bluuebunny/crossref_metadata_2025 huggingface dataset:
Coordinating cell polarization and morphogenesis through mechanical feedback
Authors: Banavar Samhita P. , Trogdon Michael , Drawert Brian , Yi Tau-Mu , Petzold Linda R. , Campàs Otger
Published: May 2020

Many cellular processes require cell polarization to be maintained as the cell changes shape, grows or moves. Without feedback mechanisms relaying information about cell shape to the polarity molecular machinery, the coordination between cell polarization and morphogenesis, movement or growth would not be possible. Here we theoretically and computationally study the role of a genetically-encoded mechanical feedback (in the Cell Wall Integrity Pathway) as a potential coordination mechanism between cell morphogenesis and polarity during budding yeast mating projection growth. We developed a coarse-grained continuum description of the coupled dynamics of cell polarization and morphogenesis as well as 3D stochastic simulations of the molecular polarization machinery in the evolving cell shape. Both theoretical approaches show that in the absence of mechanical feedback (or in the presence of weak feedback), cell polarity cannot be maintained at the projection tip during growth, with the polarization cap wandering off the projection tip, arresting morphogenesis. In contrast, for mechanical feedback strengths above a threshold, cells can robustly maintain cell polarization at the tip and simultaneously sustain mating projection growth. These results indicate that the mechanical feedback encoded in the Cell Wall Integrity pathway can provide important positional information to the molecular machinery in the cell, thereby enabling the coordination of cell polarization and morphogenesis.

Author summary

Cell migration, morphogenesis and secretion are among the vast number of cellular processes that require cells to define a preferred spatial direction to perform essential tasks. This is achieved by setting an intracellular molecular gradient that polarizes the cell. While the molecular players involved in cell polarization and some of the mechanisms that cells use to establish such molecular gradients are known, it remains unclear how cells maintain polarization as they dramatically change shape during morphogenesis, migration, etc. Here we identify a potential feedback control mechanism, encoded genetically in cells, that provides the molecular polarization machinery with the necessary information about cell geometry to maintain cell polarization during cell shape changes.
Computational image analysis reveals the structural complexity ofToxoplasma gondiitissue cysts
Authors: Bauman Neda , Ilić Andjelija , Lijeskić Olivera , Uzelac Aleksandra , Klun Ivana , Srbljanović Jelena , Ćirković Vladimir , Bobić Branko , Štajner Tijana , Djurković-Djaković Olgica
Published: May 2020

Toxoplasma gondiiis an obligate intracellular parasite infecting up to one third of the human population. The central event in the pathogenesis of toxoplasmosis is the conversion of tachyzoites into encysted bradyzoites. A novel approach to analyze the structure ofin vivo-derived tissue cysts may be the increasingly used computational image analysis. The objective of this study was to quantify the geometrical complexity ofT. gondiicysts by morphological, particle, and fractal analysis, as well as to determine if and how it is impacted by parasite strain, cyst age, and host factors. Analyses were performed on 31 images ofT. gondiibrain cysts of four type-2 strains (the reference Me49 strain and three local isolates, named BGD1, BGD14, and BGD26) using ImageJ software package. The parameters of interest included diameter, circularity, relative particle count (RPC), fractal dimension (FD), lacunarity, and packing density (PD). Although cyst diameter varied widely, its negative correlation withRPCwas observed. Circularity was remarkably close to 1, indicating that the shape of the brain cysts was a perfect circle.RPC,FD,andPDdid not vary among cysts of different strains, age, and derived from mice of different genetic background. Conversely, lacunarity, which is a measure of heterogeneity, was significantly lower for BGD1 strain vs. all other strains, and higher for Me49 vs. BGD14 and BGD26, but did not differ among Me49 cysts of different age, and derived from genetically different mice. This study is the first application of fractal analysis in describing the structural complexity ofT. gondiicysts. Despite all the differences among the analyzed cysts, most parameters remained conserved. Fractal analysis is a novel and widely accessible approach, which along with particle analysis may be applied to gain further insight intoT. gondiicyst morphology.
Rapid Isothermal Amplification and Portable Detection System for SARS-CoV-2
Authors: Ganguli A. , Mostafa A. , Berger J. , Aydin M. , Sun F. , Valera E. , Cunningham B. T. , King W. P. , Bashir R.
Published: May 2020

The COVID-19 pandemic provides an urgent example where a gap exists between availability of state-of-the-art diagnostics and current needs. As assay details and primer sequences become widely known, many laboratories could perform diagnostic tests using methods such as RT-PCR or isothermal RT-LAMP amplification. A key advantage of RT-LAMP based approaches compared to RT-PCR is that RT-LAMP is known to be robust in detecting targets from unprocessed samples. In addition, RT-LAMP assays are performed at a constant temperature enabling speed, simplicity, and point-of-use testing. Here, we provide the details of an RT-LAMP isothermal assay for the detection of SARS-CoV-2 virus with performance comparable to currently approved tests using RT-PCR. We characterize the assay by introducing swabs in virus spiked synthetic nasal fluids, moving the swab to viral transport medium (VTM), and using a volume of that VTM for performing the amplification without an RNA extraction kit. The assay has a Limit-of-Detection (LOD) of 50 RNA copies/μL in the VTM solution within 20 minutes, and LOD of 5000 RNA copies/μL in the nasal solution. Additionally, we show the utility of this assay for real-time point-of-use testing by demonstrating detection of SARS-CoV-2 virus in less than 40 minutes using an additively manufactured cartridge and a smartphone-based reader. Finally, we explore the speed and cost advantages by comparing the required resources and workflows with RT-PCR. This work could accelerate the development and availability of SARS-CoV-2 diagnostics by proving alternatives to conventional laboratory benchtop tests.

Significance Statement

An important limitation of the current assays for the detection of SARS-CoV-2 stem from their reliance on time- and labor-intensive and laboratory-based protocols for viral isolation, lysis, and removal of inhibiting materials. While RT-PCR remains the gold standard for performing clinical diagnostics to amplify the RNA sequences, there is an urgent need for alternative portable platforms that can provide rapid and accurate diagnosis, potentially at the point-of-use. Here, we present the details of an isothermal amplification-based detection of SARS-CoV-2, including the demonstration of a smartphone-based point-of-care device that can be used at the point of sample collection.
Structural Ensembles of Ribonucleic Acids From Solvent Accessibility Data: Application to the S-Adenosylmethionine (SAM)-Responsive Riboswitch
Authors: Xie Jingru , Frank Aaron T.
Published: May 2020

Riboswitches are regulatory ribonucleic acid (RNA) elements that act as ligand-dependent conformational switches. In the apo form, the aptamer domain, the region of a riboswitch that binds to its cognate ligand, is dynamic, thus requiring an ensemble-representation of its structure. Analysis of such ensembles can provide molecular insights into the sensing mechanism and capabilities of riboswitches. Here, as a proof-of-concept, we constructed a pair of atomistic ensembles of the well-studied S-adenosylmethionine (SAM)-responsive riboswitch in the absence (-SAM) and presence (+SAM) of SAM. To achieve this, we first generated a large conformational pool and then reweighted conformers in the pool using solvent accessible surface area (SASA) data derived from recently reported light-activated structural examination of RNA (LASER) reactivities, measured in the −SAM and +SAM states of the riboswitch. The differences in the resulting −SAM and +SAM ensembles are consistent with a SAM-dependent reshaping of the free landscape of the riboswitch. Interestingly, within the −SAM ensemble, we identified a conformer that harbors a hidden binding pocket, which was discovered using ensemble docking. The method we have applied to the SAM riboswitch is general, and could, therefore, be used to construct atomistic ensembles for other riboswitches, and more broadly, other classes of structured RNAs.
No evidence for increased transmissibility from recurrent mutations in SARS-CoV-2
Authors: van Dorp Lucy , Richard Damien , Tan Cedric CS. , Shaw Liam P. , Acman Mislav , Balloux François
Published: May 2020

The COVID-19 pandemic is caused by the coronavirus SARS-CoV-2, which jumped into the human population in late 2019 from a currently uncharacterised animal reservoir. Due to this extremely recent association with humans, SARS-CoV-2 may not yet be fully adapted to its human host. This has led to speculations that some lineages of SARS-CoV-2 may be evolving towards higher transmissibility. The most plausible candidate mutations under putative natural selection are those which have emerged repeatedly and independently (homoplasies). Here, we formally test whether any of the recurrent mutations that have been observed in SARS-CoV-2 are significantly associated with increased viral transmission. To do so, we develop a phylogenetic index to quantify the relative number of descendants in sister clades with and without a specific allele. We apply this index to a carefully curated set of recurrent mutations identified within a dataset of 46,723 SARS-CoV-2 genomes isolated from patients worldwide. We do not identify a single recurrent mutation in this set convincingly associated with increased viral transmission. Instead, recurrent SARS-CoV-2 mutations currently in circulation appear to be evolutionary neutral. Recurrent mutations also seem primarily induced by the human immune system via host RNA editing, rather than being signatures of adaptation to the novel human host. In conclusion, we find no evidence at this stage for the emergence of significantly more transmissible lineages of SARS-CoV-2 due to recurrent mutations.
Engineering 6-phosphogluconate dehydrogenase to improve heat tolerance in maize seed development
Authors: Ribeiro Camila , Hennen-Bierwagen Tracie A. , Myers Alan M. , Cline Kenneth , Settles A. Mark
Published: May 2020

Endosperm starch synthesis is a primary determinant of grain yield and is sensitive to high temperature stress. The maize chloroplast-localized 6-phosphogluconate dehydrogenase (6PGDH), PGD3, is critical for endosperm starch accumulation. Maize also has two cytosolic isozymes, PGD1 and PGD2 that are not required for kernel development. We found that cytosolic PGD1 and PGD2 isozymes have heat stable activity, while amyloplast-localized PGD3 activity is labile under heat stress conditions. We targeted heat-stable 6PGDH to endosperm amyloplasts by fusing theWaxy1chloroplast targeting peptide coding sequence to thePgd1andPgd2open reading frames. These WPGD1 and WPGD2 fusion proteins import into isolated chloroplasts demonstrating a functional targeting sequence. Transgenic maize plants expressing WPGD1 and WPGD2 with an endosperm specific promoter increased 6PGDH activity with enhanced heat stabilityin vitro. WPGD1 and WPGD2 transgenes complement thepgd3defective kernel phenotype indicating the fusion proteins are targeted to the amyloplast. In the field, the WPGD1 and WPGD2 transgenes can mitigate grain yield losses in high nighttime temperature conditions by increasing kernel number. These results provide insight on subcellular distribution of metabolic activities in the endosperm and suggest the amyloplast pentose phosphate pathway is a heat-sensitive step in maize kernel metabolism that contributes to yield loss during heat stress.

Significance Statement

Heat stress reduces yield in maize by affecting the number of kernels that develop and the accumulation of seed storage molecules during grain fill. Climate change is expected to increase frequency and duration of high temperature stress, which will lower grain yields. Here we show that one enzyme in central carbon metabolism is sensitive to high temperatures. By providing a heat-resistant form of the enzyme in the correct subcellular compartment, a larger number of kernels develop per plant during heat stress in the field. This genetic improvement could be included as part of integrated approaches to mitigate yield losses due to climate change.
An insertion unique to SARS-CoV-2 exhibits superantigenic character strengthened by recent mutations
Authors: Cheng Mary Hongying , Zhang She , Porritt Rebecca A. , Arditi Moshe , Bahar Ivet
Published: May 2020

Multisystem Inflammatory Syndrome in Children (MIS-C) associated with Coronavirus Disease 2019 (COVID-19) is a newly recognized condition in which children with recent SARS-CoV-2 infection present with a constellation of symptoms including hypotension, multiorgan involvement, and elevated inflammatory markers. These symptoms and the associated laboratory values strongly resemble toxic shock syndrome, an escalation of the cytotoxic adaptive immune response triggered upon the binding of pathogenic superantigens to MHCII molecules and T cell receptors (TCRs). Here, we used structure-based computational models to demonstrate that the SARS-CoV-2 spike (S) exhibits a high-affinity motif for binding TCR, interacting closely with both the α- and β-chains variable domains’ complementarity-determining regions. The binding epitope on S harbors a sequence motif unique to SARS-CoV-2 (not present in any other SARS coronavirus), which is highly similar in both sequence and structure to bacterial superantigens. Further examination revealed that this interaction between the virus and human T cells is strengthened in the context of a recently reported rare mutation (D839Y/N/E) from a European strain of SARS-CoV-2. Furthermore, the interfacial region includes selected residues from a motif shared between the SARS viruses from the 2003 and 2019 pandemics, which has intracellular adhesion molecule (ICAM)-like character. These data suggest that the SARS-CoV-2 S may act as a superantigen to drive the development of MIS-C as well as cytokine storm in adult COVID-19 patients, with important implications for the development of therapeutic approaches.

Significance

Although children have been largely spared from severe COVID-19 disease, a rare hyperinflammatory syndrome has been described in Europe and the East Coast of the United States, termed Multisystem Inflammatory Syndrome in Children (MISC). The symptoms and diagnostic lab values of MIS-C resemble those of toxic shock, typically caused by pathogenic superantigens stimulating excessive activation of the adaptive immune system. We show that SARS-CoV-2 spike has a sequence and structure motif highly similar to those of bacterial superantigens, and may directly bind to the T cell receptors. This sequence motif, not present in other coronaviruses, may explain the unique potential for SARS-CoV-2 to cause both MIS-C and the cytokine storm observed in adult COVID-19 patients.
A divergentArticulavirusin an Australian gecko identified using meta-transcriptomics and protein structure comparisons
Authors: Ortiz-Baez Ayda Susana , Eden John-Sebastian , Moritz Craig , Holmes Edward C.
Published: May 2020

The discovery of highly divergent RNA viruses is compromised by their limited sequence similarity to known viruses. Evolutionary information obtained from protein structural modelling offers a powerful approach to detect distantly related viruses based on the conservation of tertiary structures in key proteins such as the viral RNA-dependent RNA polymerase (RdRp). We utilised a template-based approach for protein structure prediction from amino acid sequences to identify distant evolutionary relationships among viruses detected in meta-transcriptomic sequencing data from Australian wildlife. The best predicted protein structural model was compared with the results of similarity searches against protein databases based on amino acid sequence data. Using this combination of meta-transcriptomics and protein structure prediction we identified the RdRp (PB1) gene segment of a divergent negative-sense RNA virus in a native Australian gecko (Geyra lauta) that was confirmed by PCR and Sanger sequencing. Phylogenetic analysis identified theGecko articulavirus(GECV) as a newly described genus within the familyAmnoonviridae, orderArticulavirales, that is most closely related to the fish virusTilapia tilapinevirus(TiLV). These findings provide important insights into the evolution of negative-sense RNA viruses and structural conservation of the viral replicase among members of the orderArticulavirales.
CD4+ T-cell epitope prediction by combined analysis of antigen conformational flexibility and peptide-MHCII binding affinity
Authors: Charles Tysheena , Moss Daniel L. , Bhat Pawan , Moore Peyton W. , Kummer Nicholas A. , Bhattacharya Avik , Mettu Ramgopal R. , Landry Samuel J.
Published: May 2020

Antigen processing in the class II MHC pathway depends on conventional proteolytic enzymes, potentially acting on antigens in native-like conformational states. CD4+ epitope dominance arises from a competition between antigen folding, proteolysis, and MHCII binding. Protease-sensitive sites, linear antibody epitopes, and CD4+ T-cell epitopes were mapped in the plague vaccine candidate F1-V to evaluate the various contributions to CD4+ epitope dominance. Using X-ray crystal structures, antigen processing likelihood (APL) predicts CD4+ epitopes with significant accuracy without considering peptide-MHCII binding affinity. The profiles of conformational flexibility derived from the X-ray crystal structures of the F1-V proteins, Caf1 and LcrV, were similar to the biochemical profiles of linear antibody epitope reactivity and protease-sensitivity, suggesting that the role of structure in proteolysis was captured by the analysis of the crystal structures. The patterns of CD4+ T-cell epitope dominance in C57BL/6, CBA, and BALB/c mice were compared to epitope predictions based on APL, peptide binding to MHCII proteins, or both. For a sample of 13 diverse antigens larger than 200 residues, accuracy of epitope prediction by the combination of APL and I-Ab-MHCII-peptide affinity approached 40%. When MHCII allele specificity is also diverse, such as in human immunity, prediction of dominant epitopes by APL alone approached 40%. Since dominant CD4+ epitopes tend to occur in conformationally stable antigen domains, crystal structures typically are available for analysis by APL; and thus, the requirement for a crystal structure is not a severe limitation.
Unique inflammatory profile is associated with higher SARS-CoV-2 acute respiratory distress syndrome (ARDS) mortality
Authors: Balnis Joseph , Adam Alejandro P. , Chopra Amit , Chieng Hau C. , Drake Lisa A. , Martino Nina , Ramos Ramon B. , Feustel Paul J. , Overmyer Katherine A. , Shishkova Evgenia , Coon Joshua J. , Singer Harold A. , Judson Marc A. , Jaitovich Ariel
Published: May 2020

The COVID19 pandemic is likely to cause more than a million of deaths worldwide, primarily due to complications from COVID19-associated acute respiratory distress syndrome (ARDS). Controversy surrounds the circulating cytokine/chemokine profile of COVID19-associated ARDS, with some groups suggesting that it is similar to non-COVID19 ARDS patients and others observing substantial differences. Moreover, while a hyperinflammatory phenotype associates with higher mortality in non-COVID19 ARDS, there is little information on the inflammatory landscape’s association with mortality in COVID19 ARDS patients. Even though the circulating leukocytes’ transcriptomic signature has been associated with distinct phenotypes and outcomes in critical illness including ARDS, it is unclear whether the mortality-associated inflammatory mediators from COVID19 patients are transcriptionally regulated in the leukocyte compartment. Here, we conducted a prospective cohort study of 41 mechanically ventilated patients with COVID19 infection using highly calibrated methods to define the levels of plasma cytokines/chemokines and their gene expressions in circulating leukocytes. Plasma IL1RA and IL8 were found positively associated with mortality while RANTES and EGF negatively associated with that outcome. However, the leukocyte gene expression of these proteins had no statistically significant correlation with mortality. These data suggest a unique inflammatory signature associated with severe COVID19.
Analysis of Covid-19 and non-Covid-19 viruses including influenza viruses to see the influence of intensive preventive measures among Japanese
Authors: Hirotsu Yosuke , Maejima Makoto , Kakizaki Yumiko , Miyashita Yoshihiro , Mochizuki Hitoshi , Omata Masao
Published: May 2020

Severe acute respiratory coronavirus 2 (SARS-CoV-2) spread and cause death in worldwide. The preventative measures and infection control are underway throughout the society and there are signs of convergence in some areas. Other viruses as well as SARS-CoV-2 cause cold-like symptoms and spread in winter. However, it is unclear to what extent SARS-CoV-2, influenza virus and other causative viruses have been prevailed since the preventative measures were implemented. In this study, we conducted multiples PCR and quantitative reverse transcription PCR using nasal swabs from 191 patients with cold-like symptoms in Japan to reveal the causative viruses. As a result, at least one virus were detected in 40 out of 191 (21%) patients. Of these, we frequently identified the human rhinovirus / enterovirus (5.8%, n=11), SARS-CoV-2 (4.2%, n=8) and human metapneumovirus (3.7%, n=7). On the other hand, no influenza virus was detected. These results shows the prevalence of causative viruses after the social preventative measures and implies the difference of infectivity between SARS-CoV-2 and influenza virus.
Joint crystallization of KCuAl[PO4]2 and K(Al,Zn)2[(P,Si)O4]2: crystal chemistry and mechanism of formation of phosphate-silicate epitaxial heterostructure
Authors: Yakubovich Olga , Kiriukhina Galina , Shvanskaya Larisa , Volkov Anatoliy , Dimitrova Olga
Published: May 2020

Two novel phases, potassium copper aluminium bis(phosphate), KCuAl[PO4]2 (I), and potassium zinc aluminium bis(phosphate-silicate), K(Al,Zn)2[(P,Si)O4]2 (II), were obtained in one hydrothermal synthesis experiment at 553 K. Their crystal structures have been studied using single-crystal X-ray diffraction. (I) is a new member of the A
+
M
2+
M
3+[PO4]2 family. Its open 3D framework built by AlO5 and PO4 polyhedra includes small channels populated by columns of CuO6 octahedra sharing edges, and large channels where K+ ions are deposited. It is assumed that the stability of this structure type is due to the pair substitution of Cu/Al with Ni/Fe, Co/Fe or Mg/Fe in different representatives of the series. From the KCuAl[PO4]2 structural features, one may suppose it is a potentially electrochemically active material and/or possible low-temperature antiferromagnet. In accordance with results obtained from X-ray diffraction data, using scanning electron microscopy, microprobe analysis and detailed crystal chemical observation, (II) is considered as a product of epitaxial intergrowth of phosphate KAlZn[PO4]2 and silicate KAlSi[SiO4]2 components having closely similar crystal structures. The assembly of `coherent intergrowth' is described in the framework of a single diffraction pattern.
Synthesis, structure and properties of layered Pr2MoO6-based oxymolybdates doped with Mg
Authors: Voronkova Valentina I. , Antipin Alexander M. , Sorokin Timofei A. , Novikova Nataliya E. , Kharitonova Elena P. , Orlova Ekaterina I. , Kvartalov Vladimir B. , Presniakov Mikhail Yu. , Bondarenko Vladimir I. , Vasiliev Alexander L. , Sorokina Nataliya I.
Published: May 2020

Undoped and Mg-doped Pr2MoO6oxymolybdate polycrystals and single crystals have been prepared by solid-state reactions and flux growth. The compounds have been characterized by powder X-ray diffraction, energy-dispersive spectroscopy, inductively coupled plasma mass spectrometry, scanning transmission electron microscopy, single crystal X-ray structure analysis, differential scanning calorimetry and thermogravimetry. The (MgO)x(Pr2O3)y(MoO3)z(x+y+z= 1) solid solution series has been shown to extend tox= 0.03. The structure of the Mg-doped Pr2MoO6single crystals can be represented as superimposed lattices of the main matrix (Pr2MoO6) and lattices in which Mo atoms are partially replaced by Mg. The incorporation of Mg atoms into the structure of Pr2MoO6results in the disordering of the praseodymium and oxygen lattices. Both the polycrystalline and single-crystal Mg-doped samples are hygroscopic.
Syntheses and structures of two novel fluorescent metal–organic frameworks generated from a tridentate donor–acceptor motif ligand
Authors: Zhao Yong-Jin , Ma Jian-Ping , Fan Jianzhong , Geng Yan , Dong Yu-Bin
Published: May 2020

The tridentate organic ligand 4,4′,4′′-(4,4,8,8,12,12-hexamethyl-8,12-dihydro-4H-benzo[9,1]quinolizino[3,4,5,6,7-defg]acridine-2,6,10-triyl)tribenzoic acid (H3L) has been synthesized (as the methanol 1.25-solvate, C48H39NO6·1.25CH3OH). As a donor–acceptor motif molecule, H3L possess strong intramolecular charge transfer (ICT) fluorescence. Through hydrogen bonds, H3L molecules construct a two-dimensional (2D) network, which pack together into three-dimensional (3D) networks with an ABC stacking pattern in the crystalline state. Based on H3L and M(NO3)2 salts (M = Cd and Zn) under solvothermal conditions, two metal–organic frameworks (MOFs), namely, catena-poly[[triaquacadmium(II)]-μ-10-(4-carboxyphenyl)-4,4′-(4,4,8,8,12,12-hexamethyl-8,12-dihydro-4H-benzo[9,1]quinolizino[3,4,5,6,7-defg]acridine-2,6-diyl)dibenzoato], [Cd(C48H37NO6)(H2O)3]
n
, I, and poly[[μ3-4,4′,4′′-(4,4,8,8,12,12-hexamethyl-8,12-dihydro-4H-benzo[9,1]quinolizino[3,4,5,6,7-defg]acridine-2,6,10-triyl)tribenzoato](μ3-hydroxido)zinc(II)], [Zn2(C48H36NO6)(OH)]
n
, II, were synthesized. Single-crystal analysis revealed that both MOFs adopt a 3D structure. In I, partly deprotonated HL
2− behaves as a bidentate ligand to link a CdII ion to form a one-dimensional chain. In the solid state of I, the existence of weak interactions, such as O—H...O hydrogen bonds and π–π interactions, plays an essential role in aligning 2D nets and 3D networks with AB packing patterns for I. The deprotonated ligand L
3− in II is utilized as a tridentate building block to bind ZnII ions to construct 3D networks, where unusual Zn4O14 clusters act as connection nodes. As a donor–acceptor molecule, H3L exhibits fluorescence with a photoluminescence quantum yield (PLQY) of 70% in the solid state. In comparison, the PL of both MOFs is red-shifted with even higher PLQYs of 79 and 85% for I and II, respectively.
Crystal structures of 6-cyclopropyl-1,3-diphenylfulvene and 6-(2,3-dimethoxynaphthyl)-1,3-diphenylfulvene
Authors: Brown Loren C. , Iacono Scott T. , Balaich Gary J.
Published: May 2020

The title compounds, 6-cyclopropyl-1,3-diphenylfulvene, C21H18, [systematic name: 5-(cyclopropylmethylidene)-1,3-diphenylcyclopenta-1,3-diene], 1, and 6-(2,3-dimethoxynaphthyl)-1,3-diphenylfulvene, C30H24O2, {systematic name: 5-[(3,4-dimethoxynaphthalen-2-yl)methylidene]-1,3-diphenylcyclopenta-1,3-diene}, 2, were prepared from 1,3-diphenylcyclopentadiene, pyrrolidine, and the corresponding aldehydes in an ethanolic solution. Each structure crystallizes with one molecule per asymmetric unit and exhibits the alternating short and long bond lengths typical of fulvenes. A network of C—H...C ring interactions as well as C—H...O interactions is observed, resulting in the compact packing found in each structure.
Crystal structure of dicaesium strontium hexacyanidoferrate(II), Cs2Sr[Fe(CN)6], from laboratory X-ray powder data
Authors: Massoni Nicolas , Moloney Mícheál P. , Grandjean Agnès , Misture Scott T. , Loye Hans-Conrad zur
Published: May 2020

Ferrocyanides with general formulaAIxBIIy[Fe(CN)6], whereAandBare cations, are thought to accept many substitutions on theAandBpositions. In this communication, the synthesis and crystal structure of Cs2Sr[Fe(CN)6] are reported. The latter was obtained from K2Ba[Fe(CN)6] particles, put in contact with caesium and strontium ions. Hence, a simultaneous ion-exchange mechanism (Cs for K, Sr for Ba) occurs to yield Cs2Sr[Fe(CN)6]. The synthesis protocol shows that K2BaFe(CN)6particles can be used for the simultaneous trapping of radioactive caesium and strontium nuclides in water streams. Cs2Sr[Fe(CN)6] adopts the cryolite structure type and is isotypic with the known compound Cs2Na[Mn(CN)6] [dicaesium sodium hexacyanidomanganate(III)]. The octahedrally coordinated Sr and Fe sites both are located on inversion centres, and the eightfold-coordinated Cs site on a general position.
Stereochemistry of the methylidene-bridged quinazoline-isoquinoline alkaloid 3-{[6,7-dimethoxy-1-(4-nitrophenyl)-1,2,3,4-tetrahydroisoquinolin-2-yl]methylidene}-1,2,3,9-tetrahydropyrrolo[2,1-b]quinazolin-9-one methanol monosolvate
Authors: Tojiboev Akmal , Zhurakulov Sherzod , Vinogradova Valentina , Englert Ulli , Wang Ruimin
Published: May 2020

Two potentially bioactive fragments, namely a tricyclic quinazoline derivative with an exocyclic alkene moiety and a substituted isoquinoline, are coupled to give 3-{[6,7-dimethoxy-1-(4-nitrophenyl)-1,2,3,4-tetrahydroisoquinolin-2-yl]methylidene}-1,2,3,9-tetrahydropyrrolo[2,1-b]quinazolin-9-one. The target product crystallizes as a methanol solvate, C29H26N4O5·CH4O, and is E configured. The alternative Z isomer would necessarily imply either considerable twist about the central double bond or very unfavourable intramolecular contacts between sterically more demanding substituents. The main residue and the co-crystallized solvent molecule aggregate to discrete pairs via a classical O—H...O hydrogen bond with a distance of 2.8581 (7) Å between the methanol OH donor and the quinazolinone O=C acceptor.
Could self-centrism rust the glitter of meaningful work? Exploring the darker sides of the construct
Authors: Pattnaik Subhra , Jena Lalatendu Kesari
Published: May 2020

Purpose

The paper explores if individuals experiencing deeply meaningful work turn self-centric and therein they negatively affect people around them. It also discusses ways to attenuate this darker effect of meaningful work.

Design/methodology/approach

Semi-structured interviews were conducted with supervisors, peers, subordinates, and family of 24 executives in the Indian Aeronautical Manufacturing Sector who scored high on the Meaningful Work scale in another empirical study carried out by the authors in early 2019.

Findings

Individuals experiencing deeply Meaningful Work get self-centric, at times, where nothing beyond work appeals to them. This negatively affects their camaraderie at work and family ties.

Originality/value

The paper adds to the scarce literature on the darker side of Meaningful Work by exploring its effect on breeding self-centrism using an Indian sample.
Direct modifications of tetrahedral meshes
Authors: Guo YuFei , Hai YongQing , Liu JianFei
Published: May 2020

Purpose

During the industrial design process, a product is usually modified and analyzed repeatedly until reaching the final design. Modifying the model and regenerating a mesh for every update during this process is very time consuming. To improve efficiency, it is necessary to circumvent the computer-aided design modeling stage when possible and directly modify the meshes to save valuable time. The purpose of this paper is to develop a method for mesh modifications.

Design/methodology/approach

In contrast to existing studies, which focus on one or a class of modifications, this paper comprehensively studies mesh union, mesh gluing, mesh cutting and mesh partitioning. To improve the efficiency of the method, the paper presents a fast and effective surface mesh remeshing algorithm based on a ball-packing method and controls the remeshing regions with a size field.

Findings

Examples and results show that the proposed mesh modification method is efficient and effective. The proposed method can be also applied to meshes with different material properties, which is very different with previous work that is only suitable for the meshes with same material property.

Originality/value

This paper proposes an efficient and comprehensive tetrahedral mesh modification method, through which engineers can directly modify meshes instead of models and save time.
Why digital goods have not replaced traditional goods: the case of e-books
Authors: Kim Jongbum , Seo Jeonghun , Zo Hangjung , Lee Hwansoo
Published: May 2020

Purpose

Electronic books (e-books) have been in the market for decades but have been unable to replace paper books. Previous studies on e-books have failed to identify significant factors affecting the adoption and diffusion of e-books. This study develops a theoretical framework to explain the adoption behavior of e-books from the perspective of user resistance.

Design/methodology/approach

After a pilot test with 50 e-book users, the research model is validated using a partial least squares structural equation modeling (PLS-SEM) technique. A web-based survey method is used to collect data from a sample of 350 people – selected from Korean e-book users and nonusers – during a week in March 2017. This study tests the reliability and validity of the integrated model of planned behavior and resistance theory and tests the hypotheses with bootstrapping resampling.

Findings

The results show that four barriers – usage, value, risk and image – cause resistance to change and users with higher resistance have lower intention to use. The moderating effect of self-efficacy between resistance to change and intention to use is confirmed. Self-efficacy interacts not only with the encouraging factors but also with resistance.

Originality/value

This study expands the understanding of users' adoption behavior of e-books by examining inhibiting factors using a novel integrated model. The findings of this research provide insights for digital product providers, especially e-book publishers, to understand why digital products have not been successful in the marketplace.
The role of the family council and protocol in planning the succession process in family firms
Authors: Matias Cláudia , Franco Mário
Published: May 2020

Purpose

The main objective of this study is to understand the role that family council and protocol can have in the planning process of family companies.

Design/methodology/approach

To reach this general objective, the qualitative approach was used using multiple case studies: seven Portuguese family companies. Data collection techniques, interviewing, direct observation and documentary analysis were used.

Findings

Based on the empirical evidence, it is concluded that the family council and family protocol help succession planning and favour the continuity and survival of the family business. However, other working groups also support the entire planning process, such as the cousin generation meeting and the New Generation Monitoring Committee (or Mentoring Committee). The development of future personal plans for the younger generations may lie in this Committee, which assists and guides the younger family members.

Practical implications

This study is pioneering in Portugal because it analyses the use of new instruments that helps the succession planning process in family firm context: the family council and family protocol. These managerial mechanisms allow to achieve the success, allowing family conflicts to be minimized, the continuity of family firms and avoiding their mortality.

Originality/value

The study contributes to increasing knowledge about the family council, the family protocol, family firm succession and its planning. It is important and innovative by studying those topics in depth, their connection being little explored in the literature. This study can be seen as a benchmarking for governance practices in other countries.
The antecedents of Muslim customers’ intention to invest in an Islamic bank’s term deposits: evidence from a Muslim majority country
Authors: Hati Sri Rahayu Hijrah , Wibowo Sigit Sulistiyo , Safira Anya
Published: May 2020

Purpose

The purpose of this study is to examine the impacts of product knowledge, perceived quality, perceived risk and perceived value on customers’ intention to invest in Islamic Banks. This study specifically examines an Islamic bank’s term deposits.

Design/methodology/approach

Structural equation modeling was used to analyze the data collected from 217 customers of an Islamic bank in Indonesia using an online survey.

Findings

This study highlights the central and dual roles of perceived risk as both the independent and the intervening variable that mediates the relationship between product knowledge and Muslim customer intention to invest in an Islamic bank’s term deposits.

Research limitations/implications

This study only investigates term deposits as one type of investment in Islamic banks. This study contributes to the literature by examining the role of product knowledge, perceived quality, perceived risk and perceived value on Muslim customer intention to invest in Islamic term deposits.

Practical implications

The results of this study highlight the requirement for Islamic banks to educate customers to improve the depositors’ product knowledge because Muslim customers’ risk and value perception and intention are strongly influenced by product knowledge.

Originality/value

The investigation of perceived risk is particularly relevant for Islamic financial products because of the inherent nature of risk sharing in Islamic finance. This study investigates the role of product knowledge in influencing the Muslim customers’ perception of risk, quality, value and their intention to invest in Islamic bank term deposits. Ideally, the profit loss sharing concept (PLS) should be applied; however, in this context, revenue sharing is applied because of Indonesia’s central bank regulation.
Electronic procurement adoption, usage and performance: a literature review
Authors: Nandankar Sunil , Sachan Amit
Published: May 2020

Purpose

Despite the substantial research in the domain of electronic procurement adoption, usage and performance (EP AUP), there is no structured review of these studies and most of the literature is in fragmented form. Therefore, the purpose of this paper is to investigate and synthesize EP AUP research in the past two decades and map key research approaches, prevailing theories and antecedents used by researchers to study EP AUP at the individual user and organizational level.

Design/methodology/approach

To evaluate and comprehend past and current patterns/themes in the EP AUP research area, a systematic literature review is undertaken. Significant peer-reviewed studies covering three categories – adoption, usage and performance and seven classification criteria are critically reviewed.

Findings

The findings reveal that most investigators mainly used “technology acceptance model,” “technology–organization–environment” framework and their extensions, demonstrating that “perceived ease of use,” “perceived usefulness,” “trust,” “organizational size,” “organizational readiness” and “behavioral intentions” are the most critical drivers of EP AUP.

Research limitations/implications

For researchers and practitioners, the review highlights a taxonomy of contextual factors to be considered for successful EP AUP. It further makes suggestions for future research meeting challenges of Industry-4.0.

Originality/value

To the best of the authors’ knowledge, this is the first systematic literature review undertaken in the field of EP that studies it from three different perspectives. It further builds on the determinants of EP AUP and classifies them in four distinct categories: organizational, individual, information system level and environmental.
Analysis of landslide area of Tulung subdistrict, Ponorogo, Indonesia in 2017 using resistivity method
Authors: Susilo Adi , Fitriah Fina , Sunaryo  , Ayu Rachmawati Eng Turniningtyas , Suryo Eko Andi
Published: May 2020

Purpose

Research has been conducted to analyze the landslide in Banaran area, Ponorogo Regency. The landslides occurred on April 1, 2017. This study was conducted to know the subsurface conditions in the Banaran area to analyze the disaster mitigation efforts. The mitigation efforts are made to reduce the risk from landslides and possible landslides.

Design/methodology/approach

The method used is the geo-electric resistivity method of Wenner–Schlumberger configuration. The research was conducted in three villages namely Banaran Village, Bekirang Village and Mendak Village.

Findings

There are 12 resistivity measuring points with a track length of 410 m and a space of 10 m. The measured resistivity range is between 1.42 Ω.m and 67.500 Ω.m. The resistivity data and the local geological maps interpreted that the rocks in the Banaran area consist of clay, tuff lapilli, volcanic breccia and andesite lava. The landslide area begins at a depth of 8–35 m below the surface which is interpreted as tuff. Also, the thickness of the landslide material and the slope is = 400 which supports the occurrence of a more prominent landslide. The results of the parameter scoring of the landslide-prone areas indicated that the research area is very vulnerable to a landslide. The results of the interpretation indicate that the geo-electric resistivity method can provide a good overview for conducting landslide analysis, that is field slippage and potential material thickness occurrence landslide.

Originality/value

This article is very specific as it attempts to discover how prone Banaran are is to landslide.
Testing the efficiency of metal's market: new evidence from a generalized spectral test
Authors: Pathak Rajesh , Gupta Ranjan Das , Taufemback Cleiton Guollo , Tiwari Aviral Kumar
Published: May 2020

Purpose

This paper aims to examine the weak form of efficiency for price series of four precious metals, i.e. gold, silver, platinum and palladium, using a generalized spectral method.

Design/methodology/approach

The method has the advantage of detecting both linear and non-linear serial dependence in the conditional mean, and it is robust to various forms of conditional heteroscedasticity. The authors use three different rolling windows for the purpose of robustness.

Findings

The authors report weak form of efficiency across metals series for almost all rolling windows. The optimum efficiency for Gold and Palladium is achieved through 250 days rolling window estimates whereas it is 500 days rolling window for silver. Platinum has similar efficiency levels across rolling windows. The degree of efficiency for metal prices is observed to be varying over time with silver market possessing highest levels of efficiency. The efficiency synchronization also varies across rolling windows and metals.

Research limitations/implications

The results reveal that metal markets are efficient for most times implying the low predictability and the low likelihood of earning abnormal returns by speculating in these markets.

Originality/value

The study uses a relatively new statistical technique, the generalized spectral test, to capture linear and non-linear serial dependence. Therefore, the results possess adequate power against departure from market efficiency.
Applied nucleation facilitates tropical forest recovery: Lessons learned from a 15‐year study
Authors: Holl Karen D. , Reid J. Leighton , Cole Rebecca J. , Oviedo‐Brenes Federico , Rosales Juan A. , Zahawi Rakan A.
Published: May 2020

Applied nucleation, mostly based upon planting tree islands, has been proposed as a cost‐effective strategy to meet ambitious global forest and landscape restoration targets.

We review results from a 15‐year study, replicated at 15 sites in southern Costa Rica, that compares applied nucleation to natural regeneration and mixed‐species tree plantations as strategies to restore tropical forest. We have collected data on planted tree survival and growth, woody vegetation recruitment and structure, seed rain, litterfall, epiphytes, birds, bats and leaf litter arthropods.

Our results indicate that applied nucleation and plantation restoration strategies are similarly effective in enhancing the recovery of most floral and faunal groups, vegetation structure and ecosystem functions, as compared to natural regeneration.

Seed dispersal and woody recruitment are higher in applied nucleation and plantation than natural regeneration treatments; canopy cover has increased substantially in both natural regeneration and applied nucleation treatments; and mortality of planted N‐fixing tree species has increased in recent years. These trends have led to rapid changes in vegetation composition and structure and nutrient cycling.

The applied nucleation strategy is cheaper than mixed‐species tree plantations, but there may be social obstacles to implementing this technique in agricultural landscapes, such as perceptions that the land is not being used productively.

Applied nucleation is likely to be most effective in cases where: planted vegetation nuclei enhance seed dispersal and seedling establishment of other species; the spread of nuclei is not strongly inhibited by abiotic or biotic factors; and the approach is compatible with restoration goals and landowner preferences.

Synthesis and applications. Results from our 15‐year, multi‐site study show that applied nucleation can be a cost‐effective strategy for facilitating tropical forest regeneration that holds promise for helping to meet large‐scale international forest restoration commitments.
Integrating crop modelling and production economics to investigate multiple nutrient deficiencies and yield gaps
Authors: Stott Kerry J. , Christy Brendan , McCaskill Malcolm , Benke Kurt K. , Riffkin Penny , O'Leary Garry J. , Norton Robert
Published: May 2020

A method is described for integrating crop modelling and production economics to quantify optimum applications of multiple nutrients and yield gaps. The method is demonstrated for crop production in the high‐rainfall zone of southern Australia. Data from a biophysical crop model were used to overcome the persistent problem of inadequate experimental data. The Mitscherlich function was expanded to accommodate four variable inputs – nitrogen, phosphorus, potassium and sulphur – and the expansion path was used to determine the economic optimum application of all four nutrients. Modelling revealed the state‐contingent yield potential and the extent to which unrealised yield could be explained by profit‐maximising behaviour and risk‐aversion by growers. If growers and their advisors were guided by the methods described, they would be better equipped to assess crop nutrient demands and limitations, predict yield potential, additional profit and the risks associated with high input systems in a variable climate. If scientists were more aware of the extra profits and the risks involved (as well as the quantitative relationships between inputs and outputs) when thinking about what to produce and how to do so, they would be more circumspect about the net benefits to be obtained from closing yield gaps.