3,109 research outputs found

    Small and large scale segmental motion in polymers: Estimating cooperativity length by ordinary relaxation experiments

    Get PDF
    We derive a suitable expression for estimating the size of the cooperatively rearranging regions (CRRs) in supercooled polymer melts by fitting data worked out by ordinary relaxation experiments carried out in isothermal conditions. As an example, the average CRR size in poly(n-butyl methacrylate) in proximity to the glass transition temperature is derived from a stress relaxation experiment performed by means of an atomic force microscopy setup. Good agreement is found with results in the literature derived from measurements of temperature fluctuations (the so-called Donth method). The temperature dependence of the CRR size is explored for poly(butadiene); in this case the segmental relaxation function is derived through a novel method for the analysis of the efficiency with which free induction decay echoes are refocused in 1H NMR experiments. It is found that the CRR size increases upon cooling. The results derived from the analysis of the NMR data are found to be in satisfactory agreement with those worked out from broadband dielectric spectroscopy data in the literatur

    City Focus: A web-based interactive 2D and 3D GIS application to find the best place in a city, using open data and open source software

    Get PDF
    City Focus is a webbased interactive 2D and 3D GIS application to find the best place in a city to live as well as to pass shorter staying. The user can select among different criteria and decide their importance by assigning weights to each of them. The application provides thematic maps displaying insights on the places which better fit the user’s preferences. The resulting map is computed through map algebra by means of Web Coverage Processing Service WCPS provided by RASDAMAN Database Management System. Data visualization is mainly based on NASA Web WorldWind opensource virtual globe. The app exploits exclusively open data as well as Free and Open Source Software (FOSS) for its implementation by enabling continuous improvements while minimizing development costs

    Is spinal muscular atrophy a disease of the motor neurons only: pathogenesis and therapeutic implications?

    Get PDF
    Spinal muscular atrophy (SMA) is a genetic neurological disease that causes infant mortality; no effective therapies are currently available. SMA is due to homozygous mutations and/or deletions in the survival motor neuron 1 gene and subsequent reduction of the SMN protein, leading to the death of motor neurons. However, there is increasing evidence that in addition to motor neurons, other cell types are contributing to SMA pathology. In this review, we will discuss the involvement of non-motor neuronal cells, located both inside and outside the central nervous system, in disease onset and progression. Even if SMN restoration in motor neurons is needed, it has been shown that optimal phenotypic amelioration in animal models of SMA requires a more widespread SMN correction. It has been demonstrated that non-motor neuronal cells are also involved in disease pathogenesis and could have important therapeutic implications. For these reasons it will be crucial to take this evidence into account for the clinical translation of the novel therapeutic approaches

    IPSC-derived neural stem cells act via kinase inhibition to exert neuroprotective effects in spinal muscular atrophy with respiratory distress type 1

    Get PDF
    Spinal muscular atrophy with respiratory distress type 1 (SMARD1) is a motor neuron disease caused by mutations in the IGHMBP2 gene, without a cure. Here, we demonstrate that neural stem cells (NSCs) from human-induced pluripotent stem cells (iPSCs) have therapeutic potential in the context of SMARD1. We show that upon transplantation NSCs can appropriately engraft and differentiate in the spinal cord of SMARD1 animals, ameliorating their phenotype, by protecting their endogenous motor neurons. To evaluate the effect of NSCs in the context of human disease, we generated human SMARD1-iPSCs motor neurons that had a significantly reduced survival and axon length. Notably, the coculture with NSCs ameliorate these disease features, an effect attributable to the production of neurotrophic factors and their dual inhibition of GSK-3 and HGK kinases. Our data support the role of iPSC as SMARD1 disease model and their translational potential for therapies in motor neuron disorders

    The LHCb ultra-fast simulation option, Lamarr: design and validation

    Full text link
    Detailed detector simulation is the major consumer of CPU resources at LHCb, having used more than 90% of the total computing budget during Run 2 of the Large Hadron Collider at CERN. As data is collected by the upgraded LHCb detector during Run 3 of the LHC, larger requests for simulated data samples are necessary, and will far exceed the pledged resources of the experiment, even with existing fast simulation options. An evolution of technologies and techniques to produce simulated samples is mandatory to meet the upcoming needs of analysis to interpret signal versus background and measure efficiencies. In this context, we propose Lamarr, a Gaudi-based framework designed to offer the fastest solution for the simulation of the LHCb detector. Lamarr consists of a pipeline of modules parameterizing both the detector response and the reconstruction algorithms of the LHCb experiment. Most of the parameterizations are made of Deep Generative Models and Gradient Boosted Decision Trees trained on simulated samples or alternatively, where possible, on real data. Embedding Lamarr in the general LHCb Gauss Simulation framework allows combining its execution with any of the available generators in a seamless way. Lamarr has been validated by comparing key reconstructed quantities with Detailed Simulation. Good agreement of the simulated distributions is obtained with two-order-of-magnitude speed-up of the simulation phase.Comment: Under review in EPJ Web of Conferences (CHEP 2023

    Breast Melanoma Metastases: Do We Know Enough? A very Rare Case with a Poor Prognosis: Case Report

    Get PDF
    The incidence of malignant melanoma (MM) is increasing especially in the western population; in Europe, the incidence is less than 10-20 new cases of melanoma per 100,000 inhabitants..

    Direct reprogramming of adult somatic cells into other lineages: past evidence and future perspectives

    Get PDF
    Direct reprogramming of an adult cell into another differentiated lineage-such as fibroblasts into neurons, cardiomyocytes, or blood cells-without passage through an undifferentiated pluripotent stage is a new area of research that has recently emerged alongside stem cell technology and induced pluripotent stem cell reprogramming; indeed, this avenue of investigation has begun to play a central role in basic biology research and regenerative medicine. Even though the field seems new, its origins go back to the 1980s when it was demonstrated that differentiated adult cells can be converted into another cell lineage through the overexpression of transcription factors, establishing mature cell plasticity. Here, we retrace transdifferentiation experiments from the discovery of master control genes to recent in vivo reprogramming of one somatic cell into another from the perspective of possible applications for the development of new therapeutic approaches for human diseases

    "Paradoxical" p16 overexpression in cutaneous melanoma: Molecular and immunohistochemical analysis of a rare phenomenon with a focus on cell cycle regulatory molecules

    Get PDF
    Background: One of the most relevant genetic alterations in cutaneous melanoma (CM) is the biallelic inactivation/loss-of-heterozygosis (LOH) of cyclin-dependent kinase inhibitor 2 A (CDKN2A), which results in the immunohistochemical loss of p16 frequently found in CM. However, we recently described a rare case of dermal/deep-seated melanoma arising in giant congenital nevus (DDM-GCN) with p16 overexpression combined with p53 loss and tumor protein 53 (TP53) mutation. Herein, we reported a case series of CM with p16 overexpression and analyzed their clinicopathologic features, immunohistochemical expression of the cell cycle regulatory molecules (CCRM: p53, p21, Cyclin D1, Rb), and mutational landscape. Methods: We retrospectively tested for p16 all cases of CM diagnosed at our institution between January 1st 2019-April 1st 2022. In CM with p16 overexpression, we reported clinicopathologic features, immunohistochemical results for melanocytic markers and CCRM, and mutational landscape investigated with a next-generation sequencing (NGS) panel. In cases with zonal p16 overexpression, the immunohistochemical assessment for melanocytic markers and CCRM, as well as the NGS analysis have been performed in both components {with and without p16 overexpression [p16(+)c and p16(-)]}. Results: Overexpression of p16 was found in 10/2879 (0.35%) CM [5/10 (50%) diffuse and 5/10 (50%) zonal]. We combined the immunohistochemical results for CCRM and molecular data to classify the cases as follows: a) Group 1 with altered expression of at least one CCRM but no TP53 mutations [3/10 (30%), all with Rb altered/lost]; b) Group 2 with altered expression of at least one CCRM and TP53 mutations [4/10 (40%), all with p53 altered]; c) Group 3 with normal expression of CCRM and no TP53 mutations [3/10 (30%), all with mutations in MAPK pathway genes (NRAS and BRAF)]. In CM with zonal p16 overexpression, the histologic appearance of p16(+)c was heterogeneous, whereas combining CCRM profiles and molecular data the cases could be categorized as follows: a) cases with the same CCRM and molecular profiles in both p16(+)c and p16(-)c; b) cases with p16(+)c showing additional genetic mutations and/or modifications of CCRM expression. Conclusions: p16 overexpression is a rare event, occurring in advanced-stage, clinically- and histologically-heterogeneous CM. These lesions may be classified into three different groups based on CCRM expression and mutational profiles (including TP53 mutation). The analysis of CM with zonal p16 overexpression suggests that, at least in a subset of cases, this phenomenon could represent a sign of "molecular progression" due to the acquisition of additional genetic mutations and/or modifications of the CCRM profile
    • …
    corecore