
Regenerative medicine and stem cell therapy may represent the solution for the treatment of non-curable human diseases such as type 1 diabetes. In this context of growing demand for functional and safe stem cells, human amniotic epithelial cells (hAECs) from term placenta have attracted increasing interest for their wide availability, stem cell properties, and differentiation plasticity, which make them a promising tool for stem cell-based therapeutic applications. We initially assayed the stemness characteristics of hAECs in serum-free conditions. Subsequently we developed a culture procedure on extracellular matrix for the formation of three-dimensional (3D) spheroids. Finally, we tested the immunomodulation and differentiation potential of hAEC spheroids: the presence of pancreatic endocrine hormones was revealed with transmission electron microscopy and immunofluorescence analyses; the release of C-peptide in hyperglycemic conditions was assayed with ELISA.The serum-free culture conditions we applied proved to maintain the basic stemness characteristics of hAECs. We also demonstrated that 3D spheroids formed by hAECs in extracellular matrix can be induced to differentiate into insulin-producing cells. Finally, we proved that control and induced cells equally inhibit the proliferation of activated mononuclear cells.The results of this study highlight the properties of amnion derived epithelial cells as promising and abundant source for cell-based therapies. In particular we are the first group to show the in vitro pancreatic induction of hAECs cultured on extracellular matrix in a 3D fashion. We accordingly propose the outcomes of this study as a novel contribution to the development of future cell replacement therapies involving placenta-derived cells
APE Results of Hadron Masses in Full QCD Simulations
We present numerical results obtained in full QCD with 2 flavors of Wilson
fermions. We discuss the relation between the phase of Polyakov loops and the
{\bf sea} quarks boundary conditions. We report preliminary results about the
HMC autocorrelation of the hadronic masses, on a lattice
volume, at with .Comment: 3 pages, compressed ps-file (uufiles), Contribution to Lattice 9
GPU-based Real-time Triggering in the NA62 Experiment
Over the last few years the GPGPU (General-Purpose computing on Graphics
Processing Units) paradigm represented a remarkable development in the world of
computing. Computing for High-Energy Physics is no exception: several works
have demonstrated the effectiveness of the integration of GPU-based systems in
high level trigger of different experiments. On the other hand the use of GPUs
in the low level trigger systems, characterized by stringent real-time
constraints, such as tight time budget and high throughput, poses several
challenges. In this paper we focus on the low level trigger in the CERN NA62
experiment, investigating the use of real-time computing on GPUs in this
synchronous system. Our approach aimed at harvesting the GPU computing power to
build in real-time refined physics-related trigger primitives for the RICH
detector, as the the knowledge of Cerenkov rings parameters allows to build
stringent conditions for data selection at trigger level. Latencies of all
components of the trigger chain have been analyzed, pointing out that
networking is the most critical one. To keep the latency of data transfer task
under control, we devised NaNet, an FPGA-based PCIe Network Interface Card
(NIC) with GPUDirect capabilities. For the processing task, we developed
specific multiple ring trigger algorithms to leverage the parallel architecture
of GPUs and increase the processing throughput to keep up with the high event
rate. Results obtained during the first months of 2016 NA62 run are presented
and discussed
Sensitivity and Specificity of Qualitative Visual Field Tests for Screening Visual Hemifield Deficits in Right-Brain-Damaged Stroke Patients
A timely detection of visual hemifield deficits (VHFDs; hemianopias or quadrantanopias) is critical for both the diagnosis and treatment of stroke patients. The present study determined the sensitivity and specificity of four qualitative visual field tests, including face description, confrontation tests (finger wiggle), and kinetic boundary perimetry, to screen large and dense VHFDs in right-brain-damaged (RBD) stroke patients. Previously, the accuracy of qualitative visual field tests was examined in unselected samples of patients with heterogeneous aetiology, in which stroke patients represented a very small fraction. Building upon existing tests, we introduced some procedural ameliorations (incl. a novel procedure for kinetic boundary perimetry) and provided a scoresheet to facilitate the grading. The qualitative visual field tests’ outcome of 67 consecutive RBD stroke patients was compared with the standard automated perimetry (SAP; i.e., reference standard) outcome to calculate sensitivity and specificity, as well as positive and negative predictive values (PPV and NPV), both for each individual test and their combinations. The face description test scored the lowest sensitivity and NPV, while the kinetic boundary perimetry scored the highest. No test returned false positives. Combining the monocular static finger wiggle test (by quadrants) and the kinetic boundary perimetry returned the highest sensitivity and specificity, in line with previous studies, but with higher accuracy (100% sensitivity and specificity). These findings indicate that the combination of these two tests is a valid approach with RBD stroke patients, prompting referral for a formal visual field examination, and representing a quick, easy-to-perform, and inexpensive tool for improving their care and prognosis
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