bluuebunny/crossref_metadata_2025 huggingface dataset:
Top-down coordination of local cortical state during selective attention
Authors: van Kempen Jochem , Gieselmann Marc A. , Boyd Michael , Steinmetz Nicholas A. , Moore Tirin , Engel Tatiana A. , Thiele Alexander
Published: March 2020

Spontaneous fluctuations in cortical excitability influence sensory processing and behavior. These fluctuations, long known to reflect global changes in cortical state, were recently found to be modulated locally within a retinotopic map during spatially selective attention. We found that periods of vigorous (On) and faint (Off) spiking activity, the signature of cortical state fluctuations, were coordinated across brain areas along the visual hierarchy and tightly coupled to their retinotopic alignment. During top-down attention, this interareal coordination was enhanced and progressed along the reverse cortical hierarchy. The extent of local state coordination between areas was predictive of behavioral performance. Our results show that cortical state dynamics are shared across brain regions, modulated by cognitive demands and relevant for behavior.

One Sentence Summary

Interareal coordination of local cortical state is retinotopically precise and progresses in a reverse hierarchical manner during selective attention.
Forced Abstinence from Alcohol Induces Sex-Specific Depression-like Behavioral and Neural Adaptations in Somatostatin Neurons in Cortical and Amygdalar Regions
Authors: Dao Nigel C. , Nair Malini S. , Magee Sarah N. , Moyer J. Brody , Sendao Veronica , Brockway Dakota F. , Crowley Nicole A.
Published: March 2020

Forced abstinence (FA) from alcohol has been shown to produce a variety of anxiety- and depression- like symptoms in animal models. Somatostatin (SST) neurons, a subtype of GABAergic neurons found throughout the brain, are a novel neural target with potential treatment implications in affective disorders, yet their role in alcohol use disorders (AUD) remains to be explored. Here, we examined the neuroadaptations of SST neurons during forced abstinence from voluntary alcohol consumption. Following six weeks of two-bottle choice alcohol consumption and protracted forced abstinence, male and female C57BL/6J mice exhibited a heightened, but sex-specific, depressive-like behavioral profile in the sucrose preference test (SPT) and forced swim test (FST), without changes in anxiety-like behaviors in the elevated plus maze (EPM) and open field test (OFT). FST-induced cFos expressions in the prefrontal cortex (PFC) and ventral bed nucleus of the stria terminalis (vBNST) were altered in FA-exposed female mice only, suggesting a sex-specific effect of forced abstinence on the neural response to acute stress. SST immunoreactivity in these regions was unaffected by forced abstinence, while differences were seen in SST/cFos co-expression in the vBNST. No differences in cFos or SST immunoreactivity were seen in the lateral central nucleus of the amygdala (CEA) and the basolateral amygdala (BLA). Additionally, SST neurons displayed opposing alterations in the PFC and vBNST, with heightened intrinsic excitability in the PFC and diminished intrinsic excitability in the vBNST. These findings provide an overall framework of forced abstinence-induced neuroadaptations in these key brain regions involved in emotional regulation and processing.
The potential SARS-CoV-2 entry inhibitor
Authors: Lung Jrhau , Lin Yu-Shih , Yang Yao-Hsu , Chou Yu-Lun , Chang Geng-He , Tsai Ming-Shao , Hsu Cheng-Ming , Yeh Reming-Albert , Shu Li-Hsin , Cheng Yu-Ching , Liu Hung Te , Wu Ching-Yuan
Published: March 2020

Outbreak of coronavirus disease 2019 (COVID-19) occurred in Wuhan and has rapidly spread to almost all parts of world. In coronaviruses, the receptor binding domain (RBD) in the distal part of S1 subunit of SARS-CoV-2 spike protein can directly bind to angiotensin converting enzyme 2 (ACE2). RBD promote viral entry into the host cells and is an important therapeutic target. In this study, we discovered that theaflavin showed the lower idock score (idock score: −7.95 kcal/mol). To confirm the result, we discovered that theaflavin showed FullFitness score of −991.21 kcal/mol and estimated ΔG of −8.53 kcal/mol for the most favorable interaction with contact area of SARS-CoV-2 RBD by SwissDock service. Regarding contact modes, hydrophobic interactions contribute significantly in binding and additional hydrogen bonds were formed between theaflavin and Arg454, Phe456, Asn460, Cys480, Gln493, Asn501 and Val503 of SARS-CoV-2 RBD, near the direct contact area with ACE2. Our results suggest that theaflavin could be the candidate of SARS-CoV-2 entry inhibitor for further study.
Inflammatory and oxidative status in European captive black rhinoceroses: a link with Iron Overload Disorder?
Authors: Pouillevet Hanae , Soetart Nicolas , Boucher Delphine , Wedlarski Rudy , Jaillardon Laetitia
Published: March 2020

Iron Overload Disorder (IOD) is a syndrome developed by captive browsing rhinoceroses like black rhinoceroses (Diceros bicornis) in which hemosiderosis settles in vital organs while free iron accumulates in the body, potentially predisposing to various secondary diseases. Captive grazing species like white rhinoceroses (Ceratotherium simum) do not seem to be affected. The pro-oxidant and pro-inflammatory properties of iron, associated with the poor antioxidant capacities of black rhinoceroses, could enhance high levels of inflammation and oxidative stress leading to rapid ageing and promoting diseases. In this prospective study, 15 black (BR) and 29 white rhinoceroses (WR) originating from 22 European zoos were blood-sampled and compared for their iron status (serum iron), liver/muscle biochemical parameters (AST, GGT, cholesterol), inflammatory status (total proteins, protein electrophoresis) and oxidative stress markers (SOD, GPX, dROMs). Results showed higher serum iron and liver enzyme levels in black rhinoceroses (P<0.01), as well as higher GPX (P<0.05) and dROM (P<0.01) levels. The albumin/globulin ratio was lower in black rhinoceroses (P<0.05) due to higher α2-globulin levels (P<0.001). The present study suggests a higher inflammatory and oxidative profile in captive BR than in WR, possibly in relation to iron status. This could be either a consequence or a cause of iron accumulation, potentially explaining rapid ageing and various diseases. Further investigations are needed to assess the prognostic value of the inflammatory and oxidative markers in captive black rhinoceroses, particularly for evaluating the impact of reduced-iron and antioxidant-supplemented diets.
Analyses of cancer incidence and other morbidities in gamma irradiated B6CF1 mice
Authors: Zander Alia , Paunesku Tatjana , Woloschak Gayle
Published: March 2020

With increasing medical radiation exposures, it is important to understand how different modes of delivery of ionizing radiation as well as total doses of exposure impact health outcomes. Our lab studied the risks associated with ionizing radiation by analyzing the Northwestern University Radiation Archive for animals (NURA). NURA contains detailed data from a series of 10 individual neutron and gamma irradiation experiments conducted on over 50,000 mice. Rigorous statistical testing on control mice from all Janus experiments enabled us to select studies that could be compared to one another and uncover unexpected differences among the controls as well as experimental animals. For controls, mice sham irradiated with 300 fractions died significantly earlier than those with fewer sham fractions. Using the integrated dataset of gamma irradiated and control mice, we found that fractionation significantly decreased the death hazard for animals dying of lymphomas, tumors, non-tumors, and unknown causes. Gender differences in frequencies of causes of death were identified irrespective of irradiation and dose fractionation, with female mice being at a greater risk for all causes of death, except for lung tumors. Irradiated and control male mice were at a significantly greater risk for lung tumors, the opposite from observations noted in humans. Additionally, we discovered that lymphoma deaths can occur quickly after exposures to high doses of gamma rays. This study systematically cross-compared outcomes of different modes of fractionation across a wide span of total doses to demonstrate that protraction modulated survival and disease status differently based on the total dose, cause of death, and sex of an animal. This novel method for analyzing the Janus datasets will lead to insightful new mechanistic hypotheses and research in the fields of radiation biology and protection.
Analyses of cancer incidence and other morbidities in neutron irradiated B6CF1 mice
Authors: Zander Alia , Paunesku Tatjana , Woloschak Gayle
Published: March 2020

The Department of Energy conduced ten large-scale neutron irradiation experiments at Argonne National Laboratory between 1972 and 1989. Using a new approach to utilize experimental controls to determine whether a cross comparison between experiments was appropriate, we amalgamated data on neutron exposures to discover that fractionation significantly improved overall survival. A more detailed investigation showed that fractionation only had a significant impact on the death hazard for animals that died from solid tumors, but did not significantly impact any other causes of death. Additionally, we compared the effects of sex, age first irradiated, and radiation fractionation on neutron irradiated mice versus cobalt 60 gamma irradiated mice and found that solid tumors were the most common cause of death in neutron irradiated mice, while lymphomas were the dominant cause of death in gamma irradiated mice. Most animals in this study were irradiated before 150 days of age but a subset of mice was first exposed to gamma or neutron irradiation over 500 days of age. Advanced age played a significant role in decreasing the death hazard for neutron irradiated mice, but not for gamma irradiated mice. Mice that were 500 days old before their first exposures to neutrons began dying later than both sham irradiated or gamma irradiated mice.
Characterization and establishment of a novel EBV strain simultaneously associated with nasopharyngeal carcinoma and B-cell lymphoma
Authors: Yu Fenggang , Syn Nicholas L. , Lu Yanan , Chong Qing Yun , Lai Junyun , Tan Wei Jian , Goh Boon Cher , MacAry Paul A. , Wang Lingzhi , Loh Kwok Seng
Published: March 2020

Epstein-Barr virus (EBV) – the prototypical human tumor virus – is responsible for 1-2% of the global cancer burden, but divergent strains seem to exist in different geographical regions with distinct predilections for causing lymphoid or epithelial malignancies. Here we report the establishment and characterization of Yu103, an Asia Pacific EBV strain with a highly remarkable provenance of being derived from nasopharyngeal carcinoma biopsy but subsequently propagated in human B-lymphoma cells and xenograft models. Unlike previously characterized EBV strains which are either predominantly B-lymphotropic or epitheliotropic, Yu103 evinces an uncanny capacity to infect and transform both B-lymphocytes and nasopharyngeal epithelial cells. Genomic and phylogenetic analyses indicated that Yu103 EBV lies midway along the spectrum of EBV strains known to drive lymphomagenesis or carcinogenesis, and harbors molecular features which likely account for its unusual properties. To our knowledge, Yu103 EBV is currently the only EBV isolate shown to drive human nasopharyngeal carcinoma and B-lymphoma, and should therefore provide a powerful novel platform for research on EBV-driven hematological and epithelial malignancies.
Biochemical characterizations of ER-resident peroxidases, GPx7 and GPx8, reveal their distinct and regulated oxidative activities
Authors: Kanemura Shingo , Sofia Elza Firdiani , Hirai Naoya , Okumura Masaki , Kadokura Hiroshi , Inaba Kenji
Published: March 2020

In the mammalian endoplasmic reticulum (ER), the diverse network comprising more than 20 members of the protein disulfide isomerase (PDI) family and more than five PDI oxidases has evolved to promote oxidative protein folding. While the canonical disulfide bond formation pathway constituted by Ero1α and PDI has been well studied so far, mechanistic and physiological bases of newly identified PDI oxidases, glutathione peroxidase-7 (GPx7) and -8 (GPx8), are only poorly understood. We here demonstrated that human GPx7 has much higher reactivity with H2O2than human GPx8, leading to efficient PDI oxidation. GPx7 forms a catalytic tetrad at the redox active site to react with H2O2efficiently and stabilize a resultantly generated sulfenylated species. While it was previously postulated that the GPx7 catalysis involved a highly reactive peroxidatic cysteine, a resolving cysteine was found to act to regulate the PDI oxidation activity of GPx7. The present study also revealed that GPx7 formed complexes preferentially with PDI and P5 in H2O2-treated cells. Altogether, human GPx7 functions as an H2O2-dependent PDI oxidase in cells whereas PDI oxidation may not be the central physiological role of human GPx8.
A regulatory program for initiation of Wnt signaling during posterior regeneration
Authors: Ramirez Alyson N. , Loubet-Senear Kaitlyn , Srivastava Mansi
Published: March 2020

Whole-body regeneration requires the re-establishment of body axes for appropriate patterning of new and old tissue. Wnt signaling has been utilized to correctly regenerate tissues along the primary axis in many animals. However, the causal molecular mechanisms that first launch Wnt signaling during regeneration are poorly characterized. We used the acoel wormHofstenia miamiato identify processes that initiate Wnt signaling. Transcriptome profiling,in situhybridization, and functional studies revealed a Wnt ligand,wnt-3, as an early wound-induced gene specifically activated in posterior-facing wound sites and was required for establishing posterior identity during regeneration.wnt-3was upregulated upon amputation in stem cells, and its inhibition affected stem cell proliferation. Ectopic expression of anterior markers inwnt-3RNAi head fragments was stem cell dependent. Chromatin accessibility data revealed thatwnt-3activation during regeneration required input from the general wound response. Additionally, the expression of a different Wnt ligand,wnt-1, prior to amputation was required for activation of wound-inducedwnt-3expression. Our study establishes a gene regulatory network for initiating Wnt signaling in posterior tissues in a bilaterian.
Cell type-specific histone acetylation profiling of Alzheimer’s Disease subjects and integration with genetics
Authors: Ramamurthy Easwaran , Welch Gwyneth , Cheng Jemmie , Yuan Yixin , Gunsalus Laura , Bennett David A. , Tsai Li-Huei , Pfenning Andreas
Published: March 2020

We profile genome-wide histone 3 lysine 27 acetylation (H3K27ac) of 3 major brain cell types from hippocampus and dorsolateral prefrontal cortex (dlPFC) of subjects with and without Alzheimer’s Disease (AD). We confirm that single nucleotide polymorphisms (SNPs) associated with late onset AD (LOAD) prefer to reside in the microglial histone acetylome, which varies most strongly with age. We observe acetylation differences associated with AD pathology at 3,598 peaks, predominantly in an oligodendrocyte-enriched population. Strikingly, these differences occur at the promoters of known early onset AD (EOAD) risk genes (APP, PSEN1, PSEN2, BACE1), late onset AD (LOAD) risk genes (BIN1, PICALM, CLU, ADAM10, ADAMTS4, SORL1andFERMT2), and putative enhancers annotated to other genes associated with AD pathology (MAPT). More broadly, acetylation differences in the oligodendrocyte-enriched population occur near genes in pathways for central nervous system myelination and oxidative phosphorylation. In most cases, these promoter acetylation differences are associated with differences in transcription in oligodendrocytes. Overall, we reveal deregulation of known and novel pathways in AD and highlight genomic regions as therapeutic targets in oligodendrocytes of hippocampus and dlPFC.
Ancestral function of Inhibitors-of-kappaB regulatesCaenorhabditis elegansdevelopment
Authors: Brena David , Bertran Joan , Porta-de-la-Riva Montserrat , Guillén Yolanda , Cornes Eric , Kukhtar Dmytro , Campos-Vicens Lluís , Fernández Lierni , Pecharroman Irene , Garcia-López Albert , Islam Khademul , Marruecos Laura , Bigas Anna , Cerón Julián , Espinosa Lluís
Published: March 2020

Mammalian IκB proteins (IκBs) exert their main function as negative regulators of NF-κB, a central signaling pathway controlling immunity and inflammation. An alternative chromatin role for IκBs has been shown to affect stemness and cell differentiation. However, the involvement of NF-κB in this function has not been excluded. NFKI-1 and IKB-1 are IκB homologs inCaenorhabditis elegans, which lacks NF-κB nuclear effectors. We found thatnfki-1andikb-1mutants display developmental defects that phenocopy mutations in Polycomb and UTX-1 histone demethylase, suggesting a role forC. elegansIκBs in chromatin regulation. Further supporting this possibility(i)we detected NFKI-1 in the nucleus of cells;(ii)NFKI-1 and IKB-1 bind to histones and Polycomb proteins,(iii)and associate with chromatinin vivo, and(iv)mutations innfki-1andikb-1alter chromatin marks. Based on these results, we propose that ancestral IκB inhibitors modulate Polycomb activity at specific gene subsets with an impact on development.
Quantitative intravital imaging revealsin vivodynamics of physiological-stress induced mitophagy
Authors: Wrighton Paul J. , Shwartz Arkadi , Heo Jin-Mi , Quenzer Eleanor D. , LaBella Kyle A. , Harper J. Wade , Goessling Wolfram
Published: March 2020

Mitophagy, the selective recycling of mitochondria through autophagy, is a crucial metabolic process induced by cellular stress, and defects are linked to aging, sarcopenia, and neurodegenerative diseases. To therapeutically target mitophagy, the fundamentalin vivodynamics and molecular mechanisms must be fully understood. Here, we generated mitophagy biosensor zebrafish lines expressing mitochondrially targeted, pH-sensitive, fluorescent probes mito-Keima and mito-EGFP-mCherry and used quantitative intravital imaging to illuminate mitophagy during physiological stresses—embryonic development, fasting and hypoxia. In fasted muscle, volumetric mitolysosome size analyses documented organelle stress-response dynamics, and time-lapse imaging revealed mitochondrial filaments undergo piecemeal fragmentation and recycling rather than the wholesale turnover observed in cultured cells. Hypoxia-inducible factor (Hif) pathway activation through physiological hypoxia or chemical or genetic modulation also provoked mitophagy. Intriguingly, mutation of a single mitophagy receptorbnip3prevented this effect, whereas disruption of other putative hypoxia-associated mitophagy genesbnip3la(nix),fundc1, pink1orprkn(Parkin) had no effect. Thisin vivoimaging study establishes fundamental dynamics of fasting-induced mitophagy and identifiesbnip3as the master regulator of Hif-induced mitophagy in vertebrate muscle.
Gamma-rhythmic input causes spike output
Authors: Lewis Christopher Murphy , Ni Jianguang , Wunderle Thomas , Jendritza Patrick , Diester Ilka , Fries Pascal
Published: March 2020

The gamma rhythm has been implicated in neuronal communication, but causal evidence remains indirect. We measured spike output of local neuronal networks and emulated their synaptic input through optogenetics. Opsins provide currents through somato-dendritic membranes, similar to synapses, yet under experimental control with high temporal precision. We expressed Channelrhodopsin-2 in excitatory neurons of cat visual cortex and recorded neuronal responses to light with different temporal characteristics. Sine waves of different frequencies entrained neuronal responses with a reliability that peaked for input frequencies in the gamma band. Crucially, we also presented white-noise sequences, because their temporal unpredictability enables analysis of causality. Neuronal spike output was caused specifically by the input’s gamma component. This gamma-specific transfer function is likely an emergent property of in-vivo networks with feedback inhibition. The method described here could reveal the transfer function between the input to any one and the output of any other neuronal group.
Universal and taxon-specific trends in protein sequences as a function of age
Authors: James Jennifer E , Willis Sara M , Nelson Paul G , Weibel Catherine , Kosinski Luke J , Masel Joanna
Published: March 2020

Extant protein-coding sequences span a huge range of ages, from those that emerged only recently in particular lineages, to those present in the last universal common ancestor. Because evolution has had less time to act on young sequences, there might be “phylostratigraphy” trends in any properties that evolve slowly with age. Indeed, a long-term reduction in hydrophobicity and in hydrophobic clustering has been found in previous, taxonomically restricted studies. Here we perform integrated phylostratigraphy across 435 fully sequenced and dated eukaryotic species, using sensitive HMM methods to detect homology of protein domains (which may vary in age within the same gene), and applying a variety of quality filters. We find that the reduction in hydrophobic clustering is universal across diverse lineages, showing limited sign of saturation. But the tendency for young domains to have higher protein structural disorder, driven primarily by more hydrophilic amino acids, is found only among young animal domains, and not young plant domains, nor ancient domains predating the existence of the last eukaryotic common ancestor. Among ancient domains, trends in amino acid composition reflect the order of recruitment into the genetic code, suggesting that events during the earliest stages of life on earth continue to have an impact on the composition of ancient sequences.
Evaluation of COVID-19 RT-qPCR test in multi-sample pools
Authors: Yelin Idan , Aharony Noga , Tamar Einat Shaer , Argoetti Amir , Messer Esther , Berenbaum Dina , Shafran Einat , Kuzli Areen , Gandali Nagam , Hashimshony Tamar , Mandel-Gutfreund Yael , Halberthal Michael , Geffen Yuval , Szwarcwort-Cohen Moran , Kishony Roy
Published: March 2020

The recent emergence of SARS-CoV-2 lead to a current pandemic of unprecedented levels. Though diagnostic tests are fundamental to the ability to detect and respond, many health systems are already experiencing shortages of reagents associated with this test. Here, testing a pooling approach for the standard RT-qPCR test, we find that a single positive sample can be detected even in pools of up to 32 samples, with an estimated false negative rate of 10%. Detection of positive samples diluted in even up to 64 samples may also be attainable, though may require additional amplification cycles. As it uses the standard protocols, reagents and equipment, this pooling method can be applied immediately in current clinical testing laboratories. We hope that such implementation of a pool test for COVID-19 would allow expanding current screening capacities thereby enabling the expansion of detection in the community, as well as in close integral groups, such as hospital departments, army units, or factory shifts.
C Terminus of DJ-1 Determines Its Homodimerization, Deglycation Activity and Suppression of Ferroptosis
Authors: Jiang Li , Chen Xiaobing , Wu Qian , Zhu Haiying , Du Chengyong , Ying Meidan , He Qiaojun , Zhu Hong , Yang Bo , Cao Ji
Published: March 2020

DJ-1 is a multi-functional protein related to cancer and autosomal early-onset Parkinson disease (PD). Besides the well-documented antioxidative stress activity, recent studies suggest that DJ-1 has the deglycation enzymatic activity and the anti-ferroptosis function. Although it has been demonstrated that DJ-1 forms the homodimerization, which dictates its antioxidative stress activity, the relationship between the dimeric structure and newly reported activities remains largely elusive. In this study, we find that the deletion mutation of the last 3 amino acids at C terminus of DJ-1 disrupts its homodimerization in both transfected and purified DJ-1 protein. Further study shows that hydrophobic L187 residue is of great importance for DJ-1 homodimerization. In addition, the ability in methylglyoxal detoxification is almost abolished in the mutation of deleting last 3 residues at C terminus (ΔC3) and point mutant L187E compared with wild type DJ-1 (DJ-1 WT). We also find that the suppression of ferroptosis is fully inhibited by ΔC3 and L187E while partially suppressed by V51C. Thus, our findings show that C terminus of DJ-1 is crucial for its homodimerization, deglycation activity and suppression of ferroptosis.
Crystal structure of a new phenyl(morpholino)methanethione derivative: 4-[(morpholin-4-yl)carbothioyl]benzoic acid
Authors: Agnimonhan Finagnon Hyacinthe , Bendeif El-Eulmi , Akanni Léon Ahoussi , Gbaguidi Ahokannou Fernand , Martin Eddy , Wenger Emmanuel , Lecomte Claude
Published: March 2020

4-[(Morpholin-4-yl)carbothioyl]benzoic acid, C12H13NO3S, a novel phenyl(morpholino)methanethione derivative, crystallizes in the monoclinic space group P21/n. The morpholine ring adopts a chair conformation and the carboxylic acid group is bent out slightly from the benzene ring mean plane. The molecular geometry of the carboxylic group is characterized by similar C—O bond lengths [1.266 (2) and 1.268 (2) Å] as the carboxylate H atom is disordered over two positions. This molecular arrangement leads to the formation of dimers through strong and centrosymmetric low barrier O—H...O hydrogen bonds between the carboxylic groups. In addition to these intermolecular interactions, the crystal packing consists of two different molecular sheets with an angle between their mean planes of 64.4 (2)°. The cohesion between the different layers is ensured by C—H...S and C—H...O interactions.
4-Amino-6-(piperidin-1-yl)pyrimidine-5-carbonitrile
Authors: Bhat Radhika , Shraddha K. N. , Begum Noor Shahina
Published: March 2020

In the title compound, C10H13N5, the piperidine ring adopts a chair conformation with the exocyclic N—C bond in an axial orientation, and the dihedral angle between the mean planes of piperidine and pyrimidine rings is 49.57 (11)°. A short intramolecular C—H...N contact generates an S(7) ring. In the crystal, N—H...N hydrogen bonds link the molecules into (100) sheets and a weak aromatic π-π stacking interaction is observed [centroid–centroid separation = 3.5559 (11) Å] between inversion-related pyrimidine rings.
Optimum sub-megawatt electric-hybrid power source selection
Authors: Picard Benoit , Picard Mathieu , Plante Jean-Sébastien , Rancourt David
Published: March 2020

Purpose

The limited energy density of batteries generates the need for high-performance power sources for emerging eVTOL applications with radical operational improvement potential over traditional aircraft. This paper aims to evaluate on-design and off-design recuperated turbogenerator performances based on newly developed compression loaded ceramic turbines, the Inside-out Ceramic Turbine (ICT), in order to select the optimum engine configuration for sub-megawatt systems.

Design/methodology/approach

System-level thermal engine modeling is combined with electric generators and power electronics performance predictions to obtain the Pareto front between efficiency and power density for a variety of engine designs, both for recuperated and simple cycle turbines. Part load efficiency for those engines are evaluated, and the results are used for an engine selection based on a simplified eVTOL mission capability.

Findings

By operating with high turbine inlet temperature, variable output speed and adequately sized recuperator, a turbogenerator provides exceptional efficiency at both nominal power and part load operation for a turbomachine, while maintaining the high power density required for aircraft. In application with a high peak-to-cruise power ratio, such power source would provide eight times the range of battery-electric power pack and an 80% improvement over the state-of-the-art simple cycle turbogenerator.

Practical implications

The implementation of a recuperator would provide additional gains especially important for military and on-demand mobility applications, notably reducing the heat signature and noise of the system. The engine low-pressure ratio reduces its complexity and combined with the fuel savings, the system could significantly reduce operational cost.

Originality/value

Implementation of radically new ICT architecture provides the key element to make a sub-megawatt recuperated turbogenerator viable in terms of power density. The synergetic combination of a recuperator, high temperature turbine and variable speed electric generator provides drastic improvement over simple-cycle turbines, making such a system highly relevant as the power source for future eVTOL applications.
Data science for business: benefits, challenges and opportunities
Authors: Medeiros Mauricius Munhoz de , Hoppen Norberto , Maçada Antonio Carlos Gastaud
Published: March 2020

Purpose

This paper aims to identify the benefits of data science (DS) for organizations, highlighting the challenges and opportunities related to developing this capability.

Design/methodology/approach

Initially, a literature review was performed. Later, empirical data were collected through a structured electronic interview answered by 211 informants, who are most experienced managers of medium and large organizations from different economic sectors, and data were submitted to content analysis.

Findings

The most frequently observed benefits are as follows: support for data analysis and insight generation with agility; creation of a data-driven culture; improvement of data quality; facilitating the understanding of the business environment, opportunity sensing; and organizational performance management. The most observed challenges are as follows: data-driven culture; DS training; allocation of investments in analytical technologies; and data governance and strategy.

Research limitations/implications

In addition, to mapping the state of the art on the subject, it contributes to the expansion of scientific knowledge through the identification and disclosure of 11 benefit indicators and 16 challenge indicators associated with analytical capabilities.

Practical implications

To transform data into information and add value to the business, organizations need to make efforts to enable executive mindset change, the formulation of strategies and governance mechanisms gave the renewal of workforce competencies and the allocation of investments in information technology.

Originality/value

A vast body of empirical evidence is gathered that consolidates different views on the benefits and challenges associated with DS for business.
SMEs motivations for CSR: an exploratory study
Authors: Grimstad Siv Marina Flø , Glavee-Geo Richard , Fjørtoft Barbro Elisabeth
Published: March 2020

Purpose

The paper aims to investigate the relationship between firms’ motivation for corporate social responsibility (CSR) and the moderating role of internationalisation.

Design/methodology/approach

The authors developed and tested a conceptual model based on a survey of 65 respondents from the Møre and Romsdal (M&R) maritime cluster. The M&R maritime cluster despite being national has strong interconnections to the global maritime industry and as such, presents a suitable context for testing our research model.

Findings

The findings show that firms’ intrinsic motivation drives CSR more than extrinsic motivation. Intrinsic motivation is understood as a firm engaging in CSR because it is the right thing to do and done out of one’s free will without compulsion or coercion. Extrinsic motivation relates to an action that is performed to achieve a separate outcome. Intrinsic and extrinsic motivations are found to be related and not mutually exclusive. The impact of intrinsic motivation on CSR was found to be contingent on the extent of the internationalisation of small and medium-sized enterprises (SMEs).

Originality/value

The key contribution of the study is the modelling of firms’ motivation for CSR activities and the contingent effect of internationalisation. In as much as companies perceive CSR activities as the right thing to do, the motive to do so also depends on the business case/profit motive. The study shows that SMEs’ intrinsic motivation is the driving force in CSR implementation and suggests that the urge by firms to give back to society is strengthened under conditions of high economic incentives and the firms’ degree of internationalisation.
Numerical Brazilian split test of pre-cracked granite with randomly distributed micro-components
Authors: Liu Shiqi , Wang Huanling , Xu Weiya , Qu Xiao , Xie W.C.
Published: March 2020

Purpose

The purpose of this paper is to investigate the mechanical behavior and propagation of cracks of numerical granite samples through the Brazilian split test and to provide a reference for predicting the behavior of real granite samples.

Design/methodology/approach

The numerical models of granite containing two fissures are established using the parallel bond model (PBM) and the smooth joint model (SJM) in PFC2D. The peak stresses, number of cracks and anisotropic ratios are obtained to study the influence of the mineral composition and the angle of inclination of rock bridge on the strength, failure mode and deformation characteristics.

Findings

The numerical results obtained show that the mineral composition has a marginal influence on the peak stress. When the angle of inclination of rock bridge β increases, the peak stress drops to its minimum value at β = 90° and then gradually increases to a relatively low level. The behavior of cracks falls into three categories based on the distribution of cracks. By analyzing the stress–strain curve and the process of crack propagation for sample No. 4 with β = 60°, it is found that the process of failure can be divided into four stages and tensile cracks dominate. The anisotropic ratios of peak stress and a number of cracks obtained show that the peak stress is low anisotropic and the number of cracks is medium anisotropic.

Originality/value

This paper presents a numerical simulation method to analyze mechanical behavior and propagation of cracks under different conditions. The proposed method and the results obtained are useful for predicting the behavior of real granite samples in laboratory and engineering projects.
Strategic factors and significance of organizational innovation and organizational learning in organizational performance
Authors: Soomro Bahadur Ali , Mangi Shahnawaz , Shah Naimatullah
Published: March 2020

Purpose

The study investigates the experience and significance of strategic factors in organizational innovation (OI) and organizational learning (OL). The study also examines the impact of OI and OL on organizational performance.

Design/methodology/approach

The study takes a quantitative approach, with cross-sectional data collected to achieve its purpose. The respondents are CEOs of different organizations. The data collection tool, a survey questionnaire, is applied to a random sample. In total, data from 360 usable cases are analyzed to infer the results.

Findings

After employing structural equation modeling (SEM), the study findings reveal the positive and significant impact of strategic factors on OI and OL, with these factors comprising personal mastery, transformational leadership, a shared vision, proactivity, and the environment. Furthermore, OI and OL have a positive and significant impact on organizational performance.

Practical implications

The study's findings may reinforce knowledge of the different strategic factors/capabilities needed to attain a satisfactory level of organizational capabilities and, consequently, may increase organizational performance and encourage entrepreneurship. An investigation of these factors may impart benefits to an organization, such as becoming more innovative or providing a boost to learning. Managers of organizations may generate circumstances to make it easier to achieve the growth of these strategic factors/capabilities.

Originality/value

The study's findings may help to develop a better understanding of strategic factors, OI, OL, and organizational performance, particularly in a developing country context.
The effects of global financial crisis on the relationship between CEO compensation and earnings management
Authors: Assenso-Okofo Oheneba , Ali Muhammad Jahangir , Ahmed Kamran
Published: March 2020

Purpose

This paper aims to examine the effects of global financial crisis (GFC) on chief executive officers’ (CEO) compensation and earnings management relationship. Specifically, the authors examine whether the recent financial crisis had moderated the relationship between CEO bonus and discretionary accruals.

Design/methodology/approach

The authors use panel data for 1,800 firm-year observations (over a period of six years from 2005 to 2010) and use univariate and multivariate tests to test their hypothesis. The authors divide the period into pre-crisis, during-crisis and post-crisis periods to examine how the different financial crisis periods affect the relationship between CEO compensation and earnings management. Various alternative tests including endogeneity test suggest that the results are robust.

Findings

The authors’ multivariate results indicate that the relationship between CEO’ compensation and earnings management changes because of the GFC.

Practical implications

The findings, therefore, justify more monitoring and scrutiny to limit the existence of opportunistic managerial behaviour and for the appropriate designing of CEO compensation packages during abnormal economic circumstances.

Originality/value

So far as the authors’ knowledge goes, this is the first study which examines the relationship between CEO compensation and earnings management during GFC.
Handling inter-organisational conflict based on bargaining power
Authors: Lu Wenxue , Wei Yuxin , Wang Rui
Published: March 2020

Purpose

This paper aims to reveal the effects of an organisation’s bargaining power on its negotiating behaviours (including integrating, obliging, compromising, dominating and avoiding) in the context of inter-organisational conflict in construction projects and investigate how organisational power distance orientation moderates the relationship between the organisation’s bargaining power and its negotiating behaviours.

Design/methodology/approach

The authors conducted a questionnaire survey among practitioners in the Chinese construction industry with the final sample consisting of 219 responses. A structural equation model was used to analyse the data and test the hypotheses.

Findings

The results reveal that an organisation’s bargaining power is positively associated with dominating and integrating behaviours but negatively associated with obliging and avoiding behaviours. Additionally, bargaining power is found to be negatively associated with compromising behaviour when the organisation has a high power distance orientation. Finally, a higher degree of power distance orientation strengthens the positive effect bargaining power has on dominating behaviour.

Practical implications

The findings can help practitioners to predict the negotiating behaviours of a counterpart according to its bargaining power and the power distance in its organisational culture. This can then enable practitioners to adjust their strategies accordingly and steer the negotiations towards a win–win outcome.

Originality/value

This study applies the approach-inhibition theory of power to inter-organisational negotiations and empirically tests the relationship between an organisation’s bargaining power and its negotiating behaviours in the context of construction projects. Additionally, this study reveals that organisational power distance orientation moderates this relationship.
Intellectual capital in non-profit organisations: lessons learnt for waqf institutions
Authors: Laallam Abdelkader , Kassim Salina , Engku Ali Engku Rabiah Adawiah , Saiti Buerhan
Published: March 2020

Purpose

This study aims to highlight the importance of intellectual capital (IC) for the operation of waqf (Islamic endowment) institutions, as few studies have discussed this issue in relation to non-profit religious organisations, particularly waqf organisations. Consequently, this study hopes to contribute to the development of waqf institutions in terms of human capital proficiency, the efficiency of operations and the effectiveness and sustainability of performance.

Design/methodology/approach

The authors reviewed a significant body of relevant studies written on various aspects of IC, to highlight the significance of considering IC in the operation of non-profit organisations (NPOs) and waqf institutions.

Findings

This study highlights the importance of IC in the operation of waqf institutions. It provides a platform that facilitates understanding of the existing obstacles and challenges in waqf institutions (such as lack of accountability, lack of funding, mismanagement and lack of trained labour, among others) and offers potential solutions through the consideration of knowledge and IC.

Research limitations/implications

This study is a conceptual analysis of IC in the context of NPOs. Future studies should conduct empirical testing, which will provide more detailed discussion and enriching insights into the issue of IC and the performance of NPOs, particularly in the case of waqf institutions.

Practical implications

This study provides several important implications for waqf institutions and other NPOs, as it sheds light on the consideration of knowledge and IC in their operations.

Originality/value

To the best of the authors’ knowledge, this study is the first to discuss the issues of waqf in the light of IC and provide an integrated framework for the operation of waqf institutions.
The emergence of servant leadership and its effectiveness in bureaucratic organizations
Authors: Kim Jungin
Published: March 2020

Purpose

By following the leadership theory, social exchange theory and social learning theory, we aimed to examine the conditions under which servant leadership (SL) develops in bureaucratic organizations and explore its influences on organizational culture and member behavior.

Design/methodology/approach

Based on a survey of the South Korean Army, this study conducted the hierarchical linear modeling (HLM) analysis to investigate the research model.

Findings

We found that SL was positively associated with formalized organizational structure and negatively associated with centralized organizational structure. Additionally, SL created a relation-oriented organizational culture (ROOC) and significantly enhanced battalion members' organizational commitment (OC). Furthermore, ROOC significantly mediated the relationship between SL and OC.

Originality/value

These results suggest that SL could emerge in both formalized and decentralized bureaucratic organizations. Moreover, SL appears to create an organizational culture that promotes collaboration, and such a ROOC seems to mediate the positive influence of SL on followers' OC.
Shear-bearing capacity analysis under static force for shear key of the reinforced concrete open-web sandwich slab applied to long-span structure
Authors: Fan Yu hui , Liu Pan pan , Shen Bo , Ma Kejian , Wu Bang , Zheng Tianhong , Yang Fang
Published: March 2020

Purpose

The reinforced concrete open-web sandwich slab is composed of upper rib, lower rib, surface plate and shear key and was applied to long-span structure crossing at 18–30 m. The shear-bearing capacity of shear key, having vital effects on the slab’s bearing capacity, is analysed to present its calculation formula used for the engineering application of the slab.

Design/methodology/approach

The shear-bearing capacity of shear key is analysed by the strut-and-tie model and the benchmark model established by the finite element method. Furthermore, the design formula of its shear capacity is given by the parametric analysis of FEM to adjust the result of the strut-and-tie model, using multivariate linear regression analysis of these parameters.

Findings

The calculation result of the benchmark model is compared with those of the strut-and-tie model and the standard formula, which indicates that the result of the strut-and-tie model is closer to that of the benchmark model than that of the standard formula. Moreover, the parametric analysis of the finite element model indicates that the volume–stirrup ratio of the shear key and the compression strength of the concrete have lesser effect on the shear capacity compared with the longitudinal reinforcement ratio and the shear-to-span ratio of the shear key and the relative section height of the rib.

Originality/value

The shear capacity of the shear key is provided in the paper by combining the finite element method and the strut-and-tie model, which is different from the calculation of the shear key in local codes and Chinese code, based on the theory of short corbel and the experiment of member. Furthermore, the formula of the shear capacity could be employed in the design and construction of the RC open-web sandwich slab, mainly used in the public and industrial multi-story building with long span to save the dwindling land resource currently.
Consumption attachments of Brazilian fans of the National Football League
Authors: Moura Bruno Melo , de Souza-Leão André Luiz Maranhão
Published: March 2020

Purpose

The National Football League (NFL), the most lucrative sports league in the world, has its second largest foreign audience in Brazil. Its Brazilian broadcasts stimulate the audience to extrapolate television reception and interact through a social media platform, seeking to integrate a collective consumption. Thus, attachments are established between consumers and league. Based on this, this study aims to analyze how the interaction in social media of the Brazilian NFL audience, during the transmissions of its games, results in consumption attachments.

Design/methodology/approach

The method undertaken was Netnography, commonly used to investigate cultural practices occurring in online environments. The research corpus consisted of messages posted on Twitterhashtags created by the ESPN Brazil channels to reverberate its broadcasts of the league between 2016-2017 and 2017-2018 seasons.

Findings

The findings of this study indicate that Brazilian audience interaction in social media establishes consumer attachment with the NFL by means of the brand elements and aspects of social life, mediated by the league.

Research limitations/implications

The research observed only the part of the Brazilian audience of the NFL that engages in the broadcasts of the games through social media.

Practical implications

The research of this study demonstrates how brands can use social media to enable social interactions that create or improve consumer attachments with them.

Originality/value

The study presents how a media brand imbricated in the American culture has been the target of attachment by Brazilian fans through social media interactions.