bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of normobaric hypoxic exercise on endothelial progenitor cell senescence byin vitrocultivation with conditioned media
Authors: Harmsen Jan-Frieder , Nebe Dennis , Brixius Klara , Schenk Alexander , Bloch Wilhelm
Published: February 2020

Objective

Circulating endothelial progenitor cells (EPCs) were shown to be affected in cardiovascular and metabolic diseases. As interventional strategies, hypoxia and exercise are both known to increase the number and enhance the function of EPCs, potentially by extending their lifespan induced by a reduced senescence. Therefore, this pilot study investigated the effect of exercise under normobaric hypoxia on the senescence of EPCs byin vitrocultivation with autologous human serum (AHS).

Methods

Four healthy trained young males (23 ± 2 years) performed an incremental cycling step test until exhaustion in a normobaric hypoxic-chamber with an average altitude of 4,000 m (O212.3%). Blood serum was taken at pre, 10 min post and 4 h post, which was later used forin vitrocultivation of EPCs. Senescence was investigated by ß-galactosidase staining.

Results

The participants spent 30-40 min in normobaric hypoxia. The EPC senescence rate was reduced 10 min (0.72 ± 0.57%) and 4 hours (0.67 ± 0.52%) after exercise compared to pre (1.89 ± 0.37%).

Conclusion

This pilot study indicates that intense exercise under normobaric hypoxia may enhance EPC function by slowing down their senescence.
Functional principal component based time-series genome-wide association in sorghum
Authors: Miao Chenyong , Xu Yuhang , Liu Sanzhen , Schnable Patrick S. , Schnable James C.
Published: February 2020

The phenotypes of plants develop over time and change in response to the environment. New engineering and computer vision technologies track phenotypic change over time. Identifying genetic loci regulating differences in the pattern of phenotypic change remains challenging. In this study we used functional principal component analysis (FPCA) to achieve this aim. Time-series phenotype data was collected from a sorghum diversity panel using a number of technologies including RGB and hyperspectral imaging. Imaging lasted for thirty-seven days centered on reproductive transition. A new higher density SNP set was generated for the same population. Several genes known to controlling trait variation in sorghum have been cloned and characterized. These genes were not confidently identified in genome-wide association analyses at single time points. However, FPCA successfully identified the same known and characterized genes. FPCA analyses partitioned the role these genes play in controlling phenotype. Partitioning was consistent with the known molecular function of the individual cloned genes. FPCA-based genome-wide association studies can enable robust time-series mapping analyses in a wide range of contexts. Time-series analysis can increase the accuracy and power of quantitative genetic analyses.
Accelerating Monte Carlo modeling of structured-light based diffuse optical imaging via “photon sharing”
Authors: Yan Shijie , Yao Ruoyang , Intes Xavier , Fang Qianqian
Published: February 2020

The increasing use of spatially-modulated imaging and single-pixel detection techniques demands computationally efficient methods for light transport modeling. Herein, we report an easy-to-implement yet significantly more efficient Monte Carlo (MC) method for simultaneously simulating spatially modulated illumination and detection patterns accurately in 3-D complex domains. We have implemented this accelerated algorithm, named “photon sharing”, in our open-source MC simulators, reporting 13.6× and 5.5× speedups in mesh- and voxel-based MC benchmarks, respectively. In addition, the proposed algorithm is readily used for accelerating the solving of inverse problems in spatially-modulated imaging systems by building Jaco-bians of all illumination-detection pattern pairs concurrently, resulting in a 12.4-fold speed improvement.

https://doi.org/10.1101/2020.02.16.951590
Single-molecule fluorescence-based approach reveals novel mechanistic insights into small heat shock protein chaperone function
Authors: Johnston Caitlin L. , Marzano Nicholas R. , Paudel Bishnu , Wright George , Benesch Justin L. P. , van Oijen Antoine M. , Ecroyd Heath
Published: February 2020

Small heat shock proteins (sHsps) are a family of ubiquitous intracellular molecular chaperones that are up-regulated under stress conditions and play a vital role in protein homeostasis (proteostasis). It is commonly accepted that these chaperones work by trapping misfolded proteins to prevent their aggregation, however fundamental questions regarding the molecular mechanism by which sHsps interact with misfolded proteins remain unanswered. Traditionally, it has been difficult to study sHsp function due to the dynamic and heterogenous nature of the species formed between sHsps and aggregation-prone proteins. Single-molecule techniques have emerged as a powerful tool to study dynamic protein complexes and we have therefore developed a novel single-molecule fluorescence-based approach to observe the chaperone action of human αB-crystallin (αBc, HSPB5). Using this approach we have, for the first time, determined the stoichiometries of complexes formed between αBc and a model client protein, chloride intracellular channel 1 (CLIC1). By examining the polydispersity and stoichiometries of these complexes over time, and in response to different concentrations of αBc, we have uncovered unique and important insights into a two-step mechanism by which αBc interacts with misfolded client proteins to prevent their aggregation. Understanding this fundamental mechanism of sHsp action is crucial to understanding how these molecular chaperone function to protect the cell from protein misfolding and their overall role in the cellular proteostasis network.
Hnf4ais required for the development of Cdh6-expressing progenitors into proximal tubules in the mouse kidney
Authors: Marable Sierra S. , Chung Eunah , Park Joo-Seop
Published: February 2020

Background

Hnf4a is a major regulator of renal proximal tubule (PT) development. In humans, a mutation inHNF4Ais associated with Fanconi renotubular syndrome (FRTS), which is caused by defective PT functions. In mice, mosaic deletion ofHnf4ain the developing kidney causes a paucity of PT cells, leading to FRTS-like symptoms. The molecular mechanisms underlying the role of Hnf4a in PT development remain unclear.

Methods

We generated a newHnf4amutant mouse model employingOsr2Cre,which effectively deletesHnf4ain developing nephrons. We characterized the mutant phenotype by immunofluorescence analysis. We performed lineage analysis to test if Cdh6-expressing cells are PT progenitors. We also performed genome-wide mapping of Hnf4a binding sites and differential gene analysis ofHnf4amutant kidneys to identify direct target genes of Hnf4a.

Results

Deletion ofHnf4awithOsr2Creled to the complete loss of mature PT cells, causing lethality in theHnf4amutant mice. We found that Cdh6high, LTLlowcells serve as PT progenitors and that they show higher proliferation than Cdh6low, LTLhighdifferentiated PT cells. We also found that Hnf4a is required for PT progenitors to develop into differentiated PT cells. Our genomic analyses revealed that Hnf4a directly regulates the expression of genes involved in transmembrane transport and metabolism.

Conclusions

Our findings show that Hnf4a promotes the development of PT progenitors into differentiated PT cells by regulating the expression of genes associated with reabsorption, the major function of PT cells.

Significance

Proximal tubule cells are the most abundant cell type in the mammalian kidney and they perform the bulk of the renal reabsorption function. Despite their importance in kidney function, the molecular mechanisms of proximal tubule development and maturation are not well understood. Here we find that, in the developing mouse kidney, Cdh6high, LTLlowcells act as proximal tubule progenitors and that Hnf4a is required for these cells to further develop into proximal tubules. Our genomic analyses show that Hnf4a directly regulate the expression of genes required for reabsorption such as transmembrane transport genes and metabolism genes. This study advances our understanding of how kidney proximal tubule cells form during development.
High-temperature live-cell imaging of cytokinesis, cell motility and cell-cell adhesion in the thermoacidophilic crenarchaeonSulfolobus acidocaldarius
Authors: Charles-Orszag Arthur , Lord Samuel J. , Mullins R. Dyche
Published: February 2020

Significant technical challenges have limited the study of extremophile cell biology. For example, the absence of methods for performing high-resolution, live-cell imaging at high temperatures (>50°C) has impeded the study of cell motility and cell division in thermophilic archaea such as model organisms from the genusSulfolobus. Here we describe a system for imaging samples at 75°C using high numerical aperture, oil-immersion lenses. With this system we observed and quantified the dynamics of cell division in the model thermoacidophilic crenarchaeonSulfolobus acidocaldarius. In addition, we observed previously undescribed dynamic cell shape changes, cell motility, and cell-cell interactions, shedding significant new light on the high-temperature lifestyle of this organism.
Effect of structural stability on endolysosomal degradation and T-cell reactivity of major shrimp allergen tropomyosin
Authors: Kamath Sandip D. , Scheiblhofer Sandra , Johnson Christopher M. , Machado Yoan , McLean Thomas , Taki Aya C , Ramsland Paul A. , Iyer Swati , Joubert Isabella , Hofer Heidi , Wallner Michael , Thalhamer Josef , Rolland Jennifer , O’Hehir Robyn , Briza Peter , Ferreira Fatima , Weiss Richard , Lopata Andreas L.
Published: February 2020

Background

Tropomyosins are highly conserved proteins, an attribute that forms the molecular basis for their IgE antibody cross-reactivity. Despite structural similarities, their allergenicity varies greatly between ingested and inhaled invertebrate sources. In this study, we investigated the relationship between the structural stability of different tropomyosins, their endolysosomal degradation patterns and T-cell reactivity.

Methods

We investigated the differences between four tropomyosins - the major shrimp allergen Pen m 1 and the minor allergens Der p 10 (dust mite), Bla g 7 (cockroach) and Ani s 3 (fish parasite) - in terms of IgE binding, structural stability, endolysosomal degradation and subsequent peptide generation, and T-cell cross-reactivity in a BALB/c murine model.

Results

Despite their conserved primary structure and consequent IgE co-reactivity, the invertebrate tropomyosins displayed different protein stabilities. Pen m 1 and Ani s 3, but not Der p 10 and Bla g 7 elicited differential melting temperatures that were pH-dependent. Endolysosomal experiments demonstrated differential degradation, as a function of stability, generating different peptide repertoires. Pen m 1 T-cell clones, with specificity for sequences highly conserved in all four tropomyosins, did not proliferate with Der p 10, Bla g 7 and Ani s 3, indicating that these peptides were not naturally produced for other invertebrate tropomyosins.

Conclusions

Our data suggest that, although invertebrate tropomyosins exhibit a high degree of IgE cross-reactivity due to conserved B-cell epitopes, they do not necessarily share identical cross-reactive T-cell epitopes. This is likely due to differential endolysosomal processing as a function of different structural stabilities.
Subcellular localization and mitotic interactome analyses identify SIRT4 as a centrosomally localized and microtubule associated protein
Authors: Bergmann Laura , Lang Alexander , Bross Christoph , Altinoluk-Hambüchen Simone , Fey Iris , Overbeck Nina , Stefanski Anja , Wiek Constanze , Kefalas Andreas , Verhülsdonk Patrick , Mielke Christian , Sohn Dennis , Stühler Kai , Hanenberg Helmut , Jänicke Reiner U. , Scheller Jürgen , Reichert Andreas S. , Ahmadian M. Reza , Piekorz Roland P.
Published: February 2020

The stress-inducible and senescence-associated tumor suppressor SIRT4, a member of the family of mitochondrial sirtuins (SIRT3, SIRT4, and SIRT5), regulates bioenergetics and metabolismviaNAD+-dependent enzymatic activities. Next to the known mitochondrial location, we found that a fraction of endogenous or ectopically expressed SIRT4, but not SIRT3, is located at the mitotic spindle apparatus in the cytosol. Confocal spinning disk microscopy revealed that SIRT4 localizes during the cell cycle dynamically at centrosomes with an intensity peak in G2and early mitosis. Moreover, SIRT4 binds to microtubules and interacts with structural (α,β-tubulin, γ-tubulin, TUBGCP2, TUBGCP3) and regulatory (HDAC6) microtubule components as detected by co-immunoprecipitation and mass spectrometric analyses of the mitotic SIRT4 interactome. Overexpression of SIRT4 resulted in a pronounced decrease of acetylated α-tubulin (K40) associated with altered microtubule dynamics in mitotic cells. SIRT4 or the N-terminally truncated variant SIRT4(ΔN28), which is unable to translocate into mitochondria, delayed mitotic progression and reduced cell proliferation. This study extends the functional roles of SIRT4 beyond mitochondrial metabolism, and suggests that SIRT4 acts as a novel centrosomal / microtubule-associated protein in the regulation of cell cycle progression. Thus, stress-induced SIRT4 may exert its role as tumor suppressor through mitochondrial as well as extramitochondrial functions, the latter associated with its localization at the mitotic spindle apparatus.
Capybara: A computational tool to measure cell identity and fate transitions
Authors: Kong Wenjun , Fu Yuheng C. , Morris Samantha A.
Published: February 2020

Transitions in cell identity are fundamental to development, reprogramming, and disease. Single-cell technologies enable the dissection of tissue composition on a cell-by-cell basis in complex biological systems. However, highly-sparse single-cell RNA-seq data poses challenges for cell-type identification algorithms based on bulk RNA-seq. Single-cell analytical tools are also limited, where they require prior biological knowledge and typically classify cells in a discrete, categorical manner. Here, we present a computational tool, ‘Capybara,’ designed to measure cell identity as a continuum, at single-cell resolution. This approach enables the classification of discrete cell entities but also identifies cells harboring multiple identities, supporting a metric to quantify cell fate transition dynamics. We benchmark the performance of Capybara against other existing classifiers and demonstrate its efficacy to annotate cells and identify critical transitions within a well-characterized differentiation hierarchy, hematopoiesis. Our application of Capybara to a range of reprogramming strategies reveals previously uncharacterized regional patterning and identifies a putativein vivocorrelate for an engineered cell type that has, to date, remained undefined. These findings prioritize interventions to increase the efficiency and fidelity of cell engineering strategies, showcasing the utility of Capybara to dissect cell identity and fate transitions. Capybara code and documentation are available athttps://github.com/morris-lab/Capybara.
Agewise mapping of genomic oxidative DNA modification demonstrates oxidative-driven reprogramming of pro-longevity genes
Authors: Aung Lynn Htet Htet , Wang Yin , Liu Zi-Qian , Li Zhe , Yu Zhongjie , Chen Xiatian , Gao Jinning , Shan Peipei , Zhou Zhixia , Li Peifeng
Published: February 2020

The accumulation of unrepaired oxidatively damaged DNA can influence both the rate of ageing and life expectancy of an organism. Mapping oxidative DNA damage sites at whole-genome scale will help us to recognize the damage-prone sequence and genomic feature information, which is fundamental for ageing research. Here, we developed an algorithm to map the whole-genome oxidative DNA damage at single-base resolution using Single-Molecule Real-Time (SMRT) sequencing technology. We sequenced the genomic oxidative DNA damage landscape of C. elegans at different age periods to decipher the potential impact of genomic DNA oxidation on physiological ageing. We observed an age-specific pattern of oxidative modification in terms of motifs, chromosomal distribution, and genomic features. Integrating with RNA-Seq data, we demonstrated that oxidative modification in promoter regions was negatively associated with the expression of pro-longevity genes, denoting that oxidative modification in pro-longevity genes may exert epigenetic potential and thus affect lifespan determination. Together, our study opens up a new field for exploration of “oxigenetics,” that focuses on the mechanisms of redox-mediated ageing.

We developed an algorithm to map the oxidative DNA damage at single-base resolution.

Oxidative DNA damage landscape in C. elegans illustrated an age-specific pattern in terms of motifs, chromosomal distribution, and genomic features.

Oxidative modification in older worms occurred higher frequency at the sex chromosome, with the preference for promoter and exon regions.

Oxidative modification in promoter regions of pro-longevity genes was negatively associated with their expression, suggesting the oxidative-driven transcript reprogramming of pro-longevity genes in physiological ageing.
Recalling a single object: going beyond the capacity debate
Authors: Sengupta Rakesh , Lewis Christelle M. , Bapi Raju S.
Published: February 2020

Working memory is now established as a limited capacity system. The debate regarding working memory has been largely between slots and resource based models. The resource model suggests that as the number of items increases, precision of recall decreases because neural resources are dynamically allocate to all the objects needed for task. Slot model on the other hand implies that an item is stored either with the highest precision or not at all. If both these models stand true then quality of memory performance would be near perfect for a single object. However, that may not be the case. In the current work, we investigated recall accuracy for feature(s) of a single object in three successive experiments. In all three experiments, the memory array consisted of a single colored oriented short line presented a short distance away from the center of the display for 1 sec. We probed recall of features from the set of color, location, orientation, and size. In experiment 1 number of recall question varied between 1 – 4 with the order randomized in each trial. In experiment 2 we chose to probe only two feature recall questions, whereas only one recall question was probed for the third experiment. In experiment 3 we varied the delay before the recall probe between 1 and 2 s. The recall response for each feature was mapped on to a continuous variable. Subjects used a color wheel to respond to color, on-screen mouse click to indicate center of the line location, click away from the center to indicate size, and a mouse click to the periphery of centered circle to indicate orientation with the slant of the resulting radial line. We calculated z-scores of errors for each feature for every subject separately. In experiment 1 that for color, location, and size the errors increase significantly with the position of the questions asked. In experiment 2, the errors increased significantly between questions for color and location (but not for orientation and size). In experiment 3, we did not see any significant increase in error with recall probe delay. Overall run-time for each trial was within 10 secs, well within the limits of operation of working memory. This drop in performance poses questions for memory mechanisms proposed by slot and resource models as both would predict near-perfect recall within the time-period for the trials.
Double-stranded RNA bending by AU-tract sequences
Authors: Marin-Gonzalez Alberto , Aicart-Ramos Clara , Marin-Baquero Mikel , Martín-González Alejandro , Suomalainen Maarit , Kannan Abhilash , Vilhena J. G. , Greber Urs F. , Moreno-Herrero Fernando , Pérez Rubén
Published: February 2020

Sequence-dependent structural deformations of the DNA double helix (dsDNA) have been extensively studied, where adenine tracts (A-tracts) provide a striking example for global bending in the molecule. In contrast to dsDNA, much less is known about how the nucleotide sequence affects bending deformations of double-stranded RNA (dsRNA). Using all-atom microsecond long molecular dynamics simulations we found a sequence motif consisting of alternating adenines and uracils, or AU-tracts, that bend the dsRNA helix by locally compressing the major groove. We experimentally tested this prediction using atomic force microscopy (AFM) imaging of long dsRNA molecules containing phased AU-tracts. AFM images revealed a clear intrinsic bend in these AU-tracts molecules, as quantified by a significantly lower persistence length compared to dsRNA molecules of arbitrary sequence. The bent structure of AU-tracts here described might play a role in sequence-specific recognition of dsRNAs by dsRNA-interacting proteins or impact the folding of RNA into intricate tertiary and quaternary structures.
Phylogeny and distribution of Y-chromosomal haplotypes in domestic, ancient and wild goats
Authors: Nijman Isaäc J. , Rosen Benjamin D. , Zheng Zhuqing , Jiang Yu , Cumer Tristan , Daly Kevin G. , Bâlteanu Valentin A. , Berger Beate , Blichfeldt Thor , Boink Geert , Carolan Sean , Cubric-Curik Vlatka , Kantanen Juha , Martínez Amparo , Mazza Raffaele , Khayatzadeh Negar , Kim Namshin , Ouchene-Khelifi Nadjet-Amina , Pereira Filipe , da Silva Anne , Simčič Mojca , Sölkner Johann , Sutherland Alison , Tigchelaar Johannes ,   Econogene Consortium, Ajmone-Marsan Paolo , Bradley Daniel G. , Colli Licia , Pompanon François , Lenstra Johannes A.
Published: February 2020

The male-specific part of the Y-chromosome is in mammalian and many other species the longest haplotype that is inherited without recombination. By its paternal transmission it has a small effective population size in species with dominant males. In several species, Y-chromosomal haplotypes are sensitive markers of population history and introgression. Previous studies have identified in domestic goats four major Y-chromosomal haplotypes Y1A, Y1B, Y2A and Y2B with a marked geographic differentiation and several regional variants. In this study we used published whole-genome sequences of 70 male goats from 16 modern breeds, 11 ancient-DNA samples and 29 samples from seven wild goat species. We identified single-copy male-specific SNPs in four scaffolds, containingSRY, ZFY, DBYwithSSX3YandUTY,andUSP9YwithUMN2001,respectively. Phylogenetic analyses indicated haplogroups corresponding to the haplotypes Y1B, Y2A and Y2B, respectively, but Y1A was split into Y1AA and Y1AB. All haplogroups were detected in ancient DNA samples from southeast Europe and, with the exception of Y1AB, in the bezoar goat, which is the wild ancestor of the domestic goats. Combining these data with those of previous studies and with genotypes obtained by Sanger sequencing or the KASP assay yielded haplogroup distributions for 132 domestic breeds or populations. The phylogeographic differentiation indicated paternal population bottlenecks on all three continents. This possibly occurred during the Neolithic introductions of domestic goats to those continents with a particularly strong influence in Europe along the Danubian route. This study illustrates the power of the Y-chromosomal haplotype for the reconstructing the history of mammalian species with a wide geographic range.
Random Forest Regression for Optimizing Variable Planting Rates for Corn and Soybean Using High-Resolution Topographical and Soil Data
Authors: Krause Margaret R. , Crossman Savanna , DuMond Todd , Lott Rodman , Swede Jason , Arliss Scott , Robbins Ron , Ochs Daniel , Gore Michael A.
Published: February 2020

In recent years, planting machinery that enables precise control of the planting rates has become available for corn (Zea maysL.) and soybean (Glycine maxL.). With increasingly available topographical and soil information, there is a growing interest in developing variable rate planting strategies to exploit variation in the agri-landscape in order to maximize production. A random forest regression-based approach was developed to model the interactions between planting rate, topography, and soil characteristics and their effects on yield based on on-farm variable rate planting trials for corn and soybean conducted at 27 sites in New York between 2014 and 2018 (57 site-years) in collaboration with the New York Corn and Soybean Growers Association. Planting rate ranked highly in terms of random forest regression variable importance while explaining relatively minimal yield variation in the linear context, indicating that yield response to planting rate likely depends on complex interactions with agri-landscape features. Models were moderately predictive of yield within site-years and across years at a particular site, while the ability to predict yield across sites was low. Relatedly, variable importance measures for the topographical and soil features varied considerably across sites. Together, these results suggest that local testing may provide the most accurate optimized planting rate designs due to the unique set of conditions at each site. The proposed method was extended to identify the optimal variable rate planting design for maximizing yield at each site given the topographical and soil data, and empirical validation of the resulting designs is currently underway.
Identification of plant enhancers and their constituent elements by STARR-seq in tobacco leaves
Authors: Jores Tobias , Tonnies Jackson , Dorrity Michael W , Cuperus Josh T , Fields Stanley , Queitsch Christine
Published: February 2020

Genetic engineering ofcis-regulatory elements in crop plants is a promising strategy to ensure food security. However, such engineering is currently hindered by our limited knowledge of plantcis-regulatory elements. Here, we adapted STARR-seq — a technology for the high-throughput identification of enhancers — for its use in transiently transformed tobacco leaves. We demonstrate that the optimal placement in the reporter construct of enhancer sequences from a plant virus, pea and wheat was just upstream of a minimal promoter, and that none of these four known enhancers was active in the 3′-UTR of the reporter gene. The optimized assay sensitively identified small DNA regions containing each of the four enhancers, including two whose activity was stimulated by light. Furthermore, we coupled the assay to saturation mutagenesis to pinpoint functional regions within an enhancer, which we recombined to create synthetic enhancers. Our results describe an approach to define enhancer properties that can be performed in potentially any plant species or tissue transformable byAgrobacteriumand that can use regulatory DNA derived from any plant genome.

One-sentence summary

We developed a high-throughput assay in transiently transformed tobacco leaves that can identify enhancers, characterize their functional elements and detect condition-specific enhancer activity.
A computational model explains and predicts substantia nigra pars reticulata responses to pallidal and striatal inputs
Authors: Phillips Ryan S. , Rosner Ian , Gittis Aryn H. , Rubin Jonathan E.
Published: February 2020

As a rodent basal ganglia (BG) output nucleus, the substantia nigra pars reticulata (SNr) is well positioned to impact behavior. SNr neurons receive GABAergic inputs from the striatum (direct pathway) and globus pallidus (GPe, indirect pathway). Dominant theories of action selection rely on these pathways’ inhibitory actions. Yet, experimental results on SNr responses to these inputs are limited and include excitatory effects. Our study combines experimental and computational work to characterize, explain, and make predictions about these pathways. We observe diverse SNr responses to stimulation of SNr-projecting striatal and GPe neurons, including biphasic and excitatory effects, which our modeling shows can be explained by intracellular chloride processing. Our work predicts that ongoing GPe activity could tune the SNr operating mode, including its responses in decision-making scenarios, and GPe output may modulate synchrony and low-frequency oscillations of SNr neurons, which we confirm using optogenetic stimulation of GPe terminals within the SNr.
Accelerated cell cycles enable organ regeneration under developmental time constraints in theDrosophilahindgut
Authors: Cohen Erez , Fox Donald T.
Published: February 2020

Individual organ development must be temporally coordinated with development of the rest of the organism. As a result, cell division in a developing organ occurs on a relatively fixed time scale. Despite this, many developing organs can regenerate cells lost to injury. How organs regenerate within the time constraints of organism development remains unclear. Here, we show the developingDrosophilahindgut regenerates by accelerating the mitotic cell cycle. This process requires JAK/STAT signaling and is achieved by decreasing G1 length during the normal period of developmental mitoses. Mitotic capacity is then terminated by the steroid hormone ecdysone receptor. This receptor activates a hindgut-specific enhancer offizzy-related, a negative regulator of mitotic cyclins. We further identify the Sox transcription factorDichaeteas an important negative regulator of injury-induced mitotic cycles. Our findings reveal how mitotic cell cycle entry mechanisms can be adapted to accomplish developmental organ regeneration.
Phosphorescent mono- and diiridium(III) complexes cyclometalated by fluorenyl- or phenyl-pyridino ligands with bulky substituents, as prospective OLED dopants
Authors: M'hamedi Ahmed , Batsanov Andrei S.
Published: February 2020

The crystal structures of tris[9,9-dihexyl-2-(5-methoxypyridin-2-yl-κN)-9H-fluoren-3-yl-κC
3]iridium pentane monosolvate, [Ir(C31H38NO)3]·C5H12, (I), di-μ2-chlorido-bis{bis[2-(5-fluoropyridin-2-yl)-9,9-dihexyl-9H-fluoren-3-yl]iridium} pentane 0.3-solvate, [Ir2(C30H35FN)4Cl2]·0.3C5H12, (II), di-μ2-cyanato-bis{bis[9,9-dihexyl-2-(5-methoxypyridin-2-yl)-9H-fluoren-1-yl]iridium} pentane monosolvate, [Ir2(C31H38NO)4(NCO)2(NCO)2]·C5H12, (III), and {μ-N,N′-bis[3,5-bis(trifluoromethyl)phenyl]oxamidato}bis(bis{2-[4-(2,4,6-trimethylphenyl)pyridin-2-yl]phenyl-κ2
C
1,N′}iridium)–chlorobenzene–pentane (1/2.3/0.4), [Ir2(C20H19N)4(C18H6F12N2O2)]·2.3C6H5Cl·0.4C5H12, (IV), synthesized in the quest for organic light-emitting devices, were determined. The bis-μ2-chloro and bis-μ2-cyanato complexes have ΔΔ and ΛΛ configurations of the distorted octahedral Ir centres in racemic crystals, whereas the oxamido complex has a centrosymmetric (meso) structure with the ΔΛ configuration. The bridging oxamido moiety has a nearly planar anti geometry. All structures show substantial disorder of both host molecules and solvents of crystallization.
Structural, Hirshfeld and DFT studies of conjugated D–π–A carbazole chalcone crystal
Authors: Zaini Muhamad Fikri , Razak Ibrahim Abdul , Khairul Wan Mohd , Arshad Suhana
Published: February 2020

A new conjugated carbazole chalcone compound, (E)-3-[4-(9,9a-dihydro-8aH-carbazol-9-yl)phenyl]-1-(4-nitrophenyl)prop-2-en-1-one (CPNC), C27H18N2O3, was synthesized using a Claisen–Schmidt condensation reaction. CPNC crystallizes in the monoclinic non-centrosymmetric space group Cc and adopts an s-cis conformation with respect to the ethylenic double bonds (C=O and C=C). The crystal packing features C—H...O and C—H...π interactions whose percentage contribution was quantified by Hirshfeld surface analysis. Quantum chemistry calculations including geometrical optimization and molecular electrostatic potential (MEP) were analysed by density functional theory (DFT) with a B3LYP/6–311 G++(d,p) basis set.
Determination of volumetric material data from boundary measurements
Authors: Löhner Rainald , Antil Harbir
Published: February 2020

Purpose

The purpose of this study is to determine the possibility of an accurate assessment of the spatial distribution of material properties such as conductivities or impedances from boundary measurements when the governing partial differential equation is a Laplacian.

Design/methodology/approach

A series of numerical experiments were carefully performed. The results were analyzed and compared.

Findings

The results to date show that while the optimization procedure is able to obtain spatial distributions of the conductivity k that reduce the cost function significantly, the resulting conductivity k is still significantly different from the target (or real) distribution sought. While the normal fluxes recovered are very close to the prescribed ones, the tangential fluxes can differ considerably.

Research limitations/implications

At this point, it is not clear why rigorous mathematical proofs yield results of convergence and uniqueness, while in practice, accurate distributions of the conductivity k seem to be elusive. One possible explanation is that the spatial influence of conductivities decreases exponentially with distance. Thus, many different conductivities inside a domain could give rise to very similar (infinitely close) boundary measurements.

Practical implications

This implies that the estimation of field conductivities (or generally field data) from boundary data is far more difficult than previously assumed when the governing partial differential equation in the domain is a Laplacian. This has consequences for material parameter assessments (e.g. for routine maintenance checks of structures), electrical impedance tomography, and many other applications.

Originality/value

This is the first time such a finding has been reported in this context.
A study on the effect of ethical leadership on teachers’ moral motivation at schools in Pakistan
Authors: Khan Shazia Rehman , Bauman David C. , Javed Uzma
Published: February 2020

Purpose

The purpose of this study was to examine the influence of ethical leadership on moral motivation of teachers in the schools of Pakistan.

Design/methodology/approach

Scenario-based experimental design was used to collect data (N = 174 teachers) from 25 schools in the city of Islamabad. Participants included 156 females and 18 males aged 23–37 years. Ethical leadership was measured at both construct and component levels (moral person and moral manager).

Findings

The results found that the moral person component of ethical leadership style heightens the moral identity (internalization)-based moral motivation, while the moral manager component and ethical leadership at construct level style increases moral identity (symbolization)-based moral motivation. Interestingly, in the absence of reward, only the moral person component of ethical leadership style maintained participants’ moral motivation.

Originality/value

The originality of this study lies in highlighting the divergence in ethical leadership style at component level that explains the differences in moral motivation of the teachers.
A geographically disaggregated analysis of multidimensional poverty in Punjab
Authors: Iqbal Asim , Siddiqui Anjum , Zafar Maryam
Published: February 2020

Purpose

The study seeks to examine the extent and the causes of multidimensional poverty as opposed to the traditional unidimensional headcount poverty measures to understand the true face of economic deprivation in Punjab, Pakistan.

Design/methodology/approach

Poverty is measured through the Alkire–Foster index at the geographically disaggregated levels of divisions and districts, and the causes of pervasive poverty are analyzed through a logit model using the Multiple Indicators Cluster Survey (MICS) comprising of 95,238 households in 9 geographical divisions and their 36 districts.

Findings

It was found that poverty in Punjab is associated with larger household size, inadequate wealth, and low levels of educational attainment, and that both matric as well as post-matric education reduced the chances of poverty of household heads by approximately 19 percent. In addition to rural poverty, the study finds evidence of urban poverty across the geographical districts of Punjab. Contrary to common belief that chances of poverty are higher in females, it was found to be more likely in males. However, the statistical significance of gender as a determinant of poverty was not observed in the majority of divisions.

Practical implications

Practical implications were for focused policy interventions in poverty alleviation.

Originality/value

The analysis of determinants of multidimensional poverty at the geographically disaggregated level of divisions is an original contribution.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/IJSE-01-2019-0037
Functional differentiation of society as a middle-range theory
Authors: Sakai Kosuke
Published: February 2020

Purpose

This paper aimed to analyze the ways in which Niklas Luhmann's theory of the functional differentiation of society can be applied to historical studies. To achieve this, a semantic analysis of the development of modern insurance in Germany during the nineteenth century was conducted.

Design/methodology/approach

Through an examination of the significant features of Luhmann's theoretical frameworks in empirical objects, Luhmann's semantic analysis was reformulated as an approach based on a middle-range theory, similar to that of Robert K. Merton, where the potential of the theory can be maximized for empirical research. This paper embodies this proposal, citing several developments within organizations that imbued insurance technology with various ideas and values.

Findings

The theory of the functional differentiation of society can be reconstructed as a working hypothesis from a methodological perspective, instead of a general theory that explains every part of society. Applying this to empirical social practices leads to progress in historical studies conducting the semantic variations connected to the institutional formation and their boundary works.

Originality/value

This paper provides a practical research perspective for historical studies in the social sciences, employing a reinterpretation of sociological theory that may be understood only as a structural presupposition of modern society. Furthermore, the increased possibility of historical-comparative studies on modern insurance is indicated by illustrating the applicability of this framework to a detailed case study of modern insurance.
I’ve got an idea! Exploring the antecedents of suggestion sharing in consumer services
Authors: Burnham Thomas
Published: February 2020

Purpose

Customer suggestions offer valuable insights to companies, and suggestion sharing is a form of engagement that strengthens customers’ relationships with firms. Yet research to date has neglected to explicitly study the antecedents of direct-to-firm consumer suggestion sharing or to adequately characterize the behavior. This paper aims to address this deficiency.

Design/methodology/approach

The research draws on two surveys using three different elicitation techniques – critical incident, direct reporting and scenario response. Inductive content analysis of consumer responses is used to derive exploratory insights regarding the range of factors that motivate and inhibit consumer suggestion sharing, with an emphasis on consumer service-related contexts.

Findings

Potential self, other and firm benefits motivate suggestion sharing, whereas a host of factors, including the effort involved, a lack of perceived firm efficacy and unpleasant sharing contexts inhibit it. The findings reveal a rich portrait of antecedents that illustrates how direct-to-firm suggestion-sharing behavior combines elements of customer citizenship behavior, customer complaint behavior and online community idea sharing.

Research limitations/implications

The research relies upon reporting by US students and consumers.

Practical implications

Service firms hoping to avail themselves of customers’ desire to contribute to their and their customers’ betterment must understand and manage the tripartite nature of consumer suggestion sharing evinced by the antecedents revealed.

Originality/value

To the best of the author’s knowledge, this research offers the first description of the range of factors that motivate and inhibit direct-to-firm consumer suggestion sharing. As such, it provides a theoretical foundation upon which future consumer suggestion-sharing research can build.
Linking employee loyalty with job satisfaction using PLS–SEM modelling
Authors: Dhir Swati , Dutta Tanusree , Ghosh Piyali
Published: February 2020

Purpose

The purpose of the present study is to empirically test a model that illustrates how person–job fit (PJF), person–organization fit (POF) and perceived supervisor support (PSS) as individualistic factors affect job satisfaction and employee loyalty in the Indian context.

Design/methodology/approach

A survey of the Indian managerial executives was conducted with a structured questionnaire to validate the proposed model. Responses of a sample of 220 have been tested using PLS–SEM modelling approach.

Findings

The factors PJF, POF and PSS are inferred to have significant impact on job satisfaction and also improve employee loyalty. In comparison to PJF and PSS, POF has emerged as the most influential determinant of the proposed model.

Practical implications

HR managers can adopt relevant practices and promote organizational policies in order to have loyal employees. This would also help organizations in increasing overall productivity at both individual and organizational levels. Recruiters could be provided with necessary tools and measures to find better and accurate means of mapping POF and PJF.

Originality/value

Establishing PJF, POF fit and PSS as individual-specific constructs, and job satisfaction as a mediator, leading to employee loyalty, is a significant contribution to research. This study finds uniqueness in the Indian context, in which these constructs have mostly been explored in isolation or as dyadic relations. Review of existing studies indicates an overlap of factors that influence both job satisfaction and employee loyalty.
High performance thermoplastic polymer for the compressive behaviour of carbon fibre reinforced composites
Authors: Liu Ankang , Wang Bing , Li Fei
Published: February 2020

Purpose

This paper aims to study the effect of elevated temperature on the compression behaviour of carbon fibre polyphenylene sulphide (CF/PPS) laminates notched and unnotched specimens made by film stacking method (FSM).

Design/methodology/approach

The surface of CF was coated with a silane coupling agent to form an effective transition layer with PPS, so as to enhance the interfacial interaction between CF and PPS. Considering the influence of fabrication pressure, forming temperature and cooling rate on the properties of laminates to obtain a reasonable preparation process. Conducting a compressive experiment of notched and unnotched specimens at different temperatures, which failure modes were examined by scanning electron microscope and stereo microscope.

Findings

The experimental observations highlight that with the increase of temperature, the transition failure mode from fibre broken to kink-band appeared in unnotched specimens, which were closely attributed to the matrix state. The notched specimens appeared more complex failure mode, which can be attributed to the joint effect of temperature and opening hole.

Research implications

A simple way of FSM for composite material laminates has been developed by using woven CF and PPS films.

Originality/value

The outcome of this study will help to understand the compression response mechanism of composite materials made by FSM at different temperature.
Implications of blockchain distributed ledger technology for records management and information governance programs
Authors: Franks Patricia C.
Published: February 2020

Purpose

The purpose of this paper is to assist records managers and information governance professionals to understand the challenges presented by their organization’s use of blockchain distributed ledger technology (DLT).

Design/methodology/approach

An extensive literature review was conducted, which revealed a multitude of articles based on research into blockchain DLT, most written from the technology perspective. This paper differs in that it applies a records management lens to an analysis of the records created, registered or stored on a blockchain. A six-stage blockchain records consideration model is provided to illustrate examples of the records management challenges presented by the implementation of blockchain DLT. Questions are posed and recommendations are made to aid the reader in developing a blockchain DLT records management and information governance strategy.

Findings

Because there is no one universal configuration for a blockchain DLT solution, each implementation must be analyzed to understand the resultant records management and information governance challenges. A series of questions that should be asked and answered can not only help records management and information governance professionals adapt their policies and practices to the technology but also provide a basis for discussion with those designing the blockchain DLT solutions so they can include records management features in their designs.

Originality/value

This paper contributes an original analysis of the implications of the adoption of Blockchain DLT for records management and information governance programs through the lens of a six-stage Blockchain Records Consideration Model.
Experimental and numerical fatigue life assessment of SAC305 solders subjected to combined temperature and harmonic vibration loadings
Authors: Gharaibeh Mohammad
Published: February 2020

Purpose

This paper aims to investigate the fatigue life performance of SAC305 ball grid array solders under combined temperature and harmonic vibration loading conditions.

Design/methodology/approach

Fatigue tests were performed using a sine dwell with resonance tracking vibration and temperature loading experiment. Finite element stress analysis was also performed to help in understanding the observed failure trends.

Findings

Fatigue test results showed that the lead-free solders tend to fail quickly in higher temperatures and higher vibration loading test conditions. The failure analysis results revealed that in low temperatures, the solder cracks are initiated and propagated at the package side. However, in high temperatures, the cracks are observed at the board side of the interconnect. In all conditions, the cracks are propagated throughout the intermetallic compound layer.

Originality/value

In the published literature, there is a lack of data in the area of fatigue assessment of lead-free solders under combined temperature and vibration loadings. This paper provides useful insights into combined thermal/vibration fatigue, i.e. reliability behavior of lead-free solder joint types.