233 research outputs found

    A perturbed MicroRNA expression pattern characterizes embryonic neural stem cells derived from a severe mouse model of spinal muscular atrophy (SMA)

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    Spinal muscular atrophy (SMA) is an inherited neuromuscular disorder and the leading genetic cause of death in infants. Despite the disease-causing gene, survival motor neuron (SMN1), encodes a ubiquitous protein, SMN1 deficiency preferentially affects spinal motor neurons (MNs), leaving the basis of this selective cell damage still unexplained. As neural stem cells (NSCs) are multipotent self-renewing cells that can differentiate into neurons, they represent an in vitro model for elucidating the pathogenetic mechanism of neurodegenerative diseases such as SMA. Here we characterize for the first time neural stem cells (NSCs) derived from embryonic spinal cords of a severe SMNΔ7 SMA mouse model. SMNΔ7 NSCs behave as their wild type (WT) counterparts, when we consider neurosphere formation ability and the expression levels of specific regional and self-renewal markers. However, they show a perturbed cell cycle phase distribution and an increased proliferation rate compared to wild type cells. Moreover, SMNΔ7 NSCs are characterized by the differential expression of a limited number of miRNAs, among which miR-335-5p and miR-100-5p, reduced in SMNΔ7 NSCs compared to WT cells. We suggest that such miRNAs may be related to the proliferation differences characterizing SMNΔ7 NSCs, and may be potentially involved in the molecular mechanisms of SMA

    What inspires young people to study physics? Results from the WG1 interviews survey

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    The talk will focus on the main results of an Interview based Survey of 1st Year University Physics Students, carried out within Working Group 1 (WG1) of the HOPE project. Among the HOPE activities, 112 interviews have been conducted in 16 universities, in order to investigate in some depth the factors that inspire young people to study physics and to identify possible critical factors which can produce the dropping out.The individual interviews have been carried out on a selection of students who had previously answered the WG1 Questionnaire on the inspirational factors, led by Gareth Jones from the Imperial College, London. In the talk, we will show how the interviews helped us to unpack the main results achieved with the questionnaire survey. In particular, we will present a comprehensive picture of \u201ccuriosity\u201d which turned out to be the predominant motivating factor and we will show how the interviews can throw extra light on reasons for comparatively low scores for factors like (i) enhancing employment prospects, (ii) effect of physics teacher, (iii) scientists in the family

    Folding mechanisms steer the amyloid fibril formation propensity of highly homologous proteins

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    Significant advances in the understanding of the molecular determinants of fibrillogenesis can be expected from comparative studies of the aggregation propensities of proteins with highly homologous structures but different folding pathways. Here, we fully characterize, by means of stopped-flow, T-jump, CD and DSC experiments, the unfolding mechanisms of three highly homologous proteins, zinc binding Ros87 and Ml153-149 and zinc-lacking Ml452-151. The results indicate that the three proteins significantly differ in terms of stability and (un)folding mechanisms. Particularly, Ros87 and Ml153-149 appear to be much more stable to guanidine denaturation and are characterized by folding mechanisms including the presence of an intermediate. On the other hand, metal lacking Ml452-151 folds according to a classic two-state model. Successively, we have monitored the capabilities of Ros87, Ml452-151 and Ml153-149 to form amyloid fibrils under native conditions. Particularly, we show, by CD, fluorescence, DLS, TEM and SEM experiments, that after 168 hours, amyloid formation of Ros87 has started, while Ml153-149 has formed only amorphous aggregates and Ml452-151 is still monomeric in solution. This study shows how metal binding can influence protein folding pathways and thereby control conformational accessibility to aggregation-prone states, which in turn changes aggregation kinetics, shedding light on the role of metal ions in the development of protein deposition diseases

    An overview of physics teacher professional development activities organized within the Italian PLS-Physics plan over the past five years

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    The Italian PLS-"Piano Lauree Scientifiche"project has among its objectives the improvement of school-university cooperation, with a special emphasis on in-service teacher professional development. In pursuit of such goal, growing resources and an increasing effort to strengthen the collaboration with schools have been employed in the past years. A working group within the physics section of the PLS project has developed a questionnaire to inquire about teacher formation activities organized during the past five years. After extensive revision and testing, the university network of PLS-Physics was asked to fill the questionnaire. The resulting data from 139 initiatives provides an interesting perspective on the kind of activities, organizational choices and educational priorities for teacher professional development within the PLS-physics project

    Probing the Residual Structure in Avian Prion Hexarepeats by CD, NMR and MD Techniques

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    Many proteins perform essential biological functions by means of regions that lacking specific organized structure exist as an ensemble of interconverting transient conformers. The characterization of such regions, including the description of their structural propensities, number of conformations and relative populations can provide useful insights. Prion diseases result from the conversion of a normal glycoprotein into a misfolded pathogenic isoform. The structures of mammal and chicken prion proteins show a similar fold with a globular domain and a flexible N-terminal portion that contains different repeated regions: octarepeats (PHGGGWGQ) in mammals and hexarepeats (PHNPGY) in chickens. The higher number of prolines in the hexarepeat region suggests that this region may retain a significant amount of residual secondary structure. Here, we report the CD, NMR and MD characterization of a peptide (2-HexaPY) composed of two hexarepeats. We combine experimental NMR data and MD to investigate at atomic level its ensemble-averaged structural properties, demonstrating how each residue of both repeats has a different quantified PPII propensity that shows a periodicity along the sequence. This feature explains the absence of cooperativity to stabilize a PPII conformation. Nonetheless, such residual structure can play a role in nucleating local structural transitions as well as modulating intra-molecular or inter-molecular interactions

    In search of the keys of deep understanding: Physics education research in Pavia

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    In this paper we present recent work of the physics education group at the University of Pavia, some of which in collaboration with other researchers. The unifying trait of research in Pavia, which the present paper aims to clarify, is its focus on conceptual understanding from a wide perspective, including the design of teaching-learning sequences, studies on teacher professional development, conceptual change research. We discuss three different examples of research directions, all concerning work performed in the past two years

    Studying colours with a smartphone

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    We show how a low-cost spectrometer, based on the use of inexpensive diffraction transmission gratings coupled with a smartphone photo camera, can be assembled and employed to obtain quantitative measurements of spectra from different sources. The analysis of spectra emitted by different light sources (incandescent bulb, fluorescent lamp, gas lamps, LEDs) helps students understand the different physical mechanisms which govern the production of light. Measurements of emission and transmission spectra allow students to focus on the differences between additive and subtractive models of colour formation. For this purpose the spectra of RGB colours emitted from an LCD screen and the transmission spectra of CMY pigments of a laser printer have been studied, using our low-cost spectroscope. A sequence of experimental activities was designed, and proposed to undergraduate students and secondary school teachers in order to study the feasibility and educational potential

    Introducing Quantum Technologies at Secondary School Level: Challenges and Potential Impact of an Online Extracurricular Course

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    Stimulated by the European project “QTEdu CSA”, within the flagship “Quantum Technologies”, a community of researchers active in the fields of quantum technologies and physics education has designed and implemented an extracurricular course on quantum physics concepts and quantum technologies applications for high school. The course, which featured eight interactive lectures, was organized online between March and May 2021 and attended by about 250 students from all over Italy. In this paper, we describe the main tenets and activities of the course. Moreover, we report on the effectiveness of the course on students’ knowledge of the basic concepts of quantum physics and students’ views about epistemic aspects and applications of quantum technologies. Results show that the designed activities were effective in improving students’ knowledge about fundamental aspects of quantum mechanics and familiarizing them with quantum technology applications
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