3,025 research outputs found

    Contributions to Open Problems on Cable Driven Robots and Persistent Manifolds for the Synthesis of Mechanisms

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    Although many efforts are continuously devoted to the advancement of robotics, there are still many open and unresolved problems to be faced. This thesis, therefore, sets out to tackle some of them with the aim of scratching the surface and look a little further for new ideas or solutions. The topics covered are mainly two. The first part deals with the development and improvement of control techniques for cable-driven robots. The second focuses on the study of persistent manifolds seen as constituting aspects of theoretical kinematics. In detail, -Part I deals with cable-driven platforms. In it, both techniques for selecting cable tensions and the design of a robust controller are developed. The aim is, therefore, to enhance the two building blocks of the overall control scheme in order to improve the performance of these robots during the execution of tracking tasks. -- The first chapter introduces to open problems and recalls the main concepts necessary to understand the following chapters; -- the contribution of the second chapter consists of the introduction of the Analytic Centre. It allows the generation of continuous and differentiable tension profiles while taking into account non-linear phenomena such as friction in the computation of tensions to be applied; -- the third chapter, although still at a preliminary stage, introduces sensitivity for tension calculation methods, offering perspectives of considerable interest for tension control in the current scientific context; -- the fourth chapter proposes the design of an adaptive controller. It allows external disturbances and/or uncertainties in the model to be faced such that the task can be performed with as little error as possible. The controller architecture is the innovative peculiarity conferring autonomy to cable systems. Initially applied to counteract wind in aerial systems it is now also used for cable breakage scenarios; -- the conclusions, at first, draw together the results obtained. In addition, they emphasise the lack of the techniques introduced in order to outline possible future paths and topics that need further investigation. - Part II delves into theoretical kinematics. The discovery and classification of invariant screw systems shed light on numerous aspects of robot mobility and synthesis. Nevertheless, this generated the emergence of new ideas and questions that are still unresolved. Among them, one of the more notable concerns the identification and classification of 5-dimensional persistent manifolds. -- Similarly to the first part, the first chapter provides an overview of the problems addressed and the theoretical notions necessary to understand the subsequent contributions; -- the second chapter contributes by directly tackling the above-mentioned question by exploiting the properties of dual quaternions, the Study quadric and differential geometry. A library of 5-persistent varieties, so far missing in the literature, is presented along with theorems that complete and generalise previous ones in the literature; -- an original work, concerning line motions and synthesis of mechanisms that generate them, is reported in the third chapter as a spin-off of the studies on persistent manifolds; -- the conclusions wrap up the obtained results trying to highlight gaps and deficiencies to be dealt with in the future. Here, two small sections are dedicated to ongoing works regarding the persistence definition and the screw systems' invariants and subvariants

    GALNT2 mRNA levels are associated with serum triglycerides in humans

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    Atherogenic dyslipidemia, characterized by high triglycerides (TG) and low high density lipoprotein (HDL)-cholesterol levels, is a feature of patients with insulin resistance, obesity, and type 2 diabetes (T2D) [1] and plays a major role in shaping the risk of cardiovascular disease. Both TG and HDL-cholesterol serum concentrations are under the control of both environmental factors and up to 95 genetic loci, unraveled by a very large genome-wide association study (GWAs) in approximately 100,000 individuals [2]. Among these loci is GALNT2, which encode for ppGal-NAc-T2, involved in O-linked glycosylation. Similarly, studies in rodents have shown that liver GALNT2 expression modulates HDL-cholesterol concentrations [2]. Based on such studies, it is conceivable that GALNT2 expression changes play a role on TG and/or HDL-cholesterol levels. To gain further insights about this hypothesis, GALNT2 expression was measured in peripheral white blood cells (PWBC), from 224 individuals with a wide range of TG and HDL-cholesterol levels, as well as other metabolic parameters and clinical conditions

    Two phase partitioning bioreactor applied to produced water treatment

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    Produced waters are the largest waste associated with the production of oil and gas; they contain dissolved salts, oil (dissolved and scattered organic compounds), chemicals and additives involved in the oil well operations, suspended particles, sand and other compounds, making their treatment very complex. In this paper, we propose the use of a TPPB (two phase partitioning bioreactor) for the biological treatment of produced waters. We model the application of the TPPB on the stream after classical pre-treatment stages: the reactor behaviour is based on the controlled release of substrate by means of an organic solvent. This study aims at developing a mathematical model for a TPPB adopting oleic alcohol (Adol 85 NF) as a solvent: we test model reliability by means of a sensitivity analysis in order to evaluate the reactor efficiency for chemical oxygen demand (COD) removal in a produced water stream, aimed at water reuse

    Caratterizzazione sperimentale di cicli di cottura di un forno domestico ad incasso

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    L'obiettivo di questa tesi era caratterizzare il forno dell'Electrolux, andando a capire quali fossero i fenomeni di scambio termico presenti all'interno della cavità durante le diverse modalità di funzionamento (statico e ventilato) ed al variare del set-point. Tale obiettivo è stato raggiunto in maniera graduale: inizialmente si è caratterizzato il forno a vuoto e, successivamente, è stato utilizzato un "mattone standard" che simulasse la reale presenza del cibo. Quest'ultimo passo è stato realizzato seguendo la normativa "TM SP000003129 - EU Energy Consumption Test for Electric Ovens" relativa alla determinazione dell'indice di efficienza del forno. Mentre il primo obiettivo è stato raggiunto con successo, la determinazione dell'indice di efficienza è stata influenzata da parametri non controllabili, facendo si che i risultati ottenuti non corrispondessero a quelli dichiarati dalla casa costruttrice

    Elastosonographic features of the metacarpophalangeal joint capsule in horses

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    Background: Capsulitis leads to the release of inflammatory mediators in the joint, causing capsular fibrosis and osteoarthritis (OA). Strain elastosonography (SE) measures the elasticity of tissue by evaluating its strain in operator-dependent deformation. The aims of the study were to assess the feasibility, repeatability, and reproducibility of SE for imaging the distal attachment of the joint capsule (DJC) of metacarpophalangeal joints in sound horses (Group S) and in horses with metacarpophalangeal OA (Group P) and to evaluate differences in the elastosonographic patterns of these horses. After a whole lameness examination, fore fetlock DJCs were assigned to Group S and Group P and were thereafter examined by two operators using SE. Qualitative (i.e., colour grading score) and semi-quantitative (i.e., elasticity index (EI) and strain ratio (SR)) methods were used to evaluate the elastograms. The inter-rater reliability (IRR), intraclass correlation coefficient (intra-CC) and interclass correlation coefficient (inter-CC) were used to compare colour grading scores and the repeatability and reproducibility of EI and SR outcomes. The same parameters were compared between groups. P < 0.05 indicated a significant finding. Results: Forty-one horses were included: 11 were in Group S and 30 were in Group P (16 with bilateral OA, 8 with left OA and 6 with right OA). IRR outcomes ranged from good to excellent. For transverse and longitudinal ultrasound scans, the colour grading score of Group S was significantly higher than the metacarpophalangeal DJCs of Group P. Both Inter-CC and intra-CC were higher in Group S than in Group P, with values always > 0.8. Significative differences in EI and SR were detected between groups and between Group S and the affected limb of Group P; values were lower in Group S than in Group P. Conclusions: SE can be a useful technique for evaluating DJCs, with good repeatability and reproducibility. DJCs appear softer in sound horses

    Suggestive evidence of a multi-cytokine resistin pathway in humans and its role on cardiovascular events in high-risk individuals

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    In cells and tissues resistin affects IL-1β, IL-6, IL-8, IL-12 and TNF-α expression, thus suggesting the existence of a multi-cytokine "resistin pathway". We investigated whether such pathway does exist in humans and, if so, if it is associated with cardiovascular risk factors and with major adverse cardiovascular events (MACE). Serum cytokines were measured in 280 healthy subjects from the Gargano Study 2 (GS2) whose BMI, waist circumference, HOMA IR, triglycerides, HDL-cholesterol, systolic and diastolic blood pressure data were available and in 353 patients with type 2 diabetes and coronary artery disease from the Gargano Heart Study (GHS)-prospective design (follow-up 5.4 ± 2.5 years; 71 MACE). In GS2, cytokines mRNA levels in white blood cells were also measured. In GS2, resistin mRNA was correlated with all cytokines expression (all p < 0.001), but IL-12B. Consistently, serum resistin was correlated with all serum cytokines (all p < 0.001), but IL-12. Expression (eRPS) and serum (sRPS) resistin pathway scores (excluding IL-12) were each other correlated (p < 0.001) and both associated with cardiovascular risk factors (all p < 0.01). In GHS, sRPS was independently associated with MACE (HR = 1.44, 95% CI = 1.10-1.90). Our data indicate the existence of a resistin pathway, which is associated with cardiovascular risk factors and which strongly and independently predicts MACE

    Evaluation of the management of Hr-HPV+/PapTest- women. Results at 1-year recall

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    With cervical cancer screening the choice of 1-year as a period of follow-up in positive high-risk HPV women without cytological lesions is still under discussion. We evaluated the management of these women and the role of HPV genotyping test. We did a cervical cancer screening study of women aged 35-64 with primary high-risk HPV test. Women positive for high-risk HPV with negative cytology were followed-up after 1 year. In this study we selected women with high-risk HPV+/PapTest- resulted high-risk HPV+ at recall and performed the PapTest and HPV genotyping test. The detection rate of squamous high grade (CIN2+) relative to the total screened cohort was 2.1‰, and it was 0.2‰ at the 1-year recall. The colposcopy performed in women referred at the 1-year recall accounted for 48.8% of the total (baseline + 1-year recall), and 84.3% of these women had no cytological lesions. The most frequent hr-HPV genotype detected was HPV16 and 66.7% of co-infections were due to HPV16 and HPV18. 54.5% of women presented a persistent infection at 1-year recall with the same HPV subtype, 50% of persistent infections was due to HPV16 and 16.7% of these were determined to be CIN2+ histological lesions. Our data show that it may be useful to extend the period of follow-up for women hr-HPV+/PapTest- so as to reduce the number of unnecessary colposcopies due to the transitory infections and that the genotyping test could help to identify the persistent infections in which HPV16 is involved

    Cognitive Health of Nonagenarians in Southern Italy: A Descriptive Analysis from a Cross-Sectional, Home-Based Pilot Study of Exceptional Longevity (Cilento Initiative on Aging Outcomes Or CIAO).

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    Background: Nonagenarians and centenarians (NCs) are an extremely fragile population, particularly in regard to their physical and cognitive function. The aim of this study was to define the neurocognitive profiles among 29 NCs and their 49 younger cohabitants aged 50-75 years from The Cilento Initiative on Aging Outcomes (CIAO) Pilot study in the South of Italy that had provided initial hypotheses regarding positive psychological traits related to exceptional longevity. Methods: During the home visits, lifestyle information with specific questionnaires, functional autonomy and the neuropsychological Mini Mental Scale Examination (MMSE), and the Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog) scale were obtained by qualified study personnel. The total blood oxidative capacity was also determined by testing the reactive derivative of oxygen metabolites (d-ROM) and by the Biological Antioxidant Potential (BAP). In all individuals, the APOE genotype determination was also performed. Results: All the subjects in both groups showed high adherence to the Mediterranean Diet. None of the NCs had severe cognitive impairment, and a very low incidence of dementia was found. The data obtained on the Activities ed Instrumental Activities of Daily Living (ADL-IADL) scale showed that the majority of NCs (16/29) were autonomous in daily life activities. The comparative assessment of NCs and cohabitants showed no significant differences in the laboratory assessment of oxidative stress and APOE genotype. Conclusion: In the Cilento Region of Southern Italy, NCs seemed to have good cognitive status when compared to younger cohabitants aging 50-65 years without significant differences in oxidative stress markers or APOE genotype. These results might be related to optimal adherence to the Mediterranean diet, although other lifestyle factors and positive personality traits may also contribute to their healthy aging. Further studies on a larger population should be performed to confirm the results of this pilot study

    2D-SWE of the Metacarpophalangeal Joint Capsule in Horses

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    (1) Two-dimensional shear wave elastography (2D-SWE) employs an ultrasound impulse to produce transversely oriented shear waves, which travel through the surrounding tissue according to the stiffness of the tissue itself. The study aimed to assess the reliability of 2D-SWE for evaluating the elastosonographic appearance of the distal attachment of the fetlock joint capsule (DJC) in sound horses and in horses with osteoarthritis (OA) (2). According to a thorough evaluation of metacarpophalangeal joint (MCPJ), adult horses were divided in a sound Group (H) and in OA Group (P). Thereafter, a 2D-SWE of MCPJs was performed. Shear wave velocity (m/sec) and Young's modulus (kPa) were calculated independently by two operators at each selected ROI. Statistical analysis was performed with R software. (3) Results: 2D-SWE had good-excellent inter-CC and intra-CC in both groups. Differences in m/s and kPa between Groups H and P were found in transverse scans with lower values in Group P. No correlation with age or DJC thickness was found. (4) Conclusions: 2D-SWE was repeatable and reproducible. In Group H, DJC was statistically stiffer than in Group P only in transverse scan. The technique showed poor sensitivity and specificity in differentiating fetlocks affected by OA

    Analysis of Catania Flash Flood Case Study by Using Combined Microwave and Infrared Technique

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    Abstract In this paper, the analysis of an extreme convective event atypical for the winter season, which occurred on 21 February 2013 on the east coast of Sicily and caused a flash flood over Catania, is presented. In just 1 h, more than 50 mm of precipitation was recorded, but it was not forecast by numerical weather prediction (NWP) models and, consequently, no severe weather warnings were sent to the population. The case study proposed is first examined with respect to the synoptic situation and then analyzed by means of two algorithms based on satellite observations: the Cloud Mask Coupling of Statistical and Physical Methods (MACSP) and the Precipitation Evolving Technique (PET), developed at the National Research Council of Italy. Both of the algorithms show their ability in the near-real-time monitoring of convective cell formation and their rapid evolution. As quantitative precipitation forecasts by NWP could fail, especially for atypical convective events like in Catania, tools like MACSP and PET shall be adopted by civil protection centers to monitor the real-time evolution of deep convection events in aid to the severe weather warning service
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