bluuebunny/crossref_metadata_2025 huggingface dataset:
Etiological factors of chronic hepatitis in Italy: a 2014 national survey
Authors: Stroffolini Tommaso , Sagnelli Evangelista , Almasio Piero L. , Andriulli Angelo , Smedile Antonina , Pirisi Mario , Sagnelli Caterina , Russello Maurizio , Coppola Nicola , de Luca Massimo , Pisaturo Mariantonietta , Rosina Floriano , Gaeta Giovanni B.
Published: May 2017

Background

The last Italian prevalence survey on chronic hepatitis (CH) conducted in 2001 showed that the hepatitis C virus (HCV) was the main agent associated with CH.

Aim

The aim of this study was to evaluate epidemiological changes in CH occurring after 13 years.

Patients and methods

Enrollment of 1392 CH consecutive patients referred to 16 Italian liver units in 2014 scattered all over the country (four in the North, four in the Center, four in the South, and four in the Islands) was performed.

Results

The mean age of the patients was 58.3 years, with a sex ratio (male/female) of 1.5. HCV infection (also with other etiologies) continues to be the most prevalent etiology (58.1%). However, this prevalence was lower (P<0.01) than the corresponding figure (76.5%) for 2001. The proportion of hepatitis B virus-related cases almost doubled over time from 12.2% in 2001 to 22.5% in 2014 (P<0.01), most probably biased because of the distribution of entecavir and tenofovir free of charge at outpatient hospital clinics after 2001. Patients reporting risky alcohol intake (also with other etiologies) accounted for 12.4% of cases, a figure lower than that reported in 2001: 19.2% (P<0.01). The proportion of nonalcoholic fatty liver disease cases nearly doubled over time (3.6% in 2001 and 6.2% in 2014; P<0.05), reflecting the greater attention over time devoted to this syndrome.

Conclusion

The decreasing role of HCV infection as an etiologic factor of CH in Italy is good news considering the high cost of the directly acting antiviral agents for HCV eradication. Metabolic factors warrant greater attention in the near future.
Novel therapies and potential therapeutic targets in the management of chronic hepatitis B
Authors: Serigado Joao M. , Izzy Manhal , Kalia Harmit
Published: May 2017

Chronic hepatitis B is a persistent and progressive inflammatory liver disease caused by infection with the hepatitis B virus (HBV). More than 240 million individuals are infected with HBV worldwide and hepatitis B accounts for an estimated 650 000 deaths annually. Approximately up to 30% of chronically infected patients will develop complications of HBV infection including, but not limited to, liver cirrhosis, end-stage liver disease, and hepatocellular carcinoma. Currently approved therapies have improved clinical outcomes, but have a considerable side-effect profile, elevated cost, and a finite course of treatment. This has led to a growing interest in research for new therapies. As the mechanisms for HBV replication are becoming better understood, new potential targets have been discovered, leading to the development of new therapies. In this article, we describe the promising therapies that are under evaluation, showing their mechanisms of action, effects, and stage of development.
Global surgery: current evidence for improving surgical care
Authors: Fuller Jennifer C. , Shaye David A.
Published: May 2017

Purpose of review

The field of global surgery is undergoing rapid transformation, owing to several recent prominent reports positioning it as a cost-effective means of relieving global disease burden. The purpose of this article is to review the recent advances in the field of global surgery.

Recent findings

Efforts to grow the global surgical workforce and procedural capacity have focused on innovative methods to increase surgeon training, enhance international collaboration, leverage technology, optimize existing health systems, and safely implement task-sharing. Computer modeling offers a novel means of informing policy to optimize timely access to care, equitably promote health and financial protection, and efficiently grow infrastructure. Tools and checklists have recently been developed to enhance data collection and ensure methodologically rigorous publications to inform planning, benchmark surgical systems, promote accurate modeling, track key health indicators, and promote safety. Creation of institutional partnerships and trainee exchanges can enrich training, stimulate commitment to humanitarian work, and promote the equal exchange of ideas and expertise.

The recent body of work creates a strong foundation upon which work toward the goal of universal access to safe, affordable surgical care can be built; however, further collection and analysis of country-specific data is necessary for accurate modeling and outcomes research into the efficacy of policies such as task-sharing is greatly needed.
Multiple Cranial Nerve Palsies in Giant Cell Arteritis
Authors: Ross Michael , Bursztyn Lulu , Superstein Rosanne , Gans Mark
Published: May 2017

Giant cell arteritis (GCA) is a systemic vasculitis of medium and large arteries often with ophthalmic involvement, including ischemic optic neuropathy, retinal artery occlusion, and ocular motor cranial nerve palsies. This last complication occurs in 2%–15% of patients, but typically involves only 1 cranial nerve. We present 2 patients with biopsy-proven GCA associated with multiple cranial nerve palsies.
A comparison between single cell RNA sequencing and single molecule RNA FISH for rare cell analysis
Authors: Torre Eduardo , Dueck Hannah , Shaffer Sydney , Gospocic Janko , Gupte Rohit , Bonasio Roberto , Kim Junhyong , Murray John , Raj Arjun
Published: May 2017

The development of single cell RNA sequencing technologies has emerged as a powerful means of profiling the transcriptional behavior of single cells, leveraging the breadth of sequencing measurements to make inferences about cell type. However, there is still little understanding of how well these methods perform at measuring single cell variability for small sets of genes and what “transcriptome coverage” (e.g. genes detected per cell) is needed for accurate measurements. Here, we use single molecule RNA FISH measurements of 26 genes in thousands of melanoma cells to provide an independent reference dataset to assess the performance of the DropSeq and Fluidigm single cell RNA sequencing platforms. We quantified the Gini coefficient, a measure of rare-cell expression variability, and find that the correspondence between RNA FISH and single cell RNA sequencing for Gini, unlike for mean, increases markedly with per-cell library complexity up to a threshold of ∼2000 genes detected. A similar complexity threshold also allows for robust assignment of multi-genic cell states such as cell cycle phase. Our results provide guidelines for selecting sequencing depth and complexity thresholds for single cell RNA sequencing. More generally, our results suggest that if the number of genes whose expression levels are required to answer any given biological question is small, then greater transcriptome complexity per cell is likely more important than obtaining very large numbers of cells.
All fingers are not the same: Handling variable-length sequences in a discriminative setting using conformal multi-instance kernels
Authors: Nikumbh Sarvesh , Ebert Peter , Pfeifer Nico
Published: May 2017

Most string kernels for comparison of genomic sequences are generally tied to using (absolute) positional information of the features in the individual sequences. This poses limitations when comparing variable-length sequences using such string kernels. For example, profiling chromatin interactions by 3C-based experiments results in variable-length genomic sequences (restriction fragments). Here, exact position-wise occurrence of signals in sequences may not be as important as in the scenario of analysis of the promoter sequences, that typically have a transcription start site as reference. Existing position-aware string kernels have been shown to be useful for the latter scenario.

In this work, we propose a novel approach for sequence comparison that enables larger positional freedom than most of the existing approaches, can identify a possibly dispersed set of features in comparing variable-length sequences, and can handle both the aforementioned scenarios. Our approach,CoMIK, identifies not just the features useful towards classification but also their locations in the variable-length sequences, as evidenced by the results of three binary classification experiments, aided by recently introduced visualization techniques. Furthermore, we show that we are able to efficiently retrieve and interpret the weight vector for the complex setting of multiple multi-instance kernels.
Enhanced guide-RNA Design and Targeting Analysis for Precise CRISPR Genome Editing of Single and Consortia of Industrially Relevant and Non-Model Organisms
Authors: Mendoza Brian J. , Trinh Cong T.
Published: May 2017

Motivation

Genetic diversity of non-model organisms offers a repertoire of unique phenotypic features for exploration and cultivation for synthetic biology and metabolic engineering applications. To realize this enormous potential, it is critical to have an efficient genome editing tool for rapid strain engineering of these organisms to perform novel programmed functions.

Results

To accommodate the use of CRISPR/Cas systems for genome editing across organisms, we have developed a novel method, named CASPER (CRISPR Associated Software for Pathway Engineering and Research), for identifying on- and off-targets with enhanced predictability coupled with an analysis of non-unique (repeated) targets to assist in editing any organism with various endonucleases. Utilizing CASPER, we demonstrated a modest 2.4% and significant 30.2% improvement (F-test, p<0.05) over the conventional methods for predicting on- and off-target activities, respectively. Further we used CASPER to develop novel applications in genome editing: multitargeting analysis (i.e. simultaneous multiple-site modification on a target genome with a sole guide-RNA (gRNA) requirement) and multispecies population analysis (i.e. gRNA design for genome editing across a consortium of organisms). Our analysis on a selection of industrially relevant organisms revealed a number of non-unique target sites associated with genes and transposable elements that can be used as potential sites for multitargeting. The analysis also identified shared and unshared targets that enable genome editing of single or multiple genomes in a consortium of interest. We envision CASPER as a useful platform to enhance the precise CRISPR genome editing for metabolic engineering and synthetic biology applications.
The prevalence and benefits of admixture during species invasions: a role for epistasis?
Authors: Barker Brittany S , Cocio Janelle E , Anderson Samantha R , Braasch Joseph E , Cang F Alice , Gillette Heather D , Dlugosch Katrina M
Published: May 2017

Species introductions often bring together genetically divergent source populations, resulting in genetic admixture. This geographic reshuffling of diversity has the potential to generate favorable new genetic combinations, facilitating the establishment and invasive spread of introduced populations. Observational support for the superior performance of admixed introductions has been mixed, however, and the broad importance of admixture to invasion questioned. Under most underlying mechanisms, admixture’s benefits should be expected to increasewith greater divergence among and lower genetic diversity within source populations. We use a literature survey to quantify the prevalence of admixture and evaluate whether it occurrs under circumstances predicted to be mostbeneficial to introduced species. We find that 39% of species are reported to be admixed when introduced. Admixed introductions come from sources with a wide range of genetic variation, but are disproportionately absent where there is high genetic divergence among native populations. We discuss multiple potential explanations for these patterns, but note that negative epistatic interactions should be expected at high divergence amongpopulations (outbreeding depression). As a case study, we experimentally cross source populations differing in divergence in the invasive plantCentaurea solstitialis. We find many positive (heterotic) interactions, but fitness benefits decline and are ultimately negative at high source divergence, with patterns suggestingcyto-nuclear epistasis. We conclude that admixture is common in species introductions and often happens under conditions expected to be beneficial to invaders, but that these conditions may be constrained by predictable negativegenetic interactions, potentially explaining conflicting evidence for admixture's benefits to invasion.
Disentangling the effects of selection and loss bias on gene dynamics
Authors: Iranzo Jaime , Cuesta José A. , Manrubia Susanna , Katsnelson Mikhail I. , Koonin Eugene V.
Published: May 2017

We combine mathematical modelling of genome evolution with comparative analysis of prokaryotic genomes to estimate the relative contributions of selection and intrinsic loss bias to the evolution of different functional classes of genes and mobile genetic elements (MGE). An exact solution for the dynamics of gene family size was obtained under a linear duplication-transfer-loss model with selection. With the exception of genes involved in information processing, particularly translation, which are maintained by strong selection, the average selection coefficient for most non-parasitic genes is low albeit positive, compatible with the observed positive correlation between genome size and effective population size. Free-living microbes evolve under stronger selection for gene retention than parasites. Different classes of MGE show a broad range of fitness effects, from the nearly neutral transposons to prophages, which are actively eliminated by selection. Genes involved in anti-parasite defense, on average, incur a fitness cost to the host that is at least as high as the cost of plasmids. This cost is probably due to the adverse effects of autoimmunity and curtailment of horizontal gene transfer caused by the defense systems and selfish behavior of some of these systems, such as toxin-antitoxin and restriction-modification modules. Transposons follow a biphasic dynamics, with bursts of gene proliferation followed by decay in the copy number that is quantitatively captured by the model. The horizontal gene transfer to loss ratio, but not the duplication to loss ratio, correlates with genome size, potentially explaining the increased abundance of neutral and costly elements in larger genomes.

SIGNIFICANCE

Evolution of microbes is dominated by horizontal gene transfer and the incessant host-parasite arms race that promotes the evolution of diverse anti-parasite defense systems. The evolutionary factors governing these processes are complex and difficult to disentangle but the rapidly growing genome databases provide ample material for testing evolutionary models. Rigorous mathematical modeling of evolutionary processes, combined with computer simulation and comparative genomics, allowed us to elucidate the evolutionary regimes of different classes of microbial genes. Only genes involved in key informational and metabolic pathways are subject to strong selection whereas most of the others are effectively neutral or even burdensome. Mobile genetic elements and defense systems are costly, supporting the understanding that their evolution is governed by the same factors.
How well do you know your mutation? Complex effects of genetic background on expressivity, complementation, and ordering of allelic effects
Authors: Chandler Christopher H. , Chari Sudarshan , Kowalski Alycia , Choi Lin , Tack David , DeNieu Michael , Pitchers William , Sonnenschein Anne , Marvin Leslie , Hummel Kristen , Marier Christian , Victory Andrew , Porter Cody , Mammel Anna , Holms Julie , Sivaratnam Gayatri , Dworkin Ian
Published: May 2017

For a given gene, different mutations influence organismal phenotypes to varying degrees. However, the expressivity of these variants not only depends on the DNA lesion associated with the mutation, but also on factors including the genetic background and rearing environment. The degree to which these factors influence related alleles, genes, or pathways similarly, and whether similar developmental mechanisms underlie variation in the expressivity of a single allele across conditions and variation across alleles is poorly understood. Besides their fundamental biological significance, these questions have important implications for the interpretation of functional genetic analyses, for example, if these factors alter the ordering of allelic series or patterns of complementation. We examined the impact of genetic background and rearing environment for a series of mutations spanning the range of phenotypic effects for both thescallopedandvestigialgenes, which influence wing development inDrosophila melanogaster. Genetic background and rearing environment influenced the phenotypic outcome of mutations, including intra-genic interactions, particularly for mutations of moderate expressivity. We examined whether cellular correlates (such as cell proliferation during development) of these phenotypic effects matched the observed phenotypic outcome. While cell proliferation decreased with mutations of increasingly severe effects, surprisingly it did not co-vary strongly with the degree of background dependence. We discuss these findings and propose a phenomenological model to aid in understanding the biology of genes, and how this influences our interpretation of allelic effects in genetic analysis.
Dynamics of the Human Antibody Repertoire following B-cell Depletion in Systemic Sclerosis
Authors: de Bourcy Charles F. A. , Dekker Cornelia L. , Davis Mark M. , Nicolls Mark R. , Quake Stephen R.
Published: May 2017

Systemic sclerosis with pulmonary arterial hypertension (SSc-PAH) is a debilitating and frequently lethal disease of unknown cause lacking effective treatment options. Lymphocyte anomalies and autoantibodies observed in systemic sclerosis have suggested an autoimmune character. Here we study the clonal structure of the B-cell repertoire in SSc-PAH using immunoglobulin heavy-chain sequencing before and after B-cell depletion. We found SSc-PAH to be associated with anomalies in B-cell development, namely altered VDJ rearrangement frequencies (reduced IGHV2-5 segment usage) and an increased somatic mutation-fixation probability in expanded B-cell lineages. SSc-PAH was also characterized by anomalies in B-cell homeostasis, namely an expanded IgD+proportion with reduced mutation loads and an expanded proportion of highly antibody-secreting cells. Disease signatures pertaining to IGHV2-5 segment usage, IgD proportions and mutation loads were temporarily reversed after B-cell depletion. Analyzing the time course of B-cell depletion, we find that the kinetics of naïve replenishment are predictable from baseline measurements alone, that release of plasma cells into the periphery can precede naïve replenishment and that modes of B-cell receptor diversity are highly elastic. Our findings shed light on the humoral immune basis of SSc-PAH and provide insights into the effect of B-cell depletion on the antibody repertoire.

Abbreviations

SSc-PAH

Systemic sclerosis with pulmonary arterial hypertension

IGH

immunoglobulin heavy-chain

BCR

B-cell receptor

CDR3

complementarity-determining region 3

Ig

immunoglobulin

AA

amino acid
STAR Chimeric Post For Rapid Detection of Circular RNA and Fusion Transcripts
Authors: Akers Nicholas K. , Schadt Eric E. , Losic Bojan
Published: May 2017

Motivation

The biological relevance of chimeric RNA alignments is now well established. Chimera arising as chromosomal fusions are often drivers of cancer, and recently discovered circular RNA are only now being characterized. While software already exists for fusion discovery and quantitation, high false positive rates and high run-times hamper scalable fusion discovery on large datasets. Furthermore, very little software is available for circular RNA detection and quantification.

Results

Here we present STAR Chimeric Post (STARChip), a novel software package that processes chimeric alignments from the STAR aligner and produces annotated circular RNA and high precision fusions in a rapid, efficient, and scalable manner that is appropriate for high dimensional medical omics datasets.

Availability and Implementation

STARChip is available athttps://github.com/LosicLab/STARChip

Contacts

bojan.losic@mssm.eduornicholas.kipp.akers@gmail.com

Supplementary Information

Supplementary figures and tables are available online.
Performance assessment of class-E inverter for capacitive power transfer system
Authors: Yusop Yusmarnita , Md. Saat Mohd. Shakir , Husin Siti Huzaimah , Kiong Nguang Sing , Hindustan Imran
Published: May 2017

Purpose

This paper aims to present a new wireless power transfer technique using capacitive coupling. The capacitive power transfer (CPT) system has been introduced as an attractive alternative to the traditional inductive coupling method. The CPT offers benefits such as simple topology, fewer components, better electromagnetic interference (EMI) performance and robustness to surrounding metallic elements.

Design/methodology/approach

A class-E inverter together with and without inductor capacitor (LC) matching circuit has been utilised in this work because of its ability to perform the DC-to-AC inversion efficiently with significant reduction in switching losses. The validity of the proposed concept has been verified by conducting a laboratory experiment of the CPT system.

Findings

The performances for both systems are analysed and evaluated. A 9.7 W output power is generated through a combined interface [printed circuit board (PCB) plate] capacitance of 2.82 nF at an operating frequency of 1 MHz, with 97 per cent efficiency for 0.25 mm coupling gap distance.

Originality value

An efficient CPT system with class-E LC matching topology is proposed in this paper. With this topology, the zero-voltage switching can be achieved even if the load is different by properly designing the LC matching transformation circuit.
An improved conformal mapping method for magnetic field analysis in surface mounted permanent magnet motors
Authors: Rezaeealam Behrooz , Rezaee-Alam Farhad
Published: May 2017

Purpose

The purpose of this paper is to present an improved conformal mapping (ICM) method that simultaneously considers the influence of relative recoil permeability of PMs, the armature reaction, the stator slotting, and the magnetic saturation on determination of the PM operating point in its different parts.

Design/methodology/approach

The ICM method is a time-effective method that considers the magnetic saturation by suitable increments in air-gap length under each tooth and also the width of slot openings. In this paper, the analytical and numerical conformal mappings such as the Schwarz-Christoffel (SC) mapping are used for magnetic field analysis due to the permanent magnets and the armature reaction in one slotted air gap. The field solution in the slotted air gap is obtained through the modulation of field solution in one slotless air-gap using the complex air-gap permeance.

Findings

The ICM method can consider the magnetic saturation in different electric loadings, and also the variation of PM operating points in its different parts.

Practical implications

The ICM method is applied to one surface mounted permanent magnet (SMPM) motor and is verified by comparing with the corresponding results obtained through finite element method (FEM), and frozen permeability finite element method (FP-FEM).

Originality/value

This paper presents an ICM method with a new technique for saturation effect modeling, which can be used to separate and calculate the on-load components of air-gap field and torque.
Start-up strategy using flywheel energy storage for superconducting DC induction heater
Authors: Yang Ping , Wang Yawei , Chang T. , Ma H. , Li Zhuyong , Jin Zhijian , Hong Zhiyong
Published: May 2017

Purpose

The purpose of this paper is to propose a hybrid driving system that couples a motor and flywheel energy storage (FES) for a megawatt-scale superconducting direct current (DC) induction heater. Previous studies have proven that a superconducting DC induction heater has great advantages in relation to its energy efficiency and heating quality. In this heater, a motor rotates an aluminium billet in a DC magnetic field and the induced eddy current causes it to be heated. When the aluminium billet begins to rotate, a high peak load torque appears at a low rotation speed. Therefore, driving the billet economically has been a great challenge when designing the driving system, which is the focus of this paper.

Design/methodology/approach

A hybrid driving system based on FES is designed to provide extra torque when the peak load torque occurs at a low rotation speed, which allows the successful start-up of the aluminium billet and the operation of the motor at its rated capacity. The mechanical structure of this hybrid driving system is introduced. A simulation model was constructed using Matlab/Simulink and the dynamic start-up process is analysed. The influence of the flywheel’s inertia and required minimum engagement speed are investigated.

Findings

The results of this paper show that the hybrid driving system that couples FES and a motor can successfully be used to start the aluminium billet rotating. The flywheel’s inertia and engagement speed are the most important parameters. The inertia of the flywheel decreases with an increase in its engagement speed.

Practical implications

The cost of the driving system is significantly reduced, which is very important in relation to the commercial potential of this apparatus.

Originality/value

A novel start-up strategy for driving the aluminium billet of a superconducting DC induction heater at low speed is proposed based on FES.
Improved energy management strategy for a hybrid fuel cell/battery system
Authors: Bendjedia Bachir , Rizoug Nassim , Boukhnifer Moussa , Bouchafaa Farid
Published: May 2017

Purpose

The purpose of this paper is to propose and compare two energy management strategies (EMSs). First, a classic method based on frequency separation with fixed limits on fuel cell (FC) power is presented and tested. Then, the improvement of the classic strategy is developed and implemented when the main enhancements are its ease of implementation, hydrogen economy and extending hybrid source lifetime.

Design/methodology/approach

The proposed EMS is developed using an online variable power limitation of the FC depending on the battery state of charge while ensuring that the energy of batteries remains in its operating depth of discharge (DOD) range.

Findings

In the objective to show the benefits of the developed strategy, a comparative analysis was conducted between two strategies. The simulation and experimental results show the effectiveness and gains obtained by the improved energy management system (IEMS) in terms of fuel economy (13 per cent) and decreasing the applied stress on the FC (22 per cent) which leads to a longer life span of the whole system.

Originality/value

The proposed approach is developed and tested by simulation. To confirm it, a test bench has been assembled as hardware in the loop (HIL) real-time system. The presented experimental results confirm the efficiency and show the providing gains of the IEMS.
Identification of continuous-time systems with multiple unknown time delays
Authors: Ghoul Yamna , Ibn Taarit Kaouther , Ksouri Moufida
Published: May 2017

Purpose

The purpose of this paper is to present a separable identification algorithm for a multiple-input single-output (MISO) continuous-time (CT) system.

Design/methodology/approach

This paper proposes an optimal method for the identification of MISO CT systems with unknown time delays by using the Simplified Refined Instrumental Variable method.

Findings

Simulations results are presented to show the performance of the proposed approach in the presence of additive output measurement noise.

Originality/value

This paper presents an optimal and robust method to separable delays and parameter identification of a MISO CT system with unknown time delays from sampled input/output data.
Analysis of linear induction machines with internal fault by MEC
Authors: Nosrati Amin , Nazarzadeh Jalal
Published: May 2017

Purpose

The purpose of this paper is to introduce an asymmetric structure of the magnetic equivalent circuit (MEC) for analysis of the linear induction machine (LIM) with an internal short circuit fault.

Design/methodology/approach

By applying a proper MEC to the LIM, a generalized relation for the inductance matrix of the machine can be directly determined. To evaluate the proposed model, the stator currents and the air-gap flux with the proposed technique are given and compared to the simulation and experimental results in the healthy and fault conditions.

Findings

The LIM is an axial flux machine with a wide range of applications in high-performance drives. Due to a well-tried effect of the first tooth and the last one (the end effect), the performance level of the LIM decreases. Also, the analysis of the linear machines in fault conditions illustrates more complexity compared to the rotary induction machine. However, the MEC is very simple, describing the behavior of the asymmetric electromechanical devices using the magnetic reluctance or the permeance of flux paths.

Originality/value

Using the proposed model, there would be some decrease in the complications of the LIM analysis in the asymmetrical conditions. Moreover, analyzing some of the characteristics of the LIM, such as turn-fault condition, it can be calculated with high accuracy.
Hysteresis loop reversing by applying Langevin approximation
Authors: Takacs Jeno
Published: May 2017

Purpose

The purpose of this paper is to model one of the unsolved problems of magnetism, the reversal of hysteresis loops, in an analytical way. The mathematical models, describing the multiphase steel used in engineering practice, without any exception, are unsuited to provide a way to reverse the hysteretic process. In this paper, a proposal is put forward to model it by using analytical expressions, applying the reversal of the Langevin function. This model works with a high accuracy, giving useful answers to a long unsolved magnetic problem, the lack of reversibility of the hysteresis loop. The use of the proposal is shown by applying the reversal of Langevin function to a sinusoidal and a triangular waveform, the two most frequently used waveforms in research, test and industrial applications. Schematic representations are given for the wave reconstruction by using the proposed method.

Design/methodology/approach

The unsolved reversibility of the hysteresis loop is approached by a simple analytical formula, providing close approximation for most applications.

Findings

The proposed solution, applying the reversal of Langevin function, to the problem provides a good practical solution.

Research limitations/implications

The simple analytical formula has been applied to a number of loops of widely different shapes and sizes with excellent results.

Practical implications

The proposed solution provides a missing mathematical tool to an unsolved problem for practical applications.

Social implications

The solution proposed will reduce the work required and provide replacement for expensive complex test instrumentation.

Originality/value

To the best of the authors’ knowledge, this approach used in this study is the first successful approach in this field, irrespective of the required waveform, and is completely independent of the model used by the user.
Numerical investigation of in-mold electromagnetic stirring process for fluid flow and solidification
Authors: Maurya Ambrish , Jha Pradeep Kumar
Published: May 2017

Purpose

The purpose of present investigation is to analyze the in-mold electromagnetic stirring (M-EMS) process and the effect of stirrer frequency on fluid flow and solidification in a continuous casting billet caster mold.

Design/methodology/approach

A hybrid approach involving finite element and finite volume method has been used for the study. Finite element model is used to calculate time variable magnetic field, which is further coupled with fluid flow and solidification equations for magneto-hydrodynamic analysis with finite volume model.

Findings

Results show that though superheat given to steel before its entry into the mold is quickly removed, solid shell formation is delayed by the use of M-EMS. Final solid shell thickness, however, is slightly reduced. Increase in frequency is found to increase the magnetic flux density and tangential velocity of liquid steel and decrease in diameter of liquid core.

Practical implications

The work is of great industrial relevance. The model may be used to design industrial setup of in-mold electromagnetic stirrer and process could be analyzed and optimized numerically.

Originality/value

The paper evaluates the influence of M-EMS and its frequency on solidification and flow behavior in the continuous casting mold. The iso-surface temperatures from pouring temperature to liquidus temperature inside the mold have been shown. The findings may be useful for the steelmakers to reduce the defect in continuous casting.
An improved unscented Kalman filter based dynamic state estimation algorithm for electric distribution Systems
Authors: Ahmad Fiaz , Muhammad Abdul Rashid Kabir , Rasool Akhtar , Ozsoy Esref Emre , Sabanoviç Asif , Elitas Meltem
Published: May 2017

Purpose

To propose an improved algorithm for the state estimation of distribution networks based on the unscented Kalman filter (IUKF). The performance comparison of unscented Kalman filter (UKF) and newly developed algorithm, termed Improved unscented Kalman Filter (IUKF) for IEEE-30, 33 and 69-bus radial distribution networks for load variations and bad data for two measurement noise scenarios, i.e. 30 and 50 per cent are shown.

Design/methodology/approach

State estimation (SE) plays an instrumental role in realizing smart grid features like distribution automation (DA), enhanced distribution generation (DG) penetration and demand response (DR). Implementation of DA requires robust, accurate and computationally efficient dynamic SE techniques that can capture the fast changing dynamics of distribution systems more effectively. In this paper, the UKF is improved by changing the way the state covariance matrix is calculated, to enhance its robustness and accuracy under noisy measurement conditions. UKF and proposed IUKF are compared under the cummulative effect of load variations and bad data based on various statistical metrics such as Maximum Absolute Deviation (MAD), Maximum Absolute Per cent Error (MAPE), Root Mean Square Error (RMSE) and Overall Performance Index (J) for three radial distribution networks. All the simulations are performed in MATLAB 2014b environment running on an hp core i5 laptop with 4GB memory and 2.6 GHz processor.

Findings

An Improved Unscented Kalman Filter Algorithm (IUKF) is developed for distribution network state estimation. The developed IUKF is used to predict network states (voltage magnitude and angle at all buses) and measurements (source voltage magnitude, line power flows and bus injections) in the presence of load variations and bad data. The statistical performance of the coventional UKF and the proposed IUKF is carried out for a variety of simulation scenarios for IEEE-30, 33 and 69 bus radial distribution systems. The IUKF demonstrated superiority in terms of: RMSE; MAD; MAPE; and overall performance index J for two measurement noise scenarios (30 and 50 per cent). Moreover, it is shown that for a measurement noise of 50 per cent and above, UKF fails while IUKF performs.

Originality/value

UKF shows degraded performance under high measurement noise and fails in some cases. The proposed IUKF is shown to outperform the UKF in all the simulated scenarios. Moreover, this work is novel and has justified improvement in the robustness of the conventional UKF algorithm.
Dependence of electrical resistivity on sintering conditions of silver layers printed by InkJet printing technology
Authors: Lukacs Peter , Pietrikova Alena , Cabuk Pavol
Published: May 2017

Purpose

The purpose of this paper is to find optimal sintering conditions of silver-based nano-inks for achieving the high electrical conductivity of the deposited layers applied on polyimide foils as well as the influence of ageing on the electrical conductivity. Therefore, the investigation in the field of silver layers deposited by inkjet printing technology is presented in this paper.

Design/methodology/approach

The four-point resistance measurements were realized for a detailed and precise analysis of the resistance of two different silver layers under different sintering conditions depending on the type of nano-ink varied about the recommended values. Highly accelerated stress tests (HASTs) were also applied as an ageing method for confirmation of the high electrical stability of the silver layers.

Findings

The results prove the strong influence of the temperature and the time of the sintering process on the sheet resistance of the investigated silver-based layers deposited by inkjet printing technology on polyimide foils. The HASTs caused significant changes in the electrical conductivity for both nano-inks presented in this paper. The existence of noticeable dependence among the resistivity, thermal treatment and ageing was proved.

Originality/value

The main benefit lays in the optimization of sintering conditions to improve the electrical conductivity of the silver layers. The paper also presents a new approach for a stability analysis of the silver layers by HASTs.
Investigating the moderating effects of organizational culture and leadership style on IT-adoption and knowledge-sharing intention
Authors: Tseng Shu-Mei
Published: May 2017

Purpose

In light of the important roles of organizational culture and leadership style in IT-adoption intention and knowledge-sharing intention, the purpose of this paper is to investigate the relationships among IT involvement, IT-adoption intention, and knowledge-sharing intention, as well as the moderating effects of organizational culture and leadership style on IT-adoption intention and knowledge-sharing intention.

Design/methodology/approach

This study begins with a literature review followed by the use of a questionnaire method and statistical analytical techniques (hierarchical regression analysis) to investigate the relationships among IT involvement, IT-adoption intention, knowledge-sharing intention, organizational culture, and leadership style.

Findings

The result showed that IT involvement has a significant and positive influence on IT-adoption intention, which further affects the knowledge-sharing intention. Moreover, organizational culture and leadership style have moderating effects on the IT adoption and knowledge-sharing intention.

Research limitations/implications

This research applied a purposive sampling method and obtained a slightly inadequate number of respondents. Therefore, it is suggested that future research should apply random sampling method to collect more responses and increase the generalizability of the findings.

Practical implications

This research suggests that organizations which adopt servant leadership or charismatic leadership, as well as organizations with clan or hierarchy cultures should work on enhancing staff’s knowledge-sharing intention by first raising their IT-adoption intention.

Originality/value

If an enterprise would like to encourage its staff to be more proactive at adopting IT and more willing to share knowledge, then it should first examine its current leadership style and organizational culture in order to propose concrete and effective methods to achieve this, and at the same time, this can help stimulate organizational learning and generate new ideas and knowledge.
KCEBSA
Authors: Kao Shu-Chen , Wu ChienHsing , Huang Chieh-Lin
Published: May 2017

Purpose

From the academic perspective, there are challenges to develop an appropriate evaluation model that is linked to both theoretical and professional viewpoints for online knowledge community evaluation (KCE). These challenges are mainly the evaluation principles, the method used to derive the evaluation items, and the techniques used to determine the importance of evaluation items to formulate the evaluation model. The purpose of this paper is to propose and develop an online KCE model by considering the Delphi method, analytic hierarchy process (AHP) technique, and balanced scorecard (BSC) approach that contains facets of member, strategy, learning and growth, and internal process.

Design/methodology/approach

The qualitative study was used to develop the KCE model. The BSC approach was used to construct the facets of evaluation model. The Delphi method and AHP technique were utilized to derive structural measure items and to determine item weight in the development process, respectively. An illustrated practical case was used to demonstrate the proposed KCE model.

Findings

The member facet is perceived the most important facet while the internal process the least, implying that the invited participants perceive that community members, as represented by member satisfaction and loyalty, are the most important factors. In the knowledge management process sub-facet, knowledge creation obtains the highest weight compared with knowledge acquisition, dissemination, and utilization. Data analysis results based on 822 survey samples for the demonstrated Yahoo!Kimo Knowledge+ case are obtained. Findings and implications are also addressed.

Originality/value

Unlike the exclusively quantitative approach, the proposed KCE model balances both qualitative and quantitative approaches. First, it performed a face-to-face collaboration based on the Delphi method to deal with the unstructured cognition, opinions, and comments of the invited participants. Second, it developed an evaluation model based on the consensus of the invited participants by using the AHP technique in which the perceived importance of measure item to their immediate super item (qualitative variable) is transformed into number (quantitative variable).
Towards accessible integrated palliative care
Authors: den Herder-van der Eerden Marlieke , Ewert Benjamin , Hodiamont Farina , Hesse Michaela , Hasselaar Jeroen , Radbruch Lukas
Published: May 2017

Purpose

Literature suggests that integrated palliative care (IPC) increases the quality of care for palliative patients at lower costs. However, knowledge on models encompassing all integration levels for successfully implementing IPC is scarce. The purpose of this paper is to describe the experiences of IPC leaders in seven European countries regarding core elements, facilitators and barriers of IPC implementation and provides recommendations for future policy and practice.

Design/methodology/approach

A qualitative interview study was conducted between December 2013 and May 2014. In total, 34 IPC leaders in primary and secondary palliative care or public health in Belgium, Germany, Hungary, Ireland, the Netherlands, Spain and the UK were interviewed. Transcripts were analysed using thematic data analysis.

Findings

IPC implementation efforts involved a multidisciplinary team approach and cross-sectional coordination. Informal professional relationships, basic medical education and general awareness were regarded as facilitators of IPC. Identified barriers included lack of knowledge about when to start palliative care, lack of collaboration and financial structures. Recommendations for improvement included access, patient-centeredness, coordination and cooperation, financing and ICT systems.

Originality/value

Although IPC is becoming more common, action has been uneven at different levels. IPC implementation largely remains provisional and informal due to the lack of standardised treatment pathways, legal frameworks and financial incentives to support multilevel integration. In order to make IPC more accessible, palliative care education as well as legal and financial support within national healthcare systems needs to be enhanced.
Pakistani LIS scholars’ altmetrics in ResearchGate
Authors: Ali Muhammad Yousuf , Richardson Joanna
Published: May 2017

Purpose

The purpose of this paper is to analyse the research performance of Pakistani library and information science (LIS) scholars, using the altmetrics provided by ResearchGate (RG).

Design/methodology/approach

Purposive sampling was used to collect profiles between 15 January 2015 and 30 April 2016 of all members of RG who had self-identified as being an LIS scholar of Pakistani nationality. Additional demographic data were obtained through a small survey administered via Google Docs. Resultant data were analysed in SPSS Version 21.

Findings

Study results were broadly consistent in terms of demographical data with previous studies of this cohort. There was a positive correlation between publications, reads, and citations for scholars who had recorded at least one publication. The majority of publications had not been published in a high impact factor journal. Academic networking site profiles create the potential for collaboration, building connections, and exchanging information.

Research limitations/implications

Some scholars eliminated from this study may have published at least one output but neglected to upload details to RG. It is a purposive, exploratory study that provides insights into future research.

Practical implications

The paper produces findings of relevance to researchers in other countries and/or disciplines who may wish to conduct a similar study of a defined cohort.

Originality/value

There have been no previous published research studies on altmetrics associated with Pakistani LIS scholars.