bluuebunny/crossref_metadata_2025 huggingface dataset:
Previous Infection Combined with Vaccination Produces Neutralizing Antibodies With Potency Against SARS-CoV-2 Variants
Authors: Ibarrondo F. Javier , Hofmann Christian , Ali Ayub , Ayoub Paul , Kohn Donald B. , Yang Otto O.
Published: August 2021

SARS-CoV-2 continues to evolve in humans. Spike protein mutations increase transmission and potentially evade antibodies raised against the original sequence used in current vaccines. Our evaluation of serum neutralizing activity in both persons soon after SARS-CoV-2 infection (in April 2020 or earlier) or vaccination without prior infection confirmed that common spike mutations can reduce antibody antiviral activity. However, when the persons with prior infection were subsequently vaccinated, their antibodies attained an apparent biologic ceiling of neutralizing potency against all tested variants, equivalent to the original spike sequence. These findings indicate that additional antigenic exposure further improves antibody efficacy against variants.

LAY SUMMARY

As SARS-CoV-2 evolves to become better suited for circulating in humans, mutations have occurred in the spike protein it uses for attaching to cells it infects. Protective antibodies from prior infection or vaccination target the spike protein to interfere with its function. These mutations can reduce the efficacy of antibodies generated against the original spike sequence, raising concerns for re-infections and vaccine failures, because current vaccines contain the original sequence. In this study we tested antibodies from people infected early in the pandemic (before spike variants started circulating) or people who were vaccinated without prior infection. We confirmed that some mutations reduce the ability of antibodies to neutralize the spike protein, whether the antibodies were from past infection or vaccination. Upon retesting the previously infected persons after vaccination, their antibodies gained the same ability to neutralize mutated spike as the original spike, suggesting that the combination of infection and vaccination drove the production of enhanced antibodies to reach a maximal level of potency. Whether this can be accomplished by vaccination alone remains to be determined, but the results suggest that booster vaccinations may help improve efficacy against spike variants.
Quantification of circadian interactions and protein abundance defines a mechanism for operational stability of the circadian clock
Authors: Bagnall James S. , Koch Alex A. , Smyllie Nicola J. , Begley Nicola , Adamson Antony , Fribourgh Jennifer L. , Spiller David G. , Meng Qing-Jun , Partch Carrie L. , Strimmer Korbinian , House Thomas A. , Hastings Michael H. , Loudon Andrew S. I.
Published: August 2021

The mammalian circadian clock exerts substantial control of daily gene expression through cycles of DNA binding. Understanding of mechanisms driving the circadian clock is hampered by lack of quantitative data, without which predictive mathematical models cannot be developed. Here we develop a quantitative understanding of how a finite pool of BMAL1 protein can regulate thousands of target sites over daily time scales. We have used fluorescent correlation spectroscopy (FCS) to track dynamic changes in CRISPR-modified fluorophore-tagged proteins in time and space in single cells across SCN and peripheral tissues. We determine the contribution of multiple rhythmic processes in coordinating BMAL1 DNA binding, including the roles of cycling molecular abundance, binding affinities and two repressive modes of action. We find that nuclear BMAL1 protein numbers determine corresponding nuclear CLOCK concentrations through heterodimerization and define a DNA residence time of 2.6 seconds for this complex. Repression of CLOCK:BMAL1 is in part achieved through rhythmic changes to BMAL1:CRY1 affinity as well as a high affinity interaction between PER2:CRY1 which mediates CLOCK:BMAL1 displacement from DNA. Finally, stochastic modelling of these data reveals a dual role for PER:CRY complexes in which increasing concentrations of PER2:CRY1 promotes removal of BMAL1:CLOCK from genes consequently enhancing ability to move to new target sites.
Cerebrospinal fluid outflow through skull channels instructs cranial hematopoiesis
Authors: Pulous Fadi E. , Cruz-Hernández Jean C. , Yang Chongbo , Kaya Zeynep , Wojtkiewicz Gregory , Capen Diane , Brown Dennis , Wu Juwell W. , Vinegoni Claudio , Yamazoe Masahiro , Grune Jana , Schloss Maximillian J. , Rohde David , Richter Dmitry , McAlpine Cameron S. , Panizzi Peter , Weissleder Ralph , Kim Dong-Eog , Swirski Filip K. , Lin Charles P. , Moskowitz Michael A. , Nahrendorf Matthias
Published: August 2021

Interactions between the immune and central nervous systems strongly influence brain health. Although the blood-brain barrier restricts this crosstalk, we now know that meningeal gateways through brain border tissues, particularly dural lymphatic vessels that allow cerebrospinal fluid outflow, facilitate intersystem communication. Here we observe that cerebrospinal fluid exits into the skull bone marrow. Fluorescent tracers injected into the cisterna magna of mice travel through hundreds of sub-millimeter skull channels into the calvarial marrow. During meningitis, bacteria usurp this perivascular route to infect the skull’s hematopoietic niches and initiate cranial hematopoiesis ahead of remote tibial sites. Because skull channels also directly provide leukocytes to meninges, the privileged sampling of brain-derived danger signals in cerebrospinal fluid by regional marrow has broad implications for neurological disorders.

One-Sentence Summary

Skull channels transport cerebrospinal fluid from the subarachnoid space to the cranial bone marrow via a perivascular route, which bacteria use during meningitis.
Experimental and mathematical models of intracellular calcium dynamics for evaluating combined anticancer effects of Afatinib and RP4010 in esophageal cancer
Authors: Chang Yan , Funk Marah , Roy Souvik , Stephenson Elizabeth , Choi Sangyong , Kojouharov Hristo , Chen Benito , Pan Zui
Published: August 2021

Targeting dysregulated Ca2+ signaling in cancer cells is an emerging chemotherapy approach. We previously reported that store-operated Ca2+ entry (SOCE) blockers, such as RP4010, are promising antitumor drugs for esophageal cancer. As a tyrosine kinase inhibitor (TKI), afatinib received FDA approval to be used in targeted therapy for patients with EGFR mutation-positive cancers. While preclinical studies and clinical trials have shown that afatinib has benefits for esophageal cancer patients, it is not known whether combination of afatinib and RP4010 could achieve better anticancer effects. Since TKI can alter intracellular Ca2+ dynamics through EGFR/phospholipase C-γ pathway, in this study, we evaluated the inhibitory effect of afatinib and RP4010 on intracellular Ca2+ oscillations in esophageal cancer cells using both experimental and mathematical simulations. Our mathematical simulation of Ca2+ oscillations could fit well with experimental data responding to aftinib or RP4010, separately or in combination. The results showed that combination of afatinib and RP4010 presented synergistic anticancer effect. This intracellular Ca2+ dynamic-based mathematical simulation approach could be useful for a rapid and cost-effective evaluation of combined targeting therapy drugs.
Aβ oligomers trigger necroptosis-mediated neurodegeneration via microglia activation in Alzheimer’s disease
Authors: Salvadores Natalia , Moreno-Gonzalez Inés , Ruiz Nazaret Gamez , Quiroz Gabriel , Vegas Laura , Escandón Marcela , Jimenez Sebastian , Vitorica Javier , Gutierrez Antonia , Soto Claudio , Court Felipe A.
Published: August 2021

Alzheimer’s disease (AD) is a major adult-onset neurodegenerative condition with no available treatment. Compelling reports point amyloid-β (Aβ) as the main etiologic agent that triggers AD. Although there is extensive evidence of detrimental crosstalk between Aβ and microglia that contributes to neuroinflammation in AD, the exact mechanism leading to neuron death remains unknown. Using postmortem human AD brain tissue, we show that Aβ pathology is associated with the necroptosis effector pMLKL. Moreover, we found that the burden of Aβo correlates with the expression of key markers of necroptosis activation. Additionally, inhibition of necroptosis by pharmacological or genetic means, reduce neurodegeneration and memory impairment triggered by Aβo in mice. Since microglial activation is emerging as a central driver for AD pathogenesis, we then tested the contribution of microglia to the mechanism of Aβo-mediated necroptosis activation in neurons. Using an in vitro model, we show that conditioned medium from Aβo-stimulated microglia elicited necroptosis in neurons through activation of TNF-α signaling, triggering extensive neurodegeneration. Notably, necroptosis inhibition provided significant neuronal protection. Together, these findings suggest that Aβo-mediated microglia stimulation in AD contributes to necroptosis activation in neurons and neurodegeneration. As necroptosis is a druggable degenerative mechanism, our findings might have important therapeutic implications to prevent the progression of AD.
Analyses of the 5’ Ends of Escherichia coli ORFs
Authors: Ward Michael , Curran James F.
Published: August 2021

Sequence biases at 5’ ends of coding sequences differ from those of the remainder of ORFs, reflecting differences in function. Internal sequence biases promote translational efficiency by several mechanisms including correlating codon usage and tRNA concentration. However, the early region may also facilitate translational initiation, establishment of the reading frame, and polypeptide processing. Here we examine the beginnings of the ORFs of an Escherichia coli K12 reference genome. The results extend previous observations of A-richness to include an overabundance of the AAA triplet in all reading frames, consistent with the hypothesis that the beginnings of ORFs contribute to initiation site accessibility. Results are also consistent with the idea that the first two amino acids are under selection because they facilitate solvation of the amino-terminus at the end of the ribosomal exit channel. Moreover, serine is highly overrepresented as the second amino acid, possibly because it can facilitate removal of the terminal formylmethionine. Non-AUG initiation codons are known to be less efficient than AUG at directing initiation, presumably because of relatively weak base pairing to the initiator-tRNA. But non-UAG initiation codons are not followed by unusual 3’ nearest neighbor codons. Moreover, the four NUG initiation codons do not differ in their propensity to frameshift in an assay known to be sensitive to base pair strength. Altogether, these data suggest that the 5’ ends of ORFs are under selection for several functions, and that initiation codon identity may not be critical beyond its role in initiation.
The contribution of cohesin to chromatid organisation is critical during chromosome segregation
Authors: Garcia-Luis Jonay , Bordelet Hélène , Thierry Agnès , Koszul Romain , Aragon Luis
Published: August 2021

Chromosome segregation requires both the separation of sister chromatids and the sustained condensation of chromatids during anaphase. In yeast cells, cohesin is not only required for sister chromatid cohesion but also plays a major role in determining the structure of individual chromatids in metaphase. Separase cleavage is thought to remove all cohesin complexes from chromosomes to initiate anaphase. It is thus not clear how the length and organisation of segregating chromatids are maintained during anaphase in the absence of cohesin. Here we show that degradation of cohesin at the anaphase onset causes aberrant chromatid segregation. Hi-C analysis on segregating chromatids demonstrates that cohesin depletion causes loss of intrachromatid organisation. Surprisingly, TEV-mediated cleavage of cohesin does not dramatically disrupt chromatid organisation in anaphase, explaining why bulk segregation is achieved. In addition, we identified a small pool of cohesin complexes bound to telophase chromosomes in wildtype cells and show that they play a role in the organisation of centromeric regions. Our data demonstrate that in yeast cells, cohesin function is not over in metaphase, but extends to the anaphase period when chromatids are segregating.

One sentence summary

Cohesin complexes on yeast chromosomes provide organisation to segregating chromatids.
The growth and expansion of meningeal lymphatic networks are affected in craniosynostosis
Authors: Ang Phillip , Matrongolo Matt , Tischfield Max A
Published: August 2021

Congenital skull malformations are associated with vascular anomalies that can impair fluid balance in the central nervous system. We previously reported that humans with craniosynostosis and mutations in TWIST1 have dural venous sinus malformations. It is still unknown whether meningeal lymphatic networks, which are patterned alongside the venous sinuses, are also affected. Using a novel skull flat mounting technique, we show that the growth and expansion of meningeal lymphatics are perturbed in Twist1 craniosynostosis models. Changes to the local meningeal environment, including hypoplastic dura and venous malformations, affect the ability of lymphatic networks to sprout and remodel. Dorsal networks along the transverse sinus are hypoplastic with reduced branching. By contrast, basal networks closer to the skull base are more variably affected, showing exuberant growth in some animals suggesting they are compensating for vessel loss in dorsal networks. Injecting molecular tracers into cerebrospinal fluid reveals significantly less drainage to the deep cervical lymph nodes, indicative of impaired lymphatic function. Collectively, our results show that meningeal lymphatic development is hindered in craniosynostosis, suggesting central nervous system waste clearance may be impeded.
Antibodies anti-SARS-CoV2 time-course in patients and vaccinated subjects: an evaluation of the harmonization of two different methods
Authors: Dittadi Ruggero , Seguso Mara , Bertoli Isabella , Afshar Haleh , Carraro Paolo
Published: August 2021

The time-course of antibodies anti SARS-CoV2 is not yet well elucidated, especially in people who underwent a vaccination campaign. In this study we measured antibodies anti-S1 and anti-RBD with two different methods both in patients and in vaccinated subjects.

108 specimens from 48 patients diagnosed as COVID-19 affected (time from the onset of symptoms from 3 to 368 days) and 60 specimens from 20 vaccinated subjects (collected after 14 days from the first dose, 14 days and 3 months after a second dose of Comirnaty) were evaluated.

We used an ELISA method that measure IgG against anti-Spike 1 and a chemiluminescence immunoassays that measure IgG anti-RBD.

In the patients, antibodies concentrations tend to decline after a few months with both methods, but persist relatively high up to nearly a year after symptoms.

In vaccinated subjects, antibodies were already detectable after the first dose, but after the booster they show a significant increase. However, the decrease is rapid, given that after 3 months after the second vaccination they are reduced to less than a quarter.

The conversion of the results into BAU units improves the relationship between the two methods. However, in vaccinated subjects there was no evidence of proportional error after the conversion, while in the patients the difference between the two methods remained significant.
Drone honey bees (Apis mellifera) are disproportionately sensitive to abiotic stressors despite expressing high levels of stress response proteins
Authors: McAfee Alison , Metz Bradley , Milone Joseph P , Foster Leonard J , Tarpy David R
Published: August 2021

Drone honey bees (haploid males) are the obligate sexual partners of queens, and the availability of healthy, high-quality drones directly affects a queen’s fecundity and productivity of her subsequent colony. Yet, our understanding of how stressors affect drone fecundity and physiology is presently limited. We investigated sex biases in susceptibility to abiotic stressors (cold stress, topical imidacloprid exposure, and topical exposure to a realistic cocktail of pesticides), and we found that drones were more sensitive to cold and imidacloprid exposure but the cocktail was not toxic at the concentrations tested. We corroborated this lack of apparent toxicity with in-hive cocktail exposures via pollen feeding. We then used quantitative proteomics to investigate protein expression profiles in the hemolymph of topically exposed workers and drones, and we show that drones express surprisingly high levels of putative stress response proteins relative to workers. Drones apparently invest in strong constitutive expression of damage-mitigating proteins for a wide range of stressors, yet they are still sensitive to stress when challenged. The robust expression of stress-response proteins suggests that drone stress tolerance systems are fundamentally rewired relative to workers, and their susceptibility to stress depends on more than simply gene dose or deleterious recessive alleles.
Human transcriptional gene regulatory network compiled from 14 data resources
Authors: Muley Vijaykumar Yogesh , König Rainer
Published: August 2021

Transcriptional regulatory network (TRN) orchestrates spatio-temporal expression of genes to generate cellular responses for survival. The transcription factors (TF) regulating expression of their target genes (TG) are the fundamental units of TRN. Several databases have been developed to catalogue human TRN based on low- and high-throughput experimental and computational studies considering their importance in understanding cellular physiology. However, literature lacks comparative assessment on the strength and weakness of each database. In this study, we compared over 2.2 million regulatory pairs between 1,379 TF and 22,518 TG assembled from 14 data resources. Our study reveals that the TF and TG were common across data resources but not their regulatory pairs. We observed that the TF and TG of the regulatory pairs showed weak expression correlation, significant gene ontology overlap, co-citations in PubMed and low numbers of TF-TG pairs representing transcriptional repression relationships. Furthermore, each TF-TG regulatory pair assigned a combined confidence score reflecting its reliability based on its presence in multiple databases and co-expression. The TRN containing 2,246,598 TF-TG pairs, of which, 44,284 with the information on TF’s activating or repressing effects on their TG is available upon request. This study brings the information about transcriptional regulation scattered over the literature and databases at one place in the form of one of the most comprehensive and complete human TRNs assembled to date, which will be a valuable resource for benchmarking TRN prediction tools, and to the scientific community working in functional genomics, gene expression and gene regulation analysis.
Membrane cholesterol interferes with tyrosine phosphorylation but facilitates the clustering and signal transduction of EGFR
Authors: Hiroshima Michio , Abe Mitsuhiro , Tomishige Nario , Hullin-Matsuda Françoise , Makino Asami , Ueda Masahiro , Kobayashi Toshihide , Sako Yasushi
Published: August 2021

Epidermal growth factor receptor (EGFR) activates major cell signaling pathways that regulate various cell responses. Its dimerization and clustering coupled with its lateral mobility are critical for EGFR function, but the contribution of the plasma membrane environment to EGFR function is unknown. Here we show, using single-molecule analysis, that EGFR mobility and clustering are altered by the depletion of cholesterol or sphingomyelin, major lipids of membrane subdomains, causing significant changes in EGFR signaling. When cholesterol was depleted, the subdomain boundary in EGFR diffusion disappeared, the fraction of EGFR pre-dimers was increased, and the ligand-induced phosphorylation of EGFR was enhanced. In addition, the depletion of either lipid prevented the formation of immobile clusters after EGF association and decreased the phosphorylation of downstream proteins. Our results revealed that cholesterol plays dichotomous roles in the signaling pathway of EGFR and that clustering in the membrane subdomains is critical for EGFR signal transduction.
Dual avatars of E. coli grxB encoded Glutaredoxin 2 perform ascorbate recycling and ion channel activities
Authors: Sreekumar Sreeshma Nellootil , Das Bhaba Krishna , Raina Rahul , Puthumadathil Neethu , Udinia Sonakshi , Kumar Amit , Sahoo Sibasis , Ravichandran Pooja , Kumar Suman , Ray Pratima , Kumar Dhiraj , Chandele Anmol , Mahendran Kozhinjampara R. , Arockiasamy Arulandu
Published: August 2021

Glutaredoxins (Grxs) are single-domain redox enzymes of the thioredoxin superfamily, and primarily function as glutathione (GSH) dependent disulphide reductases. Whereas, the E. coli Glutaredoxin 2 (EcGrx2) encoded by grxB has two conserved GST-fold domains, it still lacks a classical Grx-like functions. In this study, we show for the first time, that EcGrx2 exists in both soluble and membrane integrated forms. The soluble form associates with a previously unidentified GSH dependent dehydroascrobate (DHA) reductase, and the membrane integrated form possesses ion channel activities. Using enzyme kinetic data and structural data we unequivocally demonstrate that EcGrx2 recycles ascorbate (AsA) from DHA. This ability to recycle AsA is inhibited by Zinc (Zn2+). We also show that both wildtype and the E. coli grxB deletion mutant can be rescued from H2O2-induced oxidative stress using ascorbate as an antioxidant, which otherwise is only known as a carbon source in bacteria. Moreover, the grxB- mutant is susceptible to intracellular killing by ROS producing macrophages. We further discovered that EcGrx2 integrates into the native E. coli membrane and show that the purified soluble protein readily inserts into artificial lipid bilayer membrane and conducts ions in vitro. Our data demonstrates a highly conserved functional similarity among EcGrx2-orthologs and highlights that the utilization and subsequent recycling of ascorbate as an antioxidant by grxB harbouring gram-negative bacteria, including human pathogens, may provide a survival advantage under hostile oxidative environments.
Vectofusin-1–based T-cell transduction approach compared with RetroNectin-based transduction for generating murine chimeric antigen receptor T-cells
Authors: Patel Romil , Devashish Kartik , Singh Shubhra , Nath Pranay , Gohel Dev , Prasad Rishika , Singh Manisha , Saini Neeraj
Published: August 2021

Gene transfer into human and murine T-cells using viral-based approaches has several promising therapeutic applications including the production of chimeric antigen receptor T-cell (CAR-T) therapy. The generation of murine CAR-T is paramount to test and validate immunocompetent mouse models for CAR-T therapy. Several viral transduction enhancers already exist for gene therapy with few limitations. In this study, we tested vectofusin-1, a short cationic peptide, as a soluble transduction enhancer for gammaretroviral transduction for the generation of anti-CD19 murine CAR-T. We found that in comparison to Retronectin, Vectofusin-1 is an equally optimal transduction enhancer for the generation of murine CAR-T cells.
DNA damage signaling regulates cohesin stabilization and promotes meiotic chromosome axis morphogenesis
Authors: Yu Zhouliang , Dernburg Abby F.
Published: August 2021

A hallmark of meiosis is the reorganization of chromosomes as linear arrays of chromatin loops around a chromosome axis comprised of cohesins and regulatory proteins. Defective axis morphogenesis impairs homolog pairing, synapsis, and recombination. We find that axis assembly inC. elegansis promoted by DNA Damage Response (DDR) signaling activated at meiotic entry. Central to this regulation is downregulation of the cohesin release factor WAPL-1 by the DDR transducer kinase ATM-1, which is activated by the meiotic kinase CHK-2. Additional cohesin regulators, including ECO-1 and PDS-5, also contribute to stabilizing axis-associated cohesins. We find that downregulation of WAPL by ATM also promotes cohesin enrichment at DNA damage foci in cultured mammalian cells. Our findings reveal that the DDR and Wapl play conserved roles in cohesin regulation in meiotic prophase and proliferating cells.

One-Sentence Summary

DNA Damage Response kinase ATM phosphorylates WAPL to promote meiotic chromosome axis assembly and DNA repair
Endothelial cell signature in muscle stem cells validated by VEGFA-FLT1-AKT1 axis promoting survival of muscle stem cell
Authors: Verma Mayank , Asakura Yoko , Wang Xuerui , Zhou Kasey , Ünverdi Mahmut , Kann Allison P. , Krauss Robert S. , Asakura Atsushi
Published: August 2021

Endothelial and skeletal muscle lineages arise from common embryonic progenitors. Despite their shared developmental origin, adult endothelial cells (ECs) and muscle stem cells (MuSCs) (satellite cells) have been thought to possess distinct gene signatures and signaling pathways. Here we shift this paradigm by uncovering how adult MuSC behavior is affected by the expression of a subset of EC transcripts. We used several computational analyses including single-cell RNAseq to show that MuSCs express low levels of canonical EC markers. We demonstrate that MuSC survival is regulated by one such prototypic endothelial signaling pathway (VEGFA-FLT1). Using pharmacological and genetic gain- and loss-of-function studies, we identify the FLT1-AKT1 axis as the key effector underlying VEGFA-mediated regulation of MuSC survival. All together, our data support that the VEGFA-FLT1-AKT1 pathway promotes MuSC survival during muscle regeneration, and highlights how the minor expression of select transcripts is sufficient for affecting cell behavior.
Spatial proteomics reveals subcellular reorganization in human keratinocytes exposed to UVA light
Authors: Valerio Hellen Paula , Ravagnani Felipe Gustavo , Candela Angela Paola Yaya , da Costa Bruna Dias Carvalho , Ronsein Graziella Eliza , Di Mascio Paolo
Published: September 2021

The effects of UV light on the skin have been extensively investigated. However, systematic information about how exposure to UVA light, the least energetic but the most abundant UV radiation reaching the Earth, shapes the subcellular organization of proteins is lacking. Using subcellular fractionation, mass spectrometry-based proteomics, machine learning algorithms, immunofluorescence, and functional assays, we mapped the subcellular reorganization of the proteome of human keratinocytes in response to UVA light. Our workflow quantified and assigned subcellular localization for over 1600 proteins, of which about 200 were found to redistribute upon UVA exposure. Reorganization of the proteome affected modulators of signaling pathways, cellular metabolism, and DNA damage response. Strikingly, mitochondria were identified as one of the main targets of UVA-induced stress. Further investigation demonstrated that UVA induces mitochondrial fragmentation, up-regulates redox-responsive proteins and attenuates respiratory rates. These observations emphasize the role of this radiation as a potent metabolic stressor in the skin.
Amphiregulin mediates non-cell-autonomous effect of senescence on reprogramming
Authors: Joest Mathieu von , Chen Cheng , Douché Thibaut , Chiche Aurelie , Matondo Mariette , Li Han
Published: September 2021

Cellular senescence is an irreversible growth arrest with a highly dynamic secretome, termed the senescence-associated secretory phenotype (SASP). Senescence has been implicated in somatic reprogramming to pluripotency. The cell-intrinsic proliferation arrest is a barrier for reprogramming, whereas the SASP facilitates the cell fate conversion in nonsenescent cells. However, the mechanisms by which reprogramming-induced senescence regulates cell plasticity are not well understood. Here, we have further investigated how the heterogeneity of paracrine senescence impacts reprogramming. We show that senescence promotesin vitroreprogramming in a stress-dependent manner. We identified a catalog of SASP factors and pathways potentially involved in the cell fate conversion using an unbiased proteomic analysis. Amphiregulin (AREG), a growth factor frequently secreted by the senescent cells, promotesin vitroreprogramming by accelerating proliferation and MET via the EGFR signaling pathway. Of note, AREG treatment diminished the negative effect of donor age on reprogramming. Finally, AREG enhancesin vivoreprogramming in the skeletal muscle. Hence, senescence could facilitate cellular plasticity via various SASP factors to promote reprogramming and tissue repair.
Geometry of left-invariant Randers metric on the Heisenberg groups
Authors: Fasihi-Ramandi Ghodratallah , Azami Shahroud
Published: August 2021

Purpose

In this paper, we consider the Heisenberg groups which play a crucial role in both geometry and theoretical physics.

Design/methodology/approach

In the first part, we retrieve the geometry of left-invariant Randers metrics on the Heisenberg group H2n+1, of dimension 2n + 1. Considering a left-invariant Randers metric, we give the Levi-Civita connection, curvature tensor, Ricci tensor and scalar curvature and show the Heisenberg groups H2n+1 have constant negative scalar curvature.

Findings

In the second part, we present our main results. We show that the Heisenberg group H2n+1 cannot admit Randers metric of Berwald and Ricci-quadratic Douglas types. Finally, the flag curvature of Z-Randers metrics in some special directions is obtained which shows that there exist flags of strictly negative and strictly positive curvatures.

Originality/value

In this work, we present complete Reimannian geometry of left invarint-metrics on Heisenberg groups. Also, some geometric properties of left-invarainat Randers metrics will be studied.
Surprise: challenging design perceptions in immersive virtual reality environments? The case of designing a hospital project using a CAVE (Cave Automatic Virtual Environment)
Authors: Maftei Laura , Harty Chris
Published: September 2021

Purpose

The purpose of this paper is to examine how the use of immersive virtual reality (IVR) impacts on the surprise aspects of designing.

Design/methodology/approach

The empirical case is a new hospital in the UK wherein a CAVE (Cave Automatic Virtual Environment) type of an IVR environment was used performing six design review sessions during the bid preparation stage. Drawing from a former video-based study, the authors conducted follow-up discussions with the participants to access their perspectives on design surprises emerging from their engagement with the IVR. The study developed a reflective methodology, interviewing participants about their experiences of doing design in the immersive environment. Retrospective discussions were conducted in a data review format, through playing back video clips of the IVR design sessions and asking the participants to reflect on their IVR design experience and on design surprises emerging from their engagement with the IVR.

Findings

The findings indicate that IVRs, such as the CAVE, are not only enhancing existing understandings of design but also challenging the participants' understanding of the design as they experience the immersive version of it, provoking ruptures in current procedures and driving unanticipated changes to the design.

Originality/value

This qualitative study of surprise in design work using IVRs (for a real-life design project) brings new insights into emerging practices of designing using immersive technology, such as the CAVE.
Tell me more and make me feel proud: the role of eco-labels and informational cues on consumers' food perceptions
Authors: Donato Carmela , D'Aniello Alba
Published: August 2021

Purpose

The objective of the present research is to identify the impact of food-related and packaging-related eco-labels on consumers' perceptions of food quality and safety when an ecological claim, which explains the eco-label meaning, is provided.

Design/methodology/approach

One survey (N = 472) plus one experimental lab study were used to test the hypotheses drawn from the elaboration likelihood model. The research employed a 2 (eco-label: MSC vs FSC) × 2 (ecological claim: present vs absent) between-subjects design plus a control condition (i.e. absence of eco-label).

Findings

When the ecological claim is absent, only food-related eco-labels were found to generate a higher food evaluation. However, when the ecological claim is present, both eco-label types (i.e. food-related and packaging-related) increased food perceptions of quality and safety because of higher feelings of pride.

Originality/value

From a theoretical perspective, this research identifies both food- and packaging-related eco-labels as extrinsic cues able to affect consumers' perception of food quality and safety. Moreover, the findings of this study present practical implications for package design and health policymaking.
Vacuum oven drying of mussels: mathematical modeling, drying characteristics and kinetics study
Authors: İsmail Osman , Gökçe Kocabay Özlem
Published: August 2021

Purpose

The aim of this work was to study the effect of the different temperatures on drying kinetics and quality parameters of vacuum oven-dried mediterranean or black mussel (Mytilus galloprovincialis) specimens.

Design/methodology/approach

Drying process was performed at 50, 60 and 70 °C and a vacuum drying pressure of 0.1 kPa. The proximate composition analysis was done. Drying rates of the mussels were computed. Mathematical modeling was carried out. Effective moisture diffusivity, activation energy and total energy consumption were calculated. Color measurement was conducted.

Findings

Drying took place entirely in the falling rate period. The obtained results indicated that the drying air temperature has a remarkable influence on the moisture content and drying rate. Drying resulted in a significant increasing of protein and fat content. The Deff values ranged from 1.44 × 10−9–3.23 × 10−9 m2/s, with the activation energy 4.47 kW kg−1. The Alibas model is the most proper model to define the drying curves. This method provided high energy efficiency and quality in dried products.

Research limitations/implications

Fresh mussels grown in Eceabat location were used as the study sample. In the drying process, 50, 60, 70 °C temperatures and 0.1 kPa pressure was used. These are the limitations of the research.

Originality/value

This work is the first to report the influence of vacuum oven drying on the color changes and drying kinetics of black mussels.
Does cooperative membership impact the yield and efficiency of smallholder farmers? Evidence from potato farmers in Mongolia
Authors: Ahado Samuel , Hejkrlík Jiří , Enkhtur Anudari , Tseren Tserendavaa , Ratinger Tomáš
Published: August 2021

Purpose

The purpose of this paper is to examine the impact of agricultural cooperative membership on potato production and technical efficiency.

Design/methodology/approach

A combination of propensity score matching technique and sample selection stochastic frontier framework that addresses potential selection bias due to observable and unobservable attributes is used to estimate the effect of participation between cooperative members and non-members. Using a stochastic meta-frontier approach, the technical efficiency of farmers was estimated and compared.

Findings

The empirical results show that the effect of participation in agricultural cooperatives is associated with increased yield and technical efficiency. A comparison of group-specific frontiers indicates that cooperative members perform better than non-members. Cooperative membership decisions is significantly associated with household and farm characteristics (e.g. education, participation in off-farm work, total farmland, distance to market and geographic location).

Practical implications

The findings of this study demonstrate that cooperative organisations can be an important tool to enhance the productivity and efficiency of smallholder farmers. Successful cooperative models together with training programs designed to enlighten farmers on the importance and tangible benefits of collective action should be used to enlarge participation in cooperative organisations. In addition, governments and development agencies should implement targeted investment and capacity building programs related to irrigation management, gender-sensitive awareness and development of the internal institutional mechanisms in cooperatives for the transfer of knowledge and mutual learning so that all members benefit from cooperatives.

Originality/value

Despite the pervasive evidence of the impact of cooperatives on productivity and technical efficiency in the Asian region, this study is probably the first attempt in the crop sector in Mongolia. It provides a rigorous empirical analysis of the impact of agricultural cooperative membership on potato production and technical efficiency through a counterfactual design.
Mobile Internet adoption and technology adoption extensity: evidence from litchi growers in southern China
Authors: Cai Yi , Qi Wene , Yi Famin
Published: August 2021

Purpose

The purpose of this study is to examine the effects of mobile Internet adoption on technology adoption extensity.

Design/methodology/approach

This study uses cross-sectional data collected in 2018 from 932 smallholder litchi farmers in Guangdong Province and Guangxi Province in southern China. A Poisson regression with endogenous treatment effects (ETPR) model is applied to estimate the effects of mobile Internet adoption on technology adoption extensity.

Findings

The ETPR model results indicate that mobile Internet adoption can significantly enhance technology adoption extensity. In addition, the extensity of technology adoption is also determined by education level, training, share of litchi farming income, guidebook use and cooperative membership. Disaggregated analyses further confirm the positive impact of mobile Internet adoption on the number of capital- and labor-intensive technologies adopted.

Originality/value

This study contributes to the literature on agricultural technology adoption. The findings highlight the need to facilitate modern agricultural technology penetration by promoting the use of mobile Internet technologies.
Farm size and pesticide use: evidence from agricultural production in China
Authors: Gao Jingjing , Gai Qingen , Liu Binbin , Shi Qinghua
Published: August 2021

Purpose

China is the world's largest consumer of pesticides. To increase the use efficiency and achieve more sustainable and environmentally friendly use of pesticides in China, it is crucial to understand why Chinese farmers use such a large amount of pesticides.

Design/methodology/approach

The relationship between farm size and pesticide use was investigated by using national household-level panel data from 1995 to 2016.

Finding

Farms that are small and fragmented lead to the use of large amounts of pesticides in China. For a given crop type, three factors contribute to a negative relationship between farm size and pesticide use: the spillover effect from the use of pesticides by other farmers in the same village, the level of mechanization and the management ability of farmers. The first two factors play important roles in the cultivation of grain crops, while the last factor is the main reason why farmers with larger plots of land use fewer pesticides in the cultivation of vegetables. In addition, the effect of agricultural machinery services on reducing the use of pesticides is currently limited, and the service system in China is still insufficient, which has been pointed out that it is also due to the prevalence of small and fragmented farms.

Originality/value

The authors investigate and compare the farm size–pesticide use relationship in both grain and cash crop production. Moreover, the authors systematically explore and explain how farm size is related to a reduction in pesticide use in the cultivation of grain crops and cash crops. These results can help to better understand the role of land scale in pesticide use, lay a foundation for the formulation of policies to reduce pesticide use and provide valuable knowledge about pesticide use for other developing countries around the world.
The effect of export tax rebates on product quality: evidence from China's agricultural product processing industry
Authors: Liang Yue , Dang Jingqi , Chen Shuai
Published: September 2021

Purpose

This study aims to establish the linkage among export tax rebate (ETR), firm innovation and product quality of Chinese agricultural product processing industry (APPI), so that more targeted policy implications can be discussed.

Design/methodology/approach

Using highly disaggregated firm-product-destination-level data through 2001 to 2013 of Chinese APPI, this study employs a two-way fixed effects specification to establish the linkage between ETR and product quality, while the mediational model is adopted to examine potential mechanisms.

Findings

Baseline estimates show that a 1% increase in ETR rate leads to a significant increase in the product quality of APPI by 0.12% on the whole. However, there is a nonlinear, inverse-U shaped relationship between ETR and product quality, and the optimal inflection point occurs when ERT rate equals 0.15. Mechanism analyses show that firm innovation is an important impact channel, which explains 9.8% of quality improvement induced by raising ETR. Further heterogeneous analyses reveal both the total effects of ETR on product quality and the mediation effects of innovation are dominated by young SMEs (small and medium-size enterprises).

Practical implications

Authorities can promote the innovation and then product quality improvement of young SMEs by moderately increasing ETR rate. To ensure ETR more effective in improving quality, it is necessary for the government to encourage innovation. Authorities can reduce the risk of innovation failure for low-tech firms by increasing R&D subsidies, while ensuring innovation returns for high-tech firms in combination with stronger intellectual property protection.

Originality/value

First, this is one of the earlier studies to explore the relationship between ETR and product quality specifically for Chinese APPI. Second, we show firm innovation as an important mediator so that policies aim at raising ETR rates are eventually beneficial to product quality. Third, using the highly disaggregated data, we allow ETR rate to vary across different products, which is an improvement in the accuracy of previous literature. Finally, our research provides additional empirical evidence for revealing the micro-mechanism of ETR affecting firm behaviors.
A Markov model of COVID-19 susceptibilities, infections, recoveries and fatalities: evidence from Nigeria
Authors: Inegbedion Henry Egbezien
Published: August 2021

Purpose

The purpose of this study is to determine the proportion of the population that will be susceptible to the COVID-19 pandemic, as well as the proportions of infections, recoveries and fatalities from the COVID-19 pandemic.

Design/methodology/approach

The design was a longitudinal survey of COVID-19 infections, recoveries and fatalities in Nigeria using the data on the daily updates of the Nigeria Centre for Disease Control for the period 1 May to 23 August 2020. Markov chain analysis was performed on the data.

Findings

The results showed that in the long run, 8.4% of the population will be susceptible to COVID-19 infections, 26.4% of them will be infected, 61.2% of the infected will recover and 4% will become fatal. Thus, if this pattern of infections and recoveries continue, the majority of the infected people in Nigeria will recover whilst a very small proportion of the infected people will die.

Research limitations/implications

A dearth of the extant literature on the problem, especially from the management science perspective.

Practical implications

Results of the study will facilitate policymakers’ response to the curtailment of the pandemic in Nigeria.

Social implications

Curtailing the pandemic through the results of this study will assist in easing the social consequences of the pandemic.

Originality/value

The proposed adjustment to the susceptibilities, infections and recoveries model through the introduction of a fourth state (fatality) to get the susceptibilities, infections, recoveries and fatalities model, signalling a point of departure from previous studies.
Does perceived manager support reduce hotel supervisors' emotional exhaustion? The mediating role of control over time and negative emotions
Authors: Chen Han , Green Yvette , Williams Kim
Published: August 2021

Purpose

Supervisory employees in the hotel industry experience high levels of emotional exhaustion. The current study aims to examine the impact of perceived manager support, perceived control over time and negative emotions at others on hotel supervisors' emotional exhaustion. It further investigates the mediating role of perceived control over time and negative emotions at others on the relationship between perceived manager support and hotel supervisors' emotional exhaustion.

Design/methodology/approach

Paper questionnaires were distributed at a hotel supervisor training seminar. A total of 155 usable responses were collected from hotel supervisors. Confirmatory factor analysis and structural equation modeling were used for hypotheses testing.

Findings

Results showed that perceived manager support and perceived control over time both were negatively associated with hotel supervisors' emotional exhaustion. Negative emotions at others were positively related to hotel supervisors' emotional exhaustion. Both perceived control over time and negative emotions at others were found to mediate the relationship between perceived manager support and hotel supervisors' emotional exhaustion.

Originality/value

The study applied the job demand–resources model and the affective event theory to examine hotel supervisors' emotional exhaustion. The mediating role of perceived control over time and negative emotions at others added to the current knowledge of factors that are associated with hotel supervisory employees' emotional exhaustion.
Association between mass collaboration and knowledge management: a case ofJordan companies
Authors: Riyadh Hosam Alden , Khrais Laith T. , Alfaiza Salsabila Aisyah , Sultan Abdulsatar Abduljabbar
Published: September 2021

Purpose

The key purpose of this research paper was to identify the association between mass collaboration and knowledge management in the context of Jordanian companies. Apart from that, this study also aims to examine the moderating effect of trust and leadership on the association between mass collaboration and knowledge management.

Design/methodology/approach

In this study, the researcher has followed theprimary quantitative method. For data collection, the researcher has conducted a survey questionnaire, whereas the sample was based on 323 participants from the manufacturing sector of Jordan specifically for data analysis; the technique of structural equation modeling was implemented.

Findings

All the independent variables, including organizational structure, adoptedtechnologies in mass collaboration and collaborative learning techniques, have a significantimpact on knowledge management and leadership. Moreover, leadership was also found to be significantly moderating the association between adopted technologies in mass collaboration and knowledge management. Similarly, trust also significantly moderates the association of organizational structure and adopted technologies in mass collaboration significantly with knowledge management.

Research limitations/implications

All study respondents were from Jordan, which might limit the generalizability of the findings. The researchers also invited for more researchers in the incorporation of the time sequence in the proposed causal relations and in the organization level through which mass collaboration and knowledge management.

Originality/value

This study promises to make a valuable contribution to the existing literature, as there was a lack of evidence in the previous studies regarding the impact of mass collaboration on knowledge management within the context of Jordan.