bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Models of Ischemic Lung Damage for the Study of Therapeutic Reconditioning During Ex Vivo Lung Perfusion
Authors: Parapanov Roumen , Wang Xingyu , Wang Yabo , Debonneville Anne , Lugrin Jérôme , Liaudet Lucas , Krueger Thorsten
Published: June 2022

Background.

Ex vivo lung perfusion (EVLP) may allow therapeutic reconditioning of damaged lung grafts before transplantation. This study aimed to develop relevant rat models of lung damage to study EVLP therapeutic reconditioning for possible translational applications.

Methods.

Lungs from 31 rats were exposed to cold ischemia (CI) or warm ischemia (WI), inflated at various oxygen fractions (FiO2), followed by 3 h EVLP. Five groups were studied as follow: (1) C21 (control): 3 h CI (FiO2 0.21); (2) C50: 3 h CI (FiO2 0.5); (3) W21: 1 h WI, followed by 2 h CI (FiO2 0.21); (4) W50: 1 h WI, followed by 2 h CI (FiO2 0.5); and (5) W2h: 2 h WI, followed by 1 h CI (FiO2 0.21). Following 3 h EVLP, we measured static pulmonary compliance (SPC), pulmonary vascular resistance, lung weight gain (edema), oxygenation capacity (differential partial pressure of oxygen), and protein carbonyls in lung tissue (oxidative stress), as well as lactate dehydrogenase (LDH, lung injury), nitrotyrosine (nitro-oxidative stress), interleukin-6 (IL-6, inflammation), and proteins (permeability edema) in bronchoalveolar lavage (BAL). Perivascular edema was quantified by histology.

Results.

No significant alterations were noted in C21 and C50 groups. W21 and W50 groups had reduced SPC and disclosed increased weight gain, BAL proteins, nitrotyrosine, and LDH. These changes were more severe in the W50 group, which also displayed greater oxidative stress. In contrast, both W21 and W50 showed comparable perivascular edema and BAL IL-6. In comparison with the other WI groups, W2h showed major weight gain, perivascular edema, SPC reduction, drop of differential partial pressure of oxygen, and massive increases of BAL LDH and proteins but comparable increase of IL-6 and biomarkers of oxidative stress.

Conclusions.

These models of lung damage of increasing severity might be helpful to evaluate new strategies for EVLP therapeutic reconditioning. A model combining 1 h WI and inflation at FiO2 of 0.5 seems best suited for this purpose by reproducing major alterations of clinical lung ischemia-reperfusion injury.
MELD-GRAIL and MELD-GRAIL-Na Are Not Superior to MELD or MELD-Na in Predicting Liver Transplant Waiting List Mortality at a Single-center Level
Authors: Chetwood John D. , Wells Mark V. , Tsoutsman Tatiana , Pulitano Carlo , Crawford Michael D. , Liu Ken , Strasser Simone I. , McCaughan Geoffrey W. , Majumdar Avik
Published: June 2022

Background.

Controversy exists regarding the best predictive model of liver transplant waiting list (WL) mortality. Models for end-stage liver disease–glomerular filtration rate assessment in liver disease (MELD-GRAIL) and MELD-GRAIL-Na were recently described to provide better prognostication, particularly in females. We evaluated the performance of these scores compared to MELD and MELD-Na.

Methods.

Consecutive patients with cirrhosis waitlisted for liver transplant from 1998 to 2017 were examined in this single-center study. The primary outcome was 90-d WL mortality. MELD, MELD-Na, MELD-GRAIL, and MELD-GRAIL-Na at the time of WL registration were compared. Model discrimination was assessed with area under the receiver operating characteristic curves and Harrell’s C-index after fitting Cox models. Model calibration was examined with Grønnesby and Borgan’s modification of the Hosmer-Lemeshow formula and by comparing predicted/observed outcomes across model strata.

Results.

The study population comprised 1108 patients with a median age of 53.5 (interquartile range 48–59) y and male predominance (74.9%). All models had excellent areas under the receiver operating characteristic curves for the primary outcome (MELD 0.89, MELD-Na 0.91, MELD-GRAIL 0.89, MELD-GRAIL-Na 0.89; all comparisons P > 0.05). Youden index cutoffs for 90-d mortality were as follows: MELD, 19; MELD-Na, 22; MELD-GRAIL, 18; and MELD-GRAIL-Na, 17. Variables associated with 90-d mortality on multivariable Cox regression were sodium, bilirubin, creatinine, and international normalized ratio. There were no differences in model discrimination using Harrell’s C-index. All models were well calibrated; however, divergence between observed and predicted mortality was noted with scores ≥25.

Conclusion.

There were no demonstrable differences in discrimination or calibration of GRAIL-based models compared with MELD or MELD-Na in our cohort. This suggests that GRAIL-based models may not have meaningful improvements in discriminatory ability when applied to other settings.
Quantitative models for building and growing fated small cell networks
Authors: Diegmiller Rocky , Nunley Hayden , Shvartsman Stanislav Y. , Imran Alsous Jasmin
Published: June 2022

Small cell clusters exhibit numerous phenomena typically associated with complex systems, such as division of labour and programmed cell death. A conserved class of such clusters occurs during oogenesis in the form of germline cysts that give rise to oocytes. Germline cysts form through cell divisions with incomplete cytokinesis, leaving cells intimately connected through intercellular bridges that facilitate cyst generation, cell fate determination and collective growth dynamics. Using the well-characterized
Drosophila melanogaster
female germline cyst as a foundation, we present mathematical models rooted in the dynamics of cell cycle proteins and their interactions to explain the generation of germline cell lineage trees (CLTs) and highlight the diversity of observed CLT sizes and topologies across species. We analyse competing models of symmetry breaking in CLTs to rationalize the observed dynamics and robustness of oocyte fate specification, and highlight remaining gaps in knowledge. We also explore how CLT topology affects cell cycle dynamics and synchronization and highlight mechanisms of intercellular coupling that underlie the observed collective growth patterns during oogenesis. Throughout, we point to similarities across organisms that warrant further investigation and comment on the extent to which experimental and theoretical findings made in model systems extend to other species.
Initial source of heterogeneity in a model for cell fate decision in the early mammalian embryo
Authors: Robert Corentin , Prista von Bonhorst Francisco , De Decker Yannick , Dupont Geneviève , Gonze Didier
Published: June 2022

During development, cells from a population of common progenitors evolve towards different fates characterized by distinct levels of specific transcription factors, a process known as cell differentiation. This evolution is governed by gene regulatory networks modulated by intercellular signalling. In order to evolve towards distinct fates, cells forming the population of common progenitors must display some heterogeneity. We applied a modelling approach to obtain insights into the possible sources of cell-to-cell variability initiating the specification of cells of the inner cell mass into epiblast or primitive endoderm cells in early mammalian embryo. At the single-cell level, these cell fates correspond to three possible steady states of the model. A combination of numerical simulations and bifurcation analyses predicts that the behaviour of the model is preserved with respect to the source of variability and that cell–cell coupling induces the emergence of multiple steady states associated with various cell fate configurations, and to a distribution of the levels of expression of key transcription factors. Statistical analysis of these time-dependent distributions reveals differences in the evolutions of the variance-to-mean ratios of key variables of the system, depending on the simulated source of variability, and, by comparison with experimental data, points to the rate of synthesis of the key transcription factor NANOG as a likely initial source of heterogeneity.
Conserved reduction of m6A marks during aging and neurodegeneration is linked to altered translation of synaptic transcripts
Authors: Castro-Hernández Ricardo , Berulava Tea , Metelova Maria , Epple Robert , Centeno Tonatiuh Peña , Sakib M Sadman , Burkhart Susanne , Ninov Momchil , Bohnsack Katherine E. , Bohnsack Markus T. , Delalle Ivana , Fischer Andre
Published: June 2022

N6-methyladenosine (m6A) plays diverse roles in the regulation of mRNA metabolism. In the mammalian brain it has been linked to developmental processes and memory function. However, the precise role of m6A in the context synaptic plasticity and especially during impaired cognition are not fully understood. Here, we describe the mouse and human brain m6A epi-transcriptome in a tissue-specific manner. We furthermore show that m6A levels undergo a massive decrease across mouse brain regions as a consequence of aging. In addition, Alzheimer's disease in humans correlates with decreased N6-methylation in a similar population of transcripts that are linked to synaptic function and localized to synapses, such as the calcium/calmodulin-dependent kinase II (CaMKII). We furthermore show that reduced m6A levels impair synaptic protein-synthesis of CAMKII. Our results suggest that m6A-RNA-methylation is an important mechanism to control synaptic protein synthesis which is affected early in cognitive diseases.

Significance statement

The addition of N6-methyladenosine (m6A) to RNA plays a role in various cellular processes and its de-regulation has been linked to several devastating diseases. The precise role of m6A RNA-methylation in the adult brain is, however, not well understood. In our study, we describe the genome-wide m6A epi-transcriptome in the healthy and diseased brains of mice and humans. Our data demonstrate that a substantial amount of m6A transcripts are conserved. These transcripts are linked to the regulation of synaptic processes and are localized to synapses. In the diseases brain we detect RNA hypomethylation across multiple transcripts in all investigated brain regions and across species. At the mechanistic level we find that reduced m6A levels specifically impairs synaptic protein-synthesis.
Analysis of task-related MEG functional brain networks using dynamic mode decomposition
Authors: Partamian Hmayag , Tabbal Judie , Hassan Mahmoud , Karameh Fadi
Published: June 2022

Objective

Functional connectivity networks explain the different brain states during diverse motor, cognitive, and sensory functions. Extracting spatial network configurations and their temporal evolution is crucial for understanding the brain function during diverse behavioral tasks.

Approach

In this study, we introduce the use of dynamic mode decomposition (DMD) to extract the dynamics of brain networks. We compared DMD with principal component analysis (PCA) using real magnetoencephalography (MEG) data during motor and memory tasks.

Main Results

The framework generates dominant spatial brain networks and their time dynamics during simple tasks, such as button press and left-hand movement, as well as more complex tasks, such as picture naming and memory tasks. Our findings show that the DMD-based approach provides a better temporal resolution than the PCA-based approach.

Significance

We believe that DMD has a very high potential for deciphering the spatiotemporal dynamics of electrophysiological brain network states during tasks.
Exploiting the mediating role of the metabolome to unravel transcript-to-phenotype associations
Authors: Auwerx Chiara , Sadler Marie C. , Reymond Alexandre , Kutalik Zoltán , Porcu Eleonora
Published: June 2022

Despite the success of genome-wide association studies (GWASs) in identifying genetic variants associated with complex traits, understanding the mechanisms behind these statistical associations remains challenging. Several methods that integrate methylation, gene expression, and protein quantitative trait loci (QTLs) with GWAS data to determine their causal role in the path from genotype to phenotype have been proposed. Here, we developed and applied a multi-omics Mendelian randomization (MR) framework to study how metabolites mediate the effect of gene expression on complex traits. We identified 206 transcript-metabolite-trait causal triplets for 28 medically relevant phenotypes. Sixty-seven of these associations were missed by classical transcriptome-wide MR, which only uses gene expression and GWAS data. Among these, we identify biologically relevant pathways, such as betweenANKHand calcium levels mediated by citrate andSLC6A12and serum creatinine through modulation of the levels of the renal osmolyte betaine. We show that the signals missed by transcriptome-wide MR are found thanks to the gain in power allowed by integrating multiple omics-layer. Simulation analyses show that with larger molecular QTL studies and in case of mediated effects, our multi-omics MR framework outperforms classical MR approaches designed to detect causal relationships between single molecular traits and complex phenotypes.
Human pericytes degrade α-synuclein aggregates in a strain-dependent manner
Authors: Dieriks Birger Victor , Highet Blake , Alik Ania , Bellande Tracy , Stevenson Taylor J. , Low Victoria , Park Thomas I-H , Correia Jason , Schweder Patrick , Faull Richard L. M. , Melki Ronald , Curtis Maurice A. , Dragunow Mike
Published: June 2022

Parkinson’s disease (PD) is a progressive, neurodegenerative disorder characterised by the abnormal accumulation of α-synuclein (α-syn) aggregates. Central to disease progression is the gradual spread of pathological α-syn. α-syn aggregation is closely linked to progressive neuron loss. As such, clearance of α-syn aggregates may slow the progression of PD and lead to less severe symptoms. Evidence that non-neuronal cells play a role in PD and other synucleinopathies such as Lewy body dementia and multiple system atrophy are increasing. Our previous work has shown that pericytes — vascular mural cells that regulate the blood-brain barrier — contain α-syn aggregates in human PD brains. Here, we demonstrate that pericytes efficiently internalise fibrillar α-syn irrespective of being in a monoculture or mixed neuronal cell culture. Pericytes efficiently break down α-syn aggregates in vitro, with clear differences in the number of α-syn aggregates/cell and average aggregate size when comparing five pure α-syn strains (Fibrils, Ribbons, fibrils65, fibrils91 and fibrils110). Furthermore, pericytes derived from PD brains have a less uniform response than those derived from control brains. Our results highlight the vital role brain vasculature may play in reducing α-syn burden in PD.
Convergent approaches to delineate the metabolic regulation of tumor invasion by hyaluronic acid biosynthesis
Authors: Shimpi Adrian A. , Tan Matthew L. , Vilkhovoy Michael , Dai David , Roberts L. Monet , Kuo Joe , Huang Lingting , Varner Jeffrey D. , Paszek Matthew , Fischbach Claudia
Published: June 2022

Metastasis is the leading cause of breast cancer-related deaths and often driven by invasion and cancer-stem like cells (CSCs). Both the CSC phenotype and invasion have been associated with increased hyaluronic acid (HA) production. How these independent observations are connected, and which role metabolism plays in this process remains unclear due in part to the lack of convergent approaches that integrate engineered model systems, computational tools, and cancer biology. Using microfluidic invasion models, metabolomics, computational flux balance analysis (FBA), and bioinformatic analysis of patient data we investigated the functional links between the stem-like, invasive, and metabolic phenotype of breast cancer cells as a function of HA biosynthesis. Our results suggest that CSCs are more invasive than non-CSCs and that broad metabolic changes caused by overproduction of HA play a role in this process. Accordingly, overexpression of hyaluronic acid synthases (HAS) 2 or 3 induced a metabolic phenotype that promoted breast cancer cell stemness and invasion in vitro and upregulated a transcriptomic signature that was predictive of increased invasion and worse survival in patients. Collectively, this study suggests that HA overproduction leads to metabolic adaptations that help satisfy the energy demands necessary for 3D invasion of breast cancer stem cells further highlighting the importance of engineered model systems and multidisciplinary approaches in cancer research.
Multiplexed transcriptome discovery of RNA binding protein binding sites by antibody-barcode eCLIP
Authors: Lorenz Daniel A. , Shen Kylie A. , Her Hsuan-Lin , Rothamel Katie , Hutt Kasey R. , Nojadera Allan C. , Bruns Stephanie C. , Manakov Sergei A. , Chapman Karen B. , Yeo Gene W.
Published: June 2022

UV cross-linking and immunoprecipitation (CLIP) methodologies enable the identification of RNA binding sites of RNA-binding proteins (RBPs). Despite improvements in the library preparation of RNA fragments, the current enhanced CLIP (eCLIP) protocol requires 4 days of hands-on time and lacks the ability to process many RBPs in parallel. We present a new method termed antibody-barcode eCLIP (ABC) that utilizes DNA-barcoded antibodies and proximity ligation of the DNA oligonucleotides to RBP-protected RNA fragments to interrogate multiple RBPs simultaneously. We observe performance comparable to eCLIP with the advantage of a reduced hands-on time of 2 days and dramatically increased scaling while minimizing sample-to-sample variation and maintaining the same material requirement of a single eCLIP experiment.
Metallo-Supramolecular Branched Polymer Protects Particles from Air-water Interface in Single-Particle Cryo-Electron Microscopy
Authors: Xu Yixin , Qin Yuqi , Wang Lang , Zhang Yingyi , Wang Yufeng , Dang Shangyu
Published: June 2022

Recent technological breakthroughs in single-particle cryo-electron microscopy (cryo-EM) enabled rapid atomic structure determination of biological macromolecules. A major bottleneck in the current single particle cryo-EM pipeline is the preparation of good quality frozen cryo-EM grids, which is mostly a trial-and-error process. Among many issues, preferred particle orientation and sample damage by air-water interface (AWI) are common practical problems. Here we reported a method of applying metallo-supramolecular branched polymer (MSBP) in the cryo-sample preparation for high-resolution single-particle cryo-EM. Our data shows that MSBP keeps a majority of particles away from air-water interface and mitigates preferred orientation as verified by the analyses of apoferritin, hemagglutinin (HA) trimer and various sample proteins. The use of MSBP is a simple method to improve particle distribution for high-resolution structure determination in single-particle cryo-EM.
Rotavirus spike protein VP4 mediates viroplasm assembly by association to actin filaments
Authors: Vetter Janine , Papa Guido , Seyffert Michael , Gunasekera Kapila , Lorenzo Giuditta De , Wiesendanger Mahesa , Reymond Jean-Louis , Fraefel Cornel , Burrone Oscar R. , Eichwald Catherine
Published: June 2022

The formation of viroplasms is a well-conserved step in the rotavirus (RV) life cycle. In these structures, both virus genome replication and progeny assembly take place. A stabilized microtubule cytoskeleton and lipid droplets are required for the viroplasm formation, which involves several virus proteins. The viral spike protein VP4 has not previously been shown to have a direct role in viroplasm formation. However, it is involved with virus-cell attachment, endocytic internalization, and virion morphogenesis. Moreover, VP4 interacts with actin cytoskeleton components, mainly in processes involving virus entrance and egress, and thereby may have an indirect role in viroplasm formation. In this study, we used reverse genetics to construct a recombinant RV, rRV/VP4-BAP, which contains a biotin acceptor peptide (BAP) in the K145-G150 loop of the VP4 lectin domain, permitting live monitoring. The recombinant virus was replication competent but showed a reduced fitness. We demonstrate that rRV/VP4-BAP infection, as opposed to rRV/wt infection, did not lead to a reorganized actin cytoskeleton as viroplasms formed were insensitive to drugs that depolymerize actin and inhibit myosin. Moreover, wt VP4, but not VP4-BAP, appeared to associate with actin filaments. Similarly, VP4 in co-expression with NSP5 and NSP2 induced a significant increase in the number of viroplasm-like structures. Interestingly, a small peptide mimicking loop K145-G150 rescued the phenotype of rRV/VP4-BAP by increasing its ability to form viroplasms and hence, improve virus progeny formation. Collectively, these results provide a direct link between VP4 and the actin cytoskeleton to catalyze viroplasm assembly.

IMPORTANCE

The spike protein VP4 participates in diverse steps of the rotavirus (RV) life cycle, including virus-cell attachment, internalization, modulation of endocytosis, virion morphogenesis, and virus egress. Using reverse genetics, we constructed for the first time a recombinant RV, rRV/VP4-BAP, harboring a heterologous peptide in the lectin domain (loop K145-G150) of VP4. The rRV/VP4-BAP was replication-competent but with reduced fitness due to a defect in the ability to reorganize the actin cytoskeleton, which affected the efficiency of viroplasm assembly. This defect was rescued by adding a permeable small-peptide mimicking the wild-type VP4 loop K145-G150. In addition to revealing a new role of VP4, our findings suggest that rRV harboring an engineered VP4 could be used as a new dual vaccination platform providing immunity against RV and additional heterologous antigens.
Definition of a saxitoxin (STX) binding code enables discovery and characterization of the Anuran saxiphilin family
Authors: Chen Zhou , Zakrzewska Sandra , Hajare Holly S. , Alvarez-Buylla Aurora , Abderemane-Ali Fayal , Bogan Maximiliana , Ramirez Dave , O’Connell Lauren A. , Bois J. Du , Minor Daniel L.
Published: June 2022

American bullfrog (Rana castesbeiana) saxiphilin (RcSxph) is a high-affinity ‘toxin sponge’ protein thought to prevent intoxication by saxitoxin (STX), a lethal bis-guanidinium neurotoxin that causes paralytic shellfish poisoning (PSP) by blocking voltage-gated sodium channels (NaVs). How specific RcSxph interactions contribute to STX binding has not been defined and whether other organisms have similar proteins is unclear. Here, we use mutagenesis, ligand binding, and structural studies to define the energetic basis of Sxph:STX recognition. The resultant STX ‘recognition code’ enabled engineering of RcSxph to improve its ability to rescue NaVs from STX and facilitated discovery of ten new frog and toad Sxphs. Definition of the STX binding code and Sxph family expansion among diverse Anurans separated by ∼140 million years of evolution provides a molecular basis for understanding the roles of toxin sponge proteins in toxin resistance and for developing novel proteins to sense or neutralize STX and related PSP toxins.

Teaser

A conserved STX recognition motif from frog and toad saxiphilins defines molecular principles of paralytic toxin binding.
Hydrodynamic dissection of single cells in a microfluidic system
Authors: Paul Rajorshi , Zhang Kevin S. , Jalil Myra Kurosu , Castaño Nicolas , Kim Sungu , Tang Sindy K.Y.
Published: June 2022

Stentor coeruleus, a single-cell ciliated protozoan, is a model organism for wound healing and regeneration studies. DespiteStentor’s large size (up to 2 mm in extended state), microdissection ofStentorremains challenging. In this work, we describe a hydrodynamic cell splitter, consisting of a cross junction, capable of splittingStentorcells in a non-contact manner at a high throughput of ∼500 cells/min under continuous operation. Introduction of asymmetry in the flow field at the cross junction leads to asymmetric splitting of the cells to generate cell fragments as small as ∼8.5 times the original cell size. Characterization of cell fragment viability shows reduced 5-day survival as fragment size decreases and as the extent of hydrodynamic stress imposed on the fragments increases. Our results suggest that cell fragment size and composition, as well as mechanical stress, play important roles in the long-term repair ofStentorcells and warrant further investigations. Nevertheless, the hydrodynamic splitter can be useful for studying phenomena immediately after cell splitting, such as the closure of wounds in the plasma membrane which occurs on the order of 100 – 1000 seconds inStentor.
Inclusion of a GaAs detector model in the Photon Counting Toolkit software for the study of breast imaging systems
Authors: Ghammraoui Bahaa , Taguchi Katsuyuki , Glick Stephen J.
Published: June 2022

We present an upgraded version of the Photon Counting Toolkit (PcTK), a publicly available MATLAB tool for the simulation of semiconductor-based photon counting detectors (PCD), which has been extended and validated to account for gallium arsenide (GaAs)-based PCD(s). The modified PcTK version was validated by performing simulations and acquiring experimental data for three different cases. The LAMBDA 60 K module planar detector (X-Spectrum GmbH, Germany) based on the Medipix3 ASIC technology was used in all cases. This detector has a 500-µm thick GaAs sensor and a 256 × 256-pixel array 55 µm pixel size. The first validation was a comparison between simulated and measured spectra from a 109Cd radionuclide source. In the second validation study, experiments and simulations of mammography spectra were conducted to observe the performance of the GaAs version of the PcTK with polychromatic radiation used in conventional x-ray imaging systems. The third validation study used single event analysis to validate the spatio-energetic model of the extended PcTK version. Overall, the software provided a good agreement between simulated and experimental data, validating the accuracy of the GaAs model. The software could be an attractive tool for accurate simulation of breast imaging modalities relying on photon counting detectors and therefore could assist in their characterization and optimization.
Diurnal and eating-associated microbial patterns revealed via high-frequency saliva sampling
Authors: Hu Yichen , Amir Amnon , Huang Xiaochang , Li Yan , Huang Shi , Wolfe Elaine , Weiss Sophie , Knight Rob , Xu Zhenjiang Zech
Published: June 2022

The oral microbiome is linked to oral and systemic health, but its fluctuation under frequent daily activities remains elusive. Here, we sampled saliva at 10- to 60-min intervals to track the high-resolution microbiome dynamics during the course of human activities. This dense time series data showed that eating activity markedly perturbed the salivary microbiota, with tongue-specific Campylobacter concisus and Oribacterium sinus and dental plaque-specific Lautropia mirabilis, Rothia aeria, and Neisseria oralis increased after every meal in a temporal order. The observation was reproducible in multiple subjects and across an 11-mo period. The microbiome composition showed significant diurnal oscillation patterns at different taxonomy levels with Prevotella/Alloprevotella increased at night and Bergeyella HMT 206/Haemophilus slowly increased during the daytime. We also identified microbial co-occurring patterns in saliva that are associated with the intricate biogeography of the oral microbiome. Microbial source tracking analysis showed that the contributions of distinct oral niches to the salivary microbiome were dynamically affected by daily activities, reflecting the role of saliva in exchanging microbes with other oral sites. Collectively, our study provides insights into the temporal microbiome variation in saliva and highlights the need to consider daily activities and diurnal factors in design of oral microbiome studies.
Realizations of the abstract regular H
3 polyhedra
Authors: Aranas Jonn Angel L. , Loyola Mark L.
Published: June 2022

Regular polyhedra and related structures such as complexes and nets play a prominent role in the study of materials such as crystals, nanotubes and viruses. An abstract regular polyhedron {\cal P} is the combinatorial analog of a classical regular geometric polyhedron. It is a partially ordered set of elements called faces that are completely characterized by a string C-group (G, T), which consists of a group G generated by a set T of involutions. A realization R is a mapping from {\cal P} to a Euclidean G space that is compatible with the associated real orthogonal representation of G. This work discusses an approach to the theory of realizations of abstract regular polyhedra with an emphasis on the construction of a realization and its decomposition as a blend of subrealizations. To demonstrate the approach, it is applied to the polyhedra whose automorphism groups are abstractly isomorphic to the non-crystallographic Coxeter group H
3.
Syntheses and crystal structures of a nitro–anthracene–isoxazole and its oxidation product
Authors: Li Chun , Weaver Matthew J. , Campbell Michael J. , Natale Nicholas R.
Published: June 2022

The syntheses and structures of an unexpected by-product from an iodination reaction, namely, ethyl 5-methyl-3-(10-nitroanthracen-9-yl)isoxazole-4-carboxylate, C21H16N2O5, (I), and its oxidation product, ethyl 3-(9-hydroxy-10-oxo-9,10-dihydroanthracen-9-yl)-5-methylisoxazole-4-carboxylate, C21H17NO5 (V) are described. Compound (I) crystallizes with two molecules in the asymmetric unit in which the dihedral angles between the anthracene fused-ring systems and isoxazole ring mean planes are 88.67 (16) and 85.64 (16)°; both molecules feature a disordered nitro group. In (V), which crystallizes with one molecule in the asymmetric unit, the equivalent dihedral angle between the almost planar anthrone ring system (r.m.s. deviation = 0.029 Å) and the pendant isoxazole ring is 89.65 (5)°. In the crystal of (I), the molecules are linked by weak C—H...O interactions into a three-dimensional network and in the extended structure of (V), inversion dimers linked by pairwise O—H...O hydrogen bonds generate R
2
2(14) loops.
Working toward the sustainable development goals in earnest – critical international business perspectives on designing and implementing better interventions
Authors: Sinkovics Noemi , Vieira Luciana Marques , van Tulder Rob
Published: June 2022

Purpose

The purpose of this study is to reflect on the importance of the Sustainable Development Goals (SDG) framework as a milestone for concerted efforts to tackle the underlying grand challenges.

Design/methodology/approach

This viewpoint is predominantly conceptual in nature. However, this study adapts the University of Auckland's SDG key words to broadly map existing international business research in each SDG category across nine journals.

Findings

The SDG framework offers a positive and inclusive way forward to integrate social and environmental with economic aspects in the field of international business.

Originality/value

The inclusive nature of the SDG framework may achieve what previous labels such as social value creation and corporate social responsibility could not. It offers a path where integrating social and environmental with economic perspectives does not need to threaten the identity of the field. The SDG mapping exercise across nine selected journals clearly demonstrates that mainstream, economically focused research can continue to make valuable contributions to the SDGs as long as the discipline allows more room for integrators.
Tracking the research trends in the library and information science: a case study of India
Authors: Gupta Sangita , Gul Sumeer
Published: June 2022

Purpose

The study aims to present an insight into the research landscape of Library and Information Science (LIS) by India using a bibliometric visualization tool. The study analyses the research growth and trends, highly cited articles, productive publication titles, institutional and country collaboration.

Design/methodology/approach

The data were downloaded from the Web of Science Core Collection for a period of 20 years and analysed through VOSviewer, a data visualization software.

Findings

The results indicate that the overall annual contributions are increasing, although with uneven and slow growth from 2001 to 2014. However, the highest contributions and impact is witnessed over the past few years. All the top 10 cited papers are related to the area of information processing and management. The visualization technique made it clear that the area of research has made a transition from traditional concepts of library and information to novel ones involving big data, machine learning, altmetrics, etc. Also, the Indian Institute of Technology System, the Council of Scientific and Industrial Research and the Indian Institute of Management System have made the highest contributions. Furthermore, India shares maximum collaborations with the USA, followed by England and China.

Research limitations/implications

The findings of this study would help readers to gain understanding about the contribution of India for the development of the LIS. It would also help researchers to identify the hotspots and left out areas of research in the Indian context that require further investigation, thus would help in policy decisions and future research. Furthermore, researchers will be sensitized about the network visualizations that can also help them to get connected with the peers. The study can also help the journals to recognize the trending topics, which will provide the researchers with the opportunities to work on the same. Funding agencies can also be benefitted by the findings of the current study as they will be informed about the research areas which need to be funded.

Originality/value

There are not many research studies that highlight the research trends in the area of LIS from India and visualize the collaboration among institutions and countries. The study tries to showcase the research trends and collaborative frameworks in the field of LIS in terms of network visualization.
Effect of economic complexity on services export diversification: do foreign direct investment inflows matter?
Authors: Gnangnon Sena Kimm
Published: June 2022

Purpose

The purpose of this study is to explore the effect of economic complexity on services export diversification. This study has been built on two arguments. The first one draws from Eichengreen and Gupta (2013b) and states that countries that export complex products would have a high penetration in the international goods market and establish a network that could be exploited to expand their range of services export items. Second, by inducing higher inflows of foreign direct investment (FDI), greater economic complexity could contribute to fostering services export diversification.

Design/methodology/approach

The empirical analysis uses a panel data set of 109 countries (both developed and developing countries) over the period of 1985–2014, and in particular, non-overlapping sub-periods of five-year average data. Building on the two-step system Generalized Method of Moments, the empirical analysis has provided support for the above-mentioned two theoretical hypotheses.

Findings

The findings indicate that greater economic complexity has been associated with a higher level of services export diversification, and the magnitude of this positive effect is higher for high-income countries than for developing countries. Furthermore, the share of FDI inflows (in percentage of gross domestic product) matters for the effect of economic complexity on services export diversification. Specially, economic complexity exerts a higher positive effect on services export diversification, as the share of net FDI inflows in gross domestic product increases.

Research limitations/implications

From a policy perspective, the analysis complements previous works on the effects of economic complexity (e.g. on economic growth, income inequality, poverty, etc.), by showing that economic complexity also matters for fostering the diversification of countries' services export items. Enhancing economic complexity should be at the heart of policymakers' agenda, both at the national and international levels, given its strong positive effect on macroeconomic aggregates, including on services export diversification, the latter being also an important engine for economic growth (Anandet al., 2012; Gnangnon, 2021a; Mishraet al., 2011; Stojkoskiet al., 2016).

Practical implications

This study opens an avenue for future research on whether services export diversification influences economic complexity. One avenue for future research could also be to explore the effect of comparative advantage on goods and services (using the Balassa's revealed comparative advantage index) on services export diversification. Future works could also examine how economic complexity affects different categories of services sectors, including traditional services and modern services.

Originality/value

To the best of the author’s knowledge, this study is the first to address this topic in the literature.
A bibliometric analysis on poverty alleviation
Authors: Hassan M. Kabir , Alshater Muneer M. , Banna Hasanul , Alam Md Rabiul
Published: June 2022

Purpose

World legends and the scientific community have taken the devastating impact of poverty issue seriously which has been reflected in the growing trend of research in this area. Hence, this paper aims to conduct a bibliometric analysis on poverty alleviation literature, discuss the various dimensions of poverty alleviation and deliver some ideas for future research.

Design/methodology/approach

This study deploys a combined quali-quantitative method familiar as meta-literature review on 454 articles collected from the Web of Science (WoS) database with Social Science Citation Index (SSCI) coverage over the period 1971–2020. Using Rstudio, VOSviewer and Excel, the collected data have been analysed from different lenses.

Findings

This study considers the most contributing scientific actors like authors, journals, topics, institutions and countries as parameters for analysing articles. Based on the analysis from various perspectives, it determines five main research streams upon which it provides some potential research directions to be considered in future research.

Research limitations/implications

This study solely relies on the articles available in the WoS database with index in SSCI. However, it excludes analysing thousands of articles on the same topic available in other platforms.

Originality/value

This study provides a retrospective on the scientific works and collective efforts of scholars germane to poverty alleviation from the highest ranked journals, which would help better understand the literature development and the intellectual structure of this field.
Gender of the online influencer and follower: the differential persuasive impact of homophily, attractiveness and product-match
Authors: Gupta Pranjal , Burton Jennifer L. , Costa Barros Letícia
Published: June 2022

Purpose

The purpose of this research is to extend theoretical knowledge of key variables and their interactions that impact the persuasiveness of online influencers. The study explores the interactions between influencer gender, follower gender, influencer physical attractiveness, influencer product-match and influencer-follower homophily on persuasiveness of influencer product promotions. Although the extant literature shows the persuasive impact of attractiveness, product-match, gender and homophily, less is known about the interactions of these variables with each other and the gender of the influencer and his or her followers. These gaps in the literature are explored.

Design/methodology/approach

The study is a scenario-based experiment where respondents were randomly assigned to cells where influencer attractiveness and product-match were manipulated. The variables of homophily and respondent gender were measured and recorded, respectively. The data were collected through an online survey done through Qualtrics.

Findings

The findings show that for female influencers, homophily felt by their followers is a dominant persuasive factor, which tends to supersede the variables of attractiveness and product-match. For male influencers, homophily is an incremental persuasive variable. That is, homophily, attractiveness and product-match interact such that persuasiveness is highest when all three variables are strong.

Research limitations/implications

Limitations are that the authors used a student sample and a hypothetical scenario-based experiment. Theoretical implications are interesting in that the authors have results which add to theory on the factors that make an online influencer more persuasive. Specifically, the authors contribute by extending theoretical knowledge about the interactions of key variables that influence the impact of online influencers.

Practical implications

For a manager marketing products using influencers, it is very important to stress homophily cues for female influencers more than other variables. However, for male influencers, product knowledge or match, homophily and attractiveness all need to work simultaneously to maximize influencer persuasiveness.

Social implications

One needs to understand that physical attractiveness and perceived homophily with the influencer have significant influence and persuasiveness, regardless of product or service. Hence, there needs to be social responsibility in what is advertised and promoted, given that followers may be persuaded by influencers no matter what the product or service is.

Originality/value

To the best of the authors' knowledge, this is the first study that explores the persuasiveness of online influencers from the perspective of the variable interactions described above.
Economic policy uncertainty of China and investment opportunities: a tale of ASEAN stock markets
Authors: Mohd Thas Thaker Hassanudin , Mohd Thas Thaker Mohamed Asmy , Sakti Muhammad Rizky Prima , Sifat Imtiaz , Allah Pitchay Anwar , Iqbal Hussain Hafezali
Published: June 2022

Purpose

The purpose of this paper is to examine the effect of economic policy uncertainty (EPU) of China on investment opportunities in five ASEAN economies.

Design/methodology/approach

This paper employs advanced empirical approaches, such as Multivariate DCC-GARCH and Continuous Wavelet Transform (CWT) to test the research objective. The period of analysis involved monthly data from 2003 until 2019.

Findings

This paper provides evidence where the Malaysian stock market to be the least exposed to risks emanating from Chinese EPU, followed by Singapore, the Philippines, Thailand and Indonesia. Results for investment opportunities based on time horizon suggest, for a short-term holding period, investors are better off investing in Singapore and Indonesia, while, for medium-term holding periods, all ASEAN markets appear lucrative except for the Philippines.

Practical implications

From a managerial perspective, the outcome or findings of this study are expected to aid the retail and institutional investors in designing better strategies on diversifying a stock portfolio with different holding periods.

Originality/value

Theoretically, the findings of this study contribute fresh insights into an emerging strand of literature focusing on the transmission of regional policy. Methodologically as well, this study is a novel venture to the best of authors' knowledge.
Psychological and lifestyle predictors of mental health in higher education: how healthy are our students?
Authors: Catling Jonathan , Michail Maria , Lakhani Noureen , Devine Rory
Published: June 2022

Purpose

The continued increase in mental health problems in students in higher education is a global public health concern. This study aims to examine the predictors of mental health in the context of higher education, focusing on first-year female undergraduate students as a particularly vulnerable group.

Design/methodology/approach

Two hundred first-year female undergraduates from a UK Higher Education Institution took part in a quantitative survey. Participants completed a range of questionnaires assessing resilience, perceived stress, levels of depression, hope, general anxiety and levels of exercise.

Findings

Two significant individual predictors of depression were identified: perceived stress and resilience. A mediation analysis showed that resilience acted as mediator for the impact of stress on depression. Two significant individual predictors of anxiety were identified: stress and exercise. There were no significant mediators.

Originality/value

To the best of the authors’ knowledge, this is the first time a range of psychological and lifestyle predictors of mental health while exploring potential mediators have been investigated. From the findings, the authors suggest that psychoeducational interventions targeting resilience while also providing problem-solving strategies could augment internal resources and promote positive mental health in this particularly vulnerable group of young people.
Fabrication of fluorine and silver co-doped ZnO photodetector using modified hydrothermal method
Authors: Muhammad Aminu , Mohammad Sabah M. , Hassan Zainuriah , Rajamanickam Suvindraj , Abed Shireen Mohammed , Ashiq M.G.B.
Published: June 2022

Purpose

The purpose of this study is to dope silver (Ag) and fluorine (F) in zinc oxide (ZnO) for the enhancement of electrical and optical properties of ZnO, as previous studies reported the improvement of these properties using individual doping of F and Ag. In this paper, F and Ag co-doped ZnO nanorods were synthesized using a modified hydrothermal method.

Design/methodology/approach

The hydrothermal method was modified and used for the synthesis of the doped ZnO nanostructures, where stainless autoclave and oven were replaced with the Duran laboratory bottle and water boiler system in the process. The ultraviolet metal-semiconductor-metal photodetector (PD) was fabricated using DC sputtering method.

Findings

Vertically aligned nanorods images were captured from field emission scanning electron microscopy. XPS analysis confirmed greater spin-orbital interaction in the F and Ag co-doped ZnO sample and revealed the presence of F, Ag, Zn and O in the samples, indicating a successful doping process. X-ray diffraction revealed a hexagonal wurtzite structure with enhanced crystal quality upon co-doping. The bandgap decreased from 3.19 to 3.14 eV upon co-doping because of reduced defects density in the sample. Finally, an ultra-violet PD was fabricated with enhanced sensitivity and response times upon co-doping.

Originality/value

The low-cost, less energy-consuming Duran laboratory bottle and water boiler system were used as the substitute of expensive, more energy-consuming stainless autoclave and oven in a hydrothermal method for synthesis of F and Ag co-doped ZnO and subsequent fabrication of PD.