89 research outputs found

    On the Stiffness Analysis and Elastodynamics of Parallel Kinematic Machines

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    Dynamic Model of a Conjugate-Surface Flexure Hinge Considering Impacts between Cylinders

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    A dynamic model of a Conjugate-Surface Flexure Hinge (CSFH) has been proposed as a component for MEMS/NEMS Technology-based devices with lumped compliance. However, impacts between the conjugate surfaces have not been studied yet and, therefore, this paper attempts to fill this gap by proposing a detailed multibody system (MBS) model that includes not only rigid-body dynamics but also elastic forces, friction, and impacts. Two models based on the Lankarani-Nikravesh constitutive law are first recalled and a new model based on the contact of cylinders is proposed. All three models are complemented by the friction model proposed by Ambrosio. Then, the non-smooth Moreau time-stepping scheme with Coulomb friction is described. The four models are compared in different scenarios and the results confirm that the proposed model outcomes comply with the most reliable models

    Medical tattooing, the new frontiers: a case of nail bed reconstruction.

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    The primary objective of medical tattooing is to restore part of a patient’s physical integrity. Moreover, the procedure seeks to assist in psychological recovery from the physical and/or psychological consequences of disease, surgery or trauma. The method described in this brief note marks a step forward in the field of such tattooing. The treatment simulates reconstruction of the nail bed, as the nails of the big toes had previously been removed through a surgical avulsion procedure. This treatment, agreed with the physician and performed by a tattooist with proven experience in medical tattooing, also involved the use of specific colour nuances that resulted in an extremely realistic outcome

    Trophic preferences of three allochthonous fishes in Bormida River (Alessandria, NW Italy)

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    The introduction of alien species is currently one of the greatest threats to biodiversity conservation. This is particularly true in river systems, where in recent years the growth of allochtonous or non-native species has increased dramatically. Numerous studies have investigated the presence and the distribution of invasive species, but few focused on the trophic habits of fish species introduced into new lotic environments. This paper provides information on the diet of three alien species in the Bormida River, a lotic system previously altered by chemical pollution. Barbus barbus shows a wide trophic spectrum, feeding mostly on benthic invertebrates but also consuming terrestrial arthropods, coarse particulate organic matter, filamentous algae and, more rarely, fish. Feeding activity of Pseudorasbora parva was mostly based on aquatic invertebrates but also algae and fine particulate organic matter was frequently ingested. Regarding diet analysis of Rhodeus amarus, fine detritus and algae were the most important components in the examined guts. There are significant potential overlaps with the trophic spectrum of native species

    Neoadjuvant Treatments for Pancreatic Ductal Adenocarcinoma: Where We Are and Where We Are Going

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    Background: Pancreatic ductal adenocarcinoma (PDAC) represents a challenging disease for the surgeon, oncologist, and radiation oncologist in both diagnostic and therapeutic settings. Surgery is currently the gold standard treatment, but the role of neoadjuvant treatment (NAD) is constantly evolving and gaining importance in resectable PDACs. The aim of this narrative review is to report the state of the art and future perspectives of neoadjuvant therapy in patients with PDAC. Methods: A PubMed database search of articles published up to September 2022 was carried out. Results: Many studies showed that FOLFIRINOX or Gemcitabine-nab- paclitaxel in a neoadjuvant setting had a relevant impact on overall survival (OS) for patients with locally advanced and borderline resectable PDAC without increasing post-operative complications. To date, there have not been many published multicentre randomised trials comparing upfront surgery with NAD in resectable PDAC patients, but the results obtained are promising. NAD in resectable PDAC showed long-term effective benefits in terms of median OS (5-year OS rate 20.5% in NAD group vs. 6.5% in upfront surgery). NAD could play a role in the treatment of micro- metastatic disease and lymph nodal involvement. In this scenario, given the low sensitivity and specificity for lymph-node metastases of radiological investigations, CA 19-9 could be an additional tool in the decision-making process. Conclusions: The future challenge could be to identify only selected patients who will really benefit from upfront surgery despite a combination of NAD and surgery

    Molecular and clinical studies in five index cases with novel mutations in the GLA gene

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    Fabry disease is a metabolic and lysosomal storage disorder caused by the functional defect of the α-galactosidase A enzyme; this defect is due to mutations in the GLA gene, that is composed of seven exons and is located on the long arm of the X-chromosome (Xq21–22). The enzymatic deficit is responsible for the accumulation of glycosphingolipids in lysosomes of different cellular types, mainly in those ones of vascular endothelium. It consequently causes a cellular and microvascular dysfunction. In this paper, we described five novel mutations in the GLA gene, related to absent enzymatic activity and typical manifestations of Fabry disease. We identified three mutations (c.846_847delTC, p.E341X and p.C382X) that lead to the introduction of a stop codon in positions 297, 341 and 382. Moreover we found a missense mutation (p.R227P) in the exon 5 of the GLA gene and a single point mutation (c.639 + 5 G > T) occurring five base pairs beyond the end of the exon 4. These mutations have never been found in our group of healthy control subjects > 2300. The studied patients presented some clinical manifestations, such as cornea verticillata, hypo-anhidrosis, left ventricular hypertrophy, cerebrovascular disorders and renal failure, that, considering the null enzymatic activity, suggest that the new mutations reported here are related to the classic form of Fabry disease. The identification of novel mutations in patients with symptomatology referable to FD increases the molecular knowledge of the GLA gene and it gives clinicians an important support for the proper diagnosis of the disease

    Can Be miR-126-3p a Biomarker of Premature Aging? An Ex Vivo and In Vitro Study in Fabry Disease

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    Fabry disease (FD) is a lysosomal storage disorder (LSD) characterized by lysosomal accumulation of glycosphingolipids in a wide variety of cytotypes, including endothelial cells (ECs). FD patients experience a significantly reduced life expectancy compared to the general population; therefore, the association with a premature aging process would be plausible. To assess this hypothesis, miR-126-3p, a senescence-associated microRNA (SA-miRNAs), was considered as an aging biomarker. The levels of miR-126-3p contained in small extracellular vesicles (sEVs), with about 130 nm of diameter, were measured in FD patients and healthy subjects divided into age classes, in vitro, in human umbilical vein endothelial cells (HUVECs) "young" and undergoing replicative senescence, through a quantitative polymerase chain reaction (qPCR) approach. We confirmed that, in vivo, circulating miR-126 levels physiologically increase with age. In vitro, miR-126 augments in HUVECs underwent replicative senescence. We observed that FD patients are characterized by higher miR-126-3p levels in sEVs, compared to age-matched healthy subjects. We also explored, in vitro, the effect on ECs of glycosphingolipids that are typically accumulated in FD patients. We observed that FD storage substances induced in HUVECs premature senescence and increased of miR-126-3p levels. This study reinforces the hypothesis that FD may aggravate the normal aging process

    Fabry disease and multiple sclerosis misdiagnosis: The role of family history and neurological signs

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    Fabry disease (FD) is an X-linked inherited lysosomal storage disorder caused by a galactosidase A (a-gal A) deficiency. Central nervous system involvement and chronic white matter lesions are observed in both FD and multiple sclerosis (MS), which can confound the differential diagnosis. We analyzed the GLA gene, which encodes a-gal A, in 86 patients with clinical and neuroradiological findings consistent with MS to determine whether they had FD. We identified four women initially diagnosed with MS who had GLA mutations associated with FD. Our results indicate that family history besides neurological findings should be evaluated in patients with an uncertain diagnosis of MS. Also the involvement of organs outside the central nervous system can support the FD diagnosis

    Sports activity limitation during the COVID-19 pandemic in young Italian athletes: impact on mental health in children, adolescents, and young adults

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    IntroductionThe closure of sports centres was implemented as a preventive measure to mitigate the transmission of SARS-CoV-2. Given the observed global decline in physical activity and concurrent rise in sedentary behaviour, even among younger age groups, a retrospective cross-sectional study was undertaken to evaluate the effects of this measure on mental health in children, adolescents, and young adults during the initial phases of the COVID-19 pandemic.MethodsA total of 1,717 non-professional athletes (age range: 6–25; 53.9% males, 44.6% females) completed an online questionnaire including widely used and validated measures for mental health assessment (SDQ and PGWB-S) and questions regarding sociodemographic characteristics (such as gender), physical activity, and screen time. The association between mental health and sociodemographic characteristics, physical activity, and screen time was evaluated by using univariate and multivariable logistic regression models.ResultsIn children and adolescents, the incidence of psychological difficulties was associated with not being physically active (OR = 1.49; 95% CI: 1.09, 2.07; p = 0.015). Engaging in physical activity during the period of closures, particularly if more than twice a week, was significantly associated with less psychological difficulties for children/adolescents (OR = 0.54; 95% CI: 0.35, 0.82; p = 0.004) and psychological symptoms (i.e., psychological well-being lower than the median) for youth/young adults (OR = 0.25; 95% CI: 0.14, 0.45; p < 0.001). More psychological difficulties were also found in males for children and adolescents (OR = 1.37; 95% CI: 1.06, 1.79; p = 0.018). However, young adult males showed less psychological symptoms than females (OR = 0.35; 95% CI: 0.22, 0.55; p = 0.001). Additionally, a greater amount of screen time was associated with a higher incidence of psychological symptoms in the whole sample.ConclusionsOur results confirm the positive impact of physical activity on mental health during the COVID-19 pandemic among younger age groups. They also provide valuable insights into the risk-benefit relationship of interrupting sports activities as a preventive measure for infectious diseases
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