Education, opportunities and challenges for generation OurSpace: Taming the beast

The paper discusses the opportunities and challenges presented for current notions of schooling by adolescent online cultures. Young people are increasingly active Web 2.0 users and their interactions through these technologies are altering their social identities, styles of learning, and exchanges with others around the world. The paper argues for the need for more research to investigate this phenomenon through the use of virtual ethnography and identifies the ethical challenges that lie therein. It raises questions for school education and presents an argument for the need to study the area in culturally sensitive ways that privilege adolescents voices

Web 2.0 in the classroom? Dilemmas and opportunities inherent in adolescent web 2.0 engagement.

The paper discusses the implications of the current phenomenon of adolescent engagement in digital spaces. Young people are increasingly active Web 2.0 users, and their interactions through these technologies are altering their social identities, styles of learning, and exchanges with others around the world. The paper argues for more research to investigate this phenomenon through the use of virtual ethnography and identifies the ethical challenges that lie therein. It raises questions for school education and presents an argument for studying the area in culturally sensitive ways that privilege adolescents voices

Mobile learning for teacher professional learning: benefits, obstacles and issues

This paper reflects on the role of mobile learning in teachers professional learning. It argues that effective professional learning requires reflection and collaboration and that mobile learning is ideally suited to allow reflection-in action and to capture the spontaneity of learning moments. The paper also argues for the value of collaborations between teachers and students in professional learning. It suggests that authentic artefacts and anecdotes, captured through mobile technologies, can enable the sharing, analysis and synthesis of classroom experiences by teachers and students. Such analysis and synthesis helps to encourage collaborative reflective practice and is likely to improve teacher and student learning as a result. Ethical issues that might arise through using mobile technologies in this way are also discussed. Teacher voice is presented to indicate the range of views about mobile learning and to indicate current practices. Practical, school systemic, attitudinal and ethical factors may inhibit mobile technology adoption; these factors need to be researched and addressed to realise the potential of teacher mobile professional learning

How do early career teachers value different types of support? A scale-adjusted latent class choice model

© 2015 Elsevier Ltd. Using a discrete choice experimental approach and associated Scale-Adjusted Latent Class Model (SALCM), we quantify the relative value early career teachers (ECTs) place on various types of support in the form of affirmation, resources, collegial opportunities, mentoring, and professional development. ECTs with intentions to depart the profession, place greater relative value on the sharing of resources, cooperative teaching and planning, offsite discussions about classroom management and programming with mentors, and having a greater professional voice. In contrast, those with intentions to remain, place greater value on observation from and conversations about teaching with more experienced teachers at their school

Directional emission of light from a nano-optical Yagi-Uda antenna

The plasmon resonance of metal nanoparticles can enhance and direct light from optical emitters in much the same way that radio frequency (RF) antennas enhance and direct the emission from electrical circuits. In the RF regime, a typical antenna design for high directivity is the Yagi-Uda antenna, which basically consists of a one-dimensional array of antenna elements driven by a single feed element. Here, we present the experimental demonstration of directional light emission from a nano-optical Yagi-Uda antenna composed of an array of appropriately tuned gold nanorods. Our results indicate that nano-optical antenna arrays are a simple but efficient tool for the spatial control of light emission.Comment: 4 pages, including 4 figure

Biological evaluation of hydroxynaphthoquinones as anti-malarials

Abstract\ud \ud \ud \ud Background\ud The hydroxynaphthoquinones have been extensively investigated over the past 50 years for their anti-malarial activity. One member of this class, atovaquone, is combined with proguanil in Malarone®, an important drug for the treatment and prevention of malaria.\ud \ud \ud \ud Methods\ud Anti-malarial activity was assessed in vitro for a series of 3-alkyl-2-hydroxy-1,4-naphthoquinones (N1-N5) evaluating the parasitaemia after 48 hours of incubation. Potential cytotoxicity in HEK293T cells was assessed using the MTT assay. Changes in mitochondrial membrane potential of Plasmodium were measured using the fluorescent dye Mitrotracker Red CMXROS.\ud \ud \ud \ud Results\ud Four compounds demonstrated IC50s in the mid-micromolar range, and the most active compound, N3, had an IC50 of 443 nM. N3 disrupted mitochondrial membrane potential, and after 1 hour presented an IC50ΔΨmit of 16 μM. In an in vitro cytotoxicity assay using HEK 293T cells N3 demonstrated no cytotoxicity at concentrations up to 16 μM.\ud \ud \ud \ud Conclusions\ud N3 was a potent inhibitor of mitochondrial electron transport, had nanomolar activity against cultured Plasmodium falciparum and showed minimal cytotoxicity. N3 may serve as a starting point for the design of new hydroxynaphthoquinone anti-malarials.This work was supported by FAPESP (Fundação de Amparo a Pesquisa de São Paulo) (07/52924-0), by Malaria Pronex, and by a INCT-INBqMed (Instituto Nacional de Ciência e Tecnologia- Instituto Nacional de Ciência e Tecnologia de Biotecnologia Estrutural e Química Medicinal em Doenças Infecciosa) grant. C.R.S. Garcia and V. Ferreira are CNPQ (Conselho Nacional de Pesquisa) fellows. D.S. received a CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) Fellowship. D.R. da Rocha thanks FAPERJ (Fundação de Amparo a Pesquisa do Rio De Janeiro) for their doctoral fellowship. LNC and MM received a FAPESP Fellowship. Thanks are due to the CNPQ, CAPES and FAPERJ for funding this work.This work was supported by FAPESP (Fundação de Amparo a Pesquisa de São Paulo) (07/529240), by Malaria Pronex, and by a INCTINBqMed (Instituto Nacional de Ciência e Tecnologia Instituto Nacional de Ciência e Tecnologia de Biotecnologia Estrutural e Química Medicinal em Doenças Infecciosa) grant. C.R.S. Garcia and V. Ferreira are CNPQ (Conselho Nacional de Pesquisa) fellows. D.S. received a CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) Fellowship. D.R. da Rocha thanks FAPERJ (Fundação de Amparo a Pesquisa do Rio De Janeiro) for their doctoral fellowship. LNC and MM received a FAPESP Fellowship. Thanks are due to the CNPQ, CAPES and FAPERJ for funding this work

The C-Terminal Domain of the Arabinosyltransferase Mycobacterium tuberculosis EmbC Is a Lectin-Like Carbohydrate Binding Module

The D-arabinan-containing polymers arabinogalactan (AG) and lipoarabinomannan (LAM) are essential components of the unique cell envelope of the pathogen Mycobacterium tuberculosis. Biosynthesis of AG and LAM involves a series of membrane-embedded arabinofuranosyl (Araf) transferases whose structures are largely uncharacterised, despite the fact that several of them are pharmacological targets of ethambutol, a frontline drug in tuberculosis therapy. Herein, we present the crystal structure of the C-terminal hydrophilic domain of the ethambutol-sensitive Araf transferase M. tuberculosis EmbC, which is essential for LAM synthesis. The structure of the C-terminal domain of EmbC (EmbCCT) encompasses two sub-domains of different folds, of which subdomain II shows distinct similarity to lectin-like carbohydrate-binding modules (CBM). Co-crystallisation with a cell wall-derived di-arabinoside acceptor analogue and structural comparison with ligand-bound CBMs suggest that EmbCCT contains two separate carbohydrate binding sites, associated with subdomains I and II, respectively. Single-residue substitution of conserved tryptophan residues (Trp868, Trp985) at these respective sites inhibited EmbC-catalysed extension of LAM. The same substitutions differentially abrogated binding of di- and penta-arabinofuranoside acceptor analogues to EmbCCT, linking the loss of activity to compromised acceptor substrate binding, indicating the presence of two separate carbohydrate binding sites, and demonstrating that subdomain II indeed functions as a carbohydrate-binding module. This work provides the first step towards unravelling the structure and function of a GT-C-type glycosyltransferase that is essential in M. tuberculosis. Author Summary Top Tuberculosis (TB), an infectious disease caused by the bacillus Mycobacterium tuberculosis, burdens large swaths of the world population. Treatment of active TB typically requires administration of an antibiotic cocktail over several months that includes the drug ethambutol. This front line compound inhibits a set of arabinosyltransferase enzymes, called EmbA, EmbB and EmbC, which are critical for the synthesis of arabinan, a vital polysaccharide in the pathogen's unique cell envelope. How precisely ethambutol inhibits arabinosyltransferase activity is not clear, in part because structural information of its pharmacological targets has been elusive. Here, we report the high-resolution structure of the C-terminal domain of the ethambutol-target EmbC, a 390-amino acid fragment responsible for acceptor substrate recognition. Combining the X-ray crystallographic analysis with structural comparisons, site-directed mutagenesis, activity and ligand binding assays, we identified two regions in the C-terminal domain of EmbC that are capable of binding acceptor substrate mimics and are critical for activity of the full-length enzyme. Our results begin to define structure-function relationships in a family of structurally uncharacterised membrane-embedded glycosyltransferases, which are an important target for tuberculosis therapy

Testing foundations of quantum mechanics with photons

The foundational ideas of quantum mechanics continue to give rise to counterintuitive theories and physical effects that are in conflict with a classical description of Nature. Experiments with light at the single photon level have historically been at the forefront of tests of fundamental quantum theory and new developments in photonics engineering continue to enable new experiments. Here we review recent photonic experiments to test two foundational themes in quantum mechanics: wave-particle duality, central to recent complementarity and delayed-choice experiments; and Bell nonlocality where recent theoretical and technological advances have allowed all controversial loopholes to be separately addressed in different photonics experiments.Comment: 10 pages, 5 figures, published as a Nature Physics Insight review articl

Efficient Construction of an Inverted Minimal H1 Promoter Driven siRNA Expression Cassette: Facilitation of Promoter and siRNA Sequence Exchange

RNA interference (RNAi), mediated by small interfering RNA (siRNA), is an effective method used to silence gene expression at the post-transcriptional level. Upon introduction into target cells, siRNAs incorporate into the RNA-induced silencing complex (RISC). The antisense strand of the siRNA duplex then "guides" the RISC to the homologous mRNA, leading to target degradation and gene silencing. In recent years, various vector-based siRNA expression systems have been developed which utilize opposing polymerase III promoters to independently drive expression of the sense and antisense strands of the siRNA duplex from the same template.We show here the use of a ligase chain reaction (LCR) to develop a new vector system called pInv-H1 in which a DNA sequence encoding a specific siRNA is placed between two inverted minimal human H1 promoters (approximately 100 bp each). Expression of functional siRNAs from this construct has led to efficient silencing of both reporter and endogenous genes. Furthermore, the inverted H1 promoter-siRNA expression cassette was used to generate a retrovirus vector capable of transducing and silencing expression of the targeted protein by>80% in target cells.The unique design of this construct allows for the efficient exchange of siRNA sequences by the directional cloning of short oligonucleotides via asymmetric restriction sites. This provides a convenient way to test the functionality of different siRNA sequences. Delivery of the siRNA cassette by retroviral transduction suggests that a single copy of the siRNA expression cassette efficiently knocks down gene expression at the protein level. We note that this vector system can potentially be used to generate a random siRNA library. The flexibility of the ligase chain reaction suggests that additional control elements can easily be introduced into this siRNA expression cassette