bluuebunny/crossref_metadata_2025 huggingface dataset:
Breaching the cell-envelope barriers of gram-positive and fungal microbes by a type VI secretion system in Acidovorax citrulli
Authors: Pei Tong-Tong , Kan Yumin , Wang Zeng-Hang , Tang Ming-Xuan , Li Hao , Yan Shuangquan , Cui Yang , Zheng Hao-Yu , Luo Han , Dong Tao G.
Published: May 2021

The type VI secretion system (T6SS) is a double-tubular toxin-injection nanomachine widely found in gram-negative human and plant pathogens. The current model depicts that the T6SS spear-like Hcp tube is powered by the contraction of an outer sheath to drill through the envelope of a neighboring cell, achieving cytosol to cytosol delivery. However, gram-positive bacteria seem to be impenetrable to such T6SS action. Here we report that a plant pathogen Acidovorax citrulli (AC) deploys a highly potent T6SS to kill a range of bacteria including Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Mycobacterium smegmatis as well as fungal species including Candida albicans and Pichia pastoris. Using bioinformatic and biochemical assays, we identified a group of T6SS effectors and characterized one effector RhsB that is critical for interspecies interaction. We report that RhsB contains a conserved YD-repeat domain and a C-terminal nuclease domain. Toxicity of RhsB was neutralized by its downstream immunity proteins through direct interaction. RhsB was cleaved at the C-terminal end and a catalytic mutation within the internal aspartic protease abolished such cleavage. Collectively, the T6SS of AC displays potent activities to penetrate the cell envelope barriers of gram-positive and fungal species, highlighting the greatly expanded capabilities of T6SS in modulating microbiome compositions in complex environments.
The genetic impact of an Ebola outbreak on a wild gorilla population
Authors: Fontsere Claudia , Frandsen Peter , Hernandez-Rodriguez Jessica , Niemann Jonas , Scharff-Olsen Camilla Hjorth , Vallet Dominique , Gouar Pascaline Le , Ménard Nelly , Navarro Arcadi , Siegismund Hans R. , Hvilsom Christina , Gilbert M. Thomas P. , Kuhlwilm Martin , Hughes David , Marques-Bonet Tomas
Published: June 2021

Background

Numerous Ebola virus outbreaks have occurred in Equatorial Africa over the past decades. Besides human fatalities, gorillas and chimpanzees have also succumbed to the fatal virus. The 2004 outbreak at the Odzala-Kokoua National Park (Republic of Congo) alone caused a severe decline in the resident western lowland gorilla (Gorilla gorilla gorilla) population, with a 95% mortality rate. Here, we explore the immediate genetic impact of the Ebola outbreak in the western lowland gorilla population.

Results

Associations with survivorship were evaluated by utilizing DNA obtained from fecal samples from 16 gorilla individuals declared missing after the outbreak (non-survivors) and 15 individuals observed before and after the epidemic (survivors). We used a target enrichment approach to capture the sequences of 123 genes previously associated with immunology and Ebola virus resistance and additionally analyzed the gut microbiome which could influence the survival after an infection. Our results indicate no changes in the population genetic diversity before and after the Ebola outbreak, and no significant differences in microbial community composition between survivors and non-survivors. However, and despite the low power for an association analysis, we do detect six nominally significant missense mutations in four genes that might be candidate variants associated with an increased chance of survival.

Conclusion

This study offers the first insight to the genetics of a wild great ape population before and after an Ebola outbreak using target capture experiments from fecal samples, and presents a list of candidate loci that may have facilitated their survival.
Time-resolved cryo-EM visualizes ribosomal translocation with EF-G and GTP
Authors: Carbone Christine E. , Loveland Anna B. , Gamper Howard , Hou Ya-Ming , Demo Gabriel , Korostelev Andrei A.
Published: June 2021

During translation, a conserved GTPase elongation factor—EF-G in bacteria or eEF2 in eukaryotes—translocates tRNA and mRNA through the ribosome. EF-G has been proposed to act as a flexible motor that propels tRNA and mRNA movement, as a rigid pawl that biases unidirectional translocation resulting from ribosome rearrangements, or by various combinations of motor- and pawl-like mechanisms. Using time-resolved cryo-EM, we visualized GTP-catalyzed translocation without inhibitors, capturing elusive structures of ribosome•EF-G intermediates at near-atomic resolution. Prior to translocation, EF-G binds near peptidyl-tRNA, while the rotated 30S subunit stabilizes the EF-G GTPase center. Reverse 30S rotation releases Pi and translocates peptidyl-tRNA and EF-G by ∼20 Å. An additional 4-Å translocation initiates EF-G dissociation from a transient ribosome state with highly swiveled 30S head. The structures visualize how nearly rigid EF-G rectifies inherent and spontaneous ribosomal dynamics into tRNA-mRNA translocation, whereas GTP hydrolysis and Pi release drive EF-G dissociation.
Prediction of residue-specific contributions to binding and thermal stability using yeast surface display
Authors: Ahmed Shahbaz , Bhasin Munmun , Manjunath Kavyashree , Varadarajan Raghavan
Published: June 2021

Accurate prediction of residue burial as well as quantitative prediction of residue-specific contributions to protein stability and activity is challenging, especially in the absence of experimental structural information. This is important for prediction and understanding of disease causing mutations, and for protein stabilization and design. Using yeast surface display of a saturation mutagenesis library of the bacterial toxin CcdB, we probe the relationship between ligand binding and expression level of displayed protein, within vivosolubility inE.coliandin vitrothermal stability. We find that both the stability and solubility correlate well with the total amount of active protein on the yeast cell surface but not with total amount of expressed protein. We coupled FACS and deep sequencing to reconstruct the binding and expression mean fluorescent intensity of each mutant. The reconstructed mean fluorescence intensity (MFIseq) was used to differentiate between buried site, exposed non active-site and exposed active-site positions with high accuracy. The MFIseqwas also used as a criterion to identify destabilized as well as stabilized mutants in the library, and to predict the melting temperatures of destabilized mutants. These predictions were experimentally validated and were more accurate than those of various computational predictors. The approach was extended to successfully identify buried and active-site residues in the receptor binding domain of the spike protein of SARS-CoV-2, suggesting it has general applicability.
Microfabricated disk technology: rapid scale up in midbrain organoid generation
Authors: Mohamed Nguyen-Vi , Lépine Paula , Lacalle-Aurioles María , Sirois Julien , Mathur Meghna , Reintsch Wolfgang , Beitel Lenore K. , Fon Edward A. , Durcan Thomas M.
Published: June 2021

By providing a three-dimensional in vitro culture system with key features of the substantia nigra region in the brain, 3D neuronal organoids derived from human induced pluripotent stem cells (iPSCs) provide living neuronal tissue resembling the midbrain region of the brain. However, a major limitation of conventional brain organoid culture is that it is often labor-intensive, requiring highly specialized personnel for moderate throughput. Additionally, the methods published for long-term cultures require time-consuming maintenance to generate brain organoids in large numbers. With the increasing need for human midbrain organoids (hMOs) to better understand and model Parkinson’s disease (PD) in a dish, there is a need to implement new workflows and methods to both generate and maintain hMOs, while minimizing batch to batch variation. In this study, we developed a method with microfabricated disks to scale up the generation of hMOs. This opens up the possibility to generate larger numbers of hMOs, in a manner that minimizes the amount of labor required, while decreasing variability and maintaining the viability of these hMOs over time. Taken together, producing hMOs in this manner opens up the potential for these to be used to further PD studies.
A low repeated dose of Δ9-tetrahydrocannabinol affects memory performance through serotonergic signalling in mice
Authors: Galera-López Lorena , Salgado-Mendialdúa Victòria , Moreno Estefanía , Bergadà-Martínez Araceli , Hoffman Alexander F. , Manzanares-Sierra Irene , Busquets-Garcia Arnau , Casadó Vicent , Lupica Carl R. , Maldonado Rafael , Ozaita Andrés
Published: June 2021

Cannabis is the most widely used illicit drug worldwide. Its principal psychoactive component, Δ9-tetrahydrocannabinol (THC), acts as a partial agonist of the main cannabinoid receptor in the brain, the cannabinoid type-1 receptor (CB1R), that is responsible for the central effects of THC including memory impairment. CB1Rs may form heterodimers with the serotonin 5-HT2A receptor (5-HT2AR) which were found responsible for the memory impairment produced by acute high dose of THC in mice. In this study we investigated whether a repeated low dose of THC (1 mg/kg), with no acute consequence on memory performance, could eventually have deleterious cognitive effects. We found that this dose of THC impaired novel object-recognition memory and fear conditioning memory 24 h after the last of 7 consecutive daily treatments. At that time, a general enhancement of c-Fos expression was also observed in several brain regions of THC-exposed animals, as well as a decreased dendritic spine density on hippocampal CA1 pyramidal neurons that was accompanied by reduced long-term potentiation (LTP) at Schaffer collateral-CA1 synapses. Interestingly, an up-regulation in the expression of CB1R/5-HT2AR heterodimers was observed in the hippocampus after THC exposure and pre-treatment with the 5-HT2AR antagonist MDL 100,907 (0.01 mg/kg) prevented the enhanced heterodimerization and the THC-associated memory impairment. Together, these results reveal the significance of serotonergic signalling through 5-HT2ARs in the memory-impairing effects of repeated low doses of THC.
Viruses roam the wheat phyllosphere
Authors: Forero-Junco Laura Milena , Alanin Katrine Wacenius Skov , Djurhuus Amaru Miranda , Kot Witold , Gobbi Alex , Hansen Lars Hestbjerg
Published: June 2021

The phyllosphere comprises all the above-ground sections of plants. This niche is colonised by complex microbial communities, including algae, fungi, archaea, and bacteria1–3. They are known to induce plant growth and promote health4,5 or act as causative agents of plant diseases6–8. It is thought that the most abundant organisms are phyllobacteria2, with an estimate between 106 to 107 cells per cm2. Viruses are highly abundant across many environments, often outnumbering bacteria 10 to 19. However, not much is known about their abundance and composition in the phyllosphere, a harsh environment for viruses due to environmental variability and high UV exposure. To investigate this niche in detail, we extracted, sequenced and analysed phyllosphere virome. Using leaf samples from winter wheat (Triticum aestivum), we identified a total of 876 viral populations (vOTUs), mostly belonging to the Caudovirales order. Most of these were predicted to be lytic. Remarkably, 810 of these viral populations correspond to new viral species with no matches to known sequences. We estimate a minimum of 2.0 x106 viral particles per leaf. Overall, these findings suggest that the phyllosphere ecosystem harbours an abundant and active community of novel viruses that play essential roles in shaping this habitat.
Craniofacial cartilage organoids from human embryonic stem cells via a neural crest cell intermediate
Authors: Foltz Lauren , Levy Tyler , Possemato Anthony , Grimes Mark
Published: June 2021

Severe birth defects or major injuries to the face require surgical reconstruction and rehabilitation. The ability to make bona fide craniofacial cartilage – cartilage of the head and face – from patient-derived induced pluripotent stem cells (iPSCs) to repair these birth defects and injuries has tremendous translational applications, but is not yet possible. The neural crest is the normal developmental pathway for craniofacial cartilage, however, the knowledge of cell signaling pathways that drive neural crest differentiation into craniofacial chondrocytes is limited. Here we describe a differentiation protocol that generated self-organizing craniofacial cartilage organoids from human embryonic stem cells (hESCs) and IPSCs through a neural crest stem cell (NCSC) intermediate. Histological staining of cartilage organoids revealed tissue architecture typical of hyaline cartilage. Organoids were composed of rounded aggregates of glassy, gray matrix that contained scattered small nuclei in lacunae. Mass spectrometry shows that the organoids express robust levels of cartilage markers including aggrecan, perlecan, proteoglycans, and many collagens. Organoids expressed markers indicative of neural crest lineage, as well as growth factors that are candidates for chondrocyte differentiation factors. The data suggest that chondrocyte differentiation is initiated by autocrine loops driven by a combination of secreted growth factors that bind to chondrocyte receptors. Craniofacial cartilage organoids were continuously cultured for one year, reaching up to one centimeter in diameter. The ability to grow craniofacial cartilage from NCSCs provides insights into the cell signaling mechanisms of differentiation into craniofacial cartilage, which lays the groundwork for understanding mechanistic origins of congenital craniofacial anomalies and repairing cartilaginous structures of the head and face.
Tracking the Ancestry of Known and ‘Ghost’ Homeologous Subgenomes in Model Grass Brachypodium Polyploids
Authors: Sancho Rubén , Inda Luis A. , Díaz-Pérez Antonio , Des Marais David L. , Gordon Sean , Vogel John , Lusinska Joanna , Hasterok Robert , Contreras-Moreira Bruno , Catalán Pilar
Published: June 2021

Unraveling the evolution of plant polyploids is a challenge when their diploid progenitor species are extinct or unknown or when their progenitor genome sequences are unavailable. The subgenome identification methods cannot adequately retrieve the homeologous genomes that are present in the allopolyploids if they do not take into account the potential existence of unknown progenitors. We addressed this challenge in the widely distributed dysploid grass genus Brachypodium, which is a model genus for temperate cereals and biofuel grasses. We used a transcriptome-based phylogeny and newly designed subgenome detection algorithms coupled with a comparative chromosome barcoding analysis. Our phylogenomic subgenome detection pipeline was validated in Triticum allopolyploids, which have known progenitor genomes, and was used to infer the identities of three extant and four ‘ghost’ subgenomes in six Brachypodium polyploids (B. mexicanum, B. boissieri, B. retusum, B. phoenicoides, B. rupestre and B. hybridum), of which five contain undescribed homeologous subgenomes. The existence of the seven Brachypodium progenitor genomes in the polyploids was confirmed by their karyotypic barcode profiles. Our results demonstrate that our subgenome detection method is able to uncover the ancestral genomic components of both allo- and autopolyploids.
Integrating ecological monitoring and local ecological knowledge to evaluate conservation outcomes
Authors: Early-Capistrán Michelle María , Solana-Arellano Elena , Abreu-Grobois F. Alberto , Garibay-Melo Gerardo , Seminoff Jeffrey A. , Sáenz-Arroyo Andrea , Narchi Nemer E.
Published: June 2021

Successful conservation of long-lived species requires reliable understanding of long-term trends and historical baselines. Using a green turtle (Chelonia mydas) foraging aggregation in the northern Gulf of California, Mexico as case study, we integrated scientific monitoring data with historic catch rate reconstructions derived from Local Ecological Knowledge (LEK). Models fit to LEK and monitoring data indicate that turtle abundance is increasing, but only after ~40 years of safeguarding the species’ nesting and foraging habitats in Mexico. However, as population declines occurred 75% faster than increases, and current abundance is at ~60% of historical baseline levels, indicating the need for sustained, long-term conservation actions. This study demonstrates the potential of linking LEK and ecological science to provide critical information for conservation, by establishing reference baselines and gauging population status, while promoting equitable and sustainable futures for local communities.
A multi-tiered map of EMT defines major transition points and identifies vulnerabilities
Authors: Paul Indranil , Bolzan Dante , Youssef Ahmed , Gagnon Keith A. , Hook Heather , Karemore Gopal , Oliphant Michael UJ , Lin Weiwei , Liu Qian , Phanse Sadhna , White Carl , Padhorny Dzmitry , Kotelnikov Sergei , Andrieu Guillaume P. , Chen Christopher S. , Hu Pingzhao , Denis Gerald V. , Kozakov Dima , Raught Brian , Siggers Trevor , Wuchty Stefan , Muthuswamy Senthil K. , Emili Andrew
Published: June 2021

Epithelial to mesenchymal transition (EMT) is a complex cellular program proceeding through a hybrid E/M state linked to cancer-associated stemness, migration and chemoresistance. Deeper molecular understanding of this dynamic physiological landscape is needed to define events which regulate the transition and entry into and exit from the E/M state. Here, we quantified >60,000 molecules across ten time points and twelve omic layers in human mammary epithelial cells undergoing TGFβ-induced EMT. Deep proteomic profiles of whole cells, nuclei, extracellular vesicles, secretome, membrane and phosphoproteome defined state-specific signatures and major transition points. Parallel metabolomics showed metabolic reprogramming preceded changes in other layers, while single-cell RNA sequencing identified transcription factors controlling entry into E/M. Covariance analysis exposed unexpected discordance between the molecular layers. Integrative causal modeling revealed co-dependencies governing entry into E/M that were verified experimentally using combinatorial inhibition. Overall, this dataset provides an unprecedented resource on TGFβ signaling, EMT and cancer.
VIQoR: a web service for Visually supervised protein Inference and protein Quantification
Authors: Tsiamis Vasileios , Schwämmle Veit
Published: June 2021

Motivation

In quantitative bottom-up mass spectrometry (MS)-based proteomics the reliable estimation of protein concentration changes from peptide quantifications between different biological samples is essential. This estimation is not a single task but comprises the two processes of protein inference and protein abundance summarization. Furthermore, due to the high complexity of proteomics data and associated uncertainty about the performance of these processes, there is a demand for comprehensive visualization methods able to integrate protein with peptide quantitative data including their post-translational modifications. Hence, there is a lack of a suitable tool that provides post-identification quantitative analysis of proteins with simultaneous interactive visualization.

Results

In this article, we present VIQoR, a user-friendly web service that accepts peptide quantitative data of both labeled and label-free experiments and accomplishes the processes for relative protein quantification, along with interactive visualization modules, including the novel VIQoR plot. We implemented two parsimonious algorithms to solve the protein inference problem, while protein summarization is facilitated by a well established factor analysis algorithm called fast-FARMS followed by a weighted average summarization function that minimizes the effect of missing values. In addition, summarization is optimized by the so-called Global Correlation Indicator (GCI). We test the tool on three publicly available ground truth datasets and demonstrate the ability of the protein inference algorithms to handle degenerate peptides. We furthermore show that GCI increases the accuracy of the quantitative analysis in data sets with replicated design.

Availability and implementation

VIQoR is accessible at: http://computproteomics.bmb.sdu.dk:8192/app_direct/VIQoR/

The source code is available at: https://bitbucket.org/vtsiamis/viqor/

Contact

veits@bmb.sdu.dk

Supplementary information

Supplementary data are available at Bioinformatics online.
The impact of the spatial heterogeneity of resistant cells and fibroblasts on treatment response
Authors: M A Masud , Kim Jae-Young , Pan Cheol-Ho , Kim Eunjung
Published: June 2021

A long-standing practice in the treatment of cancer is that of hitting hard with the maximum tolerated dose to eradicate tumors. This continuous therapy, however, selects for resistant cells, leading to the failure of the treatment. A different type of treatment strategy, adaptive therapy, has recently been shown to have a degree of success in both preclinical xenograft experiments and clinical trials. Adaptive therapy is used to maintain a tumor’s volume by exploiting the competition between drug-sensitive and drug-resistant cells with minimum effective drug doses or timed drug holidays. To further understand the role of competition in the outcomes of adaptive therapy, we developed a 2D on-lattice agent-based model. Our simulations show that the superiority of the adaptive strategy over continuous therapy depends on the local competition shaped by the spatial distribution of resistant cells. Cancer cell migration and increased carrying capacity accelerate the progression of the tumor under both types of treatments by reducing the spatial competition. Intratumor competition can also be affected by fibroblasts, which produce microenvironmental factors that promote cancer cell growth. Our simulations show that the spatial architecture of fibroblasts modulates the benefits of adaptive therapy. Finally, as a proof of concept, we simulated the outcomes of adaptive therapy in multiple metastatic sites composed of different spatial distributions of fibroblasts and drug-resistant cell populations.
Proteome of actin stress fibers
Authors: Liu Shiyou , Matsui Tsubasa S. , Kang Na , Deguchi Shinji
Published: June 2021

Stress fibers (SFs), which are actomyosin structures, reorganize in response to various cues to maintain cellular homeostasis. Currently, the protein components of SFs are only partially identified, limiting our understanding of their responses. Here we isolate SFs from huma fibroblasts HFF-1 to determine with proteomic analysis the whole protein components and how they change with replicative senescence (RS), a state where cells decline in ability to replicate after repeated divisions. We found that at least 263 proteins are associated with SFs, and 101 of them are upregulated with RS, by which SFs become larger in size. Among them, we focused on eEF2 (eukaryotic translation elongation factor 2) as it exhibited upon RS the most significant increase in abundance. We show that eEF2 is critical to the reorganization and stabilization of SFs in senescent fibroblasts. Our findings provide a novel molecular basis for SFs to be reinforced to resist cellular senescence.
Minimal-invasive enhancement of auditory perception by terahertz wave modulation
Authors: Tan Xiaoxuan , Wu Kaijie , Liu Shuang , Chang Chao , Xiong Wei
Published: June 2021

Hearing impairment is a common disease affecting a substantial proportion of the global population. Currently, the most effective clinical treatment for patients with sensorineural deafness is to implant an artificial electronic cochlea. However, the improvements to hearing perception are variable and limited among healthy subjects. Moreover, cochlear implants have disadvantages, such as crosstalk derived from the currents that spread into non-target tissue between the electrodes. Here, in this work, we describe terahertz wave modulation (THM), a new, minimally invasive technology that can enhance hearing perception in animals by reversible modulation of currents in cochlear hair cells. Using single-cell electrophysiology, guinea pig audiometry, and molecular dynamics simulations (MD), we show that THM can reversibly increase mechano-electrical transducer (MET) currents (∼50% higher) and voltage-gated K+ currents in cochlear hair cells through collective resonance of −C=O groups. In addition, measurement of auditory brainstem response (ABR) in guinea pigs treated with THM indicated a ∼10 times increase in hearing sensitivity. This study thus reports a new method of highly spatially selective hearing enhancement without introducing any exogeneous gene, which has potential applications for treatment of hearing disorders as well as several other areas of neuroscience.
The liverwort Marchantia polymorpha operates a depolarization-activated Slowpoke (SLO) K+ channel that recognises pH changes in the environment
Authors: Sussmilch Frances C. , Böhm Jennifer , Gessner Guido , Maierhofer Tobias , Müller Thomas D. , Heinemann Stefan H. , Becker Dirk , Hedrich Rainer
Published: June 2021

Voltage-dependent ion channels are a prerequisite for cellular excitability and electrical communication – important traits for multicellular organisms to thrive in a changeable terrestrial environment. Based on their presence in extant embryophytes and closely-related green algae, the first plants to survive on land likely possessed genes encoding channels with homology to large-conductance calcium-activated K+ channels (BK channels from the Slo family) in addition to primary voltage-gated potassium channels from the plant VG-type family (Shaker or Kv channels). While the function and gating of Shaker channels has been characterised in flowering plants, so far knowledge of BK channels has been limited to animal models. In humans, BK-mediated K+ efflux has a critical role in sperm motility and membrane polarisation to enable fertilisation. In the liverwort Marchantia polymorpha, the MpBK2a channel gene is most highly expressed in male reproductive tissue, suggesting that these channels may function in sexual reproduction. We characterised MpBK2a channels and found them to be strongly K+-selective, outward-rectifying, 80-pS channels capable of repolarising the membrane after stimulus-dependent depolarisation. In contrast to its animal counterpart, MpBK2a is insensitive to cytoplasmic Ca2+ variations but effectively gated by pH changes. Given that this plant BK channel is active even in the presence of trace amounts of external K+ and at low pH, the liverwort channel could have stabilised the membrane potential under stressful pre-historic conditions including nutrient-depleted and acid environments as early plant pioneers conquered land.
Incommensurately modulated structure zone in α-Zr instigated by the drag force on a grain boundary
Authors: Zhang Yingdong , Li Geping , Yuan Fusen , Han Fuzhou , Ali Muhammad , Guo Wenbin , Ren Jie , Liu Chengze , Gu Hengfei , Yuan Gaihuan
Published: May 2021

Among several microstructural features found in deformed Zircaloy-4 alloy, the formation of incommensurately modulated structure (IMS) has not been studied extensively. In this study, an IMS zone in the α-Zr matrix of forged Zircaloy-4 alloy was investigated by transmission electron microscopy and related techniques. The results revealed a new intensity sequence along the (011
2) and (0113) planes, implying that an IMS was formed adjacent to a second phase particle (SPP) located at a grain boundary (GB) in the α-Zr matrix. The GB experienced maximum dragging force parallel to the [0110] direction of the α-Zr matrix, resulting in the formation of the IMS zone in the α-Zr matrix adjacent to the SPP.
The influence of strain on image reconstruction in Bragg coherent X-ray diffraction imaging and ptychography
Authors: Kim Chan , Scholz Markus , Madsen Anders
Published: June 2021

A quantitative analysis of the effect of strain on phase retrieval in Bragg coherent X-ray diffraction imaging is reported. It is shown in reconstruction simulations that the phase maps of objects with strong step-like phase changes are more precisely retrieved than the corresponding modulus values. The simulations suggest that the reconstruction precision for both phase and modulus can be improved by employing a modulus homogenization (MH) constraint. This approach was tested on experimental data from a highly strained Fe–Al crystal which also features antiphase domain boundaries yielding characteristic π phase shifts of the (001) superlattice reflection. The impact of MH is significant and this study outlines a successful method towards imaging of strong phase objects using the next generation of coherent X-ray sources, including X-ray free-electron lasers.
Effects of isentropic efficiency of turbomachinery components on entropy production for small turbojet engine
Authors: Aygün Hakan
Published: June 2021

Purpose

Usage of gas turbine engines has increased by day due to rising demand for military and civil applications. This case results in investigating diverse topics related to energy efficiency and irreversibility of these systems. The purpose of this paper is to perform a detailed entropy assessment of turbojet engines for different flight conditions.

Design/methodology/approach

In this study, for small turbojet engines used in unmanned aerial vehicles, parametric cycle analysis is carried out at (sea level-zero Mach (hereinafter phase-I)) and (altitude of 9,000 m- Mach of 0.7 (hereinafter phase-II)). Based on this analysis, variation of performance and thermodynamic parameters with respect to change in isentropic efficiency of the compressor (CIE) and turbine (TIE) is examined at both phases. In this context, the examined ranges for CIE is between 0.78 and 0.88 whereas TIE is between 0.85 and 0.95.

Findings

Increasing isentropic efficiency decreases entropy production of the small turbojet engine. Moreover, the highest entropy production occurs in the combustor in the comparison of other components. Namely, it decreases from 2.81 to 2.69 kW/K at phase-I and decreases from 1.44 to 1.39 kW/K at phase-II owing to rising CIE.

Practical implications

It is thought that this study helps in understanding the relationship between entropy production and the efficiency of components. Namely, the approach used in the current analysis could help decision-makers or designers to determine the optimum value of design variables.

Originality/value

Due to rising isentropic efficiencies of both components, it is observed that specific fuel consumption (SFC) decreases whereas specific thrust (ST) increases. Also, the isentropic efficiency of a compressor affects relatively SFC and ST higher than that of the turbine.
How privacy concerns and cultural differences affect public opinion during the COVID-19 pandemic: a case study
Authors: Xing Yunfei , Li Yuhai , Wang Feng-Kwei
Published: June 2021

Purpose

COVID-19, an infectious disease first identified in China, has resulted in an ongoing pandemic all over the world. Most of the countries have been experiencing a difficult period during the fighting of this pandemic. The purpose of this study is to explore the effect of privacy concerns and cultural differences on public opinion related to the pandemic. The authors conducted a comparative analysis of public opinion in the US and in China as a case study, in order to determine the results.

Design/methodology/approach

National policies on important issues faced during the COVID-19 pandemic in the US and in China were examined through a comparative analysis. The authors used text clustering and visualization to mine public opinion on two popular social media platforms, Twitter and Weibo. From the perspectives of concern for privacy and of national culture, this study combines qualitative and quantitative analysis to discover the acceptance level of national policies by the public in the two countries.

Findings

The anti-pandemic policies and measures of the US and China reflect the different characteristics of their respective political systems and national cultures. When considering the culture of the US, it is hard to establish and enforce a rigorous regulation on either mask wearing in public or home quarantine on the national level. The opinions of US people are diverse, regarding national COVID-19 policies, but they are rather unified on privacy issues. On the other hand, Chinese people show a high acceptance of national policies based on their mask-wearing customs and their culture of collectivism.

Originality/value

Prior studies have paid insufficient attention to the ways in which user privacy and cultural difference affect public opinion on national policies between the US and China. This case study that compares public opinion on current and topical issues which are closely bound up with public life shows originality, as it innovatively provides a cross-cultural perspective on the research of public opinion dissemination during emergencies by considering the ongoing COVID-19 pandemic.
CSR during COVID-19: exploring select organizations’ intents and activities
Authors: Ramya S.M. , Baral Rupashree
Published: June 2021

Purpose

This paper aims to explore the immediate proactive corporate social responsibility (CSR) efforts undertaken by select organizations in India in response to the coronavirus (COVID-19) pandemic and the approach they have adopted toward it.

Design/methodology/approach

Semi-structured interviews were conducted with 27 senior managers across top Bombay Stock Exchange indexed organizations from the manufacturing and services sector in India during the national COVID-19 pandemic lockdown between March and June 2020. Manual content analysis and the Gioia method were used to arrive at the insights.

Findings

Results of the analysis showcase the spirited immediate CSR measures undertaken by the select organizations in the broader interests of the community at large. The study also highlights the need for a paradox approach toward CSR strategy.

Research limitations/implications

Given that the present study adopts an exploratory qualitative research design, the scope for generalization is rather limited.

Practical implications

This paper classifies COVID-19 related initiatives undertaken by selected few top organizations in India and attempts to justify the need to opt for a paradox approach toward CSR strategy.

Originality/value

To the best of the author’s knowledge, this is one of the first few studies to have attempted to put forth a dialog at the intersection of COVID-19 and CSR with rich insights gained from qualitative data collected during India’s intense lockdown period and offering a different perspective with the inclusion of paradox theory into the discussion.
Lyapunov–Krasovskii based FPID controller for LFC in a time-delayed micro-grid system with fuel cell power units
Authors: Sabahi Kamel , Hajizadeh Amin , Tavan Mehdi
Published: June 2021

Purpose

In this paper, a novel Lyapunov–Krasovskii stable fuzzy proportional-integral-derivative (PID) (FPID) controller is introduced for load frequency control of a time-delayed micro-grid (MG) system that benefits from a fuel cell unit, wind turbine generator and plug-in electric vehicles.

Design/methodology/approach

Using the Lyapunov–Krasovskii theorem, the adaptation laws for the consequent parameters and output scaling factors of the FPID controller are developed in such a way that an upper limit (the maximum permissible value) for time delay is introduced for the stability of the closed-loop MG system. In this way, there is a stable FPID controller, the adaptive parameters of which are bounded. In the obtained adaptation laws and the way of stability analyses, there is no need to approximate the nonlinear model of the controlled system, which makes the implementation process of the proposed adaptive FPID controller much simpler.

Findings

It has been shown that for a different amount of time delay and intermittent resources/loads, the proposed adaptive FPID controller is able to enforce the frequency deviations to zero with better performance and a less amount of energy. In the proposed FPID controller, the increase in the amount of time delay leads to a small increase in the amount of overshoot/undershoot and settling time values, which indicate that the proposed controller is robust to the time delay changes.

Originality/value

Although the designed FPID controllers in the literature are very efficient in being applied to the uncertain and nonlinear systems, they suffer from stability problems. In this paper, the stability of the FPID controller has been examined in applying to the frequency control of a nonlinear input-delayed MG system. Based on the Lyapunov–Krasovskii theorem and using rigorous mathematical analyses, the stability conditions and the adaptation laws for the parameters of the FPID controller have been obtained in the presence of input delay and nonlinearities of the MG system.
A neoteric closed loop feedback controller based on correlative-elemental curvature algorithm
Authors: Das Nipan Kumar Das , Buragohain Mrinal
Published: June 2021

Purpose

The power framework has become a vital part in the day-to-day life and exhibits a rapid development in this current era. Due to the fact of huge power utilization, the power frameworks fall under several power transmission-related concerns. Precisely, frequency deviation has generated a huge impact during power transmission; this in turn highly reduces the power system stability as well as reliability too.

Design/methodology/approach

To boost the system’s efficacy, this study proposes a neoteric closed loop feedback controller in which a control algorithm named correlative-elemental-curvature algorithm is introduced with a constant threshold.

Findings

With the aim of mitigating frequency deviation, a stability analysis technique called Retrofit Lyapunov’s method is deployed in the controller. This would simultaneously reduce the load disturbances along with tie-line synchronization issues faced with the prior controllers. Optimization is carried out with the aid of duelist optimization algorithm, which tunes the controller parameters thereby mitigating the complexities while designing a loop feedback controller power framework.

Originality/value

The efficacy of the proposed work is assessed with the aid of metrics, such as integral absolute error, accuracy and settling time. Thus, the proposed work enhances the system reliability as well as the stability by mitigating the frequency deviation related issues and guarantees reliable power transmission.
E-health and interventional radiology in gynecology
Authors: Alghanimi Ibrahim
Published: May 2021

Purpose

This paper aims to summarize the radiological interventions that can be used by obstetricians and gynecologists.

Design/methodology/approach

E-health systems apply in all hospital sectors in the world; interventional radiology (IR) now includes transcatheter and percutaneous techniques that can be applied to various organ systems, including the female reproductive system and pelvis. Interventional radiologists can now offer many services to obstetricians and gynecologists. With the advent of new procedures and refinement of existing techniques, there are now a number of procedures that can be used to treat both vascular and non-vascular diseases. This review summarizes the radiological interventions that can be used by obstetricians and gynecologists.

Findings

This review is intended to help gynecologists and obstetricians understand the role of IR in their specialty. Many valuable vascular and nonvascular interventional services can be provided by radiologists for both obstetric and gynecological indications. Many of these IR procedures are minimally invasive with less risk to the patients.

Originality/value

IR is now being used to treat some conditions encountered in obstetrics and gynecology, in particular, uterine leiomyomas, placenta accreta, postpartum hemorrhage and pelvic congestion syndrome. Moreover, with the help of IR, radiologists can also manage several nonvascular pathologies, including drainage of pelvic abscesses, fallopian tube recanalization, image-guided biopsy and fluid collections involving ovarian lesions. The major challenges faced when performing obstetric IR procedures are reduction of radiation exposure for the patient and fetus and preservation of fertility. This review highlights the role of IR in the treatment of various vascular and nonvascular pathologies encountered in obstetrics and gynecology.
Systemic leadership development: impact on organizational effectiveness
Authors: Douglas Stephanie , Merritt Daisha , Roberts Robin , Watkins Daryl
Published: May 2021

Purpose

This study aims to examine the impact of leadership development programs on organizational outcomes and organizational effectiveness.

Design/methodology/approach

Using a grounded theory approach, semi-structured interviews were conducted with 15 executive leaders from aviation firms in Brazil with employees participating in a leadership development program. NVivo12 was used for coding and managing the data. Thematic analysis was performed to determine themes and categories.

Findings

The leadership development program was found to influence organizational level outcomes identified as themes of internal impact, external impact, skill development and capacity. The interviews also found that executive leaders perceived the leadership development program to impact organizational effectiveness. Connections to human capital, social capital and collective leadership were found as outcomes of the leadership development program contributing to organizational effectiveness.

Research limitations/implications

The findings are dependent upon the executive leaders’ interviews and are limited sample size. The protocol of subjective inter-coder reliability was followed supporting the credibility and dependability of the findings; however, researcher bias may still be present in qualitative studies. Generalizability outside of the Brazilian aviation context is cautioned until further studies in additional contexts and industries are completed.

Practical implications

The findings of this study support leadership development programs as impactful on organizational outcomes and effectiveness. Incorporating leadership development programs as part of human capital management strategies supports organizational effectiveness through increased collective leadership capacity, human capital development and social capital.

Originality/value

A large amount is known regarding the outcomes for individuals as a result of leadership development programs with less examination on the contribution to organizational level outcomes and organizational effectiveness. This study aids in bridging this gap.
Metaheuristic based auto-scaling for microservices in cloud environment: a new container-aware application scheduling
Authors: Sarma Subramonian Krishna
Published: June 2021

Purpose

The cloud is a network of servers to share computing resources to run applications and data storage that offers services in various flavours, namely, infrastructure as a service, platform as a service and software as a service. The containers in the cloud are defined as “standalone and self-contained units that package software and its dependencies together”. Similar to virtual machines, the virtualization method facilitates the resource on a specific server that could be used by numerous appliances.

Design/methodology/approach

This study introduces a new Dragon Levy updated squirrel algorithm (DLU-SA) for container aware application scheduling. Furthermore, the solution of optimal resource allocation is attained via defining the objective function that considers certain criteria such as “total network distance (TND), system failure (SF), balanced cluster use (BC) and threshold distance (TD)”. Eventually, the supremacy of the presented model is confirmed over existing models in terms of cost and statistical analysis.

Findings

On observing the outcomes, the total cost of an adopted model for Experimentation 1 has attained a lesser cost value, and it was 0.97%, 10.45% and 10.37% superior to traditional velocity updated grey wolf (VU-GWO), squirrel search algorithm (SSA) and dragonfly algorithm (DA) models, respectively, for mean case scenario. Especially, under best case scenario, the implemented model has revealed a minimal cost value of 761.95, whereas, the compared models such as whale random update assisted lion algorithm, VU-GWO, SSA and DA has revealed higher cost value of 761.98, 779.46, 766.62 and 766.51, respectively. Thus, the enhancement of the developed model has been validated over the existing works.

Originality/value

This paper proposes a new DLU-SA for container aware application scheduling. This is the first work that uses the DLU-SA model for optimal container resource allocation by taking into consideration of certain constraints such as TND, SF, BC and TD.
A resources gain perspective on family outcomes of proactive helping behavior
Authors: Zhou Kong , Gui Chenglin , Yin Wen-Jun , Ouyang Xi , Yuan Chunyan
Published: May 2021

Purpose

Drawing on the work-home resources (W-HR) model, this study examines the ripple effects of proactive helping behavior at work on helpers' family relationship quality at home via positive affect and work-family interpersonal capitalization, and tests the moderating role of independent self-construal in the resource spillover process.

Design/methodology/approach

Using an experience sampling methodology, data was collected (N = 382) from multiple sources in five consecutive working days. Multilevel path modeling was used to examine the hypotheses.

Findings

The results indicated that proactive helping other at work can generate affective resources for helpers, which in turn triggers them to share daily work experiences and feelings with their spouses at home, and strengthens their family relationship quality. Moreover, the effects of helping others on family relationship quality were more pronounced for helpers with relatively high independent self-construal.

Originality/value

The findings explore the enrichment effects and unintended family-related distal outcomes of helping behaviors for helpers, and contributes to the W-HR model by uncovering an affective-behavioral ripple mechanism linking work and family. Finally, our results identify the boundary condition, that proactive helping behaviors are more rewarding for helpers with higher independent self-construal.