Self-assembly of bi-functional patchy particles with anisotropic shape into polymers chains: theory and simulations

Concentrated solutions of short blunt-ended DNA duplexes, down to 6 base pairs, are known to order into the nematic liquid crystal phase. This self-assembly is due to the stacking interactions between the duplex terminals that promotes their aggregation into poly-disperse chains with a significant persistence length. Experiments show that liquid crystals phases form above a critical volume fraction depending on the duplex length. We introduce and investigate via numerical simulations, a coarse-grained model of DNA double-helical duplexes. Each duplex is represented as an hard quasi-cylinder whose bases are decorated with two identical reactive sites. The stacking interaction between terminal sites is modeled via a short-range square-well potential. We compare the numerical results with predictions based on a free energy functional and find satisfactory quantitative matching of the isotropic-nematic phase boundary and of the system structure. Comparison of numerical and theoretical results with experimental findings confirm that the DNA duplexes self-assembly can be properly modeled via equilibrium polymerization of cylindrical particles and enables us to estimate the stacking energy

Self-assembly of short DNA duplexes: from a coarse-grained model to experiments through a theoretical link

Short blunt-ended DNA duplexes comprising 6 to 20 base pairs self-assemble into polydisperse semi-flexible chains due to hydrophobic stacking interactions between terminal base pairs. Above a critical concentration, which depends on temperature and duplex length, such chains order into liquid crystal phases. Here, we investigate the self-assembly of such double-helical duplexes with a combined numerical and theoretical approach. We simulate the bulk system employing the coarse-grained DNA model recently proposed by Ouldridge et al. [ J. Chem. Phys. 134, 08501 (2011) ]. Then we evaluate the input quantities for the theoretical framework directly from the DNA model. The resulting parameter-free theoretical predictions provide an accurate description of the simulation results in the isotropic phase. In addition, the theoretical isotropic-nematic phase boundaries are in line with experimental findings, providing a route to estimate the stacking free energy.Comment: 13 pages, 10 figure

Backbone-free duplex-stacked monomer nucleic acids exhibiting Watson-Crick selectivity.

We demonstrate that nucleic acid (NA) mononucleotide triphosphates (dNTPs and rNTPs), at sufficiently high concentration and low temperature in aqueous solution, can exhibit a phase transition in which chromonic columnar liquid crystal ordering spontaneously appears. Remarkably, this polymer-free state exhibits, in a self-assembly of NA monomers, the key structural elements of biological nucleic acids, including: long-ranged duplex stacking of base pairs, complementarity-dependent partitioning of molecules, and Watson-Crick selectivity, such that, among all solutions of adenosine, cytosine, guanine, and thymine NTPs and their binary mixtures, duplex columnar ordering is most stable in the A-T and C-G combinations

Analysis of MOOC Features in a Regional Platform: Design and Delivery of Courses

At least two motivations make relevant research on regional MOOC providers: (1) they are Learning at scale environments where a large amount of data is produced, the high number of learners can show different approaches to learning, the whole population can be analysed, teaching and instructional design methods can be compared; (2) regional platforms reach the interests and needs of population groups that have only sometimes registered in international platforms. Therefore, we conducted a study at a large scale on EduOpen, an Italian MOOCs platform to which 28 institutions joined. The research aims to describe the current situation on EduOpen MOOCs, identify a latent model for the design and delivery of courses, and detect points of interest to enhance the platform’s procedure. We used courses as statistical units and identified three groups of variables: basic features, design features, and delivery features. We used multiple correspondence analysis (MCA) with descriptive statistics to answer the research questions. MCA is a method for data reduction for qualitative variables in which the categories assumed by the variables play a central role in defining a smaller number of dimensions. We found two dimensions that define the structure that underlies the design process – COURSE DENSITY and CONTENT ATTAINABILITY, and the delivery process – DIFFUSION and PARTICIPATION. Some focal points that EduOpen members can consider improving strategies in the design of the courses are related to the organization of activities and content, the scheduling of activities and whole courses, the levels of interaction in the courses, and the definition of qualified professional figures for design and tutoring

CONTENTS AND TEACHING PRACTICES FOR DIGITAL CITIZENSHIP: AN ACTION RESEARCH STUDY

Is there a connection between active teaching methodologies and digital citizenship education? We propose in this paper the results of an action-research conducted with 20 high school teachers in Reggio Emilia to analyse the issue. During the training path that is part of the research actions, made of co-design activities, participants experienced two active methodologies (Problem Based Learning and Episodes of Situated Learning) and discussed tips for producing digital learning contents. The paper presents the results of the project’s first phase, aiming to encourage and support transforming teaching practices. The activities regard the interdisciplinary field of civic education, focusing specifically on digital citizenship, one of the three thematic cores of Law n. 92/2019. The changes related to technological development involve social, cultural, and educational implications to which the school responds by educating students with a critical sense and responsibility. According to a design model already tested by the working group, the training was delivered in flipped mode with a mixture of synchronous and asynchronous online activities: teachers benefit from materials asynchronously before the live sessions in which experience and interaction are preferred. Live surveys, training activities, and focus groups provided teachers’ perception

Cluster analysis for tailored tutoring system

Nei corsi online, la presenza di tutor (disciplinari, tecnici, metodologici) \ue8 rilevante per la formazione degli studenti; le attivit\ue0 di tutorato influenzano la qualit\ue0 delle azioni didattiche e contribuiscono a creare ambienti di apprendimento online dinamici e attivi. La ricerca qui presentata mira a definire un modello per la creazione di sistemi di tutoraggio data-driven, strutturato e personalizzato, che rilevi gruppi omogenei di studenti in un corso di laurea erogato in modalit\ue0 prevalentemente a distanza per i quali attuare specifici interventi di supporto. Abbiamo scelto una tecnica di analisi multivariata dei dati, la cluster analysis, e raccolto, selezionato e utilizzato i dati personali e i dati relativi ai risultati accademici degli studenti del primo anno del Corso di Laurea in Digital Education dell\u2019Universit\ue0 di Modena e Reggio Emilia (n=110) per creare gruppi di studenti simili, identificare le caratteristiche comuni degli studenti in ogni gruppo e definire strategie di tutoraggio personalizzate per ogni cluster. L\u2019analisi ha permesso di individuare sei cluster omogenei di studenti e di definire alcune azioni di tutoraggio personalizzate per ciascun gruppo a partire dai risultati conseguiti negli esami del primo anno. Le attivit\ue0 da progettare e proporre riguardano l\u2019approfondimento dei contenuti, la motivazione e la metacognizione, coinvolgono tutor e docenti e possono svolgersi individualmente o in piccoli gruppi.In online courses, the tutoring activities are relevant for the learners\u2019 training; they affect the course quality and imply creating dynamic and active online learning environments. The research aims to define a model based on a structured and data-driven tutoring system to identify homogeneous groups of students attending a blended degree course and, then, set tailored interventions as support. We chose a multivariate data analysis technique, cluster analysis, and used personal data and academic achievements of first-year students (n=110) in Degree Course in Digital Education at the University of Modena and Reggio Emilia to create groups of similar learners, identify common characteristics of students in each group and define personalized tutoring strategies for each cluster. The analysis allows identifying six homogeneous clusters of students and defining activities to design that concern the fields of content, motivation and metacognition, involve degree course tutors and teachers, and be carried out individually or in small groups of students

A scoping review on the relationship between robotics in educational contexts and e-health

In recent years, due to technological advancement, research has been directed to the development and analysis of resources and tools related to educational robotics with particular attention to the field of special needs and training actions aimed at learners, teachers, professionals, and families. The use of robotics in all levels of education can support the development of logical and computational thinking, interaction, communication, and socialization, and the acquisition of particularly complex work practices, for example, in the medical field. The adoption of successful educational robotics training practices can be a potential tool to support rehabilitation interventions for disabilities and comprehensive training for students or future professionals in healthcare. A scoping review was conducted on the main topics “education” AND “robotics” with three specific focuses on complementary themes in educational research about ER: (1) teaching and computational thinking, (2) training in the health sector, and (3) education and special needs. The authors systematically searched two online databases, Scopus and Web of Science, up to April 2022. A total of 164 articles were evaluated, and 59 articles were analyzed, in a particular way N = 33 related to computational thinking, N = 15 related to e-health, and N = 11 related to special needs. The following four questions guided our research: (1) What are the educational and experimental experiences conducted through robotics in transdisciplinary fields? (2) What tools and resources are most used in such experiments (educational robotics kit, humanoid robots, telepresence robots etc.)? (3) What are the constitutive elements of the experiments and studies involving robotics and health in educational contexts? and (4) What are those explicitly related to students with special needs? In this study, part of the research project “Robotics and E-health: new Challenges for Education” (RECE) activated at the University of Modena and Reggio Emilia. RECE aims to investigate the training, educational, cognitive, and legal processes induced by the increasing diffusion of educational robotics and telemedicine in clinical and surgical contexts