Stepped wedge cluster randomized controlled trial designs: a review of reporting quality and design features

Background The stepped wedge (SW) cluster randomized controlled trial (CRCT) design is being used with increasing frequency. However, there is limited published research on the quality of reporting of SW-CRCTs. We address this issue by conducting a literature review. Methods Medline, Ovid, Web of Knowledge, the Cochrane Library, PsycINFO, the ISRCTN registry, and ClinicalTrials.gov were searched to identify investigations employing the SW-CRCT design up to February 2015. For each included completed study, information was extracted on a selection of criteria, based on the CONSORT extension to CRCTs, to assess the quality of reporting. Results A total of 123 studies were included in our review, of which 39 were completed trial reports. The standard of reporting of SW-CRCTs varied in quality. The percentage of trials reporting each criterion varied to as low as 15.4%, with a median of 66.7%. Conclusions There is much room for improvement in the quality of reporting of SW-CRCTs. This is consistent with recent findings for CRCTs. A CONSORT extension for SW-CRCTs is warranted to standardize the reporting of SW-CRCTs.This work was supported by the Wellcome Trust (grant number 099770/Z/12/Z to MJG); the Medical Research Council (grant number MC_UP_1302/2 to APM) and the National Institute for Health Research Cambridge Biomedical Research Centre (MC_UP_1302/4 to JMSW)

Centrifuge modelling of building response to tunnel excavation

Understanding the building response to tunnelling-induced settlements is an important aspect of urban tunnelling in soft ground. Previous centrifuge modelling research demonstrated significant potential to study this tunnel–soil–structure interaction problem. However, these recent studies were limited by simplified building models, which might result in uncertainties when interpreting the building performance to tunnelling subsidence. This paper presents an experimental modelling procedure and the results of a series of centrifuge tests, involving relatively complex surface structures subjected to tunnelling in sand. Powder-based three-dimensional (3D) printing was adopted to fabricate building models with realistic layouts, facade openings and foundations. The 3D printed material had a Young's modulus and a brittle response similar to historic masonry. Modelling effects and boundary conditions are quantified. The good agreement between the experimentally obtained results and previous research demonstrates that the soil–structure interaction during tunnel excavation is well replicated. The experimental procedure provides a framework to quantify how building features affect the response of buildings to tunnelling subsidence.The authors are grateful to EPSRC grant EP/K018221/1 and Crossrail for the financial support

Genome-Wide Identification of MicroRNAs in Response to Low Nitrate Availability in Maize Leaves and Roots

BACKGROUND: Nitrate is the major source of nitrogen available for many crop plants and is often the limiting factor for plant growth and agricultural productivity especially for maize. Many studies have been done identifying the transcriptome changes under low nitrate conditions. However, the microRNAs (miRNAs) varied under nitrate limiting conditions in maize has not been reported. MiRNAs play important roles in abiotic stress responses and nutrient deprivation. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we used the SmartArray™ and GeneChip® microarray systems to perform a genome-wide search to detect miRNAs responding to the chronic and transient nitrate limiting conditions in maize. Nine miRNA families (miR164, miR169, miR172, miR397, miR398, miR399, miR408, miR528, and miR827) were identified in leaves, and nine miRNA families (miR160, miR167, miR168, miR169, miR319, miR395, miR399, miR408, and miR528) identified in roots. They were verified by real time stem loop RT-PCR, and some with additional time points of nitrate limitation. The miRNAs identified showed overlapping or unique responses to chronic and transient nitrate limitation, as well as tissue specificity. The potential target genes of these miRNAs in maize were identified. The expression of some of these was examined by qRT-PCR. The potential function of these miRNAs in responding to nitrate limitation is described. CONCLUSIONS/SIGNIFICANCE: Genome-wide miRNAs responding to nitrate limiting conditions in maize leaves and roots were identified. This provides an insight into the timing and tissue specificity of the transcriptional regulation to low nitrate availability in maize. The knowledge gained will help understand the important roles miRNAs play in maize responding to a nitrogen limiting environment and eventually develop strategies for the improvement of maize genetics

A Carrier Class IoT Service Architecture Integrating IMS with SWE

Integrating the sensing capabilities of wireless sensor network (WSN) into the traditional telecom network is an important stage to realize future ubiquitous intelligence in the Internet of Things. Driven by the vision of service oriented architecture (SOA), this paper proposed a carrier class Internet of Things (IoT) service architecture named as MUSE. MUSE integrates WSN with IMS OSE framework to enable the WSN services to be operable and manageable. Also sensor web enablement (SWE) framework is adopted to shield the heterogeneity of different WSNs. MUSE consists of two key entities—MUSE Enabler and MUSE Gateway. On the one hand, the architecture promotes the node manageability and enriches the diversity of high level task planning flexibility. On the other hand, the architecture extends the telecom context-aware service and realizes service operability and network scalability. Moreover, the key components of the architecture and the detailed service procedure were introduced in the paper. Besides, an intelligent building prototype with 20 nodes was illustrated and the feasibility and performance of MUSE were verified at last

Creation of targeted inversion mutations in plants using an RNA-guided endonuclease

Inversions are DNA rearrangements that are essential for plant gene evolution and adaptation to environmental changes. We demonstrate the creation of targeted inversions and previously reported targeted deletion mutations via delivery of a pair of RNA-guided endonucleases (RGENs) of CRISPR/Cas9. The efficiencies of the targeted inversions were 2.6% and 2.2% in the Arabidopsis FLOWERING TIME (AtFT) and TERMINAL FLOWER 1 (AtTFL1) loci, respectively. Thus, we successfully established an approach that can potentially be used to introduce targeted DNA inversions of interest for functional studies and crop improvement

CRISPR/Cas9: A powerful tool for crop genome editing

The CRISPR/Cas9 technology is evolved from a type II bacterial immune system and represents a new generation of targeted genome editing technology that can be applied to nearly all organisms. Site-specific modification is achieved by a single guide RNA (usually about 20 nucleotides) that is complementary to a target gene or locus and is anchored by a protospacer-adjacent motif. Cas9 nuclease then cleaves the targeted DNA to generate double-strand breaks (DSBs), which are subsequently repaired by non-homologous end joining (NHEJ) or homology-directed repair (HDR) mechanisms. NHEJ may introduce indels that cause frame shift mutations and hence the disruption of gene functions. When combined with double or multiplex guide RNA design, NHEJ may also introduce targeted chromosome deletions, whereas HDR can be engineered for target gene correction, gene replacement, and gene knock-in. In this review, we briefly survey the history of the CRISPR/Cas9 system invention and its genome-editing mechanism. We also describe the most recent innovation of the CRISPR/Cas9 technology, particularly the broad applications of modified Cas9 variants, and discuss the potential of this system for targeted genome editing and modification for crop improvement