826 research outputs found

    Conception and Construction of a 3 DOF Optical Precision Sensor Integrated in Micro-Robots

    Get PDF
    This diploma project’s goal was to develop a low-cost 3 DOF position sensor of small dimension that permits to find the position and orientation of the actuated object and thus, enable a closed loop control in 3 DOF. The range in X and Y should be at least 30x30mm2 and in Theta-z 360°. An absolute code was implemented in the target in order to always track the absolute position

    The Role of Renin-Angiotensin-Aldosterone System in the Heart and Lung: Focus on COVID-19

    Get PDF
    The renin-angiotensin-aldosterone system (RAAS) firstly considered as a cardiovascular circulating hormonal system, it is now accepted as a local tissue system that works synergistically or independently with the circulating one. Evidence states that tissue RAAS locally generates mediators with regulatory homeostatic functions, thus contributing, at some extent, to organ dysfunction or disease. Specifically, RAAS can be divided into the traditional RAAS pathway (or classic RAAS) mediated by angiotensin II (AII), and the non-classic RAAS pathway mediated by angiotensin 1–7. Both pathways operate in the heart and lung. In the heart, the classic RAAS plays a role in both hemodynamics and tissue remodeling associated with cardiomyocyte and endothelial dysfunction, leading to progressive functional impairment. Moreover, the local classic RAAS may predispose the onset of atrial fibrillation through different biological mechanisms involving inflammation, accumulation of epicardial adipose tissue, and electrical cardiac remodeling. In the lung, the classic RAAS regulates cell proliferation, immune-inflammatory response, hypoxia, and angiogenesis, contributing to lung injury and different pulmonary diseases (including COVID-19). Instead, the local non-classic RAAS counteracts the classic RAAS effects exerting a protective action on both heart and lung. Moreover, the non-classic RAAS, through the angiotensin-converting enzyme 2 (ACE2), mediates the entry of the etiological agent of COVID-19 (SARS-CoV-2) into cells. This may cause a reduction in ACE2 and an imbalance between angiotensins in favor of AII that may be responsible for the lung and heart damage. Drugs blocking the classic RAAS (angiotensin-converting enzyme inhibitors and angiotensin receptor blockers) are well known to exert a cardiovascular benefit. They are recently under evaluation for COVID-19 for their ability to block AII-induced lung injury altogether with drugs stimulating the non-classic RAAS. Herein, we discuss the available evidence on the role of RAAS in the heart and lung, summarizing all clinical data related to the use of drugs acting either by blocking the classic RAAS or stimulating the non-classic RAAS

    Recurrent versus first cervical artery dissection - a retrospective study of clinical and vascular characteristics

    Get PDF
    Background and purpose Most recurrent cervical artery dissection (CeAD) events occur shortly after the acute first CeAD. This study compared the characteristics of recurrent and first CeAD events and searched for associations between subsequent events of an individual person. Methods Cervical artery dissection patients with a new CeAD event occurring during a 3-6 month follow-up were retrospectively selected in seven specialized stroke centers. Clinical and vascular characteristics of the initial and the recurrent CeADs were compared. Results The study sample included 76 patients. Recurrent CeADs were occlusive in one (1.3%) patient, caused cerebral ischaemia in 13 (17.1%) and were asymptomatic in 39 (51.3%) patients, compared to 29 (38.2%) occlusive, 42 (55.3%) ischaemic and no asymptomatic first CeAD events. In 52 (68.4%) patients, recurrent dissections affected both internal carotid arteries or both vertebral arteries, whilst 24 (31.6%) patients had subsequent dissections in both types of artery. Twelve (28.6%) of 42 patients with an ischaemic first dissection had ischaemic symptoms due to the recurrent CeADs, too. However, only one (1.3%) of 34 patients with a non-ischaemic first CeAD suffered ischaemia upon recurrence. Conclusion Recurrent CeAD typically affects the same site of artery. It causes ischaemic events less often than the first CeAD. The risk that patients who presented with solely non-ischaemic symptoms of a first CeAD will have ischaemic symptoms in the case of a recurrent CeAD seems very small.Peer reviewe

    Multifunctional platform based on electrospun nanofibers and plasmonic hydrogel. A smart nanostructured pillow for near-infrared light-driven biomedical applications

    Get PDF
    Multifunctional nanomaterials with the ability to respond to near-infrared (NIR) light stimulation are vital for the development of highly efficient biomedical nanoplatforms with a polytherapeutic approach. Inspired by the mesoglea structure of jellyfish bells, a biomimetic multifunctional nanostructured pillow with fast photothermal responsiveness for NIR light-controlled on-demand drug delivery is developed. We fabricate a nanoplatform with several hierarchical levels designed to generate a series of controlled, rapid, and reversible cascade-like structural changes upon NIR light irradiation. The mechanical contraction of the nanostructured platform, resulting from the increase of temperature to 42 °C due to plasmonic hydrogel-light interaction, causes a rapid expulsion of water from the inner structure, passing through an electrospun membrane anchored onto the hydrogel core. The mutual effects of the rise in temperature and water flow stimulate the release of molecules from the nanofibers. To expand the potential applications of the biomimetic platform, the photothermal responsiveness to reach the typical temperature level for performing photothermal therapy (PTT) is designed. The on-demand drug model penetration into pig tissue demonstrates the efficiency of the nanostructured platform in the rapid and controlled release of molecules, while the high biocompatibility confirms the pillow potential for biomedical applications based on the NIR light-driven multitherapy strategy

    The position of graptolites within Lower Palaeozoic planktic ecosystems.

    Get PDF
    An integrated approach has been used to assess the palaeoecology of graptolites both as a discrete group and also as a part of the biota present within Ordovician and Silurian planktic realms. Study of the functional morphology of graptolites and comparisons with recent ecological analogues demonstrates that graptolites most probably filled a variety of niches as primary consumers, with modes of life related to the colony morphotype. Graptolite coloniality was extremely ordered, lacking any close morphological analogues in Recent faunas. To obtain maximum functional efficiency, graptolites would have needed varying degrees of coordinated automobility. A change in lifestyle related to ontogenetic changes was prevalent within many graptolite groups. Differing lifestyle was reflected by differing reproductive strategies, with synrhabdosomes most likely being a method for rapid asexual reproduction. Direct evidence in the form of graptolithophage 'coprolitic' bodies, as well as indirect evidence in the form of probable defensive adaptations, indicate that graptolites comprised a food item for a variety of predators. Graptolites were also hosts to a variety of parasitic organisms and provided an important nutrient source for scavenging organisms

    The comparison of multipotential for differentiation of progenitor mesenchymal-like stem cells obtained from livers of young and old rats.

    Get PDF
    The presence of stem cells differentiating to hepatocytes and cholangiocytes has been previously reported in livers of young rats. Here, we have isolated, cultured, and characterized mesenchymal stem cells (MSCs) from livers of young and old rats and tested their multipotential for differentiation. The mesenchymal stem cells in liver sections were identified by the presence of markers, respectively for primary stem cells Thy-1 and CD34, for differentiation to early cholangiocytes GST and CK19, and for differentiation to hepatocytes GSTalpha and CK18. Ki67 was detected as the cell proliferation marker. Cells isolated from livers of either age group were tested in a culture for their viability following storage and were characterized for the presence of most of the markers detected in cells in situ. The results revealed age-dependent changes in the number of recovered primary MSCs. In both age groups we have observed cells changing under differentiating conditions to liver cell lineages, such as cholangiocytes and hepatocytes, as well as to non-liver cells such as adipocytes, astrocytes, neuroblasts, and osteoblasts. Our data revealed that from the livers of rats 20 months and older the primary MSCs could be isolated and expanded; however, they were significantly fewer, even though their differentiation multipotential was preserved. The mechanism involved in the differentiation of liver MSCs seemed to depend on a constellation of signals in Notch signalling pathways. Thus, our results support the idea of potential use of liver as a source of MSCs, not only for liver reconstruction but also for cell therapy in general

    Final results of the telaprevir access program: Fibroscan values predict safety and efficacy in hepatitis c patients with advanced fibrosis or cirrhosis

    Get PDF
    Background: Liver stiffness determined by transient elastography is correlated with hepatic fibrosis stage and has high accuracy for detecting severe fibrosis and cirrhosis in chronic hepatitis C patients. We evaluated the clinical value of baseline FibroScan values for the prediction of safety and efficacy of telaprevir-based therapy in patients with advanced fibrosis and cirrhosis in the telaprevir Early Access Program HEP3002. Methods: 1,772 patients with HCV-1 and bridging fibrosis or cirrhosis were treated with telaprevir plus pegylated interferon-α and ribavirin (PR) for 12 weeks followed by PR alone, the total treatment duration depending on virological response and previous response type. Liver fibrosis stage was determined either by liver biopsy or by non-invasive markers. 1,282 patients (72%) had disease stage assessed by FibroScan; among those 46% were classified as Metavir F3 at baseline and 54% as F4. Results: Overall, 1,139 patients (64%) achieved a sustained virological response (SVR) by intentionto- treat analysis. Baseline FibroScan values were tested for association with SVR and the occurrence of adverse events. By univariate analysis, higher baseline FibroScan values were predictive of lower sustained virological response rates and treatment-related anemia. By multivariate analysis, FibroScan was no longer statistically significant as an independent predictor, but higher FibroScan values were correlated with the occurrence of infections and serious adverse events. Conclusions: FibroScan has a limited utility as a predictor of safety and efficacy in patients treated with telaprevir-based triple therapy. Nevertheless it can be used in association with other clinical and biological parameters to help determine patients who will benefit from the triple regiments. © 2015 Lepida et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

    Chronic exposure to low dose of bisphenol A impacts on the first round of spermatogenesis via SIRT1 modulation.

    Get PDF
    Spermatogenesis depends on endocrine, autocrine and paracrine communications along the hypothalamus-pituitary-gonad axis. Bisphenol A (BPA), an estrogen-mimic endocrine disrupting chemical, is an environmental contaminant used to manufacture polycarbonate plastics and epoxy resins with toxic effects for male reproduction. Here we investigated whether the chronic exposure to low BPA doses affects spermatogenesis through the modulation of SIRT1, a NAD+-dependent deacetylase involved in the progression of spermatogenesis, with outcomes on apoptosis, oxidative stress, metabolism and energy homeostasis. BPA exposure via placenta first, and lactation and drinking water later, affected the body weight gain in male offspring at 45 postnatal days and the first round of spermatogenesis, with impairment of blood testis barrier, reactive oxygen species production, DNA damage and decreased expression of SIRT1. The analysis of SIRT1 downstream molecular pathways revealed the increase of acetyl-p53Lys370, ÎłH2AX foci, the decrease of oxidative stress defenses and the higher apoptotic rate in the testis of treated animals, with partial rescue at sex maturation. In conclusion, SIRT1 pathways disruption after BPA exposure can have serious consequences on the first round of spermatogenesis

    Maternal corticotropin-releasing hormone is associated with LEP DNA methylation at birth and in childhood: an epigenome-wide study in Project Viva

    Get PDF
    BackgroundCorticotropin-releasing hormone (CRH) plays a central role in regulating the secretion of cortisol which controls a wide range of biological processes. Fetuses overexposed to cortisol have increased risks of disease in later life. DNA methylation may be the underlying association between prenatal cortisol exposure and health effects. We investigated associations between maternal CRH levels and epigenome-wide DNA methylation of cord blood in offsprings and evaluated whether these associations persisted into mid-childhood.MethodsWe investigated mother-child pairs enrolled in the prospective Project Viva pre-birth cohort. We measured DNA methylation in 257 umbilical cord blood samples using the HumanMethylation450 Bead Chip. We tested associations of maternal CRH concentration with cord blood cells DNA methylation, adjusting the model for maternal age at enrollment, education, maternal race/ethnicity, maternal smoking status, pre-pregnancy body mass index, parity, gestational age at delivery, child sex, and cell-type composition in cord blood. We further examined the persistence of associations between maternal CRH levels and DNA methylation in children's blood cells collected at mid-childhood (n = 239, age: 6.7-10.3 years) additionally adjusting for the children's age at blood drawn.ResultsMaternal CRH levels are associated with DNA methylation variability in cord blood cells at 96 individual CpG sites (False Discovery Rate <0.05). Among the 96 CpG sites, we identified 3 CpGs located near the LEP gene. Regional analyses confirmed the association between maternal CRH and DNA methylation near LEP. Moreover, higher maternal CRH levels were associated with higher blood-cell DNA methylation of the promoter region of LEP in mid-childhood (P < 0.05, β = 0.64, SE = 0.30).ConclusionIn our cohort, maternal CRH was associated with DNA methylation levels in newborns at multiple loci, notably in the LEP gene promoter. The association between maternal CRH and LEP DNA methylation levels persisted into mid-childhood
    • …
    corecore