bluuebunny/crossref_metadata_2025 huggingface dataset:
Halogen-aromatic π interactions modulate inhibitor residence time
Authors: Heroven Christina , Georgi Victoria , Ganotra Gaurav K. , Brennan Paul E. , Wolfreys Finn , Wade Rebecca C. , Fernández-Montalván Amaury E. , Chaikuad Apirat , Knapp Stefan
Published: January 2018

Prolonged drug residence times may result in longer lasting drug efficacy, improved pharmacodynamic properties and “kinetic selectivity” over off-targets with fast drug dissociation rates. However, few strategies have been elaborated to rationally modulate drug residence time and thereby to integrate this key property into the drug development process. Here, we show that the interaction between a halogen moiety on an inhibitor and an aromatic residue in the target protein can significantly increase inhibitor residence time. By using the interaction of the serine/threonine kinase haspin with 5-iodotubercidin (5-iTU) derivatives as a model for an archetypal active state (type I) kinase-inhibitor binding mode, we demonstrate that inhibitor residence times markedly increase with the size and polarizability of the halogen atom. This key interaction is dependent on the interactions with an aromatic residue in the gate keeper position and we observe this interaction in other kinases with an aromatic gate keeper residue. We provide a detailed mechanistic characterization of the halogen-aromatic π interactions in the haspin-inhibitor complexes by means of kinetic, thermodynamic, and structural measurements along with binding energy calculations. Since halogens are frequently used in drugs and aromatic residues are often present in the binding sites of proteins, our results provide a compelling rationale for introducing aromatic-halogen interactions to prolong drug-target residence times.
Harnessing a Novel P450 Fatty Acid Decarboxylase fromMacrococcus caseolyticusfor Microbial Biosynthesis of Odd Chain Terminal Alkenes
Authors: Lee Jong-won , Niraula Narayan P. , Trinh Cong T.
Published: January 2018

Alkenes are industrially important platform chemicals with broad applications. In this study, we report a microbial conversion route for direct biosynthesis of medium and long chain terminal alkenes from fermentable sugars by harnessing a novel P450 fatty acid (FA) decarboxylase fromMacrococcus caseolyticus(OleTMC). We first characterized OleTMCand demonstrated itsin vitroH2O2-independent activities towards linear and saturated C10:0-C18:0 FAs, with the highest activity for C16:0 and C18:0 FAs. Combining protein homology modeling,in silicoresidue mutation analysis, and docking simulation with direct experimental evidence, we elucidated the underlying mechanism for governing the observed substrate preference of OleTMC, which depends on the size of FA binding pocket, not the catalytic site. Next, we engineered the terminal alkene biosynthesis pathway, consisting of an engineeredE. colithioesterase (TesA*) and OleTMC, and introduced this pathway intoE. colifor direct terminal alkene biosynthesis from glucose. The recombinant strainE. coliEcNN101 produced a total of 17.78 ± 0.63 mg/L odd-chain terminal alkenes, comprising of 0.9% ± 0.5% C11 alkene, 12.7% ± 2.2% C13 alkene, 82.7% ± 1.7% C15 alkene, and 3.7% ± 0.8% C17 alkene, and a yield of 0.87 ± 0.03 (mg/g) on glucose after 48 h in baffled shake flasks. To improve the terminal alkene production, we identified and overcame the electron transfer limitation in OleTMC, by introducing a two-component redox system, consisting of a putidaredoxin reductase CamA and a putidaredoxin CamB fromPseudomonas putida,into EcNN101, and demonstrated the terminal alkene production increased ∼2.8 fold after 48 h. Overall, this study provides a better understanding of the function of P450 FA decarboxylases and helps guide future protein and metabolic engineering for enhanced microbial production of target designer alkenes in a recombinant host.
Caenorhabditis elegansheterochromatin factor SET-32 plays an essential role in transgenerational establishment of nuclear RNAi-mediated epigenetic silencing
Authors: Kalinava Natallia , Ni Julie Zhouli , Gajic Zoran , Ushakov Helen , Gu Sam Guoping
Published: January 2018

Epigenetic inheritance contributes fundamentally to transgenerational physiology and fitness. Mechanistic understanding of RNA-mediated chromatin modification and transgenerational epigenetic inheritance, which inC. eleganscan be triggered by exogenous double-stranded RNA (exo-dsRNA) or facilitated by endogenous small interfering RNAs (endo-siRNAs), has mainly been limited to the post-initiation phases of silencing. Indeed, the dynamic process by which nuclear RNAi engages a transcriptionally active target, before the repressive state is stably established, remains largely a mystery. Here we found that the onset of exo-dsRNA-induced nuclear RNAi is a transgenerational process, and that establishment requires SET-32, one of the three putative histone methyltransferases (HMTs) that are required for H3K9me3 deposition at the nuclear RNAi targets. We also performed multigenerational whole-genome analyses to examine the establishment of silencing at endogenous targets of germline nuclear RNAi. The nuclear Argonaute protein HRDE-1 is essential for the maintenance of nuclear RNAi. Repairing a loss-of-function mutation inhrde-1by CRISPR restored the silencing of endogenous targets in animals carrying wild typeset-32. However, for numerous endogenous targets, repairing thehrde-1mutation in aset-32;hrde-1double mutant failed to restore their silencing states in up to 20 generations after thehrde-1repair, using a similar genome editing approach. We found that despite a prominent role in the establishment of silencing, however,set-32is completely dispensable for the maintenance of silencing once HRDE-1-dependent gene repression is established. Our study indicates that: 1) establishment and maintenance of siRNA-guided transcriptional repression are two distinct processes with different genetic requirements; and 2) the rate-limiting step of the establishment phase is a transgenerational, chromatin-based process. In addition, our study reveals a novel paradigm in which a heterochromatin factor primarily functions to promote the establishment of transgenerational silencing, expanding mechanistic understanding of the well-recognized role of heterochromatin in epigenetic maintenance.
Neural circuitry of a polycystin-mediated hydrodynamic startle response for predator avoidance
Authors: Bezares-Calderón Luis A. , Berger Jürgen , Jasek Sanja , Verasztó Csaba , Mendes Sara , Gühmann Martin , Almeda Rodrigo , Shahidi Réza , Jékely Gáspár
Published: January 2018

Startle responses triggered by aversive stimuli including predators are widespread across animals. These coordinated whole-body actions require the rapid and simultaneous activation of a large number of muscles. Here we study a startle response in a planktonic larva to understand the whole-body circuit implementation of the behavior. Upon encountering water vibrations, larvae of the annelidPlatynereisclose their locomotor cilia and simultaneously contract the body and raise the parapodia. The startle response is mediated by collar receptor neurons expressing the polycystins PKD1-1 and PKD2-1. CRISPR-generatedPKD1-1andPKD2-1mutant larvae do not startle and fall prey to a copepod predator at a higher rate. Reconstruction of the whole-body connectome of the collar-receptor-cell circuitry revealed converging feedforward circuits to the ciliary bands and muscles. The wiring diagram suggests circuit mechanisms for the intersegmental and left-right coordination of the response. Our results reveal how polycystin-mediated mechanosensation can trigger a coordinated whole-body effector response involved in predator avoidance.

Short Summary

The neuronal circuitry of thePlatynereisstartle response links polycystin-dependent hydrodynamic sensors to muscle and ciliary effector cells
Phylodynamic model adequacy using posterior predictive simulations
Authors: Duchene Sebastian , Bouckaert Remco , Duchene David A. , Stadler Tanja , Drummond Alexei J.
Published: January 2018

Rapidly evolving pathogens, such as viruses and bacteria, accumulate genetic change at a similar timescale over which their epidemiological processes occur, such that it is possible to make inferences about their infectious spread using phylogenetic time-trees. For this purpose it is necessary to choose a phylodynamic model. However, the resulting inferences are contingent on whether the model adequately describes key features of the data. Model adequacy methods allow formal rejection of a model if it cannot generate the main features of the data. We present TreeModelAdequacy (TMA), a package for the popular BEAST2 software, that allows assessing the adequacy of phylodynamic models. We illustrate its utility by analysing phylogenetic trees from two viral outbreaks of Ebola and H1N1influenza. The main features of the Ebola data were adequately described by the coalescent exponential-growth model, whereas the H1N1influenza data was best described by the birth-death SIR model.
Genome-wide prediction of bacterial effectors across six secretion system types using a feature-based supervised learning framework
Authors: Dhroso Andi , Eidson Samantha , Korkin Dmitry
Published: January 2018

Gram-negative bacteria are responsible for hundreds of millions infections worldwide, including the emerging hospital-acquired infections and neglected tropical diseases in the third-world countries. Finding a fast and cheap way to understand the molecular mechanisms behind the bacterial infections is critical for efficient diagnostics and treatment. An important step towards understanding these mechanisms is discovering bacterial effectors, the proteins secreted into the host through one of the six common secretion system types. Unfortunately, current effector prediction methods are designed to specifically target one of three secretion systems, and no accurate “secretion system-agnostic” method is available.

Here, we present PREFFECTOR, a computational feature-based approach to discover effectors in Gram-negative bacteria without prior knowledge on bacterial secretion system(s) or cryptic secretion signals. Our approach was first evaluated using several assessment protocols on a manually curated, balanced dataset of experimentally determined effectors across all six secretion systems as well as non-effector proteins. The evaluation revealed high accuracy of the top performing classifiers in PREFFECTOR, with the small false positive discovery rate across all six secretion systems. Our method was also applied to four bacteria that had limited knowledge on virulence factors or secreted effectors. PREFFECTOR web-server is freely available at: http://korkinlab.org/preffector.
Lost in Space: The Impact of Traditional Neuroimaging Methods on the Spatial Localization of Cortical Areas
Authors: Coalson Timothy S. , Van Essen David C. , Glasser Matthew F.
Published: January 2018

Localizing human brain functions is a long-standing goal in systems neuroscience. Towards this goal, neuroimaging studies have traditionally used volume-based smoothing, registered data to volume-based standard spaces, and reported results relative to volume-based parcellations. A novel 360-area surface-based cortical parcellation was recently generated using multimodal data from the Human Connectome Project (HCP), and a volume-based version of this parcellation has frequently been requested for use with traditional volume-based analyses. However, given the major methodological differences between traditional volumetric and HCP-style processing, the utility and interpretability of such an altered parcellation must first be established. By starting from automatically generated individual-subject parcellations and processing them with different methodological approaches, we show that traditional processing steps, especially volume-based smoothing and registration, substantially degrade cortical area localization when compared to surface-based approaches. We also show that surface-based registration using features closely tied to cortical areas, rather than to folding patterns alone, improves the alignment of areas, and that the benefits of high resolution acquisitions are largely unexploited by traditional volume-based methods. Quantitatively, we show that the most common version of the traditional approach has spatial localization that is only 35% as good as the best surface-based method as assessed with two objective measures (peak areal probabilities and ‘captured area fraction’ for maximum probability maps). Finally, we demonstrate that substantial challenges exist when attempting to accurately represent volume-based group analysis results on the surface, which has important implications for the interpretability of studies, both past and future, that use these volume-based methods.

Significance Statement

Most human brain imaging studies have traditionally used low-resolution images, inaccurate methods of cross-subject alignment, and extensive blurring. Recently, a high-resolution approach with more accurate alignment and minimized blurring was used by the Human Connectome Project to generate a multi-modal map of human cortical areas in hundreds of individuals. Starting from this data, we systematically compared these two approaches, showing that the traditional approach is nearly three times worse than the HCP’s improved approach in two objective measures of spatial localization of cortical areas. Further, we demonstrate considerable challenges in comparing data across the two approaches, and, as a result, argue that there is an urgent need for the field to adopt more accurate methods of data acquisition and analysis.
Frequent sgRNA-barcode Recombination in Single-cell Perturbation Assays
Authors: Xie Shiqi , Cooley Anne , Armendarez Daniel , Zhou Pei , Hon Gary C.
Published: January 2018

Simultaneously detecting CRISPR-based perturbations and induced transcriptional changes in the same cell is a powerful approach to unraveling genome function. Several lentiviral approaches have been developed, some of which rely on the detection of distally located genetic barcodes as an indirect proxy of sgRNA identity. Since barcodes are often several kilobases from their corresponding sgRNAs, viral recombination-mediated swapping of barcodes and sgRNAs is feasible. Using a self-circularization-based sgRNA-barcode library preparation protocol, we estimate the recombination rate to be ~50% and we trace this phenomenon to the pooled viral packaging step. Recombination is random, and decreases the signal-to-noise ratio of the assay. Our results suggest that alternative approaches can increase the throughput and sensitivity of single-cell perturbation assays.
Individual differences in functional brain connectivity predict temporal discounting preference in the transition to adolescence
Authors: Anandakumar Jeya , Mills Kathryn L. , Earl Eric , Irwin Lourdes , Miranda-Dominguez Oscar , Demeter Damion V. , Walton-Weston Alexandra , Karalunas Sarah , Nigg Joel , Fair Damien A.
Published: January 2018

The transition from childhood to adolescence is marked by distinct changes in behavior, including how one values waiting for a large reward compared to receiving an immediate, yet smaller, reward. While previous research has emphasized the relationship between this preference and age, it is also proposed that this behavior is related to circuitry between valuation and cognitive control systems. In this study, we examined how age and intrinsic functional connectivity strength within and between these neural systems relate to changes in discounting behavior across the transition into adolescence. We used mixed-effects modeling and linear regression to assess the contributions of age and connectivity strength in predicting discounting behavior. First, we identified relevant connections in a longitudinal sample of 64 individuals who completed MRI scans and behavioral assessments 2-3 times across ages 7-15 years (137 scans). We then repeated the analysis in a separate, cross-sectional, sample of 84 individuals (7-13 years). Both samples showed an age-related increase in preference for waiting for larger rewards. Connectivity strength within and between valuation and cognitive control systems accounted for further variance not explained by age. These results suggest that individual differences in functional neural organization can account for behavioral changes typically associated with age.
Effects of Parathyroid Hormone, Alendronate and Odanacatib on the mineralisation process in intracortical and endocortical Haversian bone of ovariectomized rabbits
Authors: Vrahnas Christina , Buenzli Pascal R , Pearson Thomas A , Pennypacker Brenda L , Tobin Mark J , Bambery Keith R , Duong Le T , Sims Natalie A
Published: January 2018

Although cortical bone strength depends on optimal bone composition, the influences of standard therapeutic agents for osteoporosis on bone mineral accrual in cortical bone are not understood. This study compared effects on cortical bone composition of two current therapeutic approaches for osteoporosis: the anti-resorptive bisphosphonate alendronate (ALN), and anabolic intermittent parathyroid hormone (PTH). The experimental anti-resorptive cathepsin K inhibitor, odanacatib (ODN) which inhibits resorption without inhibiting bone formation, was also tested.

To determine effects of these agents on Haversian remodeling and mineral accrual, we compared ALN (100μg/kg/2xweek), PTH(1-34) (15μg/kg, 5x/week) and ODN (7.5μM/day) administered for 10 months commencing 6 months after ovariectomy (OVX) in skeletally mature rabbits by histomorphometry. We used synchrotron-based Fourier-transform infrared microspectroscopy (sFTIRM), coupled to fluorochrome labelling, to measure maturation of the cortical matrixin situat both endocortical and intracortical sites of bone formation.

PTH and ODN, but not ALN, treatment increased bone toughness, and PTH treatment stimulated bone formation, not only on endocortical and periosteal bone, but also in intracortical pores. In Sham and OVX rabbits, normal matrix maturation was observed at both endocortical and intracortical sites including: mineral accrual (increasing mineral:matrix), carbonate substitution (carbonate:mineral) and collagen molecular compaction (amide I:II)in situin endocortical and intracortical bone. ALN treatment reduced bone formation on these surfaces. In ALN-treated bone, while intracortical bone matured normally, endocortical bone did not show a significant increase in mineral:matrix. ODN treatment resulted in slower mineral accrual and limited carbonate substitution. While PTH-treatment did not modify matrix maturation in endocortical bone, the initial stages of mineral accrual were slower in intracortical bone.

In conclusion, these three classes of therapy have differing effects on both bone formation, and the process of bone matrix maturation. ALN suppresses bone formation, and the normal process of matrix maturation in endocortical bone. ODN does not suppress bone formation, but limits mineral accrual. PTH stimulates bone formation, and the matrix formed matures normally in endocortical bone. The ability of PTH treatment to stimulate bone formation in intracortical bone may provide a novel additional mechanism by which PTH increases bone strength.
Regulation of global translation during the cell cycle
Authors: Stonyte Vilte , Boye Erik , Grallert Beáta
Published: January 2018

It is generally accepted that global translation varies during the cell cycle and is low in mitosis. However, addressing this issue is challenging because it involves cell synchronization, which evokes stress responses which, in turn, affect translation rates. Here we have used two approaches to measure global translation rates in different cell-cycle phases. First, synchrony in different cell-cycle phases was obtained involving the same stress, by using temperature-sensitive mutants. Second, translation and DNA content were measured by flow cytometry in exponentially growing, single cells. We found no major variation in global translation rates through the cell cycle in either fission-yeast or mammalian cells. We also measured phosphorylation of eukaryotic initiation factor-2α, an event thought to downregulate global translation in mitosis. In contrast with the prevailing view, eIF2α phosphorylation correlated poorly with downregulation of general translation and ectopically induced eIF2α phosphorylation inhibited general translation only at high levels.
An efficient and scalable pipeline for epitope tagging in mammalian stem cells using Cas9 ribonucleoprotein
Authors: Dewari Pooran Singh , Southgate Benjamin , Mccarten Katrina , Monogarov German , O’Duibhir Eoghan , Quinn Niall , Tyrer Ashley , Plumb Colin , Blin Carla , Finch Rebecca , Bressan Raul Bardini , Morrison Gillian , Jacobi Ashley M. , Behlke Mark A. , Kriegsheim Alex von , Tomlinson Simon , Krijgsveld Jeroen , Pollard Steven M.
Published: January 2018

CRISPR/Cas9 can be used for precise genetic knock-in of epitope tags into endogenous genes, simplifying experimental analysis of protein function. However, Cas9-assisted epitope tagging in primary mammalian cell cultures is often inefficient and reliant on plasmid-based selection strategies. Here we demonstrate improved knock-in efficiencies of diverse tags (V5, 3XFLAG, Myc, HA) using co-delivery of Cas9 protein pre-complexed with two-part synthetic modified RNAs (annealed crRNA:tracrRNA) and single-stranded oligodeoxynucleotide (ssODN) repair templates. Knock-in efficiencies of ~5-30%, were achieved without selection in embryonic stem (ES) cells, neural stem (NS) cells, and brain tumour-derived stem cells. Biallelic-tagged clonal lines were readily derived and used to define Olig2 chromatin-bound interacting partners. Using our novel web-based design tool, we established a 96-well format pipeline that enabled V5-tagging of sixty different transcription factors. This efficient, selection-free and scalable epitope tagging pipeline enables systematic surveys of protein expression levels, subcellular localization, and interactors across diverse mammalian stem cells.
Allele Phasing Greatly Improves the Phylogenetic Utility of Ultraconserved Elements
Authors: Andermann Tobias , Fernandes Alexandre M. , Olsson Urban , Töpel Mats , Pfeil Bernard , Oxelman Bengt , Aleixo Alexandre , Faircloth Brant C. , Antonelli Alexandre
Published: January 2018

Advances in high-throughput sequencing techniques now allow relatively easy and affordable sequencing of large portions of the genome, even for non-model organisms. Many phylogenetic studies reduce costs by focusing their sequencing efforts on a selected set of targeted loci, commonly enriched using sequence capture. The advantage of this approach is that it recovers a consistent set of loci, each with high sequencing depth, which leads to more confidence in the assembly of target sequences. High sequencing depth can also be used to identify phylogenetically informative allelic variation within sequenced individuals, but allele sequences are infrequently assembled in phylogenetic studies.

Instead, many scientists perform their phylogenetic analyses using contig sequences which result from thede novoassembly of sequencing reads into contigs containing only canonical nucleobases, and this may reduce both statistical power and phylogenetic accuracy. Here, we develop an easy-to-use pipeline to recover allele sequences from sequence capture data, and we use simulated and empirical data to demonstrate the utility of integrating these allele sequences to analyses performed under the Multispecies Coalescent (MSC) model. Our empirical analyses of Ultraconserved Element (UCE) locus data collected from the South American hummingbird genusTopazademonstrate that phased allele sequences carry sufficient phylogenetic information to infer the genetic structure, lineage divergence, and biogeographic history of a genus that diversified during the last three million years. The phylogenetic results support the recognition of two species, and suggest a high rate of gene flow across large distances of rainforest habitats but rare admixture across the Amazon River. Our simulations provide evidence that analyzing allele sequences leads to more accurate estimates of tree topology and divergence times than the more common approach of using contig sequences.
Hematopoietic stem cells differentiate into restricted myeloid progenitors before cell division
Authors: Grinenko Tatyana , Eugster Anne , Thielecke Lars , Ramazs Beata , Krueger Anja , Dietz Sevina , Glauche Ingmar , Gerbaulet Alexander , Bonin Malte von , Basak Onur , Clevers Hans , Chavakis Triantafyllos , Wielockx Ben
Published: January 2018

Hematopoietic stem cells (HSCs) continuously replenish all blood cell types through a series of differentiation steps that involve the generation of lineage-committed progenitors as well as necessary expansion due to repeated cell divisions. However, whether cell division in HSCs precedes differentiation is unclear. To this end, we used an HSC cell tracing approach and Ki67RFP knock-in mice to assess simultaneously divisional history, cell cycle progression, and differentiation of adult HSCs in vivo. Our results reveal that HSCs are able to differentiate into restricted progenitors, especially common myeloid progenitors, restricted megakaryocyte-erythroid progenitors (PreMEs) and pre-megakaryocyte progenitors (PreMegs), without undergoing cell division and even before entering the S phase of the cell cycle. Additionally, the phenotype of the undivided but differentiated progenitors correlated with expression of lineage-specific genes that manifested as functional differences between HSCs and restricted progenitors. Thus, HSC fate decisions appear to be uncoupled from physical cell division. Our results facilitate a better understanding of the mechanisms that control fate decisions in hematopoietic cells. Our data, together with separate findings from embryonic stem cells, suggest that cell division and fate choice are independent processes in pluripotent and multipotent stem cells.
Determination of porosity in anisotropic fractal systems by neutron scattering
Authors: Gu Xin , Mildner David F. R.
Published: January 2018

Small-angle scattering from two-phase isotropic systems requires the scattering to be invariant to determine the relative fractions of each phase in the material. For anisotropic systems the measurement yields a result that depends on the projection of the phases onto the scattering plane, normal to the incident radiation. When the scattering system has a unique axis such that there is no preferred direction in the plane normal to that axis, the scattering gives elliptical contours on the two-dimensional detector. Two different measurements of projected phases, one with the incident beam direction coincident with the unique axis and the other normal to that axis, can be combined to give a three-dimensional description of the system and therefore lead to a determination of the total porosity of the system.
Dynamic diffraction artefacts in Bragg coherent diffractive imaging
Authors: Hu Wen , Huang Xiaojing , Yan Hanfei
Published: January 2018

This article reports a theoretical study on the reconstruction artefacts in Bragg coherent diffractive imaging caused by dynamical diffraction effects. It is shown that, unlike the absorption and refraction effects that can be corrected after reconstruction, dynamical diffraction effects have profound impacts on both the amplitude and the phase of the reconstructed complex object, causing strong artefacts. At the dynamical diffraction limit, the reconstructed shape is no longer correct, as a result of the strong extinction effect. Simulations for hemispherical particles of different sizes show the type, magnitude and extent of the dynamical diffraction artefacts, as well as the conditions under which they are negligible.
Use of hashtags to retrieve information on the web
Authors: Buarki Hanadi , Alkhateeb Bashaer
Published: January 2018

Purpose

This paper aims to find out how people use hashtags as a medium of information retrieval and dissemination, and how they are used in social media tools, such as Instagram.

Design/methodology/approach

A quantitative question estimated the participants’ use of the hashtags during the workshop. Statistical data of the participants and their posts were collected from social network analysis tools. The posts that included the workshop’s designated hashtags were retrieved, recorded, coded and analysed to collect qualitative data.

Findings

In total, 74 (46 per cent) participants used the workshop’s hashtags to share posts, the retrieval of the hashtags declined by time and Google search engine retrieved the maximum results. It was found that a hashtag would be common when associated with descriptors, and that its use depends on its popularity, followers and its survival time. Finally, hashtags connect people, allow them to express their enthusiasm to reveal common interests and networks them through social media tools such as Instagram.

Research limitations/implications

The research limitations were in relation to the participants’ demographic information, the non-identification of their gender and hashtags being misspelt.

Practical implications

The research project summarises the experiences that social media has made connecting easier through the right use of hashtags by providing 24/7 free feedback, the possibility to exchange ideas and by their involvement in promoting and organising events. It also indicates interaction among people sharing the same interest by retrieving subject-based hashtags.

Originality/value

When retrieving information related to hashtags, it is recommended that multi-retrieval systems, social media tools and search engines should be consulted and not depend on a solo system or tool. Future research is recommended in search for a multi-retrieval social media and search engine tool that standardises the use of hashtags and will retrieve information from different platforms.
Instructor and peer influence on college student use and perceptions of Wikipedia
Authors: Garrison John C.
Published: January 2018

Purpose

This study aims to investigate how undergraduate students are influenced by instructors and peers in the ways that they use and think about Wikipedia for academic work. It examines the positive (encouraging the use of Wikipedia) and negative (discouraging the use of Wikipedia) influences of others and how these affect student behavior and attitudes.

Design/methodology/approach

Sixteen undergraduates participated in two meetings each with the principal investigator, each meeting consisting of a structured interview and a brief survey. Recorded interviews were analyzed by the investigator for patterns to compare participants’ responses.

Findings

Participants were more frequently and strongly influenced by instructors than by peers about Wikipedia, and this influence was for the most part perceived to be negative. However, the ways in which student behaviors and attitudes changed in response to this influence varied. Three categories or “influence types” emerged in the ways influence was manifested: receptive, independent and conflicted.

Practical implications

The findings of this study will aid instructors of undergraduate students by describing the likely reactions of those students to various ways of talking about Wikipedia. This information can help inform methods for teaching different kinds of students about the website.

Originality/value

Previous studies have shown how students use Wikipedia, as well as the attitudes of faculty toward Wikipedia. This study serves to bridge the gap between these areas, providing insight into how faculty and classmates’ attitudes influence student use of Wikipedia.
An author co-citation analysis of 37 years of iMetrics
Authors: Khasseh Ali Akbar , Soheili Faramarz , Mousavi Chelak Afshin
Published: January 2018

Purpose

This research aims to examine the intellectual structure of iMetrics through author co-citation analysis.

Design/methodology/approach

This research uses common techniques in bibliometrics and social network analysis. It analyses 5,944 records from the Web of Science in the field of iMetrics that are published between 1978 and 2014.

Findings

Findings indicated that researchers including “Garfield”, “Egghe”, “Glanzel”, “Leydesdorff” and “Price” have received many co-citations. The author co-citation analysis in iMetrics resulted in eight thematic clusters, including “theoretical foundations and citation analysis”, “sociology of science”, “science mapping and visualization”, “network analysis”, “classic laws of bibliometrics”, “webometrics”, “technometrics” and “miscellaneous”. “Theoretical foundations and citation analysis” is the biggest cluster which comprises 59 authors. The results suggest the crucial role of price medallists in shaping the intellectual structure of knowledge in iMetrics.

Originality/value

Extracting the patterns embedded in the knowledge structure of iMetrics studies provides beneficial information for both researchers and policymakers. This research study is valuable that used an appropriate set of records regarding both recall and precision. Furthermore, this study helps us better understand the characteristics of iMetrics, its subject areas, and the prominent authors in those areas.
Cybersecurity and information security – what goes where?
Authors: von Solms Basie , von Solms Rossouw
Published: January 2018

Purpose

The purpose of this paper is to define cybersecurity and cybersecurity governance in simplified terms – to explain to the boards of directors and executive management their responsibilities and accountabilities in this regard.

Design/methodology/approach

The primary research methodology utilized in this paper is desk research. A literature study is followed by some discussion in terms of the contribution made.

Findings

Clearly define the relationship between cybersecurity and information security, especially from a governance perspective.

Research limitations/implications

The paper is based predominantly on an ISO standard.

Originality/value

The simplification of terminology to be used in the governance of cybersecurity, together with assistance to the guiding of boards of directors regarding their duties and responsibilities as far as cybersecurity is concerned.
A process model for implementing information systems security governance
Authors: Nicho Mathew
Published: January 2018

Purpose

The frequent and increasingly potent cyber-attacks because of lack of an optimal mix of technical as well as non-technical IT controls has led to increased adoption of security governance controls by organizations. The purpose of this paper, thus, is to construct and empirically validate an information security governance (ISG) process model through the plan–do–check–act (PDCA) cycle model of Deming.

Design/methodology/approach

This descriptive research using an interpretive paradigm follows a qualitative methodology using expert interviews of five respondents working in the ISG domain in United Arab Emirates (UAE) to validate the theoretical model.

Findings

The findings of this paper suggest the primacy of the PDCA Deming cycle for initiating ISG through a risk-based approach assisted by industry-wide best practices in ISG. Regarding selection of ISG frameworks, respondents preferred to have ISO 27K supported by NIST as the core framework with other relevant ISG frameworks/standards forming the peripheral layer. The implementation focus of the ISG model is on mapping ISO 27K/NIST IT controls relevant IT controls selected from ISG frameworks from a horizontal and vertical perspective. Respondents asserted the automation of measurement and control mechanism through automation to assist in the feedback loop of the PDCA cycle.

Originality/value

The validated model helps academics and practitioners gain insight into the methodology of the phased implementation of an information systems governance process through the PDCA model, as well as the positioning of ITG and ITG frameworks in ISG. Practitioners can glean valuable insights from the empirical section of the research where experts detail the success factors, the sequential steps and justification of these factors in the ISG implementation process.
Employee fraud and misconduct: empirical evidence from a telecommunication company
Authors: Nawawi Anuar , Salin Ahmad Saiful Azlin Puteh
Published: January 2018

Purpose

The purpose of this study is to examine whether policies and procedures, one of the fundamental elements in the internal control environment, are adequate and effective in preventing fraud and unethical practices committed by employees of a company. In addition, this study attempts to assess the awareness and understanding of employees on the existence of relevant company policies and standard operating procedures for internal fraud and misconduct deterrence.

Design/methodology/approach

Five cases from one Malaysian telecommunication company were randomly selected as a case study. Content analyses were conducted on actual cases of internal fraud and wrongdoings that were investigated and the enforcement that was discharged by the company.

Findings

This study found that the company has sufficient policies and standard operating procedures to curb internal fraud and wrongdoing. However, they are ineffective and malfunction when responsible personnel violate or override the policies and procedures, irrespective of whether this is caused by carelessness, poor knowledge or clear intention to act dishonestly.

Research limitations implications

This study was conducted on only one company with a limited number of investigated fraud cases. Access to higher number of fraud cases, particularly those that involved large amount of losses and considered as high-profile cases, were denied because of confidentiality.

Practical implications

The study found that weak compliance to internal controls provides opportunities for fraud to occur, consistent with the fraud triangle theory. Fraud, committed both outside and inside an organization, can be considered as a worrying problem in the organization because of its severe impact on the reputation and bottom line figures of the company. The study provides important information to management to strengthen their compliance with the internal control system generally and policies and procedures particularly.

Originality/value

This study is original, as it focuses on the actual fraud cases that occur in the telecommunication industry, which is under-researched in fraud literature, particularly in developing markets such as Malaysia. Prior empirical research on fraud and unethical practices has concentrated on factors that contribute to fraud and the financial and non-financial impacts of fraud in an organization.
Implementation of a nationwide electronic health record (EHR)
Authors: Fragidis Leonidas L. , Chatzoglou Prodromos D.
Published: January 2018

Purpose

The purpose of this paper is to identify the best practices applied during the implementation process of a national electronic health record (EHR) system. Furthermore, the main goal is to explore the knowledge gained by experts from leading countries in the field of nationwide EHR system implementation, focusing on some of the main success factors and difficulties, or failures, of the various implementation approaches.

Design/methodology/approach

To gather the necessary information, an international survey has been conducted with expert participants from 13 countries (Denmark, Austria, Sweden, Norway, the UK, Germany, the Netherlands, Switzerland, Canada, the USA, Israel, New Zealand and South Korea), who had been playing varying key roles during the implementation process. Taking into consideration that each system is unique, with each own (different) characteristics and many stakeholders, the methodological approach followed was not oriented to offer the basis for comparing the implementation process, but rather, to allow us better understand some of the pros and cons of each option.

Findings

Taking into account the heterogeneity of each country’s financing mechanism and health system, the predominant EHR system implementation option is the middle-out approach. The main reasons which are responsible for adopting a specific implementation approach are usually political. Furthermore, it is revealed that the most significant success factor of a nationwide EHR system implementation process is the commitment and involvement of all stakeholders. On the other hand, the lack of support and the negative reaction to any change from the medical, nursing and administrative community is considered as the most critical failure factor.

Originality/value

A strong point of the current research is the inclusion of experts from several countries (13) spanning in four continents, identifying some common barriers, success factors and best practices stemming from the experience obtained from these countries, with a sense of unification. An issue that should never be overlooked or underestimated is the alignment between the functionality of the new EHR system and users’ requirements.
A multi-objective multicast routing optimization based on differential evolution in MANET
Authors: Wei Wenhong , Qin Yong , Cai Zhaoquan
Published: January 2018

Purpose

The purpose of this paper is to propose a multi-objective differential evolution algorithm named as MOMR-DE to resolve multicast routing problem. In mobile ad hoc network (MANET), multicast routing is a non-deterministic polynomial -complete problem that deals with the various objectives and constraints. Quality of service (QoS) in the multicast routing problem mainly depends on cost, delay, jitter and bandwidth. So the cost, delay, jitter and bandwidth are always considered as multi-objective for designing multicast routing protocols. However, mobile node battery energy is finite and the network lifetime depends on node battery energy. If the battery power consumption is high in any one of the nodes, the chances of network’s life reduction due to path breaks are also more. On the other hand, node’s battery energy had to be consumed to guarantee high-level QoS in multicast routing to transmit correct data anywhere and at any time. Hence, the network lifetime should be considered as one objective of the multi-objective in the multicast routing problem.

Design/methodology/approach

Recently, many metaheuristic algorithms formulate the multicast routing problem as a single-objective problem, although it obviously is a multi-objective optimization problem. In the MOMR-DE, the network lifetime, cost, delay, jitter and bandwidth are considered as five objectives. Furthermore, three QoS constraints which are maximum allowed delay, maximum allowed jitter and minimum requested bandwidth are included. In addition, we modify the crossover and mutation operators to build the shortest-path multicast tree to maximize network lifetime and bandwidth, minimize cost, delay and jitter.

Findings

Two sets of experiments are conducted and compared with other algorithms for these problems. The simulation results show that our proposed method is capable of achieving faster convergence and is more preferable for multicast routing in MANET.

Originality/value

In MANET, most metaheuristic algorithms formulate the multicast routing problem as a single-objective problem. However, this paper proposes a multi-objective differential evolution algorithm to resolve multicast routing problem, and the proposed algorithm is capable of achieving faster convergence and more preferable for multicast routing.
A hybrid particle swarm optimization algorithm for the capacitated location routing problem
Authors: Kechmane Laila , Nsiri Benayad , Baalal Azeddine
Published: January 2018

Purpose

The purpose of this paper is to solve the capacitated location routing problem (CLRP), which is an NP-hard problem that involves making strategic decisions as well as tactical and operational decisions, using a hybrid particle swarm optimization (PSO) algorithm.

Design/methodology/approach

PSO, which is a population-based metaheuristic, is combined with a variable neighborhood strategy variable neighborhood search to solve the CLRP.

Findings

The algorithm is tested on a set of instances available in the literature and gave good quality solutions, results are compared to those obtained by other metaheuristic, evolutionary and PSO algorithms.

Originality/value

Local search is a time consuming phase in hybrid PSO algorithms, a set of neighborhood structures suitable for the solution representation used in the PSO algorithm is proposed in the VNS phase, moves are applied directly to particles, a clear decoding method is adopted to evaluate a particle (solution) and there is no need to re-encode solutions in the form of particles after applying local search.
A Quantum-behaved Pigeon-Inspired Optimization approach to Explicit Nonlinear Model Predictive Controller for quadrotor
Authors: Xian Ning , Chen Zhilong
Published: January 2018

Purpose

The purpose of this paper is to simplify the Explicit Nonlinear Model Predictive Controller (ENMPC) by linearizing the trajectory with Quantum-behaved Pigeon-Inspired Optimization (QPIO).

Design/methodology/approach

The paper deduces the nonlinear model of the quadrotor and uses the ENMPC to track the trajectory. Since the ENMPC has high demand for the state equation, the trajectory needed to be differentiated many times. When the trajectory is complicate or discontinuous, QPIO is proposed to linearize the trajectory. Then the linearized trajectory will be used in the ENMPC.

Findings

Applying the QPIO algorithm allows the unequal distance sample points to be acquired to linearize the trajectory. Comparing with the equidistant linear interpolation, the linear interpolation error will be smaller.

Practical implications

Small-sized quadrotors were adopted in this research to simplify the model. The model is supposed to be accurate and differentiable to meet the requirements of ENMPC.

Originality/value

Traditionally, the quadrotor model was usually linearized in the research. In this paper, the quadrotor model was kept nonlinear and the trajectory will be linearized instead. Unequal distance sample points were utilized to linearize the trajectory. In this way, the authors can get a smaller interpolation error. This method can also be applied to discrete systems to construct the interpolation for trajectory tracking.
International leadership for the control of disease outbreaks relating to “One Health”
Authors: Plianbangchang Samlee
Published: January 2018

Purpose

In view of the current global challenge of infectious diseases transmitted from animal to man, this is a complimentary piece of paper to promote, in particular, the inter-sectorial and multi-disciplinary coordination and cooperation in their prevention and control, among all concerned agencies/organizations at both policy and operational levels, with special emphasis on the importance of leadership development within the socio-cultural context of health, and with particular reference to the concept of “One Health” that implies the intimate interaction between man and animal within their own environments/ecosystems. The paper aims to discuss these issues.

Design/methodology/approach

This is a commentary piece.

Findings

The paper directly and indirectly suggests lacunae in several areas of concern for further research and development to fill the knowledge gap in such a prevention and control.

Originality/value

This is a commentary piece.