Role of water in Protein Aggregation and Amyloid Polymorphism

A variety of neurodegenerative diseases are associated with the formation of amyloid plaques. Our incomplete understanding of this process underscores the need to decipher the principles governing protein aggregation. Most experimental and simulation studies have been interpreted largely from the perspective of proteins: the role of solvent has been relatively overlooked. In this Account, we provide a perspective on how interactions with water affect folding landscapes of A$\beta$ monomers, A$\beta_{16-22}$ oligomer formation, and protofilament formation in a Sup35 peptide. Simulations show that the formation of aggregation-prone structures (N$^*$) similar to the structure in the fibril requires overcoming high desolvation barrier. The mechanism of protofilament formation in a polar Sup35 peptide fragment illustrates that water dramatically slows down self-assembly. Release of water trapped in the pores as water wires creates protofilament with a dry interface. Similarly, one of the main driving force for addition of a solvated monomer to a preformed fibril is the entropy gain of released water. We conclude by postulating that two-step model for protein crystallization must also hold for higher order amyloid structure formation starting from N$^*$. Multiple N$^*$ structures with varying water content results in a number of distinct water-laden polymorphic structures. In predominantly hydrophobic sequences, water accelerates fibril formation. In contrast, water-stabilized metastable intermediates dramatically slow down fibril growth rates in hydrophilic sequences.Comment: 27 pages, 4 figures; Accounts of Chemical Research, 201

Challenges of Implementing E-Learning in Kenya: A Case of Kenyan Public Universities

In this paper, we discuss the challenges experienced by Kenyan public universities in implementation of e-learning and recommend possible solutions towards its successful implementation. In the last few years, most Kenyan public universities have adopted e-learning as a new approach to teaching and learning. However, the implementation challenges faced by these universities have continued to impact negatively on its effective utilization. This paper presents the findings from a survey of 148 staff of three Kenyan public universities who are currently using e-learning in blended mode approach. The purpose of this study was to investigate the challenges hindering the implementation of e-learning in Kenyan public universities. Data was collected through questionnaires, in-depth interviews and document analysis. The findings reveal that e-learning comes with some challenges that must be addressed by Kenyan public universities before successful implementation can be realized. However, the benefits and opportunities presented by e-learning far outweigh the challenges. The paper finally recommends some possible solutions that public universities could embrace towards successful implementation of e-learning

Game-based mobile learning with augmented reality: Are teachers ready to adopt it?

Although only recently mobile augmented reality (AR) games have been adopted for educational purposes, research recognizes their potential and offers guidelines for their use in education, to create smart-learning ecosystems. It is time for teachers to adopt these technologies, but are they receptive to them? The aim of this study is to reveal teachers’ readiness to adopt mobile AR technologies in their practices, after training, bridging the gap between educational practices and research in educational sciences. This paper reports a case study based on a workshop designed to support teachers’ adoption of teaching strategies involving game-based mobile learning (mLearning) with AR. The workshop was conducted under the EduPARK project and offered trainees the opportunity to collaboratively experience the use, in loco, of the EduPARK app for outdoor learning with AR, as well as prompted them to plan educational resources appropriating these technologies. Data were collected through individual questionnaires and focus group interviews, and they were analysed through descriptive statistics, the computing of the educational value scale (EVS) and of the system usability scale (SUS), as well as content analysis. The results show that teachers consider they are ready to integrate mobile AR games in their practices, but they are foreseeing difficulties that need to be addressed. This paper contributes to the field of teacher training in game-based mLearning with AR as it unveils teachers’ readiness to adopt these technologies and why. Moreover, it characterizes a typology of teacher training in this area that, according to the trainee teachers, is successful.publishe

Amyloid beta Protein and Alzheimer's Disease: When Computer Simulations Complement Experimental Studies

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