bluuebunny/crossref_metadata_2025 huggingface dataset:
Serotonin and early life stress interact to shape brain architecture and anxious avoidant behavior – a TPH2 imaging genetics approach
Authors: Liu Congcong , Xu Lei , Li Jialin , Zhou Feng , Yang Xi , Zheng Xiaoxiao , Fu Meina , Li Keshuang , Sindermann Cornelia , Montag Christian , Ma Yina , Scheele Dirk , Ebstein Richard P. , Yao Shuxia , Kendrick Keith M. , Becker Benjamin
Published: June 2019

Background

Early life stress has been associated with emotional dysregulations and altered architecture of limbic-prefrontal brain systems engaged in emotional processing. Serotonin regulates both, developmental and experience-dependent neuroplasticity in these circuits. Central serotonergic biosynthesis rates are regulated by Tryptophan hydroxylase 2 (TPH2), and transgenic animal models suggest that TPH2-gene associated differences in serotonergic signaling mediate the impact of aversive early life experiences on a phenotype characterized by anxious avoidance.

Methods

The present study employed an imaging genetics approach that capitalized on individual differences in a TPH2 polymorphism (703G/T; rs4570625) to determine whether differences in serotonergic signaling modulate the effects of early life stress on brain structure and function and punishment sensitivity in humans (n = 252).

Results

Higher maltreatment exposure before the age of 16 was associated with increased gray matter volumes in a circuitry spanning thalamic-limbic-prefrontal regions and decreased intrinsic communication in limbic-prefrontal circuits selectively in TT carriers. In an independent replication sample, associations between higher early life stress and increased frontal volumes in TT carriers were confirmed. On the phenotype level, the genotype moderated the association between higher early life stress exposure and higher punishment sensitivity. In TT carriers, the association between higher early life stress exposure and punishment sensitivity was critically mediated by increased thalamic-limbic-prefrontal volumes.

Conclusions

The present findings suggest that early life stress shapes the neural organization of the limbic-prefrontal circuits in interaction with individual variations in the TPH2 gene to promote a phenotype characterized by facilitated threat avoidance, thus promoting early adaptation to an adverse environment.
Analyzing the heterogeneity of rule-based EHR phenotyping algorithms in CALIBER and the UK Biobank
Authors: Denaxas Spiros , Parkinson Helen , Fitzpatrick Natalie , Sudlow Cathie , Hemingway Harry
Published: June 2019

Electronic Health Records (EHR) are data generated during routine interactions across healthcare settings and contain rich, longitudinal information on diagnoses, symptoms, medications, investigations and tests. A primary use-case for EHR is the creation of phenotyping algorithms used to identify disease status, onset and progression or extraction of information on risk factors or biomarkers. Phenotyping however is challenging since EHR are collected for different purposes, have variable data quality and often require significant harmonization. While considerable effort goes into the phenotyping process, no consistent methodology for representing algorithms exists in the UK. Creating a national repository of curated algorithms can potentially enable algorithm dissemination and reuse by the wider community. A critical first step is the creation of a robust minimum information standard for phenotyping algorithm components (metadata, implementation logic, validation evidence) which involves identifying and reviewing the complexity and heterogeneity of current UK EHR algorithms. In this study, we analyzed all available EHR phenotyping algorithms (n=70) from two large-scale contemporary EHR resources in the UK (CALIBER and UK Biobank). We documented EHR sources, controlled clinical terminologies, evidence of algorithm validation, representation and implementation logic patterns. Understanding the heterogeneity of UK EHR algorithms and identifying common implementation patterns will facilitate the design of a minimum information standard for representing and curating algorithms nationally and internationally.
Higher stochasticity of microbiota composition in seedlings of domesticated wheat compared to wild wheat
Authors: Özkurt Ezgi , Hassani M. Amine , Sesiz Uğur , Künzel Sven , Dagan Tal , Özkan Hakan , Stukenbrock Eva H.
Published: June 2019

Plants constitute an ecological niche for microbial communities that colonize different plant tissues and explore the plant habitat for reproduction and dispersal. The association of microbiota and plant may be altered by ecological and evolutionary changes in the host population. Seedborne microbiota, expected to be largely vertically-transferred, have the potential to co-adapt with their host over generations. Reduced host diversity because of strong directional selection and polyploidization during plant domestication and cultivation may have impacted the assembly and transmission of seed-associated microbiota. Nonetheless, the effect of plant domestication on the diversity of their associated microbes is poorly understood. Here we show that microbial communities in domesticated wheat,Triticum aestivum, are less diverse but more inconsistent among individual plants compared to the wild wheat species,T. dicoccoides. We found that diversity of microbes in seeds overall is low, but comparable in different wheat species, independent of their genetic and geographic origin. However, the diversity of seedborne microbiota that colonize the roots and leaves of the young seedling is significantly reduced in domesticated wheat genotypes. Moreover, we observe a higher variability between replicates ofT. aestivumsuggesting a stronger effect of chance events in microbial colonization and assembly. We also propagated wild and domesticated wheat in two different soils and found that different factors govern the assembly of soil-derived and seedborne microbial communities. Overall, our results demonstrate that the role of stochastic processes in seedborne microbial community assembly is larger in domesticated wheat compared to the wild wheat. We suggest that the directional selection on the plant host and polyploidization events during domestication may have decreased the degree of wheat-microbiota interactions and consequently led to a decreased stable core microbiota.
Endothelial struts, a mechanism to generate large lumenized blood vesselsde novo
Authors: Weijts Bart , Shaked Iftach , Li Wenqing , Ginsberg Mark , Kleinfeld David , Traver David
Published: June 2019

Lumenization ofde novoformed blood vessels occurs either through cell hollowing (intracellular lumen)1–3or cord hollowing (extracellular lumen)4–6and restricts thereby the initial lumen diameter to one or two endothelial cells (ECs) respectively. However, vasculogenesis can result in large diameter blood vessels, raising the question how these vessels are formed. Here, we describe an alternative model of vasculogenesis that results in the formation of large diameter vessels. In this model, ECs coalesce into a branched network of EC struts within the future lumen of the vessel. These struts maintain the patency of the vessel and serve as a scaffold for the ECs forming the vessel wall, which initially consists out of a few patches of ECs. Together, we show that endothelial struts facilitate the formation of large blood vessels without being bound by the prerequisite of a cord-like structure, nor are they restricted in size.
Local rewiring of genome - nuclear lamina interactions by transcription
Authors: Brueckner Laura , Zhao Peiyao A , van Schaik Tom , Leemans Christ , Sima Jiao , Peric-Hupkes Daniel , Gilbert David M , van Steensel Bas
Published: June 2019

Transcriptionally inactive genes are often positioned at the nuclear lamina (NL), as part of large lamina-associated domains (LADs). Activation of such genes is often accompanied by repositioning towards the nuclear interior. How this process works and how it impacts flanking chromosomal regions is poorly understood. We addressed these questions by systematic manipulation of gene activity and detailed analysis of NL interactions. Activation of genes inside LADs typically causes detachment of the entire transcription unit but rarely more than 50-100 kb of flanking DNA, even when multiple neighboring genes are activated. The degree of detachment depends on the expression level and the length of the activated gene. Loss of NL interactions coincides with a switch from late to early replication timing, but the latter can involve longer stretches of DNA. These findings show how NL interactions can be shaped locally by transcription and point to a remarkable flexibility of interphase chromosomes.
Towards automated control of embryonic stem cell pluripotency
Authors: Khazim Mahmoud , Postiglione Lorena , Pedone Elisa , Rocca Dan L. , Zahra Carine , Marucci Lucia
Published: June 2019

Mouse embryonic stem cells (mESCs) have been shown to exist in three distinct pluripotent states (ground, naïve and primed pluripotent states), depending on culture conditions. External feedback control strategies have been, so far, mainly used to automatically regulate gene expression in bacteria and yeast. Here, we exploit a microfluidics/microscopy platform and segmentation and external feedback control algorithms for the automatic regulation of pluripotency phenotypes in mESCs. We show feasibility of automatically controlling, in living mESCs, levels of an endogenous pluripotency gene, Rex1, through a fluorescent reporter, used as control output, and drugs commonly used to modulate pluripotency (i.e. MEK kinase and Gsk3β inhibitors) as control inputs. Our results will ultimately aid in the derivation of superior protocols for pluripotency maintenance and differentiation of mouse and human stem cells.
MitoFinder: efficient automated large-scale extraction of mitogenomic data in target enrichment phylogenomics
Authors: Allio Rémi , Schomaker-Bastos Alex , Romiguier Jonathan , Prosdocimi Francisco , Nabholz Benoit , Delsuc Frédéric
Published: June 2019

Thanks to the development of high-throughput sequencing technologies, target enrichment sequencing of nuclear ultraconserved DNA elements (UCEs) now allows routinely inferring phylogenetic relationships from thousands of genomic markers. Recently, it has been shown that mitochondrial DNA (mtDNA) is frequently sequenced alongside the targeted loci in such capture experiments. Despite its broad evolutionary interest, mtDNA is rarely assembled and used in conjunction with nuclear markers in capture-based studies. Here, we developed MitoFinder, a user-friendly bioinformatic pipeline, to efficiently assemble and annotate mitogenomic data from hundreds of UCE libraries. As a case study, we used ants (Formicidae) for which 501 UCE libraries have been sequenced whereas only 29 mitogenomes are available. We compared the efficiency of four different assemblers (IDBA-UD, MEGAHIT, MetaSPAdes, and Trinity) for assembling both UCE and mtDNA loci. Using MitoFinder, we show that metagenomic assemblers, in particular MetaSPAdes, are well suited to assemble both UCEs and mtDNA. Mitogenomic signal was successfully extracted from all 501 UCE libraries allowing confirming species identification using COI barcoding. Moreover, our automated procedure retrieved 296 cases in which the mitochondrial genome was assembled in a single contig, thus increasing the number of available ant mitogenomes by an order of magnitude. By leveraging the power of metagenomic assemblers, MitoFinder provides an efficient tool to extract complementary mitogenomic data from UCE libraries, allowing testing for potential mito-nuclear discordance. Our approach is potentially applicable to other sequence capture methods, transcriptomic data, and whole genome shotgun sequencing in diverse taxa.
Bacteria associated with flowers affect the reproductive success ofBrassica napusL.viascent-mediated interactions with pollinators
Authors: Farré-Armengol Gerard , Junker Robert R.
Published: June 2019

Flowers are colonized by specific bacterial communities that have been shown to affect floral scent emission and pollinator behavior. Whether these effects translate into changes in the plants’ reproductive success remains unknown. In our study, flowers ofBrassica napuswere inoculated with the phyllospheric bacteriaPantoea agglomeransandPseudomonas syringae. Next-generation 16S rRNA gene amplicon sequencing of bacterial communities associated with flowers showed that inoculation was efficient and affected bacterial communities throughout the flowering time of individual flowers. Flowers ofB. napusinoculated withP. agglomeransandP. syringaewere preferred by pollinators in the field or in olfactometer assays. Presumably due to the increased visitation rates, inoculated plants produced more seeds of tendentially higher quality per flower. Floral scent emissions were affected by time after inoculation and by treatment with bacterial strains, potentially explaining the behavioral responses of pollinators. Controlled laboratory experiments showed that bacteria emit volatiles through their own metabolism and that the concentrations of some floral volatiles can be reduced by bacteria. Furthermore, our results also suggest that bacteria can use floral scent compounds as carbon sources. Our results demonstrate a significant effect of floral bacteria on the pollination and reproduction of entomophilous plants that is at least partly mediated by their effects on floral chemical signaling.
Genome-wide analysis reveals a switch in the translational program upon oocyte meiotic resumption
Authors: Luong Xuan G. , Daldello Enrico Maria , Rajkovic Gabriel , Yang Cai-Rong , Conti Marco
Published: June 2019

During oocyte maturation, changes in gene expression depend exclusively on translation and degradation of maternal mRNAs rather than transcription. Execution of this translation program is essential for assembling the molecular machinery required for meiotic progression, fertilization, and embryo development. With the present study, we used a RiboTag/RNA-Seq approach to explore the timing of maternal mRNA translation in quiescent oocytes as well as in oocytes progressing through the first meiotic division. This genome-wide analysis reveals a global switch in maternal mRNA translation coinciding with oocyte re-entry into the meiotic cell cycle. Messenger RNAs whose translation is highly active in quiescent oocytes invariably become repressed during meiotic re-entry, whereas transcripts repressed in quiescent oocytes become activated. Experimentally, we have defined the exact timing of the switch, the repressive function of CPE elements, and identified a novel role for CPEB1 in maintaining constitutive translation of a large group of maternal mRNAs during maturation.
Hypoxia-Induced PIM Kinase and Laminin-Activated Integrin α6 Mediate Resistance to PI3K Inhibitors in Bone-Metastatic CRPC
Authors: Toth Rachel K. , Tran Jack D. , Muldong Michelle T. , Nollet Eric A. , Schulz Veronique V. , Jensen Corbin , Hazelhurst Lori A. , Corey Eva , Durden Donald , Jamieson Christina , Miranti Cindy K. , Warfel Noel A.
Published: June 2019

Bone-metastatic castration-resistant prostate cancer (CRPC) is lethal due to inherent resistance to androgen deprivation therapy, chemotherapy, and targeted therapies. Despite the fact that a majority of CRPC patients (approximately 70%) harbor a constitutively active PI3K survival pathway, targeting the PI3K/mTOR pathway has failed to increase overall survival in clinical trials. Here, we identified two separate and independent survival pathways induced by the bone tumor microenvironment that are hyperactivated in CRPC and confer resistance to PI3K inhibitors. The first pathway involves integrin α6β1-mediated adhesion to laminin and the second involves hypoxia-induced expression of PIM kinases. In vitro and in vivo models demonstrate that these pathways transduce parallel but independent signals that promote survival by reducing oxidative stress and preventing cell death. We further demonstrate that both pathways drive resistance to PI3K inhibitors in PTEN-negative tumors. These results provide preclinical evidence that combined inhibition of integrin α6β1 and PIM kinase in CRPC is required to overcome tumor microenvironment-mediated resistance to PI3K inhibitors in PTEN-negative tumors within the hypoxic and laminin-rich bone microenvironment.
Deconvoluting signals downstream of growth and immune receptor kinases by phosphocodes of the BSU1 family phosphatases
Authors: Park Chan Ho , Bi Yang , Youn Ji-Hyun , Kim So-Hee , Kim Jung-Gun , Xu Nicole Y. , Shrestha Ruben , Burlingame Alma L , Xu Shou-Ling , Mudgett Mary Beth , Kim Seong-Ki , Kim Tae-Wuk , Wang Zhi-Yong
Published: June 2019

Hundreds of leucine-rich repeat receptor kinases (LRR-RKs) have evolved to control diverse processes of growth, development, and immunity in plants; the mechanisms that link LRR-RKs to distinct cellular responses are not understood. Here we show that two LRR-RKs, the brassinosteroid hormone receptor BRI1 (BRASSINOSTEROID INSENSITIVE 1) and the flagellin receptor FLS2 (FLAGELLIN SENSING 2), regulate downstream glycogen synthase kinase 3 (GSK3) and mitogen-activated protein (MAP) kinases, respectively, through phosphocoding of the BRI1-SUPPRESSOR1 (BSU1) phosphatase. BSU1 was previously identified as a component that inactivates GSK3s in the BRI1 pathway. We found surprisingly that loss of the BSU1 family phosphatases activates effector-triggered immunity (ETI) and impairs flagellin-triggered MAP kinase activation and immunity. The flagellin-activated BOTRYTIS-INDUCED KINASE 1 (BIK1) phosphorylates BSU1 at serine-251. Mutation of serine-251 reduces the ability of BSU1 to mediate flagellin-induced MAP kinase activation and immunity, but not its abilities to suppress ETI and interact with GSK3, which is enhanced through the phosphorylation of BSU1 at serine-764 upon brassinosteroid signaling. These results demonstrate that BSU1 plays an essential role in immunity and transduces brassinosteroid-BRI1 and flagellin-FLS2 signals using different phosphorylation sites. Our study illustrates that phosphocoding in shared downstream components provides signaling specificities for diverse plant receptor kinases.
CD44 alternative splicing is a sensor of intragenic DNA methylation in tumors
Authors: Batsché Eric , Mauger Oriane , Kornobis Etienne , Hopkins Benjamin , Hanmer-Lloyd Charlotte , Muchardt Christian
Published: June 2019

DNA methylation (meDNA) is a suspected modulator of alternative splicing, while splicing in turn is involved in tumour formations nearly as frequently as DNA mutations. Yet, the impact of meDNA on tumorigenesis via its effect on splicing has not been thoroughly explored. Here, we find that HCT116 colon carcinoma cells inactivated for the DNA methylases DNMT1 and DNMT3b undergo a partial epithelial to mesenchymal transition (EMT) associated with alternative splicing of the CD44 transmembrane receptor. The skipping of CD44 variant exons is in part explained by altered expression or splicing of splicing and chromatin factors. A direct effect of meDNA on alternative splicing was sustained by transient depletion of DNMT1 and the methyl-binding genes MBD1, MBD2, and MBD3. Yet, local changes in intragenic meDNA also altered recruitment of MBD1 protein and of the chromatin factor HP1γ known to alter transcriptional pausing and alternative splicing decisions. We further tested if meDNA level has sufficiently strong direct impact on the outcome of alternative splicing to have a predictive value in the MCF10A model for breast cancer progression and in patients with acute lymphoblastic leukemia (B ALL). We found that a small number of differentially spliced genes mostly involved in splicing and signal transduction is systematically correlated with local meDNA. Altogether, our observations suggest that, although DNA methylation has multiple avenues to alternative splicing, its indirect effect may be also mediated through alternative splicing isoforms of these sensors of meDNA.
A systems-biology approach to molecular machines: Exploration of alternative transporter mechanisms
Authors: George August , Bisignano Paola , Rosenberg John M. , Grabe Michael , Zuckerman Daniel M.
Published: June 2019

Motivated by growing evidence for pathway heterogeneity and alternative functions of molecular machines, we demonstrate a computational approach for investigating two questions: (1) Are there multiple mechanisms (state-space pathways) by which a machine can perform a given function, such as cotransport across a membrane? (2) How can additional functionality, such as proofreading/error-correction, be built into machine function using standard biochemical processes? Answers to these questions will aid both the understanding of molecular-scale cell biology and the design of synthetic machines. Focusing on transport in this initial study, we sample a variety of mechanisms by employing Metropolis Markov chain Monte Carlo. Trial moves adjust transition rates among an automatically generated set of conformational and binding states while maintaining fidelity to thermodynamic principles and a user-supplied fitness/functionality goal. Each accepted move generates a new model. The simulations yield both single and mixed reaction pathways for cotransport in a simple environment with a single substrate along with a driving ion. In a “competitive” environment including an additional decoy substrate, several qualitatively distinct reaction pathways are found which are capable of extremely high discrimination coupled to a leak of the driving ion, akin to proofreading. The array of functional models would be difficult to find by intuition alone in the complex state-spaces of interest.

Author summary

Molecular machines, which operate on the nanoscale, are proteins/complexes that perform remarkable tasks such as the selective absorption of nutrients into the cell by transporters. These complex machines are often described using a fairly simple set of states and transitions that may not account for the stochasticity and heterogeneity generally expected at the nanoscale at body temperature. New tools are needed to study the full array of possibilities. This study presents a novel in silico method to systematically generate testable molecular-machine kinetic models and explore alternative mechanisms, applied first to membrane transport proteins. Our initial results suggest these transport machines may contain mechanisms which ‘detoxify’ the cell of an unwanted toxin, as well as significantly discriminate against the import of the toxin. This novel approach should aid the experimental study of key physiological processes such as renal glucose re-absorption, rational drug design, and potentially the development of synthetic machines.
Accurate and efficient discretisations for stochastic models providing near agent-based spatial resolution at low computational cost
Authors: Fadai Nabil T. , Baker Ruth E. , Simpson Matthew J.
Published: June 2019

Understanding how cells proliferate, migrate, and die in various environments is essential in determining how organisms develop and repair themselves. Continuum mathematical models, such as the logistic equation and the Fisher-Kolmogorov equation, can describe the global characteristics observed in commonly-used cell biology assays, such as proliferation and scratch assays. However, these continuum models do not account for single-cell-level mechanics observed in high-throughput experiments. Mathematical modelling frameworks that represent individual cells, often called agent-based models, can successfully describe key single-cell-level features of these assays, but are computationally infeasible when dealing with large populations. In this work, we propose an agent-based model with crowding effects that is computationally efficient and matches the logistic and Fisher-Kolmogorov equations in parameter regimes relevant to proliferation and scratch assays, respectively. This stochastic agent-based model allows multiple agents to be contained within compartments on an underlying lattice, thereby reducing the computational storage compared to existing agent-based models that allow one agent per site only. We propose a systematic method to determine a suitable compartment size. Implementing this compartment-based model with this compartment size provides a balance between computational storage, local resolution of agent behaviour, and agreement with classical continuum descriptions.
Molecular and crystal structure of 5,9-dimethyl-5H-pyrano[3,2-c:5,6-c′]bis[2,1-benzothiazin]-7(9H)-one 6,6,8,8-tetroxide dimethylformamide monosolvate
Authors: Rybalka Andrii , Shishkina Svitlana , Ukrainets Igor , Sidorenko Lyudmila , Sim Galina
Published: June 2019

The title molecule crystallizes as a dimethylformamide monosolvate, C19H14N2O6S2·C3H7NO. The molecule was expected to adopt mirror symmetry but slightly different conformational characteristics of the condensed benzothiazine ring lead to point group symmetry 1. In the crystal, molecules form two types of stacking dimers with distances of 3.464 (2) Å and 3.528 (2) Å between π-systems. As a result, columns extending parallel to [100] are formed, which are connected to intermediate dimethylformamide solvent molecules by C—H...O interactions.
Decomposing social networking site regret: a uses and gratifications approach
Authors: Islam A.K.M. Najmul , Mäntymäki Matti , Kefi Hajer
Published: June 2019

Purpose

Regret is an undesirable yet very common outcome of social networking site (SNS) use. To date, the literature has examined SNS regret at an aggregate level. The purpose of this paper is to decompose the dimensions and constituents of SNS regret into networking regret and brand page regret, to better understand it, and examine how the two facets of regret are created by SNS use intensity and gratification. The authors also decomposed SNS activities into networking activities and brand page activities and positioned them as predictors of networking regret and brand page regret, respectively.

Design/methodology/approach

The authors drew on uses and gratifications theory and positioned interpersonal connectivity and exhibitionism as the antecedents of networking activities as well as informational value and exhibitionism as the antecedents of brand page activities. The authors collected data from 246 Facebook users from France and analyzed the data using the partial least squares approach.

Findings

The results show that use intensity has a marginal effect on both brand page and networking regret. However, exhibitionism was found to reinforce the effect of use intensity on both brand page and networking regret. It also had a positive effect on both networking and brand page activities. The other two gratifications, interpersonal connectivity and informational value, had a positive effect on networking and brand page activities, respectively.

Originality/value

To date, empirical attempts at investigating decomposed SNS regret have been rare. The paper fills this theoretical and empirical gap and contributes to the literature on regret in an SNS use context.
The None in Three Victim Responsiveness Assessment (Ni3: VRA): a new outcome measure for intimate partner violence (IPV) prevention programs
Authors: Debowska Agata , Boduszek Daniel , Willmott Dominic , Jones Adele D.
Published: June 2019

Purpose

The purpose of this paper is to develop and validate the None in Three Victim Responsiveness Assessment (Ni3: VRA) examining affective and cognitive responsiveness toward victims of intimate partner violence.

Design/methodology/approach

Data were collected at two time points in a sample of 359 young people from Barbados and Grenada (56.27 percent female; M age=12.73 years).

Findings

Confirmatory factor analysis results indicated that the Ni3: VRA scores are best captured by a two-factor solution, including affective and cognitive dimensions. A test-retest correlation confirmed the reliability of the Ni3: VRA over time. Affective responsiveness formed a significant positive association with caring/cooperative behavior.

Originality/value

The Ni3: VRA can be used for the evaluation of preventive strategies aimed at reducing the rates of IPV.
A model of the dark side of expatriate–host country national relationships
Authors: Ljubica Jasenko , Shaffer Margaret , Tin Sabrina , McKouen Kevin
Published: June 2019

Purpose

The purpose of this paper is to develop a nomological model of the dark side of expatriate–host country national (HCN) relationships by identifying and explaining the development and the types of expatriate–HCN disruptive relationship behaviors (DRBs), their antecedents and consequences.

Design/methodology/approach

The authors conducted semi-structured interviews (n=27) with both expatriates and HCNs, focusing on DRBs that they exhibit toward each other, the factors preceding them (antecedents) and the mechanisms through which they affect the relationship between expatriates and HCNs, as well as the outcomes of such behaviors.

Findings

The findings show that relational dysfunction emanates from multilevel differences between expatriates and HCNs, and these differences induce workplace conflicts. These conflicts increase relational (emotional, social, instrumental and opportunity) costs that render both dyadic members to evaluate their relationship and socially categorize each other negatively, thus, detaching from the relationship. This detachment then leads to disruptive relational behaviors that amplify the conflicts and detachment dynamics and worsen interpersonal and intergroup dynamics, ultimately resulting in relational breakdown.

Research limitations/implications

This study possesses methodological (e.g. relatively small number of interviewees) and conceptual (e.g. high degree of comprehensiveness) limitations. However, these offer implications for further research as they open a multitude of promising research avenues that could enhance the proposed model.

Originality/value

This is the first study the authors are aware of that focuses on discovering and explaining the nomological network of the dark side of expatriate–HCN relationships. The use of interdependence theory to understand cross-cultural relationships is novel. As such, it delivers theoretical and empirical contributions and fosters further research efforts.
Privatising land in England
Authors: Layard Antonia
Published: June 2019

Purpose

This paper aims to analyse the extent to which privatising – or denationalising land – has legal and policy effects.

Design/methodology/approach

It applies the law in context scholarship to the question of land privatisation.

Findings

Of all the recent privatisations in England, the most valuable, and yet least recorded, is of land. According to one estimate, two million hectares or 10 per cent of the Britain landmass, left the public sector for private ownership between 1979 and 2018. Privatisations include land that is sold, leased or where a public body changes its status. This paper aims to explore these privatisations, considering them as denationalisations, concluding that the effects are most significant in housing where the differences between social and private renting in relation to rents, the security of tenure and housing quality are striking. Moreover, although other public law restraints on the state-owned property are often limited, they are also still significant, facilitating scrutiny, particularly in combination with the public sector equality duty or site-specific duties for libraries, allotments or playing fields. All the sites disposed of to private developers, landlords and companies have lost these protections.

Originality/value

This is the first time this question has been considered in this way from a legal perspective.
Authentic leadership and employee performance: mediating role of organizational commitment
Authors: Hadian Nasab Ali , Afshari Leila
Published: June 2019

Purpose

The purpose of this paper is to investigate the effect of authentic leadership (AL) on employee performance (EP) and to examine the mediating role of organizational commitment (OC).

Design/methodology/approach

Data were obtained from all employees (216) of tourism agencies in Guilan province (Iran) using a 19-item survey. In total, 173 questionnaires were returned, yielding a response rate of 80 percent. A mediation model was outlined and tested using structural equation modeling.

Findings

The results showed that AL had a significant effect on EP and OC. The findings further demonstrated the significance of the relationship between OC and EP confirming the mediating role of OC.

Practical implications

This study suggests that managers can promote OC and consequently EP by adopting an AL style. In addition, the managerial and theoretical foundations generated by this study can be considered a solution for improving EP.

Originality/value

This study contributes to the EP literature by providing a plausible explanation of the mediating role of OC in connecting AL to EP.
Small investors’ internet sentiment and return predictability
Authors: Klemola Antti
Published: June 2019

Purpose

The purpose of this paper is to propose a novel and new direct measurement of small investor sentiment in the equity market. The sentiment is based on the individual investors’ internet search activity.

Design/methodology/approach

The author measures unexpected changes in the small investor sentiment with AR (1) process, where the residuals capture the unexpected changes in small investor sentiment. The author employs vector autoregressive, Granger causality and linear regression models to estimate the association between the unexpected changes in small investor sentiment and future equity market returns.

Findings

An unexpected increase in the search popularity of the term bear market is negatively associated with the following week’s equity market returns. An unexpected increase in the spread (the difference in popularities between a bull market and a bear market) is positively associated with the following week’s equity market returns. The author finds that these effects are stronger for small-sized companies.

Originality/value

By author’s knowledge, the paper is the first that measures the small investor sentiment that is based on the internet search activity for keywords used in the American Association of Individual Investor’s (AAII) survey questions. The paper proposes an alternative small investor sentiment measure that captures the changes in small investor sentiment in more timely fashion than the AAII survey.
Machining performance of 3D-printed ABS electrode coated with copper in EDM
Authors: Danade Ujwal A. , Londhe Shrikant D. , Metkar Rajesh M.
Published: June 2019

Purpose

Rapid tooling (RT) technique using rapid prototyping (RP) process has been looked upon as an approach which reduces time and cost of production. This study aims to produce electrode for electrical discharge machining (EDM) from acrylonitrile butadiene styrene (ABS) material using the fused deposition modeling (FDM) process of RP. The electrode is coated with copper to a depth of 1 mm by using electroplating to make it conductive. This electrode is termed as RP electrode. The performance of RP electrode having square shape is compared with that of solid electrode of copper having identical size.

Design/methodology/approach

In this study, the work piece material is chosen to be titanium Grade-V alloy (Ti-Al6-V4). The input parameters on the EDM machine such as discharge current, pulse on time and voltage are studied, and experiments are designed using the Taguchi method.

Findings

The results pertaining to the material removal rate (MRR), electrode wear rate (EWR) and surface roughness (Ra) are reported. It is found that the performance of a coated RP electrode is equally satisfactory when compared with that of a solid electrode.

Originality/value

This paper reports the machining performance of a square-shaped ABS electrode coated with copper. This technique, particularly when the electrode is of intricate shape, saves on cost and time of production of electrode to be used for EDM.
Temperature distribution simulations during electron beam freeform fabrication process based on the fully threaded tree
Authors: Yin Yajun , Duan Wei , Wu Kai , Li Yangdong , Zhou Jianxin , Shen Xu , Wang Min
Published: June 2019

Purpose

The purpose of this study is to simulate the temperature distribution during an electron beam freeform fabrication (EBF3) process based on a fully threaded tree (FTT) technique in various scales and to analyze the temperature variation with time in different regions of the part.

Design/methodology/approach

This study presented a revised model for the temperature simulation in the EBF3 process. The FTT technique was then adopted as an adaptive grid strategy in the simulation. Based on the simulation results, an analysis regarding the temperature distribution of a circular deposit and substrate was performed.

Findings

The FTT technique was successfully adopted in the simulation of the temperature field during the EBF3 process. The temperature bands and oscillating temperature curves appeared in the deposit and substrate.

Originality/value

The FTT technique was introduced into the numerical simulation of an additive manufacturing process. The efficiency of the process was improved, and the FTT technique was convenient for the 3D simulations and multi-pass deposits.
Does personality drive price bubbles?
Authors: Oehler Andreas , Wedlich Florian , Wendt Stefan , Horn Matthias
Published: June 2019

Purpose

The purpose of this study is to analyze whether differences in market-wide levels of investor personality influence experimental asset market outcomes in terms of limit orders, price levels and price bubbles.

Design/methodology/approach

Investor personality is determined by a questionnaire. These data are combined with data from 17 experimental asset markets. Two approaches are used to estimate market-wide levels of investor personality. First, the market-wide average of each personality trait is determined; second, the percentage of individuals with comparable personality in a market is computed. Overall, 364 undergraduate business students participated in the questionnaire and the experimental asset markets.

Findings

Limits and transaction prices are higher in markets with higher mean values in participants’ extraversion and openness to experience and lower mean values in participants’ agreeableness and neuroticism. In markets with lower mean values of subjects’ openness to experiences more overpriced transactions are observed. In markets with a higher proportion of extraverted subjects and a lower proportion of neurotic subjects higher limits and transaction prices are observed. Bubble phases last longer in markets with a higher proportion of extraverted and a lower proportion of neurotic subjects.

Originality/value

Overall, the findings suggest that market-wide personality levels influence market outcomes. As a consequence, market-wide levels of personality help to explain prices in auctions with limited number of participants. Additionally, studies that analyze the influence of subjects’ characteristics, including risk aversion, emotional states or overconfidence, on market outcomes should also consider personality traits as potential underlying factor.
The endoparasitoid Psyllaephagus arenarius benefits from ectoparasitic venom via multiparasitism with the ectoparasitoid Tamarixia lyciumi
Authors: Wu Peng‐Xiang , Ma Bao‐Xu , Wu Feng‐Ming , Xu Jing , Zhang Run‐Zhi
Published: June 2019

As solitary nymphal parasitoids of Paratrioza sinica, the ectoparasitoid Tamarixia lyciumi and the endoparasitoid Psyllaephagus arenarius act as effective biocontrol agents. Thus, it is necessary to facilitate mass productions of both species. Despite showing an excellent parasitic ability, Ps. arenarius is often trapped fatally inside 5th‐instar nymphs of Pa. sinica due to strong host immunity. To improve the emergence rate of Ps. arenarius, we evaluated whether Ps. arenarius could utilize T. lyciumi venom via multiparasitism, so the parasitism characteristics of both species were examined between separate‐existence (monoparasitism only) and co‐existence (mono‐ and multiparasitism) systems. Further, the parasitism characteristics of Ps. arenarius on venom‐injected hosts with/without T. lyciumi eggs were tested to further identify the facilitator. The results showed the parasitism rate of T. lyciumi was increased while that of Ps. arenarius did not change from separate‐existence to co‐existence systems. The intrinsic performances of two species in monoparasitism did not differ between separate‐ and co‐existence systems. From monoparasitism (separate‐existence) to multiparasitism (co‐existence), no differences were detected in the intrinsic performances of T. lyciumi, but those of Ps. arenarius were greatly improved. After T. lyciumi venom injection, the parasitism characteristics of Ps. arenarius did not differ between venom‐injected hosts with T. lyciumi eggs and those without, further indicating Ps. arenarius benefited from the venom of T. lyciumi females rather than T. lyciumi egg/larval secretions. Instead of negative effects, multiparasitism with ectoparasitoids improves endoparasitoids due to ectoparasitic venom. The study increases host resource utilization and provides creative ways for mass production of endoparasitoids.
Ageing in men with normal spermatogenesis alters spermatogonial dynamics and nuclear morphology in Sertoli cells
Authors: Pohl E. , Höffken V. , Schlatt S. , Kliesch S. , Gromoll J. , Wistuba J.
Published: June 2019

Background

Ageing in men is believed to be associated with fertility decline and elevated risk of congenital disorders for the offspring. The previous studies also reported reduced germ and Sertoli cell numbers in older men. However, it is not clear whether ageing in men with normal spermatogenesis affects the testis and germ cell population dynamics in a way sufficient for transmitting adverse age effects to the offspring.

Objectives

We examined men with normal spermatogenesis at different ages concerning effects on persisting testicular cell types, that is the germ line and Sertoli cells, as these cell populations are prone to be exposed to age effects.

Material and methods

Ageing was assessed in testicular biopsies of 32 patients assigned to three age groups: (i) 28.8 ± 2.7 years; (ii) 48.1 ± 1 years; and (iii) 70.9 ± 6.2 years, n = 8 each, with normal spermatogenesis according to the Bergmann–Kliesch score, and in a group of meiotic arrest patients (29.9 ± 3.8 years, n = 8) to decipher potential links between different germ cell types. Besides morphometry of seminiferous tubules and Sertoli cell nuclei, we investigated spermatogenic output/efficiency, and dynamics of spermatogonial populations via immunohistochemistry for MAGE A4, PCNA, CREM and quantified A‐pale/A‐dark spermatogonia.

Results

We found a constant spermatogenic output (CREM‐positive round spermatids) in all age groups studied. In men beyond their mid‐40s (group 2), we detected increased nuclear and nucleolar size in Sertoli cells, indirectly indicating an elevated protein turnover. From the 7th decade (group 3) of life onwards, testes showed increased proliferation of undifferentiated spermatogonia, decreased spermatogenic efficiency and elevated numbers of proliferating A‐dark spermatogonia.

Discussion and conclusion

Maintaining normal sperm output seems to be an intrinsic determinant of spermatogenesis. Ageing appears to affect this output and might provoke compensatory proliferation increase in A spermatogonia which, in turn, might hamper germ cell integrity.
Circulating Power: Humanitarian Logistics, Militarism, and the United Arab Emirates
Authors: Ziadah Rafeef
Published: June 2019

While critical authors have interrogated the roots of business logistics, this paper extends the analysis and contributes to a larger critique of the cohering field of Humanitarian Logistics (HL), noting the overlap in the logistical cartographies of militarism and humanitarianism. The focus is on the UAE's expanding logistics space into the Horn of Africa and the production of specialised HL zones like Dubai International Humanitarian City (DIHC). The article makes three core arguments. First, a logistics lens enables us to expand the study of aid beyond immediate conflict zones, into more distant spaces often constructed as “stable”. Second, the placement of logistics at the core of aid delivery has been a key mechanism for inserting market imperatives into humanitarian activities. Third, this gives countries outside the advanced core, such as the UAE, power to leverage and expand their logistics space for multiple purposes, in war making, aid, and commercial activities.
Consistent alterations in faecal microbiomes of patients with primary sclerosing cholangitis independent of associated colitis
Authors: Rühlemann Malte , Liwinski Timur , Heinsen Femke‐Anouska , Bang Corinna , Zenouzi Roman , Kummen Martin , Thingholm Louise , Tempel Marie , Lieb Wolfgang , Karlsen Tom , Lohse Ansgar , Hov Johannes , Denk Gerald , Lammert Frank , Krawczyk Marcin , Schramm Christoph , Franke Andre
Published: June 2019

Background

Single‐centre studies reported alterations of faecal microbiota in patients with primary sclerosing cholangitis (PSC). As regional factors may affect microbial communities, it is unclear if a microbial signature of PSC exists across different geographical regions.

Aim

To identify a robust microbial signature of PSC independent of geography and environmental influences.

Methods

We included 388 individuals (median age, 47 years; range, 15‐78) from Germany and Norway in the study, 137 patients with PSC (n = 75 with colitis), 118 with ulcerative colitis (UC) and 133 healthy controls. Faecal microbiomes were analysed by 16S rRNA gene sequencing (V1‐V2). Differences in relative abundances of single taxa were subjected to a meta‐analysis.

Results

In both cohorts, microbiota composition (beta‐diversity) differed between PSC patients and controls (P < 0.001). Random forests classification discriminated PSC patients from controls in both geographical cohorts with an average area under the curve of 0.88. Compared to healthy controls, many new cohort‐spanning alterations were identified in PSC, such as an increase of Proteobacteria and the bile‐tolerant genus Parabacteroides, which were detected independent from geographical region. Associated colitis only had minor effects on microbiota composition, suggesting that PSC itself drives the faecal microbiota changes observed.

Conclusion

Compared to healthy controls, numerous microbiota alterations are reproducible in PSC patients across geographical regions, clearly pointing towards a microbiota composition that is shaped by the disease itself and not by environmental factors. These reproducibly altered microbial populations might provide future insights into the pathophysiology of PSC.