bluuebunny/crossref_metadata_2025_split huggingface dataset:
Human iPSC-derived mesodermal progenitor cells preserve their vasculogenesis potential after extrusion and form hierarchically organized blood vessels
Authors: Dogan Leyla , Scheuring Ruben , Wagner Nicole , Ueda Yuichiro , Wörsdörfer Philipp , Groll Jürgen , Ergün Süleyman 
Published: May 2021

AbstractPost-fabrication formation of a proper vasculature remains an unresolved challenge in bioprinting. Established strategies focus on the supply of the fabricated structure with nutrients and oxygen and either rely on the mere formation of a channel system using fugitive inks, or additionally use mature endothelial cells and/or peri-endothelial cells such as smooth muscle cells for the formation of blood vessels in vitro. Functional vessels, however, exhibit a hierarchical organization and multilayered wall structure that is important for their function. Human induced pluripotent stem cell-derived mesodermal progenitor cells (hiMPCs) have been shown to possess the capacity to form blood vessels in vitro, but have so far not been assessed for their applicability in bioprinting processes. Here, we demonstrate that hiMPCs, after formulation into an alginate / collagen type 1 bioink and subsequent extrusion, retain their ability to give rise to the formation of complex vessels that display a hierarchical network in a process that mimicks the embryonic steps of vessel formation by vasculogenesis. Histological evaluations at different time points of extrusion revealed initial formation of spheres, followed by lumen formation and further structural maturation as evidenced by building a multilayered vessel wall and a vascular network. These findings are supported by immunostainings for endothelial and peri-endothelial cell markers as well as electron microscopic analyses at the ultrastructural level. Moreover, capillary-like vessel structures deposited a basement membrane-like matrix structure at the basal side between the vessel wall and the alginate-collagen matrix. These results evidence the applicability and great potential of hiMPCs for the bioprinting of vascular structures mimicking the basic morphogenetic steps of de novo vessel formation during embryogenesis.
Cytokinin oxidase/dehydrogenase family genes exhibit functional divergence and overlap in ricegrowth and development, especially in control of tillering
Authors: Rong Chenyu , Liu Yuexin , Chang Zhongyuan , Liu Ziyu , Ding Yanfeng , Ding Chengqiang 
Published: May 2021

ABSTRACTCytokinins play key roles in plant growth and development; hence, cytokinin biosynthesis and degradation have been extensively studied. Cytokinin oxidase/dehydrogenases (CKXs) are a group of enzymes that regulate oxidative cleavage to maintain cytokinin homeostasis. In rice, 11 OsCKX genes have been identified to date; however, most of their functions remain unknown. Here, we comprehensively analyzed the expression patterns and functions of OsCKX genes. Using CRISPR/Cas9 technology, we constructed mutants of all OsCKX genes to determine the functions of OsCKXs in rice development. The results revealed that the single osckx and higher-order osckx4 osckx9 mutant lines showed functional overlap and subfunctionalization. Notably, the osckx1 osckx2 and osckx4 osckx9 double mutants displayed contrasting phenotypic changes in tiller number and panicle size compared to the wild type. Moreover, we identified several genes with significantly altered expression in osckx4 and osckx9 single and double mutant plants. Many differentially expressed genes were found to be associated with auxin and cytokinin pathways. Additionally, the cytokinins in osckx4 osckx9 mutants were increased compared to the wild type. Overall, our findings provide new insights into the functions of OsCKX genes in rice growth and may be used as a foundation for future studies aimed at improving rice yield. Key words: Cytokinin, expression pattern, OsCKX, panicle, phenotype, rice, tillerHighlightThe osckx4 osckx9 double mutant had a significantly greater number of tillers, whereas the osckx1 osckx2 double mutant showed the opposite phenotypic change, compared to the wild type
Neutrophils impose strong selective pressure against PfEMP1 variants implicated in cerebral malaria
Authors: Zelter Tamir , Strahilevitz Jacob , Simantov Karina , Yajuk Olga , Jensen Anja Ramstedt , Dzikowski Ron , Granot Zvi 
Published: May 2021

AbstractPlasmodium falciparum, the deadliest form of human malaria, remains one of the major threats to human health in endemic regions. Its virulence is attributed to its ability to modify infected red blood cells (iRBC) to adhere to endothelial receptors by placing variable antigens known as PfEMP1 on the surface of the red cell. PfEMP1 expression on the red cell surface determines the cytoadhesive properties of the iRBCs and is implicated in severe manifestations of malaria. To evade antibody mediated responses the parasite undergoes continuous switches of expression between different PfEMP1 variants. Recently it became clear that in addition to antibody mediated responses, PfEMP1 triggers an innate immune response, however, the role of neutrophils, the most abundant white blood cells in the human circulation, in malaria remains elusive. Here we show that neutrophils recognize and kill blood stages of several P. falciparum isolates, and we identify neutrophil ICAM-1 and specific PfEMP1s implicated in cerebral malaria as the key molecules involved in this killing. Our data provide mechanistic insight into the interactions between neutrophils and iRBCs and demonstrate the important influence of PfEMP1 on the selective innate response to cerebral malaria.
Morph-specific investment in testes mass in a trimorphic beetle, Proagoderus watanabei
Authors: Parrett Jonathan M. , Slade Eleanor M. , Knell Robert J. 
Published: May 2021

AbstractWhen competition between males for mates is intense it is common to find that some males will adopt alternative tactics for acquiring fertilisations, often involving the use of ‘sneak’ tactics whereby males avoid contests. These alternative tactics are sometimes associated with discrete differences in male morphology, with sneak males investing less in weaponry but more in traits such as testes which will give an advantage in sperm competition. In some cases it appears that males develop into more than two morphs, with a number of examples of tri- and even tetramorphic arthropod species being described. Here we analyse the scaling relations of the dung beetle species Proagoderus watanabei, which expresses two distinct weapon traits: paired head horns and a pronotal horn. We find that males of this species are trimorphic, with alpha males expressing long head horns and a pronotal horn, beta males with long head horns but no pronotal horn, and gamma males with short head horns only. We also find that alpha males invest less in testes than do beta or gamma males, indicating that beta and gamma males in this species probably experience higher risks of sperm competition than do alphas.
Using Repetitive Control to Enhance Force Control During Human-Robot Interaction in Quasi-Periodic Tasks
Authors: McGrath Robert L. , Sergi Fabrizio 
Published: May 2021

AbstractWe investigated the use of repetitive control (RC) to enhance force control during human-robot interaction in quasi-periodic tasks. We first developed a two-mass spring damper model and formulated three different RCs under force control: a 1st order RC (RC-1), a 3rd order RC designed for random period error, and a 3rd order RC designed for constant period error. Then, we quantified the performance of these three RCs through simulations and experiments conducted on a bench top linear platform, subject to nominal cyclical inputs (input signal and fundamental frequency: 0.5 Hz), and subject to inputs with random and constant period errors. Moreover, we compared the performance achieved with the RCs with those achievable with a passive proportional controller (PPC), subject to known theoretical limits for passivity and coupled stability.In both simulated and real-world experiments, the root mean square force error under nominal conditions was reduced most effectively by the RC-1 to 0.7% and 12.9%, respectively, of the error achieved with the PPC. Subject to inputs with constant period errors, RCs performed better than PPC for period error values below 0.05 Hz, with the RC-1 performing significantly better than both 3rd order RCs. Subject to inputs with random period errors, all RCs performed better than PPC up to 0.11 Hz of frequency error. Our results indicate that RC can successfully integrated in force control schemes to improve performance beyond the one achievable with a PPC, in the range of period variability expected in applications such as walking assistance and rehabilitation.
The SWI/SNF and RSC Cooperatively Remodel the Promoters of Unfolded Protein Response Targets and Heat Shock Genes
Authors: Sahu Rakesh Kumar , Singh Sakshi , Tomar Raghuvir Singh 
Published: May 2021

AbstractThe ATP-dependent chromatin remodelling complexes maintain the chromatin dynamics, enabling the gene expression or its silencing. The SWI/SNF subfamily remodelers (SWI/SNF and RSC) generally promote gene expression by displacing or evicting nucleosomes at the promoter regions. Their action creates a nucleosome-depleted region where transcription machinery accesses the DNA. Their involvement has been shown critical for the induction of stress-responsive transcription programs. Although the role of SWI/SNF and RSC complexes in transcription regulation of heat shock responsive genes is well studied, their involvement at other pathway genes such as UPR, HSP and PQC is less known. In this study, we showed that the SWI/SNF occupies promoters of UPR, HSP and PQC genes in response to the unfolded protein stress, and its recruitment at UPR promoters is dependent on the Hac1 transcription factor and other epigenetic factors like Ada2 and Ume6. Disruption of SWI/SNF’s activity does not affect the remodelling of these promoters or gene expression. However, inactivation of both RSC and SWI/SNF complexes diminishes expression of most of the UPR, HSP and PQC genes tested. Altogether these results suggest that these two remodelers work together or one compensates the loss of the other to ensure optimal induction of the stress-responsive genes.
FTY720 (Fingolimod), a modulator of sphingosine-1-phosphate receptors, increases baseline hypothalamic-pituitary adrenal axis activity and alters behaviors relevant to affect and anxiety
Authors: Corbett Brian , Luz Sandra , Sotuyo Nathaniel , Pearson-Leary Jiah , Moorthy Ganesh S. , Zuppa Athena F. , Bhatnagar Seema 
Published: May 2021

AbstractFTY720 (fingolimod) is an analog of sphingosine, a ubiquitous sphingolipid. Phosphorylated FTY720 (FTY720-P) non-selectively binds to sphingosine-1-phosphate receptors (S1PRs) and regulates multiple cellular processes including cell proliferation, inflammation, and angiogenesis. We recently demonstrated that S1PR3 expression in the medial prefrontal cortex (mPFC) of rats promotes stress resilience and that S1PR3 expression in blood may serve as a biomarker for PTSD. Here we investigate the effects of FTY720 in regulating the stress response. We found that single and repeated intraperitoneal injections of FTY720 increased baseline plasma adrenocorticotropic hormone (ACTH) and corticosterone concentrations. FTY720 also mitigated restraint-induced increases in ACTH and corticosterone. FTY720 reduced social anxiety- and despair-like behavior as assessed by increased social interaction time and reduced time spent immobile in the Porsolt forced swim test. In blood, FTY720 administration reduced lymphocyte and reticulocyte counts, but raised erythrocyte counts. FTY720 also reduced mRNA of angiopoietin 1, endothelin 1, plasminogen 1, Vegf-B, and Mmp2 in the medial prefrontal cortex, suggesting that FTY720 reduced angiogenesis. The antidepressant-like and anxiolytic-like effects of FTY720 may be attributed to reduced angiogenesis as increased stress-induced blood vessel density in the brain contributes to depression- and anxiety-like behavior in rats. Together, these results suggest that S1PRs regulate baseline HPA axis activity but reduces social anxiety and despair providing further evidence that S1PRs are important and novel regulators of stress-related functions.
Cold survival and its molecular mechanisms in a locally adapted nematode population
Authors: Wang Wenke , Flury Anna G. , Garrison Jennifer L. , Brem Rachel B. 
Published: May 2021

AbstractSince Darwin, evolutionary biologists have sought to understand the drivers and mechanisms of natural trait diversity. The field advances toward this goal with the discovery of phenotypes that vary in the wild, their relationship to ecology, and their underlying genes. Here, we established resistance to extreme low temperature in the free-living nematode Caenorhabditis briggsae as an ecological and evolutionary model system. We found that C. briggsae strains of temperate origin were strikingly more cold-resistant than those isolated from tropical localities. Transcriptional profiling revealed expression patterns unique to the resistant temperate ecotype, including dozens of genes expressed at high levels even after multiple days of cold-induced physiological slowdown. Mutational analysis validated a role in cold resistance for seven such genes. As the temperate C. briggsae population likely diverged only ~700 years ago from tropical ancestors, our findings highlight a candidate case of very rapid, robust, and genetically complex adaptation, and shed light on the mechanisms at play.
Live 3D imaging and mapping of shear stresses within tissues using incompressible elastic beads
Authors: Souchaud Alexandre , Boutillon Arthur , Charron Gaëlle , Asnacios Atef , Noûs Camille , David Nicolas B. , Graner François , Gallet François 
Published: May 2021

ABSTRACTTo investigate the role of mechanical constraints in morphogenesis and development, we develop a pipeline of techniques based on incompressible elastic sensors. These techniques combine the advantages of incompressible liquid droplets, which have been used as precise in situ shear stress sensors, and of elastic compressible beads, which are easier to tune and to use. Droplets of a polydimethylsiloxane (PDMS) mix, made fluorescent through specific covalent binding to a rhodamin dye, are produced by a microfluidics device. The elastomer rigidity after polymerization is adjusted to the tissue rigidity. Its mechanical properties are carefully calibrated in situ, for a sensor embedded in a cell aggregate submitted to uniaxial compression. The local shear stress tensor is retrieved from the sensor shape, accurately reconstructed through an active contour method. In vitro, within cell aggregates, and in vivo, in the prechordal plate of the Zebrafish embryo during gastrulation, our pipeline of techniques demonstrates its efficiency to directly measure the three dimensional shear stress repartition within a tissue, and its time evolution.
Feedback-related EEG dynamics separately reflect decision parameters, biases, and future choices
Authors: Kirschner Hans , Fischer Adrian G. , Ullsperger Markus 
Published: May 2021

AbstractOptimal decision making in complex environments requires dynamic learning from unexpected events. To speed up learning, we should heavily weight information that indicates state-action-outcome contingency changes and ignore uninformative fluctuations in the environment. Often, however, unrelated information is hard to ignore and can potentially bias our learning. Here we used computational modelling and EEG to investigate learning behaviour in a modified probabilistic choice task that introduced two types of unexpected events that were irrelevant for optimal task performance, but nevertheless could potentially bias learning: pay-out magnitudes were varied randomly and, occasionally, feedback presentation was enhanced by visual surprise. We found that participants’ overall good learning performance was biased by distinct effects of these non-normative factors. On the neural level, these parameters are represented in a dynamic and spatiotemporally dissociable sequence of EEG activity. Later in feedback processing the different streams converged on a central to centroparietal positivity reflecting a final pathway of adaptation that governs future behaviour.
Spatial organization of chromosomes leads to heterogeneous chromatin motion and drives the liquid- or gel-like dynamical behavior of chromatin
Authors: Salari Hossein , Stefano Marco Di , Jost Daniel 
Published: May 2021

AbstractChromosome organization and dynamics are involved in regulating many fundamental processes such as gene transcription and DNA repair. Experiments unveiled that chromatin motion is highly heterogeneous inside cell nuclei, ranging from a liquid-like, mobile state to a gel-like, rigid regime. Using polymer modeling, we investigate how these different physical states and dynamical heterogeneities may emerge from the same structural mechanisms. We found that the formation of topologically-associating domains (TADs) is a key driver of chromatin motion heterogeneity. In particular, we demonstrated that the local degree of compaction of the TAD regulates the transition from a weakly compact, fluid state of chromatin to a more compact, gel state exhibiting anomalous diffusion and coherent motion. Our work provides a comprehensive study of chromosome dynamics and a unified view of chromatin motion enabling to interpret the wide variety of dynamical behaviors observed experimentally across different biological conditions, suggesting that the ‘liquid’ or ‘solid’ behaviour of chromatin are in fact two sides of the same coin.
Dimension-Selective Attention and Dimensional Salience Modulate Cortical Tracking of Acoustic Dimensions
Authors: Symons Ashley E. , Dick Fred , Tierney Adam T. 
Published: May 2021

AbstractSome theories of auditory categorization suggest that auditory dimensions that are strongly diagnostic for particular categories - for instance voice onset time or fundamental frequency in the case of some spoken consonants - attract attention. However, prior cognitive neuroscience research on auditory selective attention has largely focused on attention to simple auditory objects or streams, and so little is known about the neural mechanisms that underpin dimension-selective attention, or how the relative salience of variations along these dimensions might modulate neural signatures of attention. Here we investigate whether dimensional salience and dimension-selective attention modulate cortical tracking of acoustic dimensions. In two experiments, participants listened to tone sequences varying in pitch and spectral peak frequency; these two dimensions changed at systematically different rates. Inter-trial phase coherence (ITPC) and EEG signal amplitude at the rates of pitch and spectral change allowed us to measure cortical tracking of these dimensions. In Experiment 1, tone sequences varied in the size of the pitch intervals, while the size of spectral peak intervals remained constant. Neural entrainment to pitch changes was greater for sequences with larger compared to smaller pitch intervals, with no difference in entrainment to the spectral dimension. In Experiment 2, participants selectively attended to either the pitch or spectral dimension. Neural entrainment was stronger in response to the attended compared to unattended dimension for both pitch and spectral dimensions. These findings demonstrate that bottom-up and top-down attentional mechanisms enhance the cortical tracking of different acoustic dimensions within a single sound stream.
New integrable (2+1)- and (3+1)-dimensional shallow water wave equations: multiple soliton solutions and lump solutions
Authors: Wazwaz Abdul-Majid 
Published: May 2021

Purpose
This study aims to develop two integrable shallow water wave equations, of higher-dimensions, and with constant and time-dependent coefficients, respectively. The author derives multiple soliton solutions and a class of lump solutions which are rationally localized in all directions in space.

Design/methodology/approach
The author uses the simplified Hirota’s method and lump technique for determining multiple soliton solutions and lump solutions as well. The author shows that the developed (2+1)- and (3+1)-dimensional models are completely integrable in in the Painlené sense.

Findings
The paper reports new Painlevé-integrable extended equations which belong to the shallow water wave medium.

Research limitations/implications
The author addresses the integrability features of this model via using the Painlevé analysis. The author reports multiple soliton solutions for this equation by using the simplified Hirota’s method.

Practical implications
The obtained lump solutions include free parameters; some parameters are related to the translation invariance and the other parameters satisfy a non-zero determinant condition.

Social implications
The work presents useful algorithms for constructing new integrable equations and for the determination of lump solutions.

Originality/value
The paper presents an original work with newly developed integrable equations and shows useful findings of solitary waves and lump solutions.
Teacher job satisfaction in Taiwan: making the connections with teacher attitudes, teacher self-efficacy and student achievement
Authors: Tsai Po , Antoniou Panayiotis 
Published: May 2021

PurposeThis paper aims to describe the findings of a study investigating the relationships between teacher attitudes to teaching mathematics, teacher self-efficacy, student achievement and teacher job satisfaction in Taiwan.Design/methodology/approachData were collected from 110 fifth grade primary school teachers and their students (n = 2,334) between 10 and 10 years old. A teacher questionnaire and a criterion-reference test in mathematics were distributed during the academic year 2016–2017. The data were analysed using confirmatory factor analysis and stepwise linear regression.FindingsThe results revealed that teacher attitudes to teaching mathematics, efficacy in classroom environment and student achievement in mathematics could, to some extent, explain variations in teacher job satisfaction. Of all the variables, teacher attitudes to teaching mathematics explained the largest portion of the variance in teacher job satisfaction.Originality/valueThese findings support the proposition that teacher attitudes to teaching mathematics affect teacher job satisfaction, which is in turn, translatable into enhanced teacher effectiveness. It is important to note that this study explores the impact of student achievement on teacher job satisfaction (and not the other way round), which is a relationship that remains under-researched and needs further investigation. Implications of the findings are discussed, and suggestions for further studies are provided.