bluuebunny/crossref_metadata_2025 huggingface dataset:
Completeness of Descriptions of Repetitive Transcranial Magnetic Stimulation Intervention
Authors: Chantebel Romain , Chesneau Adélise , Tavernier Elsa , El-Hage Wissam , Caille Agnès
Published: October 2018

Objectives

Repetitive transcranial magnetic stimulation (rTMS) is an innovative therapeutic option in major depressive disorder (MDD). A complete description of the procedure in reports of randomized controlled trials (RCTs) is a prerequisite for implementation of rTMS in clinical practice. The aim of this study was to evaluate the completeness of descriptions of the intervention in RCTs assessing rTMS in MDD.

Methods

We performed a systematic review of RCTs evaluating rTMS in MDD and published until August 2016. We searched PubMed, the Cochrane library, and PsycINFO to identify eligible trials. The completeness of the intervention description was evaluated by the use of an adapted-to-rTMS version of the Template for Intervention Description and Replication (TIDieR) checklist. We defined core items that are the most essential to be reported. Missing information was then sought from additional sources and by e-mailing authors.

Results

We identified 98 trials reporting 134 interventions. None of the interventions were completely described in the full text of the articles, even after searching additional sources. After contacting the authors, 14 (10.4%) of 134 interventions were completely described. The core items were completely described in 74 (55.2%) of 134 interventions after contacting the authors.

Conclusions

We found that rTMS interventions delivered in RCTs are incompletely reported, which prevents their adequate implementation in clinical practice and accurate interpretation of their efficacy. We encourage authors, editors, and reviewers to use the existing reporting guidelines and specifically the TIDieR checklist when describing the intervention. We provide an adapted-to-rTMS TIDieR checklist that could help in the reporting of future trials.
Wide-area all-optical neurophysiology in acute brain slices
Authors: Farhi Samouil L. , Parot Vicente J. , Grama Abhinav , Yamagata Masahito , Abdelfattah Ahmed S. , Adam Yoav , Lou Shan , Jun Kim Jeong , Campbell Robert E. , Cox David D. , Cohen Adam E.
Published: October 2018

Optical tools for simultaneous perturbation and measurement of neural activity open the possibility of mapping neural function over wide areas of brain tissue. However, spectral overlap of actuators and reporters presents a challenge for their simultaneous use, and optical scattering and out-of-focus fluorescence in tissue degrade resolution. To minimize optical crosstalk, we combined an optimized variant (eTsChR) of the most blue-shifted channelrhodopsin reported to-date with a nuclear-localized red-shifted Ca2+ indicator, H2B-jRGECO1a. To perform wide-area optically sectioned imaging in tissue, we designed a structured illumination technique that uses Hadamard matrices to encode spatial information. By combining these molecular and optical approaches we made wide-area maps, spanning cortex and striatum, of the effects of antiepileptic drugs on neural excitability and on the effects of AMPA and NMDA receptor blockers on functional connectivity. Together, these tools provide a powerful capability for wide-area mapping of neuronal excitability and functional connectivity in acute brain slices.
LPM: a latent probit model to characterize the relationship among complex traits using summary statistics from multiple GWASs and functional annotations
Authors: Ming Jingsi , Wang Tao , Yang Can
Published: October 2018

Much effort has been made toward understanding the genetic architecture of complex traits and diseases. Recent results from genome-wide association studies (GWASs) suggest the importance of regulatory genetic effects and pervasive pleiotropy among complex traits. In this study, we propose a unified statistical approach, aiming to characterize relationship among complex traits, and prioritize risk variants by leveraging regulatory information collected in functional annotations. Specifically, we consider a latent probit model (LPM) to integrate summary-level GWAS data and functional annotations. The developed computational framework not only makes LPM scalable to hundreds of annotations and phenotypes, but also ensures its statistically guaranteed accuracy. Through comprehensive simulation studies, we evaluated LPM’s performance and compared it with related methods. Then we applied it to analyze 44 GWASs with nine genic category annotations and 127 cell-type specific functional annotations. The results demonstrate the benefits of LPM and gain insights of genetic architecture of complex traits. The LPM package is available athttps://github.com/mingjingsi/LPM.
Cellular determinants of metabolite concentration ranges
Authors: Eloundou-Mbebi Jeanne M. O. , Küken Anika , Basler Georg , Nikoloski Zoran
Published: October 2018

Cellular functions are shaped by reaction networks whose dynamics are determined by the concentrations of underlying components. However, cellular mechanisms ensuring that a component’s concentration resides in a given range remain elusive. We present network properties which suffice to identify components whose concentration ranges can be efficiently computed in mass-action metabolic networks. We show that the derived ranges are in excellent agreement with simulations from a detailed kinetic metabolic model of Escherichia coli. We demonstrate that the approach can be used with genome-scale metabolic models to arrive at predictions concordant with measurements from Escherichia coli under different growth scenarios. By application to 14 genome-scale metabolic models from diverse species, our approach specifies the cellular determinants of concentration ranges that can be effectively employed to make predictions for a variety of biotechnological and medical applications.

Author Summary

We present a computational approach for inferring concentration ranges from genome-scale metabolic models. The approach specifies a determinant and molecular mechanism underling facile control of concentration ranges for components in large-scale cellular networks. Most importantly, the predictions about concentration ranges do not require knowledge of kinetic parameters (which are difficult to specify at a genome scale), provided measurements of concentrations in a reference state. The approach assumes that reaction rates follow the mass action law used in the derivations of other types of kinetics. We apply the approach with large-scale kinetic and stoichiometric metabolic models of organisms from different kingdoms of life to show that we can identify a proportion of metabolites to which our approach is applicable. By challenging the predictions of concentration ranges in the genome-scale metabolic network of E. coli with real-world data sets, we further demonstrate the prediction power and limitations of the approach.
Signal Transduction in Human Cell Lysate via Dynamic RNA Nanotechnology
Authors: Hochrein Lisa M. , Ge Tianjia J. , Schwarzkopf Maayan , Pierce Niles A.
Published: October 2018

Dynamic RNA nanotechnology with small conditional RNAs (scRNAs) offers a promising conceptual approach to introducing synthetic regulatory links into endogenous biological circuits. Here, we use human cell lysate containing functional Dicer and RNases as a testbed for engineering scRNAs for conditional RNA interference (RNAi). scRNAs perform signal transduction via conditional shape change: detection of a subsequence of mRNA input X triggers formation of a Dicer substrate that is processed to yield siRNA output anti-Y targeting independent mRNA Y for destruction. Automated sequence design is performed using the reaction pathway designer within NUPACK to encode this conditional hybridization cascade into the scRNA sequence subject to the sequence constraints imposed by X and Y. Because it is difficult for secondary structure models to predict which subsequences of mRNA input X will be accessible for detection, here we develop the RNAhyb method to experimentally determine accessible windows within the mRNA that are provided to the designer as sequence constraints. We demonstrate the programmability of scRNA regulators by engineering scRNAs for transducing in both directions between two full-length mRNAs X and Y, corresponding to either the forward molecular logic "if X then not Y" or the reverse molecular logic "if Y then not X". In human cell lysate, we observe a strong OFF/ON conditional response with low crosstalk, corresponding to a ~20-fold increase in production of the siRNA output in response to the cognate vs non-cognate full-length mRNA input. Because diverse biological pathways interact with RNA, scRNAs that transduce between detection of endogenous RNA inputs and production of biologically active RNA outputs hold great promise as a synthetic regulatory paradigm.
AMPK signaling regulates expression of urea cycle enzymes in response to changes in dietary protein intake
Authors: Heibel Sandra Kirsch , McGuire Peter J , Haskins Nantaporn , Majumdar Himani Datta , Rayavarapu Sree , Nagaraju Kanneboyina , Hathout Yetrib , Brown Kristy , Tuchman Mendel , Caldovic Ljubica
Published: October 2018

Abundance of urea cycle enzymes in the liver is regulated by the dietary protein intake. Although urea cycle enzyme levels rise in response to a high protein diet, signaling networks that sense dietary protein intake and trigger changes in expression of urea cycle genes have not been identified. The aim of this study was to identify signaling pathway(s) that respond to changes in protein intake and regulate expression of urea cycle genes in mice and human hepatocytes. Mice were adapted to either control or high (HP) protein diets followed by isolation of liver protein and mRNA and integrated analysis of the proteomic and transcriptome profiles. HP diet led to increased expression of mRNA and enzymes in amino acid degradation pathways, and decreased expression of mRNA and enzymes in carbohydrate and fat metabolism, which implicated AMPK as a possible regulator. Primary human hepatocytes, treated with AICAR an activator of AMPK, were used to test whether AMPK regulates expression of urea cycle genes. The abundance ofCPS1andOTCmRNA increased in hepatocytes treated with AICAR, which supports a role for AMPK signaling in regulation of the urea cycle. Because AMPK is either a target of drugs used to treat type-2 diabetes, these drugs might increase the expression of urea cycle enzymes in patients with urea cycle disorders, which could be the basis of a new therapeutic approach.

Author summary

Integrated analysis of transcriptional and proteomic profiles of the liver tissue from mice fed different protein content diets revealed that AMPK signaling pathway regulates expression of urea cycle enzymes.
Existence and implications of population variance structure
Authors: Musharoff Shaila , Park Danny , Dahl Andy , Galanter Joshua , Liu Xuanyao , Huntsman Scott , Eng Celeste , Burchard Esteban G. , Ayroles Julien F. , Zaitlen Noah
Published: October 2018

Identifying the genetic and environmental factors underlying phenotypic differences between populations is fundamental to multiple research communities. To date, studies have focused on the relationship between population and phenotypic mean. Here we consider the relationship between population and phenotypic variance, i.e., “population variance structure.” In addition to gene-gene and gene-environment interaction, we show that population variance structure is a direct consequence of natural selection. We develop the ancestry double generalized linear model (ADGLM), a statistical framework to jointly model population mean and variance effects. We apply ADGLM to several deeply phenotyped datasets and observe ancestry-variance associations with 12 of 44 tested traits in ~113K British individuals and 3 of 14 tested traits in ~3K Mexican, Puerto Rican, and African-American individuals. We show through extensive simulations that population variance structure can both bias and reduce the power of genetic association studies, even when principal components or linear mixed models are used. ADGLM corrects this bias and improves power relative to previous methods in both simulated and real datasets. Additionally, ADGLM identifies 17 novel genotype-variance associations across six phenotypes.
Mcidas mutant mice reveal a two-step process for the specification and differentiation of multiciliated cells in mammals
Authors: Lu Hao , Anujan Priyanka , Zhou Feng , Zhang Yiliu , Ling Chong Yan , Bingle Colin D. , Roy Sudipto
Published: October 2018

Motile cilia on multiciliated cells (MCCs) function in fluid clearance over epithelia. Studies with Xenopus embryos and patients with the congenital respiratory disorder reduced generation of multiple motile cilia, have implicated the nuclear protein MCIDAS (MCI), in the transcriptional regulation of MCC specification and differentiation. Recently, a paralogous protein, GMNC, was also shown to be required for MCC formation. Surprisingly, and in contrast to the presently held view, we find that Mci mutant mice can specify MCC precursors. However, these precursors cannot produce multiple basal bodies, and mature into single ciliated cells. We show that MCI is required specifically to induce deuterosome pathway components for the production of multiple basal bodies. Moreover, GMNC and MCI associate differentially with the cell-cycle regulators E2F4 and E2F5, which enables them to activate distinct sets of target genes (ciliary transcription factor genes versus genes for basal body generation). Our data establish a previously unrecognized two-step model for MCC development: GMNC functions in the initial step for MCC precursor specification. GMNC induces Mci expression, which then drives the second step of basal body production for multiciliation.

SUMMARY STATEMENT

We show how two GEMININ family proteins function in mammalian multiciliated cell development: GMNC regulates precursor specification and MCIDAS induces multiple basal body formation for multiciliation.
Estimating Residue-Specific Accuracies of Protein Structure Models Using Molecular Dynamics Simulations
Authors: Hu Jing-Hao , Xun Sang-Ni , Wu Hao-Nan , Wu Yun-Dong , Jiang Fan
Published: October 2018

Estimating the accuracy of a structure model is very crucial to promote the usefulness of protein structure prediction methods. Currently, a vast majority of successful model quality assessment (or model accuracy estimation, MAE) methods are knowledge-based. Based on molecular dynamics (MD) simulation with a recently developed residue-specific force field (RSFF2), we develop a method for absolute MAE at per-residue level. Using a training set of 31 models and a test set of 24 models from different proteins, the MAE performance of our MD-based method can reach or even exceed state-of-the-art single-model MAE methods within a short simulation time (less than one nanosecond). In addition, a simple combination of knowledge-based method with the MD-based method can give more accurate MAE than any of the constituent methods.
Miniaturization and optimization of 384-well compatible metagenomic sequencing library preparation
Authors: Mayday Madeline Y , Khan Lillian M , Chow Eric D , Zinter Matt S , DeRisi Joseph L
Published: October 2018

Preparation of high-quality sequencing libraries is a costly and time-consuming component of metagenomic next generation sequencing (mNGS). While the overall cost of sequencing has dropped significantly over recent years, the reagents needed to prepare sequencing samples are likely to become the dominant expense in the process. Furthermore, libraries prepared by hand are subject to human variability and needless waste due to limitations of manual pipetting volumes. Reduction of reaction volumes, combined with sub-microliter automated dispensing of reagents without consumable pipette tips, has the potential to provide significant advantages. Here, we describe the integration of several instruments, including the Labcyte Echo 525 acoustic liquid handler and the iSeq and NovaSeq Illumina sequencing platforms, to miniaturize and automate mNGS library preparation, significantly reducing the cost and the time required to prepare samples. Through the use of External RNA Controls Consortium (ERCC) spike-in RNAs, we demonstrated the fidelity of the miniaturized preparation to be equivalent to full volume reactions. Furthermore, detection of viral and microbial species from cell culture and patient samples was also maintained in the miniaturized libraries. For 384-well mNGS library preparations, we achieved a savings of over 80% in materials and reagents alone, and reduced preparation time by 90% compared to manual approaches, without compromising quality or representation within the library.
Dietary sulfate-driven and gut dysbiosis-triggered breast cancer-related gene upregulation
Authors: YanPingf CHEN , Tao LIAO , LiLi TAN , DongMei CHEN , Qin XU , JianPing Song , QingPing ZHEN
Published: October 2018

By gut microbiota metagenomic analysis, we found that the abundance of sulfatase-secreting bacteria (SSB) in the gut of mice fed chondroitin sulfate (CS) increases with significant individual difference. The fluctuation of lipopolysaccharide (LPS) and pro-inflammatory indicators with significant individual and tissue variations was also observed. After mice were fed mixed with CS or injected separately with LPS, the breast cancer-related transcriptional factor genes, BCL11A and RUNX1, were upregulated, whereas the tumor suppressor gene, TP53BP1, were downregulated. Further, the mammary myopithelium marker CK5/6, the mammary hyperplasia marker Ki-67, and other tumor markers were also upregulated. While the exogenous estradiol does not induce the expression of BCL11A, RUNX1, and TP53BP1, the estrogen receptor (ER) agonist Fulvestrant that mimics estradiol action not only elevates estradiol concentrations, but also upregulates tumor marker expression levels, revealing that ER inflammatory inactivation and hyperestrogenemia induction might be the etiological cues of breast cancer origin. This study has preliminarily established a possible correlation of gut microbiota dysbiosis and chronic low-grade inflammation with the early-phase onset of breast cancer in mice. The statistical insignificance of test data was attributed to the individual difference of gut microbiota compositions, which determining the individual and tissue variations of systemic inflammation.
jouvence, a new small nucleolar RNA required in the gut extends lifespan in Drosophila
Authors: Mellottée Lucille , Soulé Stéphanie , Arab Abdelkrim , Chen Chongjian , Martin Jean-René
Published: October 2018

Longevity is influenced by various genetic and environmental factors, but the underlying mechanisms remain poorly understood. Here, we functionally characterise a new Drosophila small nucleolar RNA (snoRNA), named jouvence whose loss of function dramatically reduces lifespan. A transgene containing the genomic region of jouvence rescues the longevity in mutant, while its overexpression in wild-type flies increases lifespan. Jouvence is expressed in epithelial cells of the gut. Targeted expression of jouvence specifically in the enterocytes increases lifespan, indicating that its role in the control of longevity takes place in these cells. A transcriptomic analysis performed from the gut reveals that several genes are either up-or down-regulated in mutant indicating that the snoRNA-jouvence might be involved in transcriptional control. Finally, since snoRNAs are structurally and functionally well conserved throughout evolution, we identified putative jouvence orthologue in mammals including humans, suggesting that its function in longevity might be conserved through evolution.
Investigation of novel functions of three genes in oriental river prawn,Macrobrachium nipponense: Molecular Cloning, Expression, andIn situHybridization Analysis
Authors: Jin Shubo , Fu Hongtuo , Hu Yuning , Sun Shengming , Jiang Sufei , Xiong Yiwei , Qiao Hui , Zhang Wenyi , Gong Yongsheng , Wu Yan
Published: October 2018

Three genes were predicted to be potentially involved in the male sexual development inM.nipponense, including the Gem-associated protein 2-like isoform X1 (GEM), Ferritin peptide, and DNA polymerase zeta catalytic subunit (Rev3). In this study, we aimed to investigate their novel functions in depth. The full-length cDNA sequence of Mn-GEM was 1,018 bp, encoding 258 amino acids. The partial Mn-Rev3 cDNA sequence was 6,832 bp, encoding 1,203 amino acids. Tissue distribution indicated that all of these three genes have higher expression level in testis and androgenic gland, implying their novel functions in male sexual development. In situ hybridization analysis further confirmed the novel roles of these three genes. Rev3 promote the testis development during the whole reproductive cycle, while GEM and ferritin only promote the activation of testis development. Besides, these three genes play essential roles in funicular structure development surrounding the androgenic gland cells, which promote and support the formation of androgenic gland cells. The expression in hepatopancreas cells also suggested their role in immune system inM. nipponense.This study advances our understanding of male sexual development inM. nipponense, as well as providing the basis for further studies of male sexual differentiation and development in crustaceans.
Prevalence and correlates of anemia among children aged 6-23 months in Wolaita Zone, Southern Ethiopia
Authors: Alemayehu Mihiretu , Meskele Mengistu , Alemayehu Bereket , Yakob Bereket
Published: October 2018

Background

Anemia, the world’s most common micro-nutrient deficiency disorder, can affect a person at any time and at all stages of life, although children aged 6 -23 months are particularly at higher risk. If left untreated, it adversely affects the health, cognitive development, school achievement, and work performance. However, littlewas investigated among young children in Sub-Saharan countries including Ethiopia. This research aimed to investigate its magnitude and correlates to address the gap and guide design of evidence based intervention.

Methods

A community-based cross-sectional study was conducted from May -June 2016 in rural districts of Wolaita Zone. Multi-stage sampling technique was applied to select 990 mother-child pairs. Socio-demography, health and nutritional characteristics were collected by administering interview type questionnaire to mothers/care-givers. Blood samples were taken to diagnose anemia by using HemoCue device, and status was determined using cut-offs used for children aged 6-59 months. Hemoglobin concentration below 11.0 g/dl was considered anemic. Data were analyzed with Statav 14. Bivariate and multivariable logistic regressions were applied to identify candidate and predictor variables respectively. Statistical significance was determined at p-value < 0.05 at 95% confidence interval.

Results

The mean hemoglobin level of children was 10.44±1.3g/dl, and 65.7% of them were anemic. Among anemic children, 0.4% were severely anemic (<7.0g/dl), while 28.1% and 37.2% were mildly (10.0-10.9g/dl) and moderately (7.0-9.9g/dl) anemic, respectively. In the multivariable analysis, having maternal age of 35 years and above (AOR=1.96), being government employee (AOR=0.29),being merchant (AOR= 0.43) and ‘other’ occupation (AOR=3.17) were correlated with anemia in children in rural Wolaita. Similarly, receiving antihelminthic drugs (AOR= 0.39), being female child (AOR= 1.76), consuming poor dietary diversity (AOR=1.40), and having moderate household food insecurity (AOR=1.72) were associated with anemia in rural Wolaita.

Conclusion

A large majority of children in the rural Wolaita were anemic and the need for proven public health interventions such as food diversification, provision of anti-helminthic drugs and ensuring household food security is crucial. In addition, educating women on nutrition and diet diversification, as well as helping them with alternative sources of income might be interventions in the study area.
Deficient skeletal muscle regeneration after injury induced by a Clostridium perfringens strain associated with gas gangrene
Authors: Zúñiga-Pereira Ana Mariel , Carlos Santamaría Carlos , Gutiérrez José María , Alape-Girón Alberto , Flores-Díaz Marietta
Published: October 2018

Very little is known about the muscle regeneration process that follows myonecrosis induced by C. perfringens, the main agent of gas gangrene. This study revealed that, in a murine model of the infection with a sublethal inoculum of C. perfringens, muscle necrosis occurs concomitantly with significant vascular damage, which limits the migration of inflammatory cells. A significant increase in cytokines that promote inflammation explains the presence of inflammatory infiltrate; however, an impaired IFNγ expression, a reduced number of Ml macrophages, a deficient phagocytic activity, and the prolongation of the permanence of inflammatory cells, lead to deficient muscle regeneration. The expression of TGFβ1 and the consequent accumulation of collagen in the muscle, likely contribute to the fibrosis observed 30 days after infection. These results provide new information on the pathogenesis of gas gangrene caused by C. perfringens, shed light on the basis of the poor muscle regenerative activity, and may open new perspectives for the development of novel therapies for patients suffering this disease.
Corrosion of steel due to iron oxidizing bacteria
Authors: Sachan Reena , Singh Ajay Kumar
Published: October 2018

Purpose

The purpose of this study is to investigate microbial influenced corrosion of steel because of iron oxidizing bacteria (IOB).

Design/methodology/approach

Carbon steel was selected for this study. Winogradsky media was used for isolation of IOB and as test solution for corrosion measurements. Electrochemical tests and immersion test were conducted to estimate the corrosion rate and extent of pitting. The corroded surface was analysed by SEM and corrosion products formed over the metal surface were identified by XRD and Fourier transformed infrared. Biofilm formed over the corroded metal was analysed by UV-visible spectroscopy for its extracellular polymeric substances (EPS) constituents.

Findings

Presence of IOB in Winogradsky medium enhances corrosion. Uniform and localized corrosion increases with increased bacterial concentration and EPS constituents of the biofilm. Iron sulphite formation as one of the corrosion products has been suggested to be responsible for increased corrosion attack in the inoculated media in comparison to control media where corrosion product observed is iron hydrogen phosphate which is protective in nature.

Originality/value

This work correlates increased corrosion of steel in the presence of bacteria with the nature of corrosion products formed over it in case of IOB. Formation of corrosion products is governed by various electrochemical reactions; hence, inhibition of such reactions may lead to reduce or stop the formation of such products which enhances corrosion and thereby may reduce the extent of microbial induced corrosion.
Effects of second phases on the formation mechanism and corrosion resistance of phosphate conversion film on AZ80 Mg alloy
Authors: Xu Zubin , Song Yingwei , Dong Kaihui , Shan Dayong , Han En-Hou
Published: October 2018

Purpose

The formation and corrosion processes of a conversion film on the AZ80 Mg alloy with different second phases were compared to clarify the effect of microstructure on the quality of protective coatings.

Design/methodology/approach

The size and distribution of second phases in the edge and central regions of the AZ80 cast ingot exhibit a great difference. The film growth processes and their corrosion resistance on the edge and central regions of the AZ80 cast ingot were investigated by scanning electron microscope observations, immersion tests and electrochemical measurements.

Findings

The results indicate that second phases act as micro-cathodes and hydrogen evolution reaction occurs on their surface, which is not beneficial for the deposition of the conversion film.

Originality/value

The conversion film formed on the central regions of AZ80 cast ingot with a low volume fraction of second phases exhibits a more uniform surface and higher corrosion resistance than that formed on the edge regions of the sample with a higher volume fraction of second phases.
Partially feasible solution space for integrated SATS operations
Authors: Miksa Wojciech Jerzy , Goetzendorf-Grabowski Tomasz
Published: October 2018

Purpose

The purpose of this paper is to investigate the feasibility of solving an integrated flight scheduling, fleet assignment and crew pairing problem for an on-demand service using a small, up to 19-seater, aircraft.

Design/methodology/approach

Evolutionary algorithm is developed to solve the problem. Algorithm design assumes indirect solution representation that allows to evaluate partially feasible solutions only and speed up calculations. Tested algorithm implementation takes advantage of the graphic processing unit.

Findings

Performed tests confirm that the algorithm can successfully solve the defined integrated scheduling problem.

Practical implications

The presented algorithm allows to optimise on-demand transport service operation within minutes.

Social implications

Optimisation of operation cost contributes to better accessibility of transport.

Originality/value

The presented integrated formulation allows to avoid sub optimal solutions that are results of solving sequential sub problems. Indirect representation and evaluation strategy can be applied to speed up calculations in other problems as well.
Keeping twin turbocharged engine power at flight altitudes
Authors: Khodaparast Mohammad Reza , Agha Seyed Mirza Bozorg Mohsen , Kheradmand Saeid
Published: October 2018

Purpose

The purpose of this paper is the selection and arrangement of turbochargers set for internal combustion engine which could keep engine power in an altitude of up to 12.2 km above sea level.

Design/methodology/approach

In the current research, the target engine, a one-dimensional four-stroke 1,600 cc piston engine has been simulated and the manufacturer’ results have been validated. Depending on engine size, three proper types of Garret turbochargers GT30, GT25 and GT20 were selected for this engine. Then, the engine and a combination of two turbochargers have been modeled one-dimensionally. A control system was used for regulation of different pressure ratios between the two turbochargers.

Findings

The parametric analysis shows that using the combination of GT20, GT30 turbochargers with a properly controlled pressure ratio leads to a constant output power with little changes at different altitudes which enable achieving an altitude of 12.2 km for the target engine.

Practical implications

Adaptation of the internal combustion engine with a twin turbocharger using one-dimensional modeling.

Originality/value

The one-dimensional analysis provided an overall picture of the effective performance of turbochargers functioning in different altitudes and loads. It presents a new method for adopting of turbochargers set with internal combustion engines for propulsion medium-altitude aircraft.
Does a high women quota in supervisory boards influence firm success?
Authors: Binder Bettina C.K.
Published: October 2018

Purpose

The purpose of this paper is to investigate the relationship between the success of the 50 EURO STOXX companies as measured by the earnings before taxes (EBT) and the percentage of female members on their supervisory boards.

Design/methodology/approach

The paper relies on data extracted from the annual reports of the 50 EURO STOXX companies in 2015 and from financial websites.

Findings

The paper provides the existence of a weak correlation between companies’ performance as measured by EBT and the percentage of women on supervisory boards.

Research limitations/implications

This study has two main limitations: first, a single key performance indicator was used to measure firms’ success; and second, the study offers insights related only to the year 2015. The analysis could be extended over a larger time span while some other variables could be considered in a more holistic approach.

Practical implications

The paper raises awareness that there is much to be done with regard to the presence of women on boards, and readers, investors and business owners gain an insight on the business environment and women active on European corporate boards.

Originality/value

By concentrating on the companies of the EURO STOXX 50 Index, the study offers a good image of the European business environment.
Multi-objective optimization of the dimple/protrusion channel with pin fins for heat transfer enhancement
Authors: Luo Lei , Du Wei , Wang Songtao , Wu Weilong , Zhang Xinghong
Published: October 2018

Purpose

The purpose of this paper is to investigate the optimal geometry parameters in a dimple/protrusion-pin finned channel with high thermal performance.

Design/methodology/approach

The BSL turbulence model is used to calculate the flow structure and heat transfer in a dimple/protrusion-pin finned channel. The optimization algorithm is set as Non-dominated Sorting Genetic Algorithm II (NSGA-II). The high Nusselt number and low friction factor are chosen as the optimization objectives. The pin fin diameter, dimple/protrusion diameter, dimple/protrusion location and dimple/protrusion depth are applied as the optimization variables. An in-house code is used to generate the geometry model and mesh. The commercial software Isight is used to perform the optimization process.

Findings

The results show that the Nusselt number and friction factor are sensitive to the geometry parameters. In a pin finned channel with a dimple, the Nusselt number is high at the rear part of the dimple, while it is low at the upstream of the dimple. A high dissipative function is found near the pin fin. In the protrusion channel, the Nusselt number is high at the leading edge of the protrusion. In addition, the protrusion induces a high pressure drop compared to the dimpled channel.

Originality/value

The originality of this paper is to optimize the geometry parameters in a pin finned channel with dimple/protrusion. This is good application for the heat transfer enhancement at the trailing side for the gas turbine.
A strategy for large-scale scalar advection in large eddy simulations that use the linear eddy sub-grid mixing model
Authors: Arshad Salman , Kong Bo , Kerstein Alan , Oevermann Michael
Published: October 2018

Purpose

The purpose of this numerical work is to present and test a new approach for large-scale scalar advection (splicing) in large eddy simulations (LES) that use the linear eddy sub-grid mixing model (LEM) called the LES-LEM.

Design/methodology/approach

The new splicing strategy is based on an ordered flux of spliced LEM segments. The principle is that low-flux segments have less momentum than high-flux segments and, therefore, are displaced less than high-flux segments. This strategy affects the order of both inflowing and outflowing LEM segments of an LES cell. The new splicing approach is implemented in a pressure-based fluid solver and tested by simulation of passive scalar transport in a co-flowing turbulent rectangular jet, instead of combustion simulation, to perform an isolated investigation of splicing. Comparison of the new splicing with a previous splicing approach is also done.

Findings

The simulation results show that the velocity statistics and passive scalar mixing are correctly predicted using the new splicing approach for the LES-LEM. It is argued that modeling of large-scale advection in the LES-LEM via splicing is reasonable, and the new splicing approach potentially captures the physics better than the old approach. The standard LES sub-grid mixing models do not represent turbulent mixing in a proper way because they do not adequately represent molecular diffusion processes and counter gradient effects. Scalar mixing in turbulent flow consists of two different processes, i.e. turbulent mixing that increases the interface between unmixed species and molecular diffusion. It is crucial to model these two processes individually at their respective time scales. The LEM explicitly includes both of these processes and has been used successfully as a sub-grid scalar mixing model (McMurtry et al., 1992; Sone and Menon, 2003). Here, the turbulent mixing capabilities of the LES-LEM with a modified splicing treatment are examined.

Originality/value

The splicing strategy proposed for the LES-LEM is original and has not been investigated before. Also, it is the first LES-LEM implementation using unstructured grids.
Hotel-like hospital rooms’ impact on patient well-being and willingness to pay
Authors: Suess Courtney , Mody Makarand Amrish
Published: October 2018

Purpose

The study aims to examine how features that foster a sense of control, create positive distractions and provide access to social support influence patients’ well-being and, subsequently, their likelihood to choose hotel-like hospital rooms and their willingness to pay higher out-of-pocket expenses for such rooms. While there is increasing evidence to suggest the importance of the provision of hospitality in healthcare settings, research on these developments remains under-represented, particularly in the hospitality literature. In response, the present study builds on Ulrich’s (1991) theory of supportive design to examine patient responses to hotel-like features in a hospital room.

Design/methodology/approach

Using data from a survey of 406 patients, the authors used structural equation modeling to test the model.

Findings

Consistent with supportive design principles, the infusion of hotel-like features that foster a sense of control for patients, create positive distractions and provide access to social support was found to positively impact patients’ physical and mental well-being, which, in turn, increased their likelihood to choose a hospital room with hotel-like features and their willingness to pay for such rooms.

Practical Implications

Findings attest to the need for healthcare providers to make the necessary investment in hotel-like features and to leverage the communicative power of these environmental cues. Social support in the form of hospitality-trained and certified healthcare staff was found to be the most important hotel-like feature, which also presents significant commercial opportunities for hospitality companies and professionals.

Originality Value

The study represents one of the first attempts to empirically develop a structured model to examine the infusion of hospitality into healthcare. It provides researchers with a theoretically supported framework for future inquiry into the domain. It also makes a significant contribution to advancing the research on patient well-being in healthcare settings and demonstrates the importance of hospitality to such endeavors.
Hotel performance and research streams: a network cluster analysis
Authors: Sainaghi Ruggero , Baggio Rodolfo , Phillips Paul , Mauri Aurelio G.
Published: October 2018

Purpose

This paper aims to provide a review of hotel performance within the hospitality and tourism research domain. The authors use network analysis to examine two research questions. The first relates to ascertaining general trends within the hotel performance literature, and the second focuses on identifying the salient streams and sub-topics.

Design/methodology/approach

Articles were selected according to three criteria: keywords, journals and year of publication. The analysis embraces 20 years (1996-2015). These choices assure a wide coverage of the literature. Using these three criteria, the sample includes 1,155 papers. For the analysis, the authors created a network of papers designated as nodes, and the citations among the papers as links. A network approach recognizes the internal structure of the network by identifying groups of nodes (papers) that are more densely connected between themselves than to other nodes within the network (modules, clusters or communities).

Findings

The authors found 761 papers that were “connected” studies within the network. By contrast, 34 per cent of the sample (394 papers) consists of “unconnected” studies. Excluding outliers, the net sample was 734 articles. The authors identify 14 clusters, which they break down into several sub-topics. The authors conclude by providing some conclusions regarding trends and future research directions. With regards to salient topics, cross-citation and network analysis provide a detailed picture of where the literature comes from and where it currently stands. Conclusions are articulated at the theoretical and empirical levels.

Originality/value

Compared with previous hotel performance reviews, the approach followed by this study enables the discovery of an analytical research map, which is able to identify both clusters and sub-topics populating each segment. Researchers are able to position their work and identify issues that are in growth and decline.
Brand satisfaction
Authors: Nysveen Herbjørn , Oklevik Ove , Pedersen Per Egil
Published: October 2018

Purpose

This paper aims to examine the influence of a brand’s innovativeness and green image on customers’ sensory, affective, cognitive, relational and behavioral brand experience and, through that, on brand satisfaction.

Design/methodology/approach

To collect primary data, the study used a list of 1,754 e-mail addresses from a hotel in Norway. Of the invited respondents, 283 completed the questionnaire.

Findings

The study shows positive influences of perceived brand innovativeness and green image on the experience dimensions. The influences of the brand experience dimensions on brand satisfaction are mixed. The results indicate that the brand experience dimensions partially mediate the influences of perceived brand innovativeness and green image on brand satisfaction. The study also shows a positive influence of perceived brand innovativeness on perceived green image.

Practical implications

The paper highlights the importance of carefully managing brands’ innovativeness and green image to improve brand experiences and satisfaction with the hotel.

Originality/value

Few studies exist on hotel brand experience, and therefore, future studies should identify antecedents and consequences of hotel brand experience (King, 2017; Khan and Rahman, 2017). This paper examines the role of hotel brand experiences with an explicit focus on the antecedents of such experiences.
Why clinicians involved with adverse events need much better support
Authors: Kable Ashley K. , Spigelman Allan D.
Published: October 2018

Purpose

The purpose of this paper is to draw attention to the problem of second victims involved in adverse events and their need for adequate support.

Design/methodology/approach

The impact on second victims involved in adverse events and implications for organisational support were determined from previous studies and relevant publications about this problem.

Findings

The impact of adverse events on health professionals who are involved in them can be profound. These second victims can suffer extreme emotional distress, anxiety regarding perceptions of their competence and professional isolation, and may endure long-term professional and personal consequences. Some of the more severe outcomes include leaving the profession, symptoms of post-traumatic stress disorder and suicide. Many studies report a substantial lack of organisational support for second victims. Key strategies have been recommended for organisations to implement to support second victims.

Originality/value

The authors note that recently published studies continue to report that organisational support is inadequate for second victims. Improved mechanisms of support would prevent the loss of second victims from the workforce, and ameliorate the severity and duration of the impact on second victims.
Do cognitive appraisals moderate the link between qualitative job insecurity and psychological-behavioral well-being?
Authors: Charkhabi Morteza
Published: October 2018

Purpose

The purpose of this paper is to detect the association between qualitative job insecurity and well-being related outcomes and to determine the extent to which cognitive appraisals of job insecurity moderate this association. According to appraisal theory, it is anticipated a hindrance appraisal of job insecurity to amplify and a challenge appraisal of job insecurity to buffer this association.

Design/methodology/approach

To test the hypotheses, 250 healthcare employees from different departments of an Iranian large public hospital were recruited. Participants responded to scales on qualitative job insecurity, cognitive appraisals, job satisfaction, emotional exhaustion, absenteeism and presenteeism.

Findings

Results showed that qualitative job insecurity negatively influenced both psychological and behavioral well-being; however, this influence was greater for psychological well-being than for behavioral well-being. Besides, the moderation tests showed that only the hindrance appraisals of job insecurity amplified the link between job insecurity and psychological outcomes.

Research limitations/implications

This study sampled employees from a public hospital and did not include employees from private hospitals. This may limit the generalizability of the findings. Also, due to using a cross-sectional research design we encourage future studies to replicate the same findings using other different research designs.

Practical implications

The findings aid occupational health psychologists to design particular interventions for protecting those aspects of employee’s well-being that are more vulnerable when qualitative job insecurity is chronically perceived.

Originality/value

Together, these findings suggest that the hindrance appraisals of qualitative job insecurity are more likely to moderate the link between job insecurity and well-being outcomes.
Halogen-free ionic liquids as synthetic ester oil antiwear additives
Authors: Wang Zeyun
Published: October 2018

Purpose

This paper aims to investigate the tribological properties of 1,4-bis(2-ethylhexyl) sulfosuccinate anion-based ionic liquids (ILs) when used as lubricant additives in synthetic ester oil.

Design/methodology/approach

The 1,4-bis(2-ethylhexyl) sulfosuccinate anion-based ILs containing different cation-imidazolium and organo-ammonium were synthesized and characterized. Their tribological performances as lubricant additives were assessed on ball-on-flat tribological tester. Their compatibility with typical additives (such as viscosity improver, antioxidant, pour point depressant and anti-rusting agent) were evaluated on a four-ball friction and wear tester.

Findings

It was found that the synthesized ILs demonstrated more effective friction reduction and antiwear properties than the base synthetic ester oil. The ILs worked well with the other typical additives, such as viscosity improver, antioxidant, pour point depressant and anti-rusting agent.

Originality/value

The results of the experimental studies demonstrated the potential of 1,4-bis(2-ethylhexyl) sulfosuccinate anion-based ILs as additives for improving friction reduction and antiwear abilities of synthetic ester oil.