bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of necroptosis in chronic hepatic inflammation and liver disease in Cu/Zn superoxide dismutase deficient mice
Authors: Mohammed Sabira , Nicklas Evan H , Thadathil Nidheesh , Selvarani Ramasamy , Royce Gordon H , Richardson Arlan , Deepa Sathyaseelan S.
Published: August 2020

Mice deficient in the antioxidant enzyme Cu/Zn-superoxide dismutase (Sod1−/−or Sod1KO mice) develop spontaneous hepatocellular carcinoma (HCC) with age. Similar to humans, HCC development in Sod1KO mice progresses from fatty liver disease to non-alcoholic steatohepatitis (NASH) with fibrosis, which eventually progresses to HCC. Because liver inflammation is the main mechanism that drives the disease progression in chronic liver disease (CLD) and because necroptosis is a major source of inflammation, we tested the hypothesis that increased necroptosis in the liver plays a role in increased inflammation and progression to fibrosis and HCC in Sod1KO mice. Phosphorylation of MLKL (P-MLKL), a well-accepted marker of necroptosis, and expression of MLKL protein were significantly increased in the livers of Sod1KO mice compared to WT mice indicating increased necroptosis. Similarly, phosphorylation of RIPK3 and RIPK3 protein levels were also significantly increased. Markers of pro-inflammatory M1 macrophages, NLRP3 inflammasome, and transcript levels of pro-inflammatory cytokines and chemokines, e.g., TNFα, IL-6, IL-1β, and Ccl2 that are associated with human NASH and HCC, were significantly increased. Markers of fibrosis and oncogenic transcription factor STAT3 were also upregulated in the livers of Sod1KO mice. Short term treatment of Sod1KO mice with necrostatin-1s (Nec-1s), a necroptosis inhibitor, significantly reduced necroptosis, pro-inflammatory cytokines, fibrosis markers and STAT3 activation. Our data show for the first time that necroptosis-mediated inflammation contributes to fibrosis and HCC progression in Sod1KO mice, a mouse model of accelerated aging and progressive HCC development. These findings suggest that necroptosis might be a target for treating NASH and HCC.
The effect of whey protein on viral infection and replication of SARS-CoV-2 and pangolin coronavirus in vitro
Authors: Fan Huahao , Luo Yuqian , Hong Bixia , Wang Liqin , Jin Xiangshu , Chen Yangzhen , Hu Yunjia , Li Tong , Zhuang Hui , Zhou Yi-Hua , Tong Yigang , Xiang Kuanhui
Published: August 2020

Since the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in human breastmilk, little is known about the antiviral property of human breastmilk to SARS-CoV-2 and its related pangolin coronavirus (GX_P2V). Here we present for the first time that whey protein from human breastmilk effectively inhibited both SARS-CoV-2 and GX_P2V by blocking viral attachment, entry and even post-entry viral replication. Moreover, human whey protein inhibited infectious virus production proved by the plaque assay. We found that whey protein from different species such as cow and goat also showed anti-coronavirus properties. And commercial bovine milk also showed similar activity. Interestingly, the main antimicrobial components of breastmilk, such as Lactoferrin and IgA antibody, showed limited anti-coronavirus activity, indicating that other factors of breastmilk may play the important anti-coronavirus role. Taken together, we reported that whey protein inhibits SARS-CoV-2 and its related virus of GX_P2V. These results rule out whey protein as a direct-acting inhibitor of SARS-CoV-2 and GX_P2V infection and replication and further investigation of its molecular mechanism of action in the context of COVID-19.
Origin of exponential growth in nonlinear reaction networks
Authors: Lin Wei-Hsiang , Kussell Edo , Young Lai-Sang , Jacobs-Wagner Christine
Published: August 2020

Exponentially growing systems are prevalent in nature, spanning all scales from biochemical reaction networks in single cells to food webs of ecosystems. How exponential growth emerges in nonlinear systems is mathematically unclear. Here, we describe a general theoretical framework that reveals underlying principles of long-term growth: scalability of flux functions and ergodicity of the rescaled systems. Our theory shows that nonlinear fluxes can generate not only balanced growth, but also oscillatory or chaotic growth modalities, explaining non-equilibrium dynamics observed in cell cycles and ecosystems. Our mathematical framework is broadly useful in predicting long-term growth rates from natural and synthetic networks, analyzing the effects of system noise and perturbations, validating empirical and phenomenological laws on growth rate, and studying autocatalysis and network evolution.

Significance

Natural systems (e.g., cells, ecosystems) generally consist of reaction networks (e.g., metabolic networks, food webs) with nonlinear flux functions (e.g., Michaelis-Menten kinetics, density-dependent selection). Despite their complex nonlinearities, these systems often exhibit simple exponential growth in the long term. How exponential growth emerges from nonlinear networks remains elusive. Our work demonstrates mathematically how two principles, multivariate scalability of flux functions and ergodicity of the rescaled system, guarantee a well-defined rate of growth. By connecting ergodic theory, a powerful branch of mathematics, to the study of growth in biology, our theoretical framework can recapitulate various growth modalities (from balanced growth to periodic, quasi-periodic or even chaotic behaviors), greatly expanding the types of growing systems that can be studied.
Single-cell atlas of tumor clonal evolution in liver cancer
Authors: Ma Lichun , Wang Limin , Chang Ching-Wen , Heinrich Sophia , Dominguez Dana , Forgues Marshonna , Candia Julián , Hernandez Maria O. , Kelly Michael , Zhao Yongmei , Tran Bao , Hernandez Jonathan M. , Davis Jeremy L. , Kleiner David E. , Wood Bradford J. , Greten Tim F. , Wang Xin Wei
Published: August 2020

Tumor evolution is a key feature of tumorigenesis and plays a pivotal role in driving intratumor heterogeneity, treatment failure and patients’ prognosis. Here we performed single-cell transcriptome profiling of 46 primary liver cancers from 37 patients enrolled for interventional studies. We surveyed the landscape of ~57,000 malignant and non-malignant cells and determined tumor cell clonality by developing a machine learning-based consensus clustering method. We found evidence of tumor cell branching evolution using hierarchical clustering, RNA velocity as well as reverse graph embedding methods. Interestingly, an increasing tumor cell clonality was tightly linked to patients’ prognosis, accompanied by a polarized immune cell landscape. We identified osteopontin as a key player for tumor cell evolution and microenvironmental reprogramming. Our study offers insight into the collective behavior of tumor cell communities in liver cancer as well as potential drivers for tumor evolution in response to therapy.
Longitudinal changes in aperiodic and periodic activity in electrophysiological recordings in the first seven months of life
Authors: Schaworonkow Natalie , Voytek Bradley
Published: August 2020

Neuronal oscillations emerge in early human development. These periodic oscillations are thought to rapidly change in infancy and stabilize during maturity. Given their numerous connections to physiological and cognitive processes, as well as their pathological divergence, understanding the trajectory of oscillatory development is important for understanding healthy human brain development. This understanding is complicated by recent evidence that assessment of periodic neuronal oscillations is confounded by aperiodic neuronal activity, which is an inherent feature of electrophysiological neuronal recordings. Recent cross-sectional evidence shows that this aperiodic signal progressively shifts from childhood through early adulthood, and from early adulthood into later life. None of these studies, however, have been performed in infants, nor have they been examined longitudinally. Here, we analyzed non-invasive EEG data from 22 typically developing infants, across multiple time points, ranging between 38 and 203 days old. We show that the progressive flattening of the EEG power spectrum begins in very early development, continuing through the first several months of life. These results highlight the importance of separating the periodic and aperiodic neuronal signals, because the aperiodic signal can bias measurement of neuronal oscillations. Given the infrequent, bursting nature of oscillations in infants, we recommend the use of quantitative time domain approaches that isolate bursts and uncover changes in waveform properties of oscillatory bursts.
Influence of climate forecasts, data assimilation, and uncertainty propagation on the performance of near-term phenology forecasts
Authors: Taylor Shawn D. , White Ethan P.
Published: August 2020

Evaluation of ecological forecasts is a vital step in the continuous improvement of near-term ecological forecasts. Here we performed a thorough evaluation of a near-term phenological forecast system which has been operating for several years. We evaluated point forecast accuracy and the reliability of the prediction intervals. We also tested the contribution of upstream climate forecasts on phenology forecast proficiency. We found that 9 month climate forecasts contributed little skill overall, though some species did benefit from them. The assimilation of observed winter and spring temperature provided the largest improvement of forecast skill throughout the spring. We also found that phenology forecast prediction intervals were most robust when uncertainty was propagated from climate, phenological model, and model parameters as opposed to using climate uncertainty alone. Our analysis points the way toward several potential improvements to the forecasting system, which can be re-evaluated at a future date in a continuous cycle of forecast refinement.
Spontaneous activity competes externally evoked responses in sensory cortex
Authors: Karvat Golan. , Alyahyay Mansour , Diester Ilka
Published: August 2020

The functional role of spontaneous brain activity, especially in relation to external events, is a longstanding key question in neuroscience. Intrinsic and externally-evoked activities were suggested to be anticorrelated, yet inferring an antagonistic mechanism between them remains a challenge. Here, we used beta-band (15-30 Hz) power as a proxy of spontaneous activity in the rat somatosensory cortex during a detection task. Beta-power anticorrelated with sensory-evoked-responses, and high rates of spontaneously occurring beta-bursts predicted reduced detection. By applying a burst-rate detection algorithm in real-time and trial-by-trial stimulus-intensity adjustment, this influence could be counterbalanced. Mechanistically, bursts in all bands indicated transient synchronization of cell assemblies, but only beta-bursts were followed by a reduction in firing-rate. Our findings reveal that spontaneous beta-bursts reflect a dynamic state that competes with external stimuli.
Protein Plasticity and its Role in Cellular Functions
Authors: Ilyas Sidra , Manan Abdul
Published: August 2020

The contribution of redox active properties of cysteines in intrinsically disordered regions (IDRs) of proteins is not very well acknowledged. Despite of providing structural stability and rigidity, intrinsically disordered cysteines are exceptional redox sensors and the redox status of the protein defines its structure. Experimental evidence suggests that the conformational heterogeneity of cysteines in intrinsically disordered proteins (IDPs) is related to numerous functions including regulation, structural changes and fuzzy complex formation. The unusual plasticity of IDPs make them suitable candidate to interact with many clients under specific conditions. Binding capabilities, dimerization and folding or unfolding nature of IDPs upon interaction with multiple clients assign distinct conformational changes associated with disulfide formation. Here we are going to focus on redox activity of IDPs, their dramatic roles that are not only restricted to cellular redox homeostasis and signaling pathways but also provide antioxidant, anti-apoptotic, binding and interactive power.
Mecp2 Deficiency Alters M1/M2 Gene Expresion in Bone Marrow-Derived Macrophages Upon Stimulation
Authors: Zalosnik M.I , De Filippis B , De Simone R. , Pietraforte D. , Laviola G. , Degano A.L
Published: August 2020

Rett Syndrome (RTT) is a neurodevelopmental disorder mostly caused by mutations in the X-linked gene, MeCP2, which encodes for methyl-CpG binding protein 2 (MeCP2). MeCP2 is member of a family of methyl binding proteins that control the expression of several genes according to the genomic context. Emerging evidence suggests that immune dysfunctions would actively contribute to the pathogenesis of RTT. Macrophages are key effector cells that participate in several critical aspects of immune responses. The aim of our work was to assess the response of macrophagesin vitroin the context of polarizing stimuli. We used bone marrow-derived macrophages (BMDM) obtained from MeCP2308/ymice, a mouse model that carries a truncated form of MeCP2. Since MeCP2 is expressed as a “partially functional” protein in humans with RTT it becomes crucial to establish how the presence of a mutant form of MeCP2 affects immune responses to support the normal homeostasis of individuals. MeCP2 deficiency induced exacerbation of pro-inflammatory mediators and deficient immune regulatory responses under polarizing conditions. These findings suggest that MeCP2 plays a role in the establishment of macrophage polarization in the context of immune activation. Present results may have important implications in understanding RTT pathogenesis and for developing potential treatments.

Conflict of interest

The authors declare no conflicts of interest.
STRATEGIC IDENTIFICATION OF NEW GENETIC DIVERSITY TO EXPAND LENTILLens culinarisMedik. PRODUCTION USING NEPAL AS AN EXAMPLE
Authors: Neupane Sandesh , Dhakal Rajeev , Wright Derek M. , Shrestha Deny Kumar , Dhakal Bishnu , Bett Kirstin E.
Published: August 2020

This article is written to disseminate descriptive results obtained from field experiments conducted at Bardiya, Nepal, during winter 2016 and 2017 on 324 diverse lentil (L. culinarisMedik.) genotypes obtained from genebanks and breeding programs around the world. Lentil genotypes were examined for phenological traits related to adaptation, and recommendations for potential incorporation of new exotic genotypes into Nepalese breeding programs are presented. In addition, predictions of days to flowering based on temperature and photoperiod are used to identify genotypes that hold suitability for specific growing regions in Nepal, allowing for the potential expansion of growing regions. From this study we found many potentially adapted genotypes for terai, mid-hill and high hill growing regions, the list consists of a number of large-seeded lines with yellow cotyledons, an entirely new market class of lentils in Nepal. This paper primarily targets lentil breeders and agronomists; furthermore, it can be equally informative to extension workers involved in the pulse crop research and development in Nepal and other countries with similar climatic conditions.
A toolkit to generate inducible and interconvertibleDrosophilatransgenes
Authors: Wendler Franz , Park Sangbin , Hill Claire , Galasso Alessia , Chang Kathleen R. , Awan Iman , Sudarikova Yulia , Bustamante-Sequeiros Mar , Liu Sichen , Sung Ethan , Aisabonoko Gabrielle , Kim Seung K. , Baena-Lopez Luis Alberto
Published: August 2020

The existence of three independent binary systems for conditional gene expression (Gal4/UAS; LexA/LexAop; QF/QUAST) has greatly expanded versatile genetic analyses in the fruit flyDrosophila melanogaster; however, the experimental application of these tools is limited by the need to generate multiple collections of non-interchangeable transgenic fly strains for each inducible gene expression system. To address this practical limitation, we developed a modular vector that contains the regulatory elements from all three binary systems, enabling Gal4-, LexA- or QF-dependent expression of transgenes. Our methods also incorporate DNA elements that facilitate independent site-specific recombination and elimination of regulatory UAS, LexAop or QUAST modules with spatial and temporal control, thus offering unprecedented possibilities and logistical advantages forin vivogenetic modulation and efficient interconversion of overexpression transgenic fly lines.
Structure and contingency determine mutational hotspots for flower color evolution
Authors: Wheeler Lucas C , Wing Boswell A , Smith Stacey D
Published: August 2020

Evolutionary genetic studies have uncovered abundant evidence for genomic hotspots of phenotypic evolution, as well as biased patterns of mutations at those loci. However, the theoretical basis for this concentration of particular types of mutations at particular loci remains largely unexplored. In addition, historical contingency is known to play a major role in evolutionary trajectories, but has not been reconciled with the existence of such hotspots. For example, do the appearance of hotspots and the fixation of different types of mutations at those loci depend on the starting state and/or on the nature and direction of selection? Here we use a computational approach to examine these questions, focusing the anthocyanin pigmentation pathway, which has been extensively studied in the context of flower color transitions. We investigate two transitions that are common in nature, the transition from blue to purple pigmentation and from purple to red pigmentation. Both sets of simulated transitions occur with a small number of mutations at just four loci and show strikingly similar peaked shapes of evolutionary trajectories, with the mutations of largest effect occurring early but not first. Nevertheless, the types of mutations (biochemical vs. regulatory) as well as their direction and magnitude are contingent on the particular transition. These simulated color transitions largely mirror findings from natural flower color transitions, which are known to occur via repeated changes at a few hotspot loci. Still, some types of mutations observed in our simulated color evolution are rarely observed in nature, suggesting that pleiotropic effects further limit the trajectories between color phenotypes. Overall, our results indicate that the branching structure of the pathway leads to a predictable concentration of evolutionary change at hotspot loci, but the types of mutations at these loci and their order is contingent on the evolutionary context.
Xylem systems genetics analysis reveals a key regulator of lignin biosynthesis in Populus deltoides
Authors: Balmant Kelly M. , Noble Jerald D. , C. Alves Filipe , Dervinis Christopher , Conde Daniel , Schmidt Henry W. , Vazquez Ana I. , Barbazuk William B. , Campos Gustavo de los , Resende Marcio F.R. , Kirst Matias
Published: August 2020

Despite the growing resources and tools for high-throughput characterization and analysis of genomic information, the discovery of the genetic elements that regulate complex traits remains a challenge. Systems genetics is an emerging field that aims to understand the flow of biological information that underlies complex traits from genotype to phenotype. In this study, we used a systems genetics approach to identify and evaluate regulators of the lignin biosynthesis pathway in Populus deltoides by combining genome, transcriptome, and phenotype data from a population of 268 unrelated individuals of P. deltoides. The discovery of lignin regulators began with the quantitative genetic analysis of the xylem transcriptome and resulted in the detection of 6706 and 4628 significant local- and distant-eQTL associations, respectively. Among the locally regulated genes, we identified the R2R3-MYB transcription factor MYB125 (Potri.003G114100) as a putative trans-regulator of the majority of genes in the lignin biosynthesis pathway. The expression of MYB125 in a diverse population positively correlated with lignin content. Furthermore, overexpression of MYB125 in transgenic poplar resulted in increased lignin content, as well as altered expression of genes in the lignin biosynthesis pathway. Altogether, our findings indicate that MYB125 is involved in the control of a transcriptional coexpression network of lignin biosynthesis genes during secondary cell wall formation in P. deltoides.
Rapid Birth or Death of Centromeres on Fragmented Chromosomes in Maize
Authors: Liu Yalin , Su Handong , Zhang Jing , Shi Lindan , Liu Yang , Zhang Bing , Bai Han , Liang Shuang , Gao Zhi , Birchler James A. , Han Fangpu
Published: August 2020

Comparative genomics has revealed common occurrences in karyotype evolution such as chromosomal end-to-end fusions and insertions of one chromosome into another near the centromere, as well as many cases of de novo centromeres that generate positional polymorphisms. However, how rearrangements such as dicentrics and acentrics persist without being destroyed or lost remains unclear. Here, we sought experimental evidence for the frequency and timeframe for inactivation and de novo formation of centromeres in maize (Zea mays). The pollen from plants with supernumerary B chromosomes was gamma-irradiated and then applied to normal maize silks of a line without B chromosomes. In ∼8,000 first-generation seedlings, we found many B–A translocations, centromere expansions, and ring chromosomes. We also found many dicentric chromosomes, but a fraction of these show only a single primary constriction, which suggests inactivation of one centromere. Chromosomal fragments were found without canonical centromere sequences, revealing de novo centromere formation over unique sequences; these were validated by immunolocalization with Thr133-phosphorylated histone H2A, a marker of active centromeres, and chromatin immunoprecipitation-sequencing with the CENH3 antibody. These results illustrate the regular occurrence of centromere birth and death after chromosomal rearrangement during a narrow window of one to potentially only a few cell cycles for the rearranged chromosomes to be recognized in this experimental regime.
In situ structural studies during denaturation of natural and synthetically crosslinked collagen using synchrotron SAXS
Authors: Zhang Yi , Buchanan Jenna , Naffa Rafea , Mansel Bradley , Maidment Catherine , Holmes Geoff , Prabakar Sujay
Published: August 2020

Collagen is an important biomacromolecule, making up the majority of the extracellular matrix in animal tissues. Naturally occurring crosslinks in collagen stabilize its intermolecular structure in vivo, whereas chemical treatments for introducing synthetic crosslinks are often carried out ex vivo to improve the physical properties or heat stability of the collagen fibres for applications in biomaterials or leather production. Effective protection of intrinsic natural crosslinks as well as allowing them to contribute to collagen stability together with synthetic crosslinks can reduce the need for chemical treatments. However, the contribution of these natural crosslinks to the heat stability of collagen fibres, especially in the presence of synthetic crosslinks, is as yet unknown. Using synchrotron small-angle X-ray scattering, the in situ role of natural and synthetic crosslinks on the stabilization of the intermolecular structure of collagen in skins was studied. The results showed that, although natural crosslinks affected the denaturation temperature of collagen, they were largely weakened when crosslinked using chromium sulfate. The development of synergistic crosslinking chemistries could help retain the intrinsic chemical and physical properties of collagen-based biological materials.
Self-assembly of block copolymers under non-isothermal annealing conditions as revealed by grazing-incidence small-angle X-ray scattering
Authors: Fernández-Regúlez Marta , Solano Eduardo , Evangelio Laura , Gottlieb Steven , Pinto-Gómez Christian , Rius Gemma , Fraxedas Jordi , Gutiérrez-Fernández Edgar , Nogales Aurora , García-Gutiérrez Mari Cruz , Ezquerra Tiberio A. , Pérez-Murano Francesc
Published: August 2020

An accurate knowledge of the parameters governing the kinetics of block copolymer self-assembly is crucial to model the time- and temperature-dependent evolution of pattern formation during annealing as well as to predict the most efficient conditions for the formation of defect-free patterns. Here, the self-assembly kinetics of a lamellar PS-b-PMMA block copolymer under both isothermal and non-isothermal annealing conditions are investigated by combining grazing-incidence small-angle X-ray scattering (GISAXS) experiments with a novel modelling methodology that accounts for the annealing history of the block copolymer film before it reaches the isothermal regime. Such a model allows conventional studies in isothermal annealing conditions to be extended to the more realistic case of non-isothermal annealing and prediction of the accuracy in the determination of the relevant parameters, namely the correlation length and the growth exponent, which define the kinetics of the self-assembly.
The structure of PfGH50B, an agarase from the marine bacterium Pseudoalteromonas fuliginea PS47
Authors: Pluvinage Benjamin , Robb Craig S. , Jeffries Roderick , Boraston Alisdair B.
Published: August 2020

The recently identified marine bacterium Pseudoalteromonas fuliginea sp. PS47 possesses a polysaccharide-utilization locus dedicated to agarose degradation. In particular, it contains a gene (locus tag EU509_06755) encoding a β-agarase that belongs to glycoside hydrolase family 50 (GH50), PfGH50B. The 2.0 Å resolution X-ray crystal structure of PfGH50B reveals a rare complex multidomain fold that was found in two of the three previously determined GH50 structures. The structure comprises an N-terminal domain with a carbohydrate-binding module (CBM)-like fold fused to a C-terminal domain by a rigid linker. The CBM-like domain appears to function by extending the catalytic groove of the enzyme. Furthermore, the PfGH50B structure highlights key structural features in the mobile loops that may function to restrict the degree of polymerization of the neoagaro-oligosaccharide products and the enzyme processivity.
Tetragonal crystal form of the cyanobacterial bicarbonate-transporter regulator SbtB from Synechocystis sp. PCC 6803
Authors: Bu Guanhong , Simmons Chad R. , Nielsen David R. , Nannenga Brent L.
Published: August 2020

The PII-like protein SbtB has been identified as a regulator of SbtA, which is one of the key bicarbonate transporters in cyanobacteria. While SbtB from Synechocystis sp. PCC 6803 has previously been shown to be a trimer, a new crystal form is reported here which crystallizes in what is thought to be a non-native tetramer in the crystal, with the C-terminus in an extended conformation. The crystal structure shows the formation of an intermolecular disulfide bond at Cys94 between SbtB monomers, which may stabilize this conformation in the crystal. This motivates the need for future studies to investigate the potential role that the oxidation and reduction of these cysteines may play in the activation and/or function of SbtB.
Immigrants' entrepreneurial motivation in Europe: liabilities and assets
Authors: García-Cabrera Antonia Mercedes , Lucía-Casademunt Ana Maria , Padilla-Angulo Laura
Published: August 2020

Purpose

This paper examines how the institutional distance between immigrants' country of residence and country of origin, as well as the regulative and normative aspects of institutions in immigrants' country of residence, social context variables and individual psycho-behavioural factors, condition immigrants' entrepreneurial motivation (i.e. mainly by necessity, by a combination of necessity and opportunity, or mainly by opportunity), which is in contrast to the previous literature on immigrant entrepreneurship that mainly focuses on micro-level factors.

Design/methodology/approach

By using hierarchical linear regression models to test our hypotheses, the authors analyse 468 first-generation immigrant entrepreneurs settled in 31 European countries using data from the European Working Conditions Survey (6th EWCS; Eurofound, 2015 database) combined with other datasets to derive the macro-level variables (i.e. the Doing Business Project; Hofstede et al., 2010).

Findings

The authors find that distance in the normative aspects of institutions harms entrepreneurial opportunity motivation. At the same time, however, opportunity motivation is likely to benefit from both the normative aspects of institutions that reduce locals' opportunity motivation and the distance in the regulative aspects of institutions.

Originality/value

This article analyses immigrant entrepreneurship in Europe, which has been under-examined in the extant literature, and takes into account the micro-, meso- and macro-level factors affecting the entrepreneurial motivation of immigrants in Europe. This analysis responds to the need already highlighted by previous research to include not only micro-level factors but also meso- and macro-level factors in the analysis of immigrant entrepreneurship (Aliaga-Isla and Rialp, 2013).
The impact of board and audit committee characteristics on corporate social responsibility: evidence from the Iranian stock exchange
Authors: Mohammadi Shaban , Saeidi Hadi , Naghshbandi Nader
Published: August 2020

Purpose

The purpose of this study is to investigate the effect of board and audit committee characteristics on corporate social responsibility (CSR) in Iranian companies listed in stock exchanges.

Design/methodology/approach

This is a descriptive-correlational and an applied research. The statistical population of this research is all companies listed in Tehran Stock Exchange and the research period is from 2012 to 2018. Using screening method a sample of 150 companies was selected. Multivariate regression and the software Eviews 10 were used for data analysis and hypothesis testing.

Findings

The results indicated that board size had a significant effect on CSR; board independence had a significant effect on CSR; managerial ownership did not have a significant effect on CSR; CEO duality did not have a significant effect on CSR; audit committee size had a significant effect on CSR; audit committee independence had a significant effect on CSR; and financial expertise of audit committee members had a significant effect on CSR.

Originality/value

The present study is the first research performed on the effect of board and audit committee characteristics on CSR in Iran. The results of this study contribute to the literature on the effect of board and audit committee characteristics on CSR and provide suggestions for capital market participants. CSR helps reduce asymmetric distribution of information among the internal and external organizational entities and reduce agency problems and conflicts among different groups. Based on the results, an effective audit committee as an effective mechanism enhances the credibility of financial and non-financial reporting such as social responsibility, which means that an effective audit committee can improve the level of voluntary disclosure of information through effective oversight of the reporting process. It is also suggested that companies focus on audit committee characteristics to increase the level of CSR.
Exploring barriers to sexual transmitted infections (STIs) and HIV testing among young black sub-Sahara African (BSSA) communities in diaspora, UK
Authors: Nyashanu Shinga Nicole , Nyashanu Mathew , Ekpenyong Mandu Stephene
Published: August 2020

Purpose

Sexual transmitted infections (STIs) are associated with high stigma leading to poor sexual health-seeking behaviour and mental health problems. Although human immunodeficiency virus (HIV) prevention has generally been successful in many communities across the world, statistics for young people have remained relatively low, especially among most affected communities such as the black sub-Sahara African (BSSA) communities. This paper aims to explore the barriers to STIs and HIV testing among young BSSA communities living in the UK.

Design/methodology/approach

The research study used an explorative qualitative approach. The study included 6 focus groups comprising 10 people each (N = 60), and 12 one-to-one follow-up interviews were held with the research participants. Two one-to-one follow-up interviews were held from each focus group (N = 12).

Findings

The study found that perceived risk taking, perceived HIV test embarrassment, sexual health professionals’ attitudes, perceived HIV as death sentence, limited educational awareness and general HIV stigma prevented research participants from testing and impacted on their mental health well-being.

Originality/value

There is a need to increase sexual health and mental health education awareness among young BSSA communities. More importantly culturally sensitive interventions to reduce the impact of HIV stigma need to be rolled out in different diverse communities. This study is the first of its kind to look at the barriers affecting young BSSA communities in accessing sexual health testing services in the UK.
A decision support system to assure high-performance maintenance service
Authors: Aiello Giuseppe , Benítez Julio , Carpitella Silvia , Certa Antonella , Enea Mario , Izquierdo Joaquín , La Cascia Marco
Published: August 2020

Purpose

This study aims to propose a decision support system (DSS) for maintenance management of a service system, namely, a street cleaning service vehicle. Referring to the information flow management, the blockchain technology is integrated in the proposed DSS to assure data transparency and security.

Design/methodology/approach

The DSS is designed to efficiently handle the data acquired by the network of sensors installed on selected system components and to support the maintenance management. The DSS supports the decision makers to select a subset of indicators (KPIs) by means of the DEcision-MAaking Trial and Evaluation Laboratory method and to monitor the efficiency of performed preventive maintenance actions by using the mathematical model.

Findings

The proposed maintenance model allows real-time decisions on interventions on each component based on the number of alerts given by sensors and taking into account the annual cost budget constraint.

Research limitations/implications

The present paper aims to highlight the implications of the blockchain technology in the maintenance field, in particular to manage maintenance actions’ data related to service systems.

Practical implications

The proposed approach represents a support in planning, executing and monitoring interventions by assuring the security of the managed data through a blockchain database. The implications regard the monitoring of the efficiency of preventive maintenance actions on the analysed components.

Originality/value

A combined approach based on a multi-criteria decision method and a novel mathematical programming model is herein proposed to provide a DSS supporting the management of predictive maintenance policy.
Researching with the Sturm und Drang of COVID-19: telling tales of teachers' teaching
Authors: Pelosi Ligia , Vicars Mark
Published: August 2020

Purpose

The purpose of this paper is to reflect on the effects of COVID-19 on teachers' pedagogical approaches, and how this has consequences for student learning.

Design/methodology/approach

This paper explores the impact of COVID-19 through teachers' experiences, perceptions from a critical cultural perspective. The paper draws on preservice and graduate teachers' narrative reflections as articulated through Instagram posts.

Findings

This paper articulates a comparison between the concept of Sturm und Drang and the contemporary landscape of teaching and learning remotely as a result of COVID-19 lockdown restrictions and limitations.

Research limitations/implications

The data upon which this paper is based were limited to five participants' accounts taken from the teacherwhispers Instagram site. They indicate relevant themes but are not representative of the overall phenomenon that COVID-19 has generated.

Practical implications

This paper is representative of the particular elements encountered when drawing upon an online-based methodological approach. It suggests the productive affordances of technology for narrating lived experience in a professional context.

Social implications

Retelling embodied narratives can be a fraught affair. This paper brings together associative experiences of COVID-19 to draw together individual stories to narrate a collective experience.

Originality/value

This paper addresses a dynamically evolving phenomenon. As such, it is highly original and explores dilemmas, situations and implications that have not previously been addressed.
Seed size and weight of 129 tree species in Japan
Authors: Kimura Megumi K. , Mizuki Inoue , Kawamura Ryoma , Koike Misato , Furumoto Ryo , Kusumoto Buntarou , Fuji Akinori , Kubota Yasuhiro , Enoki Tsutomu
Published: August 2020

Information on seed morphology and fruiting phenology related to fitness and reproductive strategy is important for plant ecology and evolution. Although seed morphology is highly variable across years, regions and mother trees even within the same species, seed mass and size are often reported as averages or ranges for each species in existing databases or picture books. Unfortunately, freely available seed trait data for individual seeds are limited. This paper reports data on morphology (seed length, width and height) and dry weight of individual seeds from 129 tree species in Japan. It includes data from 79 genera in 44 families collected from various forests located in cool temperate to subtropical regions in Japan, including species not reported in previous databases. We mainly used seeds from the collections of the Forest Tree Gene Bank Program, but new seeds were also collected. If possible, multiple seeds were collected from multiple mother trees of the same species. This paper also reports data of the sampling month and date, which indicates the fruiting season of trees at the sampling site. By comparing these data to past or future data, we hope that it will aid in understanding the effects of climate change on fruiting phenology.

The complete data set for this abstract published in the Data Paper section of the journal is available in electronic format in MetaCat in JaLTER at http://db.cger.nies.go.jp/JaLTER/metacat/metacat/ERDP-2020-14.1/jalter-en.
Sodium hexametaphosphate’s impact on hydrodynamic parameters of milk fat globule membrane
Authors: Ali Fatma , Tian Kangming , Liu Xuhui , Atehli Dima , Wang Jianming
Published: August 2020

Being able to stabilise milk fat globule particles after pasteurisation over time and reduce the phase separation and migration rate of the cream layer would be of great interest. This study examined the prolonged destabilisation of MFGM emulsions after blending with sodium hexametaphosphate (SHMP) with respect to particle migration, fat globule size distribution, phase separation, variations in the raw signal and serum‐phase protein levels. Low SHMP levels in blended MFGM reduced the interactions between fat droplets during heating. Low SHMP concentrations are recommended for stabilising MFGM.
“Unreasonable” ventricular pacings
Authors: Zhang Yubin , Liu Tong , Korantzopoulos Panagiotis
Published: August 2020

A 66‐year‐old man, implanted Abbott dual‐chamber pacemaker, was admitted to our hospital due to recurrent palpitation. ECG was recorded on admission, which created a diagnostic confusion: What accounts for the appearance of the VP in the setting of a stable intrinsic atrioventricular (AV) conduction? In this case, we will focus on the logical reasoning in the analysis of Pacing ECG.
Allovalency observed by transferred NOE: interactions of sulfated tyrosine residues in the N‐terminal segment of CCR5 with the CCL5 chemokine
Authors: Kessler Naama , Akabayov Sabine R. , Moseri Adi , Cohen Leah S. , Sakhapov Damir , Bolton David , Fridman Brandon , Kay Lewis E. , Naider Fred , Anglister Jacob
Published: August 2020

The N‐terminal segment of the chemokine receptor Human CC chemokine receptor 5 (CCR5), Nt‐CCR5, contains four tyrosine residues, Y3, Y10, Y14, and Y15. Sulfation of at least two of these tyrosine residues was found to be essential for high‐affinity binding of CCR5 to its chemokine ligands. Here, we show that among the monosulfated Nt‐CCR5(8‐20) peptide surrogates (sNt‐CCR5) those sulfated at Y15 and Y14 have the highest affinity for the CC chemokine ligand 5 (CCL5) chemokine in comparison with monosulfation at position Y10. Sulfation at Y3 was not investigated. A peptide sulfated at both Y14 and Y15 has the highest affinity for CCL5 by up to a factor of 3, in comparison with the other disulfated (sNt‐CCR5) peptides. Chemical shift perturbation analysis and transferred nuclear Overhauser effect measurements indicate that the sulfated tyrosine residues interact with the same CCL5‐binding pocket and that each of the sulfated tyrosines at positions 10, 14, and 15 can occupy individually the binding site on CCL5 in a similar manner, although with somewhat different affinity, suggesting the possibility of allovalency in sulfated Nt‐CCR5 peptides. The affinity of the disulfated peptides to CCL5 could be increased by this allovalency and by stronger electrostatic interactions.
Shape Memory Alloy Bimorph Microactuators by Lift-Off Process
Authors: Sun Hao , Luo Jianjun , Ren Zhongjing , Lu Ming , Nykypanchuk Dmytro , Mangla Sundeep , Shi Yong
Published: August 2020

This study aims to develop a new fabrication process to create high-precision patterned shape memory alloy (SMA) bimorph micro-actuators by the e-beam evaporation technique. To examine the effect of the annealing process on nitinol (NiTi) thin film characteristics, the as-deposited and annealed NiTi thin films are, respectively, investigated. X-ray diffraction (XRD) results demonstrate the crystallization of NiTi thin films after annealing at 600 °C. The transformation behaviors of NiTi thin films during heating and cooling are studied using the differential scanning calorimeter (DSC). Furthermore, scanning electron microscopy (SEM) images indicate that SMA bimorph micro-actuators with high-precision features can be fabricated by the lift-off process, without any wet or dry etching procedures, and their thermomechanical behaviors are experimentally verified by comparing them with that of finite element analysis simulation results.
On the Effects of Injection Strategy, Exhaust Gas Recirculation, and Intake Boost on TSCI With Wet Ethanol
Authors: Gainey Brian , Yan Ziming , Rahimi-Boldaji Mozhgan , Lawler Benjamin
Published: August 2020

Using a split injection of wet ethanol, where a portion of the fuel is injected during the compression stroke, has been shown to be an effective way to enable thermally stratified compression ignition (TSCI), an advanced combustion mode that aims to control the heat release process by enhancing thermal stratification, thereby extending the load range of low temperature combustion (LTC). Wet ethanol is the ideal fuel candidate to enable TSCI because it has a high latent heat of vaporization and low equivalence ratio sensitivity. Previous work has shown “early” compression stroke injections (−150 to −100 deg aTDC) have the potential to control the start of combustion (SOC) while “mid” compression stroke injections (−90 to −30 deg aTDC) have the potential to control in-cylinder thermal stratification, thereby controlling the heat release rate. In this work, a mixture of 80% ethanol and 20% water by mass is used to further study the injection strategy of TSCI combustion. Additionally, the impact of external, cooled exhaust gas recirculation (EGR), and intake boost on the effectiveness of a TSCI with wet ethanol to control the heat release process are investigated. It was found that neither external, cooled EGR, nor intake boost level has any impact on the effectiveness of the compression stroke injection(s) at controlling the burn rate of TSCI. External, cooled EGR has the potential to increase the overall tailpipe combustion efficiency, while intake boost has the potential to decrease NOx emissions at the expense of combustion efficiency by lowering the global equivalence ratio.
Sea turtle bycatch by different types of fisheries in southern Spain
Authors: Marco Adolfo , Vázquez Cristina , Abella-Pérez Elena
Published: August 2020

The bycatch of sea turtles by large-scale fisheries is receiving an increasing attention in recent years due to the high impact it causes on these endangered species. This issue was evaluated in southern Spanish waters that harbor an important feeding ground of loggerhead and leatherback turtles, including the endangered Eastern Atlantic loggerhead population. To quantify the impact that different fisheries represents to sea turtles, 272 fishermen answered to detailed illustrated questionnaires in all the main ports of Andalusia and Murcia (Spain) during 2014. This study has updated the knowledge of turtle bycatch in the southwestern Mediterranean revealing a widespread impact of fisheries on sea turtles. Fishermen recognized an annual catch of 2.3 turtles per boat. Considering the census of operative large-scale fishing boats in the study area (1182), more than 2840 sea turtles could be bycaught per year in that area. Most captures (96.2%) were produced during the summer. These fisherman answers suggest a severe impact of most legal fisheries (surface longline, purse seine, trawling and small-scale fisheries) on loggerhead feeding grounds in the southwestern Mediterranean. Fishermen suggested that drift fishing conducted by foreign or illegal fishermen and almadrabas are also causing a significant bycatch of turtles. Several measures such as reviewing compliance of current fishing and environmental regulations, modifying fishing techniques to reduce turtle bycatch, facilitating the rescue and handle of wound turtles and their transport to the port for recovery, and recognizing the efforts of anglers to perform a more sustainable fishing, are recommended to mitigate this impact.
Plasma waves in a different frame
Authors: Macchi A.
Published: August 2020

A tutorial description of plasma waves in a cold plasma, with emphasis on their application in plasma-based electron accelerators, is presented. The basic physics of linear plasma oscillations and waves and the principle of electron acceleration in a plasma wave are discussed without assuming any previous knowledge of plasma physics. It is shown that estimating key parameters for plasma acceleration such as the maximum or “wave breaking” amplitude and the corresponding energy gained by electrons “surfing” the wave requires a relativistic and nonlinear analysis. This can be done with little mathematical complexity by using a Lorentz transformation to a frame co-moving at the phase velocity of the wave. The transformation reduces the problem to a second-order ordinary differential equation as originally found by Chian [Plasma Phys. 21, 509 (1979)] so that the analysis can exploit the analogy with the mechanical motion of a particle in a potential well.
Numerical and analytical study of the bound states of the −α/x2 potential
Authors: Nguyen Thanh Xuan , Marsiglio F.
Published: August 2020

The quantum mechanical bound states of the −α/x2 potential are truly anomalous. We revisit this problem by adopting a slightly modified version of this potential, one that adopts a cutoff in the potential arbitrarily close to the origin. The resulting solutions are completely well-defined and “normal,” and provide us with additional insight into the solutions of the “bare” −α/x2 potential. We present results here as a case study in undergraduate research—two independent methodologies are used: one analytical (albeit with very unfamiliar non-elementary functions) and one numerical (with a very straightforward methodology). These play complementary roles in arriving at solutions and achieving insights into this problem.