542 research outputs found

    Sull'emissione filatelica celebrativa del MMD anniversario del giuramento della plebe al Monte Sacro e dell'istituzione del tribuno della plebe

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    Sommario: 1. Il Tribunato della plebe nell’età repubblicana; 2. Da Augusto al XVII secolo; 3. Dal XVIII secolo alla Rivoluzione russa; 4. Dall’Ombudsman al Defensor del pueblo

    Analisi cartografica e GPS di punti fiduciali

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    Scopo di questo lavoro \ue8 l'analisi cartografica di punti fiduciali (P.F.), attraverso la comparazione delle coordinate di un dataset di sessanta vertici presenti nella citt\ue0 di Palermo. Come supporto cartografico di riferimento \ue8 stato preso la carta ufficiale del Comune di Palermo, che \ue8 in formato digitale ed \ue8 stata recentemente realizzata con metodo aerofotogrammetrico (2007). Le coordinate dei punti fiduciali sono state confrontate con differenti supporti cartografici e web: mappe catastali georiferite (nel sistema nazionale Gauss-Boaga), mappe derivanti dagli applicativi web Google Earth e fiduciali.it. Oltre ai confronti con i supporti cartografici dei P.F., \ue8 stata effettuata una vasta campagna di rilievi GPS/GNNS in modalita NRTK con stazionamenti fuoricentro, legati alla particolare natura dei punti rilevati (in maggioranza spigoli di fabbricati); questo metodo, ampiamente utilizzato in letteratura, ha richiesto un lavoro molto oneroso poich\ue9 \ue8 stato necessario rilevare direttamente i P.F. L'analisi sviluppata dimostra l'adeguatezza del rilievo NRTK alla determinazione delle coordinate dei P.F., mentre i risultati provenienti dagli applicativi Google Earth e fiduciali.it sono in forte discontinuit\ue0 rispetto alla Cartografia Tecnica Comunale

    On the motion/stiffness decoupling property of articulated soft robots with application to model-free torque iterative learning control

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    This paper tackles the problem of controlling articulated soft robots (ASRs), i.e., robots with either fixed or variable elasticity lumped at the joints. Classic control schemes rely on high-authority feedback actions, which have the drawback of altering the desired robot softness. The problem of accurate control of ASRs, without altering their inherent stiffness, is particularly challenging because of their complex and hard-to-model nonlinear dynamics. Leveraging a learned anticipatory action, Iterative Learning Control (ILC) strategies do not suffer from these issues. Recently, ILC was adopted to perform position control of ASRs. However, the limitation of position-based ILC in controlling variable stiffness robots is that whenever the robot stiffness profile is changed, a different input action has to be learned. Our first contribution is to identify a wide class of ASRs, whose motion and stiffness adjusting dynamics can be proved to be decoupled. This class is described by two properties that we define: strong elastic coupling - relative to motors and links of the system, and their connections - and homogeneity - relative to the characteristics of the motors. Furthermore, we design a torque-based ILC scheme that, starting from a rough estimation of the system parameters, refines the torque needed for the joint positions tracking. The resulting control scheme requires minimum knowledge of the system. Experiments on variable stiffness robots prove that the method effectively generalizes the iterative procedure w.r.t. the desired stiffness profile and allows good tracking performance. Finally, potential restrictions of the method, e.g., caused by friction phenomena, are discussed

    Decentralized Trajectory Tracking Control for Soft Robots Interacting With the Environment

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    Despite the classic nature of the problem, trajectory tracking for soft robots, i.e., robots with compliant elements deliberately introduced in their design, still presents several challenges. One of these is to design controllers which can obtain sufficiently high performance while preserving the physical characteristics intrinsic to soft robots. Indeed, classic control schemes using high-gain feedback actions fundamentally alter the natural compliance of soft robots effectively stiffening them, thus de facto defeating their main design purpose. As an alternative approach, we consider here using a low-gain feedback, while exploiting feedforward components. In order to cope with the complexity and uncertainty of the dynamics, we adopt a decentralized, iteratively learned feedforward action, combined with a locally optimal feedback control. The relative authority of the feedback and feedforward control actions adapts with the degree of uncertainty of the learned component. The effectiveness of the method is experimentally verified on several robotic structures and working conditions, including unexpected interactions with the environment, where preservation of softness is critical for safety and robustness

    Locally advanced leiomyosarcoma of the spleen. A case report and review of the literature

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    <p>Abstract</p> <p>Background</p> <p>Leiomyosarcomas are rare tumours, predominantly localized in the stomach, small intestine and retroperitoneum. Only one case of primary leiomyosarcoma of the spleen is described in human beings in literature.</p> <p>Case presentation</p> <p>We report a case of locally advanced primary leiomyosarcoma of the spleen in a 54 year-old woman, diagnosed only after splenectomy, performed with the suspicion of splenic haematoma.</p> <p>Conclusion</p> <p>Due to the lack of cases, no specific chemotherapy regimen has been tested to provide a longer survival.</p

    Combined platelet-rich plasma and lipofilling treatment provides great improvement in facial skin-induced lesion regeneration for scleroderma patients

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    Background: The use of stem cells, including mesenchymal stem cells (MSCs), for regenerative medicine is gaining interest for the clinical benefits so far obtained in patients. This study investigates the use of adipose autologous tissue in combination with platelet-rich plasma (PRP) to improve the clinical outcome of patients affected by systemic sclerosis (SSc). Methods: Adipose-derived mesenchymal stem cells (AD-MSCs) and PRPs were purified from healthy donors and SSc patients. The multilineage differentiation potential of AD-MSCs and their genotypic-phenotypic features were investigated. A cytokine production profile was evaluated on AD-MSCs and PRPs from both healthy subjects and SSc patients. The adipose tissue-derived cell fraction, the so-called stromal vascular fraction (SVF), was coinjected with PRP in the perioral area of SSc patients. Results: Histopathological and phenotypical analysis of adipose tissue from SSc patients revealed a disorganization of its distinct architecture coupled with an altered cell composition. Although AD-MSCs derived from SSc patients showed high multipotency, they failed to sustain a terminally differentiated progeny. Furthermore, SVFs derived from SSc patients differed from healthy donors in their MSC-like traits coupled with an aberrant cytokine production profile. Finally, the administration of PRP in combination with autologous SVF improved buccal's rhyme, skin elasticity and vascularization for all of the SSc patients enrolled in this study. Conclusions: This innovative regenerative therapy could be exploited for the treatment of chronic connective tissue diseases, including SSc

    Cytotoxic activity of a plant extract on cancer cells

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    Chemoprevention by natural products may be considered a promising approach to cancer control and management [1]. Many studies have demonstrated antiproliferative, cytostatic and cytotoxic activities of phytochemicals against cancer cells [2]. In this study, a plant extract from Arctium lappa, Berberis vulgaris and Eschscholtia californica was tested as potential anticancer agent. The antitumoral activity of this plant extract was tested on four human cancer cell lines: MCF-7 (breast carcinoma cells), Huh-7 (hepatic carcinoma cells), HTB-43 (oropharyngeal carcinoma cells) and ECV- 304 (urinary bladder carcinoma cells). The efficacy of the extract was compared to the common chemotherapeutic agent cyclophosphamide. Three plant extract concentrations were tested: 800, 650 and 450 ng/ml; for cyclophosphamide, three concentrations were assayed, according to literature data: 1300, 1000 and 850 ng/ml [3]. In addition, plant extract and cyclophosphamide were tested on two primary cell lines as controls, human gingival fibroblasts and human mammary fibroblasts. Cell viability was evaluated by the MTT [(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, Sigma] colorimetric assay and the new xCELLigence system (Roche) for real-time monitoring of cell viability. All concentrations of plant extract exhibited a high level of cytotoxicity on MCF-7, Huh-7, HTB-43 and ECV-304 cancer cells, similar to cyclophosphamide, though they slightly reduced viability of human gingival and mammary fibroblasts. Conversely, the conventional chemotherapeutic drug showed a marked cytotoxicity on control cells. The potential of the plant extract has been demonstrated in vitro on various types of cancers, suggesting a possible use of this natural product as a promising anticancer agent. Further studies are needed to ascertain its efficacy in vivo and to elucidate its mechanism(s) of action at molecular and biochemical levels

    Longitudinal association of 25-Hydroxyvitamin D with adipokines and markers of glucose metabolism among Brazilian pregnant women

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    This study aimed to evaluate the longitudinal association of vitamin D status with glycaemia, insulin, Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), adiponectin and leptin. A prospective cohort with 181 healthy, pregnant Brazilian women was followed at the 5th–13th, 20th–26th, and 30th–36th gestational weeks. In this cohort, 25(OH)D plasma concentrations were analysed using liq¬uid chromatography-tandem mass spectrometry. Vitamin D status was categorized as sufficient or insufficient using the Endocrine Society Practice Guidelines (ES) (≥75/<75 nmol/L) and the Institute of Medicine (IOM) (≥50/<50 nmol/L) thresholds. Linear mixed-effect regression models were employed to evaluate the association between vitamin D status and each outcome, considering the interaction terms between vitamin D status and gestational age (P<0.1). At baseline, 70.7% of pregnant women had 25(OH)D levels <75 nmol/L and 16% had levels <50 nmol/L. Women with sufficient vitamin D status at baseline, using both the ES and IOM thresholds, presented lower glycaemia than those with insufficient 25(OH)D. Pregnant women with 25(OH)D concentrations <75 nmol/L showed lower insulin (β=-0.12; 95% CI -0.251, 0.009; P=0.069) and adiponectin (β=-0.070; 95% CI -0.150, 0.010; P=0.085) concentrations throughout pregnancy than those with 25(OH)D levels ≥75 nmol/L. Pregnant women with 25(OH)D <50 nmol/L at baseline presented significantly higher leptin concentrations than those with 25(OH)D levels ≥50 nmol/L (β=-0.253, 95% CI: -0.044; 0.550, P=0.095). The baseline status of vitamin D influences the biomarkers involved in glucose metabolism. Vitamin D sufficient women at baseline had higher increases of insulin and adiponectin changes throughout gestation than those who were insufficient
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