bluuebunny/crossref_metadata_2025 huggingface dataset:
Integration of mouse ovary morphogenesis with developmental dynamics of the oviduct, ovarian ligaments, and rete ovarii
Authors: McKey Jennifer , Anbarci Dilara N. , Bunce Corey , Ontiveros Alejandra E. , Behringer Richard R. , Capel Blanche
Published: May 2021

Morphogenetic events during development of the fetal ovary are crucial to the establishment of female fertility. However, the effects of structural rearrangements of the ovary and surrounding reproductive tissues on ovary morphogenesis remain largely uncharacterized. Using tissue clearing and lightsheet microscopy, we found that ovary folding correlated with regionalization into cortex and medulla. Relocation of the oviduct to the ventral aspect of the ovary led to ovary encapsulation, and mutual attachment of the ovary and oviduct to the cranial suspensory ligament likely triggered ovary folding. Development of the rete ovarii correlated with events of ovary morphogenesis. Using genetic mouse models in which the oviduct and rete ovarii are perturbed, we found the oviduct is required for ovary encapsulation. This study reveals novel relationships among the ovary and surrounding tissues and paves the way for functional investigation of the relationship between architecture and differentiation of the mammalian ovary.
Machine learning-guided acyl-ACP reductase engineering for improved in vivo fatty alcohol production
Authors: Greenhalgh Jonathan C. , Fahlberg Sarah A. , Pfleger Brian F. , Romero Philip A.
Published: May 2021

Fatty acyl reductases (FARs) catalyze the reduction of thioesters to alcohols and are key enzymes for the microbial production of fatty alcohols. Many existing metabolic engineering strategies utilize these reductases to produce fatty alcohols from intracellular acyl-CoA pools; however, acting on acyl-ACPs from fatty acid biosynthesis has a lower energetic cost and could enable more efficient production of fatty alcohols. Here we engineer FARs to preferentially act on acyl-ACP substrates and produce fatty alcohols directly from the fatty acid biosynthesis pathway. We implemented a machine learning-driven approach to iteratively search the protein fitness landscape for enzymes that produce high titers of fatty alcohols in vivo. After ten design-test-learn rounds, our approach converged on engineered enzymes that produce over twofold more fatty alcohols than the starting natural sequences. We further characterized the top identified sequence and found its improved alcohol production was a result of an enhanced catalytic rate on acyl-ACP substrates, rather than enzyme expression or KM effects. Finally, we analyzed the sequence-function data generated during the enzyme engineering to identify sequence and structure features that influence fatty alcohol production. We found an enzyme’s net charge near the substrate-binding site was strongly correlated with in vivo activity on acyl-ACP substrates. These findings suggest future rational design strategies to engineer highly active enzymes for fatty alcohol production.
AxonDeep: Automated Optic Nerve Axon Segmentation in Mice with Deep Learning
Authors: Deng Wenxiang , Hedberg-Buenz Adam , Soukup Dana A. , Taghizadeh Sima , Wang Kai , Anderson Michael G. , Garvin Mona K.
Published: May 2021

Purpose

Optic nerve damage is the principal feature of glaucoma and contributes to vision loss in many diseases. In animal models, nerve health has traditionally been assessed by human experts that grade damage qualitatively or manually quantify axons from sampling limited areas from histologic cross sections of nerve. Both approaches are prone to variability and are time consuming. First-generation automated approaches have begun to emerge, but all have significant shortcomings. Here, we seek improvements through use of deep-learning approaches for segmenting and quantifying axons from cross sections of mouse optic nerve.

Methods

Two deep-learning approaches were developed and evaluated: (1) a traditional supervised approach using a fully convolutional network trained with only labeled data and (2) a semi-supervised approach trained with both labeled and unlabeled data using a generative-adversarial-network framework.

Results

From comparisons with an independent test set of images with manually marked axon centers and boundaries, both deep-learning approaches outperformed an existing baseline automated approach and similarly to two independent experts. Performance of the semi-supervised approach was superior and implemented into AxonDeep.

Conclusion

AxonDeep performs automated quantification and segmentation of axons from healthy appearing nerves, and those with mild to moderate degrees of damage, similar to that of experts without the variability and constraints associated with manual performance.

Translational Relevance

Use of deep learning for axon quantification provides rapid, objective, and higher throughput analysis of optic nerve that would otherwise not be possible.
Hemangiosarcoma Cells Promote Conserved Host-Derived Hematopoietic Expansion
Authors: Kim Jong Hyuk , Schulte Ashley J. , Sarver Aaron L. , Angelos Mathew G. , Frantz Aric M. , Forster Colleen L. , O’Brien Timothy D. , Cornax Ingrid , O’Sullivan M. Gerard , Cheng Nuojin , Lewellen Mitzi , Oseth LeAnn , Kumar Sunil , Bullman Susan , Pedamallu Chandra Sekhar , Goyal Sagar M. , Meyerson Matthew , Lund Troy C. , Alfoldi Jessica , Breen Matthew , Lindblad-Toh Kerstin , Dickerson Erin B. , Kaufman Dan S. , Modiano Jaime F.
Published: May 2021

Hemangiosarcoma and angiosarcoma are soft-tissue sarcomas of blood vessel-forming cells in dogs and humans, respectively. These vasoformative sarcomas are aggressive and highly metastatic, with disorganized, irregular blood-filled vascular spaces. Our objective was to define molecular programs which support the niche that enables progression of canine hemangiosarcoma and human angiosarcoma. Dog-in-mouse hemangiosarcoma xenografts recapitulated the vasoformative and highly angiogenic morphology and molecular characteristics of primary tumors. Blood vessels in the tumors were complex and disorganized, and they were lined by both donor and host cells, a trait that was not observed in xenografts from canine osteosarcoma and lymphoma. In some cases, the xenografted hemangiosarcoma cells created exuberant myeloid hyperplasia and gave rise to lymphoproliferative tumors of mouse origin. We did not uncover a definitive transmissible etiology, but our functional analyses indicate that hemangiosarcoma cells generate a microenvironment that supports expansion and differentiation of hematopoietic progenitor populations. We conclude that canine hemangiosarcomas, and possibly human angiosarcomas, originate from stromal cells that are part of the bone marrow niche and that these cells may also support the growth of hematopoietic tumors.

Significance

We demonstrate that molecular programs supporting expansion of immune and inflammatory cells in hemangiosarcoma resemble those of bone marrow niche cells, providing insights into the potential roles of these cells - whether physiological or pathological - in creating a permissive environment for the progression of hematopoietic malignancies.
Use of an enclosed elk population to assess two non-invasive methods for estimating population size
Authors: Brazeal Jennifer L. , Sacks Benjamin N.
Published: May 2021

Non-invasive genetic sampling and spatially explicit capture-recapture (SCR) models are used increasingly to estimate abundance of wildlife populations, but have not been adequately tested on gregarious animals such as elk (Cervus canadensis), for which correlated space use and movements violate model assumptions of independence. To evaluate the robustness and accuracy of SCR, and to assess the utility of an alternative non-invasive method for estimating density of gregarious ungulates, we utilized a tule elk (Cervus canadensis nannodes) population of known size within a fenced enclosure on the San Luis National Wildlife Refuge in central California. We evaluated fecal genetic SCR to camera trap-based random encounter model (REM) approaches to density estimation based on comparison to the true abundance. We also subsampled the dataset to explore the effects of varying search effort and elk density on the precision and accuracy of results. We found that SCR outperformed REM methods in the full datasets, and reliably provided accurate (relative bias <10%) and reasonably precise (relative standard error ≤20%) estimates of density at moderately low to high densities (6–17 elk/km2), when the subsampling scenarios yielded a minimum average of 20 recaptures. We also found that the number of samples used to construct detection histories was a reliable predictor of precision, and could be used to establish minimum sampling requirements in future population surveys of elk. Although field-testing in free-ranging populations is needed, our results suggest that non-invasive genetic SCR is a promising tool for future population studies and monitoring of elk and potentially other gregarious ungulates. In contrast, the REM estimate of density was highly inaccurate, imprecise, and highly sensitive to camera parameters.
Intranasal vasopressin like oxytocin increases social attention by influencing top-down control, but additionally enhances bottom-up control
Authors: Zhuang Qian , Zheng Xiaoxiao , Becker Benjamin , Lei Wei , Xu Xiaolei , Kendrick Keith M.
Published: May 2021

The respective roles of the neuropeptides arginine vasopressin (AVP) and oxytocin (OXT) in modulating social cognition and for therapeutic intervention in autism spectrum disorder have not been fully established. In particular, while numerous studies have demonstrated effects of oxytocin in promoting social attention the role of AVP has not been examined. The present study employed a randomized, double-blind, placebo (PLC)-controlled between-subject design to explore the social- and emotion-specific effects of AVP on both bottom-up and topdown attention processing with a validated emotional anti-saccade eye-tracking paradigm in 80 male subjects (PLC = 40, AVP = 40). Our findings showed that AVP increased the error rate for social (angry, fearful, happy, neutral and sad faces) but not non-social (oval shapes) stimuli during the anti-saccade condition and reduced error rates in the pro-saccade condition. Comparison of these findings with a previous study (sample size: PLC = 33, OXT = 33) using intranasal oxytocin revealed similar effects of the two peptides on anti-saccade errors but a significantly greater effect of AVP on pro-saccades. Both peptides also produced a post-task anxiolytic effect by reducing state anxiety. Together these findings suggested that both AVP and OXT decrease goal-directed top-down attention control to social salient stimuli but that AVP more potently increased bottom-up social attentional processing.
Formylglycine-generating enzyme-like proteins constitute a novel family of widespread type VI secretion system immunity proteins
Authors: Lopez Juvenal , Le Nguyen-Hung , Moon Ki Hwan , Salomon Dor , Bosis Eran , Feldman Mario F.
Published: May 2021

Competition is a critical aspect of bacterial life, as it enables niche establishment and facilitates the acquisition of essential nutrients. Warfare between Gram-negative bacteria is largely mediated by the type VI secretion system (T6SS), a dynamic nanoweapon that delivers toxic effector proteins from an attacking cell to adjacent bacteria in a contact-dependent manner. Effector-encoding bacteria prevent self-intoxication and kin cell killing by the expression of immunity proteins, which prevent effector toxicity by specifically binding their cognate effector and occluding its active site. In this study, we investigate Tsi3, a previously uncharacterized T6SS immunity protein present in multiple strains of the human pathogen Acinetobacter baumannii. We show that Tsi3 is the cognate immunity protein of the antibacterial effector of unknown function Tse3. Our bioinformatic analyses indicate that Tsi3 homologs are widespread among Gram-negative bacteria, often encoded within T6SS effector-immunity modules. Surprisingly, we found that Tsi3 homologs possess a characteristic formylglycine-generating enzyme (FGE) domain, which is present in various enzymatic proteins. Our data shows that Tsi3-mediated immunity is dependent on Tse3-Tsi3 protein-protein interactions and that Tsi3 homologs from various bacteria do not protect against Tse3-dependent bacterial killing. Thus, we conclude that Tsi3 homologs are unlikely to be functional enzymes. Collectively, our work identifies FGE domain-containing proteins as important mediators of immunity against T6SS attacks and indicates that the FGE domain can be co-opted as a scaffold in multiple proteins to carry out diverse functions.

Importance

Despite the wealth of knowledge on the diversity of biochemical activities carried out by T6SS effectors, comparably little is known about the various strategies bacteria employ to prevent susceptibility to T6SS-dependent bacterial killing. Our work establishes a novel family of T6SS immunity proteins with a characteristic FGE domain. This domain is present in enzymatic proteins with various catalytic activities. Our characterization of Tsi3 expands the known functions carried out by FGE-like proteins to include defense during T6SS-mediated bacterial warfare. Moreover, it highlights the evolution of FGE domain-containing proteins to carry out diverse biological functions.
DegP initiates regulated processing of filamentous hemagglutinin in Bordetella bronchiseptica
Authors: Johnson Richard M. , Nash Zachary M. , Dedloff Margaret R. , Shook John , Cotter Peggy A.
Published: May 2021

Filamentous hemagglutinin (FhaB) is a critical virulence factor for both Bordetella pertussis, the causal agent of whooping cough, and the closely related species Bordetella bronchiseptica. FhaB is an adhesin, suppresses inflammatory cytokine production, and protects against phagocytic cell clearance during infection. Regulated degradation of the FhaB C-terminal prodomain is required to establish a persistent infection in mice. Two proteases, CtpA in the periplasm and SphB1 on the bacterial surface, are known to mediate FhaB processing, and we recently determined that CtpA functions before, and controls the FhaB cleavage site of, SphB1. However, the data indicate that another periplasmic protease must initiate degradation of the prodomain by removing a portion of the FhaB C terminus that inhibits CtpA-mediated degradation. Using a candidate approach, we identified DegP as the initiating protease. Deletion of degP or substitution of its predicted catalytic residue resulted in reduced creation of FHA′, the main product of FhaB processing, and an accumulation of full-length FhaB in whole cell lysates. Also, FHA′ was no longer released into culture supernatants in degP mutants. Alterations of the FhaB C terminus that relieve inhibition of CtpA abrogate the need for DegP, consistent with DegP functioning prior to CtpA in the processing pathway. DegP is not required for secretion of FhaB through FhaC or for adherence of the bacteria to host cells, indicating that DegP acts primarily as a protease and not a chaperone for FhaB in B. bronchiseptica. Our results highlight a role for HtrA family proteases in activation of virulence factors in pathogenic bacteria.

Importance

Two-partner secretion (TPS) systems are broadly distributed among Gram-negative bacteria and play important roles in bacterial pathogenesis. FhaB-FhaC is the prototypical member of the TPS family and here we identified the protease that initiates a processing cascade that controls FhaB function. Our results are significant because they provide insight into the molecular mechanism underlying the ability of Bordetella species to prevent clearance by phagocytic cells, which is critical for bacterial persistence in the lower respiratory tract. Our findings also highlight an underappreciated role for HtrA family proteases in processing specific bacterial virulence factors.
An enhanced inverted encoding model for neural reconstructions
Authors: Scotti Paul S. , Chen Jiageng , Golomb Julie D.
Published: May 2021

Here we present a more interpretable and versatile approach for reconstructing the contents of perception, attention, and memory from neuroimaging data. Our enhanced inverted encoding model (eIEM) incorporates theoretical and methodological improvements including proper accounting of population-level tuning functions and a trial-by-trial prediction error-based metric where reconstruction quality is measured in meaningful units. Added functionality and improved flexibility is further gained via eIEM’s novel goodness-of-fit feature: for trial-by-trial reconstructions, goodness-of-fits are obtained independently (non-circularly) to prediction error and can be applied to any IEM procedure or decoding metric, resulting in improved reconstruction quality and brain-behavior correlations, and more creative applications. We validate eIEM from methodological principles, simulated neuroimaging datasets, and three pre-existing fMRI datasets spanning perception, attention, and working memory. Notably, eIEM is easy to apply and broadly accessible – our Python package (https://pypi.org/project/inverted-encoding)implements eIEM in one line of code – and is easily modifiable to compare performance metrics and/or scale up to more complex models.
Influence of environmental temperature on mouth-form plasticity in Pristionchus pacificus acts through daf-11-dependent cGMP signaling
Authors: Lenuzzi Maša , Witte Hanh , Riebesell Metta , Rödelspereger Cristian , Hong Ray L. , Sommer Ralf J.
Published: May 2021

Mouth-form plasticity in the nematode Pristionchus pacificus has become a powerful system to identify the genetic and molecular mechanisms associated with phenotypic (developmental) plasticity. In particular, the identification of developmental switch genes that can sense environmental stimuli and reprogram developmental processes has confirmed long-standing evolutionary theory. Together with the associated gene regulatory networks, these developmental switch genes have been important to show that plasticity is consistent with the Modern Synthesis of evolution. However, how these genes are involved in the direct sensing of the environment, or if the switch genes act downstream of another, primary environmental sensing mechanism, remains currently unknown. Here, we study the influence of environmental temperature on mouth-form plasticity. Using forward and reverse genetic technology including CRISPR/Cas9, we show that mutations in the guanylyl cyclase Ppa-daf-11, the Ppa-daf-25/AnkMy2 and the cyclic nucleotide-gated channel Ppa-tax-2 eliminate the response to elevated temperatures. Together, our study indicates that DAF-11, DAF-25 and TAX-2 have been co-opted for environmental sensing during mouth-form plasticity regulation in P. pacificus. This work suggests that developmental switch genes integrate environmental signals including perception by cGMP signaling.
Maturation of Human Long-lived Plasma Cells Results in Resistance to Apoptosis by Transcriptional and Epigenetic Regulation
Authors: Joyner Chester J. , Ley Ariel M. , Nguyen Doan C. , Ali Mohammad , Corrado Alessia , Tipton Christopher , Scharer Christopher D. , Mi Tian , Woodruff Matthew C , Hom Jennifer , Boss Jeremy M. , Duan Meixue , Gibson Greg , Roberts Danielle , Andrews Joel , Lonial Sagar , Sanz Inaki , Lee F. Eun-Hyung
Published: May 2021

Antibody secreting cells (ASC) circulate after vaccination and migrate to the bone marrow (BM) where a subset known as long-lived plasma cells (LLPC) persist and secrete antibodies for a lifetime. The mechanisms of how circulating ASC become LLPC are not well elucidated. Here, we show that human blood ASCs have distinct morphology, transcriptomes, and epigenetics compared to BM LLPC. LLPC acquire transcriptional and epigenetic changes in the apoptosis pathway to support their survival. Upregulation of pro-survival gene expression accompanies downregulation of pro-apoptotic gene expression in LLPC. While pro-apoptotic gene loci are less accessible, pro-survival gene loci are not always accompanied by accessibility changes. Importantly, we show similar LLPC morphological and transcriptional maturation of blood ASC in response to the novel in vitro BM mimetic. In all, our study demonstrates that blood ASC in the BM microniche must undergo morphological and molecular changes to mature into apoptotic-resistant LLPC.
Kap-β2/Transportin mediates β-catenin nuclear transport in Wnt signaling
Authors: Hwang Woong Y. , Kostiuk Valentyna , González Delfina P. , Lusk C. Patrick , Khokha Mustafa K.
Published: May 2021

Wnt signaling is essential for many aspects of embryonic development including the formation of the primary embryonic axis. In addition, excessive Wnt signaling drives multiple diseases including cancer highlighting its importance for disease pathogenesis. β-catenin is a key effector in this pathway that translocates into the nucleus and activates Wnt responsive genes. However, due to our lack of understanding of β-catenin nuclear transport, therapeutic modulation of Wnt signaling has been challenging. Here, we took an unconventional approach to address this long-standing question by exploiting a heterologous model system, the budding yeast Saccharomyces cerevisiae, which contains a conserved nuclear transport machinery. In contrast to prior work, we demonstrate that β-catenin accumulates in the nucleus in a Ran dependent manner, suggesting the use of a nuclear transport receptor (NTR). Indeed, a systematic and conditional inhibition of NTRs revealed that only Kap104, the orthologue of Kap-β2/Transportin-1 (TNPO1), was required for β-catenin nuclear import. We further demonstrate direct binding between TNPO1 and β-catenin that is mediated by a conserved amino acid sequence that resembles a PY NLS. Finally, using Xenopus secondary axis and TCF/LEF reporter assays, we demonstrate that our results in yeast can be directly translated to vertebrates. By elucidating the NLS in β-catenin and its cognate NTR, our study provides new therapeutic targets for a host of human diseases caused by excessive Wnt signaling. Indeed, we demonstrate that a small chimeric peptide designed to target TNPO1 can reduce Wnt signaling as a first step towards therapeutics.
A single heterozygous mutation in COG4 disrupts zebrafish early development via Wnt signaling
Authors: Xia Zhi-Jie , Zeng Xin-Xin I. , Tambe Mitali , Ng Bobby G. , Dong P. Duc S. , Freeze Hudson H.
Published: May 2021

Saul-Wilson syndrome (SWS) is a rare, skeletal dysplasia with progeroid appearance and primordial dwarfism. It is caused by a heterozygous, dominant variant (p.G516R) in COG4, a subunit of the Conserved Oligomeric Golgi (COG) complex involved in intracellular vesicular transport. Our previous work has shown the intracellular disturbances caused by this mutation; however, the pathological mechanism of SWS needs further investigation. We sought to understand the molecular mechanism of specific aspects of the SWS phenotype by analyzing SWS-derived fibroblasts and zebrafish embryos expressing this dominant variant. SWS fibroblasts accumulate glypicans, a group of heparan sulfate proteoglycans (HSPGs) critical for growth and bone development through multiple signaling pathways. Consistently, we find that glypicans are increased in embryos expressing the COG4p.G516R variant. These animals show phenotypes consistent with convergent extension (CE) defects during gastrulation, shortened body length, and malformed jaw cartilage chondrocyte intercalation at larval stages. Since non-canonical Wnt signaling was shown in zebrafish to be related to the regulation of these processes by Glypican 4, we assessed wnt levels and found a selective increase of wnt4 transcripts in the presence of COG4p.G516R. Moreover, overexpression of wnt4 mRNA phenocopies these developmental defects. LGK974, an inhibitor of Wnt signaling corrects the shortened body length at low concentrations but amplifies it at slightly higher concentrations. WNT4 and the non-canonical Wnt signaling component phospho-JNK are also elevated in cultured SWS-derived fibroblasts. Similar results from SWS cell lines and zebrafish point to altered non-canonical Wnt signaling as one possible mechanism underlying SWS pathology.
Elucidating the structural features of ABCA1 in its heterogeneous membrane environment
Authors: S Sunidhi , Sacher Sukriti , Garg Parth , Ray Arjun
Published: May 2021

ATP Binding Cassette Transporter A1 (ABCA1) plays an integral part in Reverse Cholesterol Transport (RCT) and is critical for maintaining lipid homeostasis. One theory of lipid efflux by the transporter (alternating access) proposes that ABCA1 harbours two different conformations that provide alternating access for lipid binding and release. This is followed by a sequestration via a direct interaction between ABCA1 and its partner, ApoA1. The alternative theory (lateral access) proposes that ABCA1 obtains lipids laterally from the membrane to form a temporary extracellular “reservoir”. This reservoir contains an isolated lipid monolayer due to the net accumulation of lipids in the exofacial leaflet. Recently, a full-length Cryo-EM structure of this 2,261-residue transmembrane protein showed its discreetly folded domains and have detected the presence of a tunnel enclosed within ECDs but not in theTMDs giving it an outward-facing conformation. This structure was hypothesized to substantiate the lateral access theory, whereby ApoA1 obtained lipids from the proximal end laterally. Utilizing long time-scale multiple replica atomistic molecular dynamics simulations (MDS), we simulated the structure in a large heterogeneous lipid environment and found that along with several large conformational changes, the protein harbours a continuous tunnel that traverses the entire length of the protein. In this study, we have characterized ABCA1 and the lipid dynamics along with the protein-lipid interactions in the heterogeneous environment, providing novel insights into understanding ABCA1 conformation at an atomistic level.
The experiences of fathers who have a child with autism spectrum disorder: from birth to adulthood
Authors: Dewey Katherine , Hodgkinson Melanie
Published: May 2021

Purpose

The purpose of this study is to explore fathers’ experiences of raising a child with autism spectrum disorder (ASD), taking into consideration how this experience fluctuates as their child develops from infancy to adulthood.

Design/methodology/approach

Semi-structured interviews were used to investigate the experiences of fathers who have a young adult with ASD. Seven fathers participated in this study. Data was analysed using thematic analysis.

Findings

Four themes were identified, these were: ubiquitous impact, divergent support, impeding factors and facilitating factors.

Practical implications

Findings from this study highlighted the pervasive impacts of having a child with ASD. This study highlighted the need to educate health-care professionals, the general public and prospective fathers. Creating “dads groups” could help to direct fathers towards other people who understand their situation. Finally, trialling methods to accelerate fathers’ acceptance, such as acceptance and commitment therapy (ACT), could help to reduce psychological stress.

Originality/value

To date, most research largely focusses on mothers’ experiences, as mothers are typically seen as the primary caregiver. Previous research also tends to focus on the earlier years of life. This research addresses the often-overlooked topic of fathers’ experiences, investigating their experience of having a child with ASD from birth through to adulthood.
Re-designing the business organization using disruptive innovations based on blockchain-IoT integrated architecture for improving agility in future Industry 4.0
Authors: Rane Santosh B. , Narvel Yahya Abdul Majid
Published: May 2021

Purpose

Blockchain and Internet of Things (IoT) technologies have recently gained much attention for Industry 4.0. With the emergence of disruptive technologies, it has become essential to redesign the business for innovations based on blockchain–IoT integrated architecture that helps organizations to improve agility in their operations. The paper aims to discuss this issue.

Design/methodology/approach

An industrial pump was Sensorized and IoTized to monitor its operations on real time and take predictive measures for managing these assets with more agility. The developed architecture was further extended for proposing the use of blockchain and how it can benefit the organization.

Findings

The known features of blockchain such as increasing the capacity of decentralization, trust-less transactions, security and allowing autonomous coordination of the devices along with the boons of IoT will help achieve the motto of improving agility in Industry 4.0.

Originality/value

This paper gives a new dimension to utilization of blockchain technology. blockchain along with IoT that gives a way forward for industries like manufacturing, oil and gas, engineering and construction, utilities, etc. to re-designing the business organization in a more agile way.
How does investor sentiment impact stock volatility? New evidence from Shanghai A-shares market
Authors: Xie Dejun , Cui Yu , Liu Yujian
Published: May 2021

Purpose

The focus of the current research is to examine whether mixed-frequency investor sentiment affects stock volatility in the China A-shares stock market.

Design/methodology/approach

Mixed-frequency sampling models are employed to find the relationship between stock market volatility and mixed-frequency investor sentiment. Principal analysis and MIDAS-GARCH model are used to calibrate the impact of investor sentiment on the large-horizon components of volatility of Shanghai composite stocks.

Findings

The results show that the volatility in Chinese stock market is positively influenced by B–W investor sentiment index, when the sentiment index encompasses weighted mixed frequencies with different horizons. In particular, the impact of mixed-frequency investor sentiment is most significantly on the large-horizon components of volatility. Moreover, it is demonstrated that mixed-frequency sampling model has better explanatory powers than exogenous regression models when accounting for the relationship between investor sentiment and stock volatility.

Practical implications

Given the various unique features of Chinese stock market and its importance as the major representative of world emerging markets, the findings of the current paper are of particularly scholarly and practical significance by shedding lights to the applicableness GARCH-MIDAS in the focused frontiers.

Originality/value

A more accurate and insightful understanding of volatility has always been one of the core scholarly pursuits since the influential structural time series modeling of Engle (1982) and the seminal work of Engle and Rangel (2008) attempting to accommodate macroeconomic factors into volatility models. However, the studies in this regard are so far relatively scarce with mixed conclusions. The current study fills such gaps with improved MIDAS-GARCH approach and new evidence from Shanghai A-share market.
Mixed EHL numerical analysis and leakage experiment of skeleton reciprocating oil seal
Authors: Yang Hua-Lin , Li Xiulong , Sun Weiwei , Deng Fang , Du Jie
Published: May 2021

Purpose

This paper aims to present the mixed elastohydrodynamic lubrication (EHL) model and obtain the leakage characteristics for the skeleton reciprocating oil seal.

Design/methodology/approach

The model consists of a finite element analysis of the contact pressure, a fluid mechanics analysis of the fluid film, a contact analysis of the asperity contact pressure, a deformation analysis of the seal lip and an iterative numerical simulation process.

Findings

Simulation results show that the leakage is in direct proportion to the seal roughness and speed, and in inverse proportion to the fluid viscosity. Comparisons with the experimental results verify the validity of the mixed EHL model.

Originality/value

This study provides a helpful method to calculate the leakage of the skeleton reciprocating oil seal, which shortens its development cycles.
Design and fabrication of an online inductive sensor for identification of ferrous wear particles in engine oil
Authors: Talebi Abolfazl , Hosseini Seyed Vahid , Parvaz Hadi , Heidari Mehdi
Published: May 2021

Purpose

The presence of ferrous wear debris in lubricating oil may cause progressive damage in the internal combustion engines. Online monitoring of the size and concentration of these particles in the oil is a way to optimize the engine performance and its life cycle.

Design/methodology/approach

In this study, an online sensor was designed and fabricated to identify ferrous wear particles in the engine oil based on the induction method. The diameter of the sensor outlet duct was designed as small as possible to generate a high-intensity magnetic induction and achieve a proper sensitivity in the sensor. The experiments were designed and performed in offline mode. Furthermore, to evaluate the actual performance of the sensor in presence of iron particles in the oil, online tests were performed at different sizes and concentrations.

Findings

It was concluded from offline tests that the highest sensitivity of the sensor occurs at the frequency and voltage of 2.5 kHz and 120 V, respectively. According to the results of the online tests, the larger the particle size, the higher the peaks at the sensor output. Also, a high density of the peaks was observed in the sensor output graphs as the concentration of particles was increased.

Originality/value

The proposed sensor was able to identify ferrous wear particles larger than 125 µm separately, which is the failure limit in the internal combustion engines.
Normal fractal contact stiffness model among three disks of rod-fastening rotor system with considering friction and the asperities interaction
Authors: Wang Nanshan , Liu Heng , Liu Yi
Published: May 2021

Purpose

The purpose of this study is to develop a normal contact stiffness (NCS) model among three disks of the assembled rotor system, which systematically considers the friction coefficient, the asperities interaction and the elastoplastic contact regime.

Design/methodology/approach

Based on the revised fractal theory, considering the friction effect, the elastoplastic contact regime and the asperities interaction in a simple way, the total NCS among three disks of the rod-fastening rotor bearing system is established. Effects of fractal dimension and roughness, friction coefficient, asperities interaction and material properties on the normal stiffness are investigated by simulations and the relevant comparisons are given for examining the reasonability of the proposed model.

Findings

NCS will decrease when asperities interaction and friction are included. As the load increases, the influences of asperities interaction and friction on stiffness become serious. NCS will be enhanced when the elastoplastic regime is considered.

Originality/value

A comprehensive NCS model is developed. It provides a theoretical basis for the modeling of the NCS for multi-interfaces.
Does disease outbreak news impact equity, commodity and foreign exchange market? Investors' fear of the pandemic COVID-19
Authors: Shaikh Imlak , Huynh Toan Luu Duc
Published: May 2021

Purpose

Market volatility is subject to good or bad news and even responses to fake news and policy changes. In this piece of work, the authors consider the effects of the recent COVID-19 pandemic event on the global equity market, commodities and FX market, measured in terms of the investors' fear index.

Design/methodology/approach

In this empirical work, the authors employ time series-based regression models followed by augmented dummy regressions and growth of the COVID-19.

Findings

COVID-19-induced investors' fear appears to be higher in the equity segment for the first time since the market crash of 1987 and the global financial crisis of 2008–2009. Furthermore, this disease outbreak shock has been more pronounced in terms of crude oil prices. Besides, a market participant in the commodity and FX market has paid a disproportionate premium to protect such pandemic development. Findings show that Options act as the best hedge against an uncertainty like COVID-19 and that option-based implied volatility is the best measure of investors' fear and market volatility.

Practical implications

This study has practical implications for the financial markets, e.g. (1) Contagious disease outbreak news matters for the equity, commodity, and foreign exchange markets – empirical outcome validates the theory of market efficiency valid for the Options. (2) Option's implied volatility is the best indicator of investor fear measured for the unprecedented economic news. Further implication holds for the policymakers and society, e.g. (1) The unavailability of short-selling could be one plausible reason for increased uncertainty and volatility; hence, policymakers should look upon this issue at the exchange level. (2) Any market needs multiple lines of risk management, effective price discovery and attractive liquidity.

Originality/value

The study is novel in terms of presenting market behavior amid COVID-19 across global equity markets and commodities and FX markets.
Abusive supervision and the knowledge worker productivity: the mediating role of knowledge management processes
Authors: Ahmed Quba , Sumbal Muhammad Saleem , Akhtar Muhammad Naseer , Tariq Hussain
Published: May 2021

Purpose

Drawing upon the theoretical underpinning of knowledge worker productivity, this study aims to examine the relationship between abusive supervision and knowledge management (KM) process (creation, application and sharing of knowledge) and its impact on the knowledge worker productivity in knowledge-intensive organizations.

Design/methodology/approach

Hypothesis were tested through PROCESS Macro in IBM SPSS v.26 on a sample of 204 employees working in banking sector of Pakistan. Confirmatory factor analysis was conducted to test the model fitness through AMOS v. 26.

Findings

The results showed that the relationship between abusive supervision and KM process (creation, application and sharing of knowledge) is negative and highly significant, i.e. greater the abusive supervision in the banking sector, the lower is the engagement in KM processes. Furthermore, there is a positive and highly significant relationship between the KM process and knowledge worker productivity. Finally, the study indicates the negative impact of abusive supervision on the knowledge worker productivity through the mediating mechanism of knowledge management processes.

Research limitations/implications

A key limitation is that the study is cross-sectional, and the findings may only be generalizable to developing countries context.

Originality/value

Previous studies have focused on supervisor–employee relationship but not in the context of knowledge worker productivity. This article fulfills this gap through understanding the impact of abusive supervision on the knowledge worker productivity in relation to KM processes (knowledge creation, sharing and application) by drawing upon the theoretical underpinning of knowledge worker productivity.
Putting knowledge to work: the combined role of marketing and sales employees’ knowledge and motivation to produce superior customer experiences
Authors: Peñalba-Aguirrezabalaga Carmela , Sáenz Josune , Ritala Paavo , Vanhala Mika
Published: May 2021

Purpose

This paper aims to adopt a contextual approach to the knowledge-performance linkage by deepening into the role of marketing and sales employees’ knowledge resources in the generation and delivery of superior customer experiences (CEs) and into the motivational antecedents of knowledge acquisition and development.

Design/methodology/approach

To gather information about the variables studied in this research, a survey was conducted among Spanish firms with at least 100 employees, resulting in a representative sample of 346 companies. Structural equation modeling based on partial least squares was then applied to test the hypothesized relationships.

Findings

The results show that employees’ motivation (and especially intrinsic motivation) affects CE both directly and indirectly through its influence on marketing-specific human capital. More precisely, customer knowledge and different types of marketing-related skills (creativity, targeting, problem-solving, social media management and communication skills) are the only constituents of marketing-specific human capital that significantly affect relative CE performance (i.e. performance vis-à-vis competitors), while product/service and market knowledge do not play a relevant role.

Originality/value

The results contribute both to the knowledge management and intellectual capital literatures by highlighting the motivational levers of human capital in the context of the marketing and sales function and the specific types of employee knowledge resources that induce superior CEs. Consequently, marketing and sales managers are provided with useful guidance to shape their human resource management policies and to establish their knowledge priorities.
Exploring social networking sites and problem-based learning in healthcare education in Taiwan: a difference analysis
Authors: Wang Wei-Tsong , Lin Ying-Lien
Published: May 2021

Purpose

This study aimed to examine whether the use of wiki-systems in healthcare internship courses that adopt a problem-based learning approach may have significant influences on the relationships among students' relationship commitment, knowledge-sharing behavior and perceived problem-based learning performance in the context of higher education.

Design/methodology/approach

This study adopted a quasi-experimental approach. Cross-sectional survey data collected from 187 undergraduate students in Taiwan were used for the data analysis procedures. The students in the experimental group used wiki-systems and a set of information and communication technologies as learning tools, while the students in the control group used the same set of information and communication technologies only. The statistical techniques of independent t-tests and component-based structural equation modeling were adopted to examine the research hypotheses.

Findings

The results reveal significant differences between the experimental and control groups concerning relationship commitment, knowledge-sharing behavior, independent study and active participation. However, there was no significant difference between the two groups regarding group interaction and reasoning skills. Additionally, all the hypotheses regarding the relationships among constructs were supported.

Originality/value

Wiki-systems have unique features that can enhance the effectiveness of problem-based learning activities. This study is among the first to investigate how wiki-systems may affect the effectiveness of problem-based learning processes by investigating the relationships among healthcare students' relationship commitment, knowledge-sharing behavior and perceived problem-based learning performance. The results of this study can advance the current understanding of the effectiveness of wiki-based problem-based learning in the context of healthcare education.
The curvilinear effect of top management team task-related demographic faultlines on over-investment
Authors: Xie Qing , Li Wuwei , Zhang Yuanyuan
Published: May 2021

Purpose

This study empirically examines the curvilinear relationship between top management team task-related demographic faultlines and over-investment, as well as how biodemographic faultlines and industrial environment moderate the curvilinear relationship between task-related demographic faultlines and over-investment.

Design/methodology/approach

The study designs the panel data from the listed companies of China's growth enterprises board (GEB) (set up by Shenzhen Stock Exchange in 2009) in the period 2011–2016 and uses hierarchical regression analysis and grouping regression analysis in exploring the curvilinear relationship with the variables involved.

Findings

The study provides empirical insights into the relationship on top management team (TMT) task-related demographic faultlines and over-investment, as well as how biodemographic faultlines and industrial environment moderate the relationship between task-related demographic faultlines and over-investment. It suggests that the relationship between task-related demographic faultlines and over-investment is significantly inverted-U. Furthermore, biodemographic faultlines and industrial environment can strengthen the inverted-U relationship between TMT task-related demographic faultlines and over-investment.

Research limitations/implications

The study investigates the influence of task-related demographic faultlines on firm over-investment. The sample is restricted to the listed companies on GEM in China and limited in size. It is also not concerned with the cross-culture contrastive analysis between the Chinese- and Western-listed companies.

Practical implications

The findings suggest that strong/weak TMT task-related demographic faultlines is beneficial in promoting rational investment, but medium TMT task-related demographic faultlines may lead to over-investment.

Originality/value

The study within the crossed-categorization theory, the study provides a contemporary research path by moderating biodemographic faultlines and industrial environments to explain the long-ignored impact of TMT faultlines within a new perspective of firm investment efficiency with a recent significant sample of new emerging countries (e.g. China).
Discriminant analysis-based modeling of cotton fiber and yarn properties
Authors: Sarker Baneswar , Chakraborty Shankar
Published: May 2021

Purpose

Like all other natural fibers, the physical properties of cotton also vary owing to changes in the related genetic and environmental factors, which ultimately affect both the mechanics involved in yarn spinning and the quality of the yarn produced. However, information is lacking about the degree of influence that those properties impart on the spinnability of cotton fiber and the strength of the final yarn. This paper aims to discuss this issue.

Design/methodology/approach

This paper proposes the application of discriminant analysis as a multivariate regression tool to develop the causal relationships between six cotton fiber properties, i.e. fiber strength (FS), fiber fineness (FF), upper half mean length (UHML), uniformity index (UI), reflectance degree and yellowness and spinning consistency index (SCI) and yarn strength (YS) along with the determination of the respective contributive roles of those fiber properties on the considered dependent variables.

Findings

Based on the developed discriminant function, it can be revealed that FS, UI, FF and reflectance degree are responsible for higher YS. On the other hand, with increasing values of UHML and fiber yellowness, YS would tend to decrease. Similarly, SCI would increase with higher values of FS, UHML, UI and reflectance degree, and its value would decrease with increasing FF and yellowness.

Originality/value

The discriminant functions can effectively envisage the contributive role of each of the considered cotton fiber properties on SCI and YS. The discriminant analysis can also be adopted as an efficient tool for investigating the effects of various physical properties of other natural fibers on the corresponding yarn characteristics.