bluuebunny/crossref_metadata_2025 huggingface dataset:
Insulator Activities of Nucleosome-Excluding DNA Sequences Without Bound Chromatin Looping Proteins
Authors: Matsushima Yuki , Sakamoto Naoaki , Awazu Akinori
Published: January 2019

Chromosomes consist of various domains with different transcriptional activities separated by chromatin boundary sequences such as insulator sequences. Recent studies suggested that CTCF or other chromatin loop-forming protein binding sequences represented typical insulators. Alternatively, some long nucleosome-excluding DNA sequences were also reported to exhibit insulator activities in yeast and sea urchin chromosomes although specific binding of loop-forming proteins were not expected for them. However, the mechanism of the insulator activities of these sequences and the possibilities of similar insulators existing in other organisms remained unclear. In this study, we first constructed and performed simulations of a coarse-grained chromatin model containing nucleosome-rich and nucleosome-excluding DNA regions. We found that a long nucleosome-excluding region between two nucleosome-rich regions could markedly hinder the associations of two neighboring chromatin regions owing to the stronger long-term-averaged rigidity of the nucleosome-excluding region compared to that of nucleosome-rich regions. Subsequent analysis of the genome wide nucleosome positioning, protein binding, and DNA rigidity in human cells revealed that some nucleosome-excluding rigid DNA sequences without bound chromatin looping proteins could exhibit insulator activities, functioning as chromatin boundaries in various regions of human chromosomes.
Data-driven spectral analysis for coordinative structures in periodic systems with unknown and redundant dynamics
Authors: Fujii Keisuke , Takeishi Naoya , Kibushi Benio , Kouzaki Motoki , Kawahara Yoshinobu
Published: January 2019

Living organisms dynamically and flexibly operate a great number of components. As one of such redundant control mechanisms, low-dimensional coordinative structures among multiple components have been investigated. However, structures extracted from the conventional statistical dimensionality reduction methods do not reflect dynamical properties in principle. Here we regard coordinative structures in biological periodic systems with unknown and redundant dynamics as a nonlinear limit-cycle oscillation, and apply a data-driven operator-theoretic spectral analysis, which obtains dynamical properties of coordinative structures such as frequency and phase from the estimated eigenvalues and eigenfunctions of a composition operator. First, from intersegmental angles during human walking, we extracted the speed-independent harmonics of gait frequency. Second, we discovered the speed-dependent time-evolving behaviors of the phase on the conventional low-dimensional structures by estimating the eigenfunctions. Our approach contributes to the understanding of biological periodic phenomena with unknown and redundant dynamics from the perspective of nonlinear dynamical systems.
Distributed DNA-based Communication in Populations of Synthetic Protocells
Authors: Joesaar Alex , Yang Shuo , Bögels Bas , der Linden Ardjan van , Kumar B.V.V.S. Pavan , Dalchau Neil , Phillips Andrew , Mann Stephen , de Greef Tom F. A.
Published: January 2019

Developing distributed communication platforms based on orthogonal molecular communication channels is a crucial step towards engineering artificial multicellular systems. Here, we present a general and scalable platform entitled ‘Biomolecular Implementation of Protocellular Communication’ (BIO-PC) to engineer distributed multichannel molecular communication between populations of non-lipid semipermeable microcapsules. Our method leverages the modularity and scalability of enzyme-free DNA strand-displacement circuits to develop protocellular consortia that can sense, process and respond to DNA-based messages. We engineer a rich variety of biochemical communication devices capable of cascaded amplification, bidirectional communication and distributed computational operations. Encapsulating DNA strand-displacement circuits further allows their use in concentrated serum where non-compartmentalized DNA circuits cannot operate. BIO-PC enables reliable execution of distributed DNA-based molecular programs in biologically relevant environments and opens new directions in DNA computing and minimal cell technology.
Increased spontaneous EEG signal diversity during stroboscopically-induced altered states of consciousness
Authors: Schwartzman David J. , Schartner Michael , Ador Benjamin B. , Simonelli Francesca , Chang Acer Y.-C. , Seth Anil K.
Published: January 2019

What are the global neuronal signatures of altered states of consciousness (ASC)? Recently, increases in neural signal diversity, compared to those found in wakeful rest, have been reported during psychedelic states. Neural signal diversity has previously been identified as a robust signature of the state of consciousness, showing lower scores during sleep or anaesthesia compared to wakeful rest. The increased neural signal diversity during psychedelic states raises the additional possibility that it may also reflect the increased diversity of subjective experiences associated with these states. However, psychedelic states involve widespread neuropsychopharmacological changes, only some of which may be associated with altered phenomenology. Therefore, we used stroboscopic stimulation to induce non-pharmacological altered states of consciousness while measuring the diversity of EEG signals. Stroboscopic stimulation caused substantial increases in the intensity and range of subjective experiences, with reports of both simple and complex visual hallucinations. These experiences were accompanied by increases in EEG signal diversity scores (measured using Lempel-Ziv complexity) exceeding those associated with wakeful rest, in line with studies of the psychedelic state. Our findings support the proposal that EEG signal diversity reflects the diversity of subjective experience that is associated with different states of consciousness.
Rapid memory reactivation at movie event boundaries promotes episodic encoding
Authors: Silva Marta , Baldassano Christopher , Fuentemilla Lluís
Published: January 2019

Segmentation of continuous experience into discrete events is driven by rapid fluctuations in encoding stability at context shifts (i.e., event boundaries), yet the mechanisms underlying the online formation of event memories are poorly understood. We investigated the neural spatiotemporal similarity patterns of the scalp electrophysiological (EEG) activity of 30 participants watching a 50 min movie and found that event boundaries triggered rapid reinstatement of the just-encoded movie event EEG patterns. We also found that the onset of memory reinstatement at boundary onset (around 1500ms) was preceded by an N400-like ERP component, which likely reflects the detection of a context switch between the current and just-encoded event. A data-driven approach based on Hidden Markov Modeling allowed us to detect event boundaries as shifts between stable patterns of brain EEG activity during encoding and identify their reactivation during a free recall task. These results provide the first neurophysiological underpinnings for how the memory system segments a continuous stream of experience into episodic events.
A device to collect exhaled breath to study biomarkers in small animal models
Authors: Liu Yongtao , Hou Yutong , Hua Yuanrui , Gao Youhe
Published: January 2019

Biomarkers are measurable changes associated with disease. Exhaled breath provides many signs of bodily changes and has been proposed to be a good early biomarker source because it lacks homeostatic mechanisms. Earlier biomarker detection can provide earlier diagnosis, which can bring about more choices and more time for treatment. The benefit of studying exhaled breath in animal models is that most interfering factors can be avoided, and earlier changes in disease may be found. However, there is currently no device that can effectively collect exhaled breath from small animals. In this study, such a device was designed, constructed, and used for the study of candidate biomarkers from the exhale breaths of a papain-induced pulmonary emphysema rat model.
An EDS1-SAG101 complex functions in TNL-mediated immunity in Solanaceae
Authors: Gantner Johannes , Ordon Jana , Kretschmer Carola , Guerois Raphaël , Stuttmann Johannes
Published: January 2019

EDS1 (Enhanced disease susceptibility 1) forms mutually exclusive heterodimers with its interaction partners PAD4 (Phytoalexin-deficient 4) and SAG101 (Sensecence-associated gene 101). Collectively, these complexes are required for resistance responses mediated by nucleotide-binding leucine-rich repeat-type immune receptors (NLRs) possessing an N-terminal Toll-interleukin-1 receptor-like domain (TNLs). Here, immune functions of EDS1 complexes were comparatively analyzed in a mixed species approach relying on Nicotiana benthamiana (Nb), Solanum lycopersicum (Sl) and Arabidopsis thaliana (At). Genomes of most Solanaceae plants including Nb and Sl encode for two SAG101 isoforms, which engage into distinct complexes with EDS1. By a combination of genome editing and transient complementation, we show that one of these EDS1-SAG101 complexes, and not an EDS1-PAD4 complex as previously described in At, is necessary and sufficient for all tested TNL-mediated immune responses in Nb. Intriguingly, not this EDS1-SAG101 module, but mainly Solanaceae EDS1-PAD4 execute immune functions when transferred to At, and TNL functions are not restored in Nb mutant lines by expression of At EDS1 complexes. We conclude that EDS1 complexes do not represent a complete functional module, but co-evolve with additional factors, most likely protein interaction partners, for their function in TNL signaling networks of individual species. In agreement, we identify a large surface on SlEDS1 complexes required for immune activities, which may function in partner recruitment. We highlight important differences in TNL signaling networks between At and Nb, and genetic resources in the Nb system will be instrumental for future elucidation of EDS1 molecular functions.
The impact of Temporal Artery Biopsy for the diagnosis of Giant Cell Arteritis in clinical practice in a tertiary University Hospital
Authors: Kaltsonoudis E , Pelechas E , Papoudou-Bai A , Markatseli E.T. , Elisaf M , Voulgari PV , Drosos AA
Published: January 2019

Background

Temporal artery biopsy (TAB) is useful in assisting with giant cell arteritis (GCA) diagnosis but lacks sensitivity. The aim of our study was to assess the diagnostic impact of TAB histology in patients with suspected GCA on hospital admission.

Methods

A prospectively maintained database was queried for all TABs performed between 1-1-2000 until 31-12-2017 at the University Hospital of Ioannina. Thus, inclusion criteria were made on the grounds of every patient that underwent a TAB during the above-mentioned period, regardless of demographic, clinical and laboratory data.

Results

Two hundred forty-five TABs were included (149 females and 96 males), with a mean age of 64.5 (±3.5) years. The mean symptoms duration until admission to the hospital was 8.6 (±1.3) weeks and all had elevated acute phase reactants on admission. The reasons of admission were fever of unknown origin (FUO) in 114 (46.5%) patients, symptoms of polymyalgia rheumatica (PMR) in 84 (34.3%), new headache in 33 (13.5%), anemia of chronic disease (ACD) in 8 (3.32%) and eye disturbances in 6 (2.5%) patients. Positive results were found in 49 (20%) TABs. More specifically, in 14% of patients with FUO, 21% in those with PMR, while in patients with a new headache the percentage was 27%. Finally, 5 out of 6 (83.3%) of patients with ocular symptoms and only one (12.5%) of those suffering from ACD. Visual manifestations and FUO are correlated with a positive TAB.

Conclusion

It seems that TAB is useful in assisting with GCA diagnosis, but lacks sensitivity.
Forest canopy, a proxi of light intensity, arrests Pinus radiata invasion: basic science to conserve the Coastal Maulino forest, Central Chile
Authors: Gómez Persy , Murúa Maureen , Martín José San , Goncalves Estefany , Bustamante Ramiro
Published: January 2019

Coastal Maulino forest is an endemic forest of central Chile, which has suffered a large history of disturbance, being replaced by large extensions of Pinus radiata plantations. This land transformation conveys high rates of pines invasion into native remnants. In this study we examined to what extent structural features of forest patches explains invisibility of this forest-type. Within eight forest fragments, we sampled 162 plots (10 x 10 m2 each). We quantified seedling pine density and related this estimates with tree cover, litter depth, PAR radiation, and diversity of the resident community. Our results indicate that canopy cover was the most important variable to determine seedling pine density within forest fragments. To preserve the Coastal Maulino forest and the biodiversity containing on it, it seems to be necessary to maintain the native canopy cover. These actions can be highly effective even if we cannot avoid a massive seed arrival from pine plantations which will be unable to regenerate under well conserved native forests.
Viral infection enhances vomocytosis of intracellular fungi via Type I interferons
Authors: Seoane Paula I , Taylor-Smith Leanne M. , Stirling David , Bell Lucy C. K. , Noursadeghi Mahdad , Bailey Dalan , May Robin C.
Published: January 2019

Cryptococcus neoformans is an opportunistic human pathogen, which causes serious disease in immunocompromised hosts. Infection with this pathogen is particularly relevant in HIV+ patients, where it leads to around 200,000 deaths per annum. A key feature of cryptococcal pathogenesis is the ability of the fungus to survive and replicate within the phagosome of macrophages, as well as its ability to escape via a novel non-lytic mechanism known as vomocytosis. We have been exploring whether viral infection affects the interaction between C. neoformans and macrophages. Here we show that viral infection enhances cryptococcal vomocytosis without altering phagocytosis or intracellular proliferation of the fungus. This effect occurs with distinct, unrelated human viral pathogens and is recapitulated when macrophages are stimulated with the anti-viral cytokine interferon alpha (IFNα). Importantly, the effect is abrogated when type-I interferon signalling is blocked, thus underscoring the importance of type-I interferons in this phenomenon. Our results highlight the importance of incorporating specific context cues while studying host-pathogen interactions. By doing so, we found that acute viral infection may trigger the release of latent cryptococci from intracellular compartments, with significant consequences for disease progression.

Non-Technical Author Summary

Infectious diseases are typically studied in the laboratory in isolation, but in real life people often encounter multiple infections simultaneously. Here we investigate how the innate immune response to the fatal fungus Cryptococcus neoformans is influenced by viral coinfection. Whilst virally-infected macrophages retain a normal capacity to engulf and kill Cryptococci, they demonstrate a dramatically enhanced propensity to expel them via the process known as non-lytic expulsion or vomocytosis. Activation of vomocytosis is independent of the type of virus encountered, since both HIV and measles (two entirely unrelated viral pathogens) trigger the same effect. Instead it is driven by interferon-α, a generic ‘antiviral’ response, which signals back to the infected macrophage, triggering expulsion of the fungus. We propose that this hitherto unobserved phenomenon represents a ‘reprioritisation’ pathway for innate immune cells, by which they can alter the frequency with which they expel one pathogen (Cryptococcus) depending on the level of threat from a secondary viral infection.
Structural differences between the Woodchuck hepatitis virus core protein in dimer and capsid states indicate entropic and conformational regulation of assembly
Authors: Zhao Zhongchao , Wang Joseph Che-Yen , Gonzalez-Gutierrez Giovanni , Venkatakrishnan Balasubramanian , Zlotnick Adam
Published: January 2019

Hepadnaviruses are hepatotropic enveloped DNA viruses with an icosahedral capsid. Hepatitis B virus (HBV) causes chronic infection in an estimated 240 million people; Woodchuck Hepatitis virus (WHV), an HBV homologue, has been an important model system for drug development. The dimeric capsid protein (Cp) plays multiple functions during the viral life cycle and thus has become an important target for a new generation of antivirals. Purified HBV and WHV Cp spontaneously assemble into 120-dimer capsids. Though they have 65% identity, WHV Cp has error-prone assembly with stronger protein-protein association. We have taken advantage of the differences in assembly to investigate the basis of assembly regulation. We have determined the structures of the WHV capsid to 4.5 Å resolution by cryo-EM and the WHV Cp dimer to 2.9 Å resolution by crystallography and examined the biophysical properties of the dimer. We found, in dimer, the subdomain that makes protein-protein interactions is partially disordered and rotated 21° from its position in capsid. This subdomain is susceptible to proteolysis, consistent with local disorder. These data show there is an entropic cost for assembly that is compensated for by the energetic gain of burying hydrophobic interprotein contacts. We propose a series of stages in assembly that incorporate disorder-to-order transition and structural shifts. WHV assembly shows similar susceptibility to HBV antiviral molecules, suggesting that HBV assembly follows similar transitions and indicating WHV’s importance as a model system for drug development. We suggest that a cascade of structural changes may be a common mechanism for regulating high fidelity capsid assembly in HBV and other viruses.

Author summary

Capsid assembly is a key step in the Hepatitis B virus (HBV) life cycle; it requires sophisticated regulation to ensure the production of capsids and viruses with high-fidelity. HBV capsids are constructed from 120 self-assembling capsid protein dimers (Cp). It was hypothesized that changes in Cp structure regulated the assembly reaction. Here we determined structures of dimer and capsid for Woodchuck Hepatitis virus (WHV), an HBV homologue. We observed that the component of the dimer involved in subunit-subunit interactions undergoes a disorder-order transition and changes structure concomitant with assembly. Meanwhile WHV Cp displays similar susceptibility to HBV antiviral. We propose that this structural transition entropically regulates assembly and may be a common theme in other viruses.
PepQuery enables fast, accurate, and convenient proteomic validation of novel genomic alterations
Authors: Wen Bo , Wang Xiaojing , Zhang Bing
Published: January 2019

Massively parallel or second-generation sequencing-based genomic studies continuously identify new genomic alterations that may lead to novel protein sequences, which are attractive candidates for disease biomarkers and therapeutic targets after proteomic validation. Integrative proteogenomic methods have been developed to use mass spectrometry (MS)-based proteomics data for such validation. These methods replace the reference sequence database in proteomic database searching with a customized protein database that incorporates sample- or disease-specific sequences derived from DNA or RNA sequencing, thus enabling the identification of novel protein sequences. Although useful, this spectrum-centric approach requires a full evaluation of all possible spectrum-peptide pairs, which is time-consuming, error-prone, and difficult to apply. Here, we present PepQuery, a peptide-centric approach that focuses on only novel DNA or protein sequences of interest. PepQuery allows quick and easy proteomic validation of genomic alterations without customized database construction. We demonstrated the sensitivity and specificity of the approach in validating completely novel proteins, novel splice junctions, and single amino acid variants using simulations and experimental data. Notably, enabling unrestricted modification searching in PepQuery reduced false positives by up to 95%. We implemented PepQuery as both web-based and stand-alone applications. The web version provides direct access to more than half a billion MS/MS spectra from the Clinical Proteomic Tumor Analysis Consortium (CPTAC) and other cancer proteomic studies. The stand-alone version supports batch analysis and user-provided MS/MS data. PepQuery will increase the usage of proteogenomics beyond the proteomics community and will broaden the application of proteogenomics in personalized medicine.
A new, deep quinoxaline-based cavitand receptor for the complexation of benzene
Authors: Pinalli Roberta , Trzciński Jakub W. , Dalcanale Enrico , Massera Chiara
Published: January 2019

We report the synthesis of a new macrocyclic receptor, namely 2,8,14,20-tetrahexyl-4,24:6,10:12,16:18,22-O,O′-tetrakis[2,3-dihydro-[1,4]dioxino[2,3-g]quinoxalin-7,8-diyl]resorcin[4]arene, DeepQxCav, obtained by the addition of ethylene glycol ditosylate to an octahydroxy quinoxaline cavitand. A 1:1 supramolecular complex of this cavitand with benzene has been obtained and analysed through X-ray diffraction analysis. The complex, of general formula C92H88O16N8·C6H6, crystallizes in the space group C2/c, with the cavitand host located about a twofold rotation axis. The benzene guest, which is held inside the cavity by C—H...π interactions and dispersion forces, is disordered over two equivalent sites, one in a general position and one lying on a twofold axis. The crystal structure features C—H...O hydrogen bonds and C—H...π interactions involving the alkyl chains, the aromatic rings, and the O atoms of the dioxane moiety of the resorcinarene scaffold. The crystal studied was refined as a two-component twin.
Crystal structure and Hirshfeld surface analysis of poly[[di-μ3-glycine-lithium] perchlorate]
Authors: Revathi Palanisamy , Mohan Janani S. , Balakrishnan Thangavelu , Ramamurthi Kandasamy , Thamotharan Subbiah
Published: January 2019

In the title salt, {[Li(C2H5NO2)2]ClO4}
n
, the Li+ cation is coordinated by four carboxylate oxygen atoms of the glycine molecules with a distorted tetrahedral geometry. The glycine exists in a zwitterionic form with protonated amino and deprotonated carboxylate groups. In the crystalline state, the title salt is primarily stabilized by intermolecular N—H...O and Cα—H...O interactions which interconnect various units. Hirshfeld surface analysis indicates that the intermolecular H...O/O...H interactions are the most important contributors to the crystal packing.
Redetermination of the crystal structure of tetralithium octafluoridozirconate(IV), Li4ZrF8, from single-crystal X-ray data
Authors: Chemey Alexander T. , Albrecht-Schmitt Thomas E.
Published: January 2019

Presented herein is the crystal-structure redetermination of Li4ZrF8 from single-crystal X-ray data. Alkali zirconium fluorides are important in nuclear-relevant technologies, and zirconium is commonly employed as an analogue for tetravalent f-block elements. The previous structure report of this species is based on powder X-ray data [Dugat et al. (1995). J. Solid State Chem.
120, 187–196] but there has never been a refined structure model from single-crystal data. The octafluoridozirconate moieties are held together by electrostatic attraction to lithium ions without sharing of fluoride sites between zirconium(IV) ions.
The structure of the AliC GH13 α-amylase from Alicyclobacillus sp. reveals the accommodation of starch branching points in the α-amylase family
Authors: Agirre Jon , Moroz Olga , Meier Sebastian , Brask Jesper , Munch Astrid , Hoff Tine , Andersen Carsten , Wilson Keith S. , Davies Gideon J.
Published: January 2019

α-Amylases are glycoside hydrolases that break the α-1,4 bonds in starch and related glycans. The degradation of starch is rendered difficult by the presence of varying degrees of α-1,6 branch points and their possible accommodation within the active centre of α-amylase enzymes. Given the myriad industrial uses for starch and thus also for α-amylase-catalysed starch degradation and modification, there is considerable interest in how different α-amylases might accommodate these branches, thus impacting on the potential processing of highly branched post-hydrolysis remnants (known as limit dextrins) and societal applications. Here, it was sought to probe the branch-point accommodation of the Alicyclobacillus sp. CAZy family GH13 α-amylase AliC, prompted by the observation of a molecule of glucose in a position that may represent a branch point in an acarbose complex solved at 2.1 Å resolution. Limit digest analysis by two-dimensional NMR using both pullulan (a regular linear polysaccharide of α-1,4, α-1,4, α-1,6 repeating trisaccharides) and amylopectin starch showed how the Alicyclobacillus sp. enzyme could accept α-1,6 branches in at least the −2, +1 and +2 subsites, consistent with the three-dimensional structures with glucosyl moieties in the +1 and +2 subsites and the solvent-exposure of the −2 subsite 6-hydroxyl group. Together, the work provides a rare insight into branch-point acceptance in these industrial catalysts.
Structure of interferon-stimulated gene product 15 (ISG15) from the bat species Myotis davidii and the impact of interdomain ISG15 interactions on viral protein engagement
Authors: Langley Caroline , Goodwin Octavia , Dzimianski John V. , Daczkowski Courtney M. , Pegan Scott D.
Published: January 2019

Bats have long been observed to be the hosts and the origin of numerous human diseases. Bats, like all mammals, rely on a number of innate immune mechanisms to combat invading pathogens, including the interferon type I, II and III responses. Ubiquitin-like interferon-stimulated gene product 15 (ISG15) is a key modulator of these interferon responses. Within these pathways, ISG15 can serve to stabilize host proteins modulating innate immune responses and act as a cytokine. Post-translational modifications of viral proteins introduced by ISG15 have also been observed to directly affect the function of numerous viral proteins. Unlike ubiquitin, which is virtually identical across all animals, comparison of ISG15s across species reveals that they are relatively divergent, with sequence identity dropping to as low as ∼58% among mammals. In addition to serving as an obstacle to the zoonotic transmission of influenza, these ISG15 species–species differences have also long been shown to have an impact on the function of viral deISGylases. Recently, the structure of the first nonhuman ISG15, originating from mouse, suggested that the structures of human ISG15 may not be reflective of other species. Here, the structure of ISG15 from the bat species Myotis davidii solved to 1.37 Å resolution is reported. Comparison of this ISG15 structure with those from human and mouse not only underscores the structural impact of ISG15 species–species differences, but also highlights a conserved hydrophobic motif formed between the two domains of ISG15. Using the papain-like deISGylase from Severe acute respiratory syndrome coronavirus as a probe, the biochemical importance of this motif in ISG15–protein engagements was illuminated.
Learning organization and work performance in Bandung city government in Indonesia: a path modeling statistical approach
Authors: Anggara Widi Galih , Febriansyah Hary , Darmawan Rony , Cintyawati Cici
Published: January 2019

Purpose

This study aims to explore the applicability of the learning organization (LO) concept as a predictor of work performance (WP) using partial least square (PLS) as a statistical method to explain the presence or absence of relationships between those latent variables.

Design/methodology/approach

An empirical approach was conducted on a research sample of a local government in Indonesia. The design of this study is a cross-sectional study using a closed-ended questionnaire, and PLS is used as a statistical method.

Findings

The results show evidence of internal consistency and construct reliability and provide a sound answer that the LO concept can explain a considerable proportion of the WP. This indicates that LO could be considered as the predictor of WP.

Originality/value

To date, studies on the benefit of becoming an LO have been increasing since the publication of Senge’s book, The Fifth Discipline, in the 1990s. However, such research efforts are directed primarily at assessing financial and knowledge performance (Swanson and Chermack, 2013). Very few studies have focused on the benefits associated with becoming an LO with an emphasis on individual performance using the behavioral aspect.
Numerical investigation on turbulent convective heat transfer of nanofluid flow in a square cross-sectioned duct
Authors: Şenay Gülbanu , Kaya Metin , Gedik Engin , Kayfeci Muhammet
Published: January 2019

Purpose

The purpose of this study is to numerically investigate the heat transfer enhancement by using two different nanofluids flow throughout the square duct under a constant heat flux (500 × 103 W/m2).

Design/methodology/approach

In numerical computations, ANSYS Fluent code based on the finite volume method was used to solve governing equations by iteratively. Water, Al2O3-water and TiO2-water nanofluids were used for different flow velocities changing 1 m/s to 8 m/s (i.e. Reynolds number varying from 3,000 to 100,000).

Findings

The results were compared with results published previously in the literature and close agreement was observed especially considering Dittus and Boelter correlation for water. It was found that from the obtained results, increasing flow velocity and volume fractions of nanoparticles has caused to increase Nu number for all cases. Besides, variations of pressure drop, Darcy friction factor are presented graphically and discussed in detail. The results are consistent with a deviation of 1.3 to 15 per cent with the results of other researchers.

Originality/value

The effects of the Re numbers and volume fractions of nanoparticles (0.01 ≤ Φ ≤ 0.04) on the heat transfer and fluid flow characteristics such as average Nu number, pressure drop (ΔP) and Darcy friction factor (f) were investigated.
Do characteristics of the regulatory content have different impact on the risk in the electricity sector?
Authors: Taffarel Marinês , da Silva Wesley Vieira , da Veiga Claudimar Pereira , Clemente Ademir , Mairesse Siluk Julio Cezar
Published: January 2019

Purpose

The purpose of this study is to determine if the Brazilian electricity sector is differently affected by the characteristics of the content in the regulatory legislation.

Design/methodology/approach

For better robustness of the research, the authors analyzed the period from 1995 to 2013, totaling 4,510 observations. To this end, the selection of regulatory legislation was conducted through Markov regime switching. To identify the characteristics of profile and intensity of regulatory content in each legislation, we applied the content analysis technique.

Findings

The main findings of this study position this research in the vanguard regarding other research in the area by showing that all regulatory measures whose characteristics denote market profile of strong and medium intensity affect the risk of electric utilities in Brazil. As contribution from this research, it can be hypothesized that for provisional measures/laws events, the profile and intensity of regulatory content are relevant and have different impact on the risk of stocks and, therefore, should be considered in the design and development of public policies.

Originality/value

The paper investigates by means of content analysis, the profile and intensity characteristics of the content present in the regulatory legislation and to present the impact of these characteristics on the risk of the electric energy Sector in Brazil. The research results showed that it is not all regulatory events that impact the stock market. Therefore, regulatory risk estimates must consider the intensity and scope of each legislation, given that legislation with a higher regulatory content that seeks to modify the sector’s operating rules more deeply tends to have a greater impact on the risk of companies that operate in regulated sectors. Therefore, the paper shows originality and evolution for the researchers in the area, with new and significant information.
Enhancing organizational innovation in Indian automobile industry
Authors: Chaubey Akriti , Sahoo Chandan Kumar
Published: January 2019

Purpose

This study aims to focus on examining the impact of transformational leadership on employee creativity to enhance organizational innovation through mediating effect of intrinsic motivation and the moderating effect of organizational culture on the relationship between employee creativity and organizational innovation in Indian automobile industries.

Design/methodology/approach

Responses were collected from engineers, managers and R&D professionals from car manufacturing and R&D units from southern India through a structured questionnaire. The data were analyzed using IBM SPSS version 20. The validity of the constructs and the theoretical model were confirmed by applying structural equation modeling approach using IBM SPSS Amos version 20.

Findings

Empirical findings proved that transformational leadership has a positive effect on employee creativity, as mediated by intrinsic motivation. Studies also revealed that employees tend to exhibit higher creative potential when they are exposed to a higher degree of distinct shared assumptions, values and beliefs, which governs their behavior in an organization.

Research limitations/implications

As research was carried out in Indian automobile manufacturing and R&D units, it cannot be generalized across the broader range of sectors and international environment.

Originality/value

This research is unique in its attempt to empirically test the moderating effect of organizational culture in enhancing organizational innovation in Indian automobile industry.
Managing the unexpected in megaprojects: riding the waves of resilience
Authors: Nachbagauer Andreas G.M. , Schirl-Boeck Iris
Published: January 2019

Purpose

Risk management and uncertainty in megaprojects is a flourishing topic in project management, while the unexpected is still a neglected matter. The purpose of this paper is to offer conceptual clarifications of the unexpected based on second-order-cybernetics and systems theory. While transferring findings from organisation theory to project management, the article provides fresh insights into managing the unexpected in megaprojects.

Design/methodology/approach

Being grounded on constructionism and systems theory, the conceptual paper explores selected research approaches from organisation theory: research on high-reliability organising, organisational resilience and organisational improvising, on contributions to managing the unexpected in megaprojects. Using the framework of meaning i.e. the factual, social and temporal dimensions, challenges of handling the unexpected are analysed and (effects of) decision-making structures for such projects are defined.

Findings

This paper argues that classic project management, while neglecting the fundamental distinction between risk, uncertainty and the unexpected, sticks to a planning-and-controlling approach. But the unexpected cannot be planned; however, organisations and managers can prepare for the unexpected. This requests a balance between structure and self-organisation in planning, communication, hierarchy and organisational culture. Understanding the contradictions inherent in managing megaprojects allows for smart decision-making when riding the waves of resilience.

Originality/value

The study adds to the literature on complexity and uncertainty in project management by enhancing the view to include the unexpected. While rejecting the universal applicability of rationality-based risk and controlling conceptions, shifting to second-order cybernetics and integrating elements of resilient organising increases the understanding of handling the unexpected in megaprojects.
The role of cognitive moral development in tax
compliance decision making
Authors: Iqbal Syaiful , Sholihin Mahfud
Published: January 2019

Purpose

This paper aims to investigate the role of cognitive moral development (CMD)
in tax compliance decision. In particular, the study compares tax compliance
degree in two different tax systems: synergistic and antagonistic tax
climates.

Design/methodology/approach

Build on the CMD theory, this study uses a paper and pencil laboratory
experiment that involved 157 participants to test the hypotheses.

Findings

CMD has significant contribution to the tax compliance decision, especially
for taxpayers at both the pre-conventional and conventional level. Taxpayers
who have achieved post-conventional level, however, do not shift their
compliance degree even when the tax climate changed. The present results
support the CMD theory.

Originality/value

To the best of the authors’ knowledge, the present study is the first
to investigate the role of CMDin tax compliance decision by comparing two
different tax systems: synergistic and antagonistic tax climates. This study
has theoretical and practical contributions. From theoretical perspective,
the findings provide evidence that CMD influence tax compliance
decision-making processes. In the practical terms, this research may provide
a deep insight on the important of government and tax authorities to improve
the taxpayers’ moral cognitive, e.g. through any activities which
aims to boost them to the level of post-conventional.
Tribological behaviors of the thick metal coating for the contact mechanical seal under the water-lubricated conditions
Authors: Zhang Guo-yuan , Dang Jia-qi , Zhao Wei-gang , Yan Xiu-tian
Published: January 2019

Purpose

The serious friction and wear problem occurs on the mechanical seal’s faces during the start-up stage of the high-speed turbopump for a liquid rocket engine. This paper aims to propose a kind of thick metal alloy coatings on the surface of the seal’s rotor so as reduce the friction and wear.

Design/methodology/approach

With the pin-disk (the graphite pin and the disk with the metal coating) tribology-tester, the tribological behaviors of four metal coatings are investigated. The special friction coefficients under the dry friction, boundary friction and different temperatures of water-lubricated conditions were obtained.

Findings

The test results show that the thick metal coating has a good performance of the wear resistance and friction reduction; and the friction coefficients of a Sn-Sb-Cu coating under the dry friction and water-lubricated conditions are 0.377 and 0.043, respectively, and the corresponding mass wear volumes are only 2.74 and 0.81 mg, respectively.

Originality/value

The thick metal coating scheme for the mechanical seal’s faces might lend itself to the harsh working conditions of the low-viscosity liquid rocket engine.
Enhanced generation efficiency of singlet oxygen for methylene blue released from hydroxyapatite-MB@tannic acid-Fe(III) ions
Authors: Wang Wenhao , Shi Rujing , Zhang Wei , Sun Haibin , Ge Xiaolu , Li Chengfeng
Published: January 2019

Purpose

The purpose of this paper is to improve the generation efficiency of singlet oxygen of methylene blue molecules through finely controlling their aggregation states in drug carriers.

Design/methodology/approach

As a photosensitiser in photodynamic therapy, methylene blue (MB) was loaded on citrate-modified hydroxyapatite (HAp) through an electrostatic interaction and followed by encapsulation of coordination complexes of tannic acid (TA) and Fe(III) ions. Ultraviolet-visible absorption spectrum of the supernatant after incubation of samples was recorded at certain time interval to investigate the release behaviour of MB. Photodynamic activity of MB was determined by the oxidation reaction of uric acid by singlet oxygen generated by MB under illumination.

Findings

Almost all MB molecules were immediately released from HAp-MB, whilst an initial burst release of MB from HAp-MB@TA was followed by a sustainable and pH-sensitised release. In comparison with HAp-MB, photocatalystic reduction of HAp-MB@TA by titanium dioxide hardly occurred under illumination, indicating the stability against reduction to leukomethylene blue in vitro. Generation efficiency of singlet oxygen by MB released from HAp-MB@TA was significantly higher than that from HAp-MB because of the control of TA and Fe(III) ions complexes on molecular structures of released MB.

Originality/value

A facile method was herein demonstrated to optimise the generation efficiency of singlet oxygen by controlling aggregation states of PS molecules and improve PDT efficiency to damage tumour tissues.
The ecology of sexual conflict: Temperature variation in the social environment can drastically modulate male harm to females
Authors: García‐Roa Roberto , Chirinos Valeria , Carazo Pau
Published: January 2019

Sexual conflict is a fundamental driver of male/female adaptations, an engine of biodiversity and a crucial determinant of population viability. Sexual conflict frequently leads to behavioural adaptations that allow males to displace their rivals, but in doing so harm those same females they are competing to access, which can decrease population viability and facilitate extinction.

We are far from understanding what factors modulate the intensity of sexual conflict and particularly the role of ecology in mediating underlying behavioural adaptations.

In this study, we show that, in Drosophila melanogaster, variations in environmental temperature of ±4°C decrease male harm impact on female fitness by between 45% and 73%. Rate‐sensitive fitness estimates indicate that such modulation results in an average rescue of population productivity of 7% at colder temperatures and 23% at hotter temperatures.

Our results: (a) show that the thermal ecology of social interactions can drastically modulate male harm via behavioural plasticity, (b) identify a potentially crucial ecological factor to understand how sexual conflict operates in nature and (c), along with recent studies, suggest that behaviourally plastic responses can lessen the negative effect of sexual conflict on population viability in the face of rapid environmental temperature changes.

A plain language summary is available for this article.
Flowering resources distract pollinators from crops: Model predictions from landscape simulations
Authors: Nicholson Charlie C. , Ricketts Taylor H. , Koh Insu , Smith Henrik G. , Lonsdorf Eric V. , Olsson Ola
Published: January 2019

Enhancing floral resources is a widely accepted strategy for supporting wild bees and promoting crop pollination. Planning effective enhancements can be informed with pollination service models, but these models should capture the behavioural and spatial dynamics of service‐providing organisms. Model predictions, and hence management recommendations, are likely to be sensitive to these dynamics.

We used two established models of pollinator foraging to investigate whether habitat enhancement improves crop visitation; whether this effect is influenced by pollinator foraging distance and landscape pattern; and whether behavioural detail improves model predictions.

The more detailed central place foraging model better predicted variation in bee visitation observed between habitat types, because it includes optimized trade‐offs between patch quality and distance. Both models performed well when predicting visitation rates across broader scales.

Using real agricultural landscapes and simulating habitat enhancements, we show that additional floral resources can have diverging effects on predicted crop visitation. When only co‐flowering resources were added, optimally foraging bees concentrated in enhancements to the detriment of crop pollination. For both models, adding nesting resources increased crop visitation. Finally, the marginal effect of enhancements was greater in simple landscapes.

Synthesis and applications. Model results help to identify the conditions under which habitat enhancements are most likely to increase pollination services in agriculture. Three design principles for pollinator habitat enhancement emerge: (a) enhancing only flowers can diminish services by distracting pollinators away from crops, (b) providing nesting resources is more likely to increase bee populations and crop visitation and (c) the benefit of enhancements will be greatest in landscapes that do not already contain abundant habitat.
The GnRH analogues affect novel neuropeptide SMIM20/phoenixin and GPR173 receptor expressions in the female rat hypothalamic–pituitary–gonadal (HPG) axis
Authors: Suszka‐Świtek Aleksandra , Pałasz Artur , Filipczyk Łukasz , Menezes Itiana Castro , Mordecka‐Chamera Kinga , Angelone Tommaso , Bogus Katarzyna , Bacopoulou Flora , Worthington John J. , Wiaderkiewicz Ryszard
Published: January 2019

The recently discovered peptide phoenixin (PNX) and its receptor GPR173 are novel factors that exhibit a large spectrum of regulatory activity, especially when considered as a central modulator of GnRH‐related hormonal control of reproductive processes. It has been already proven that GnRH agonists and antagonists can modulate peptidergic signalling in the HPG axis. Despite these findings, there is so far no information regarding the influence of treatment with GnRH analogues on SMIM20/phoenixin signalling in the hypothalamic–pituitary–gonadal axis. In the current study, SMIM20/phoenixin and GPR173 mRNA levels were measured in the hypothalamus, pituitary and ovaries of female rats in the dioestrus phase following treatment with GnRH‐R agonist (buserelin) and antagonist (cetrorelix) using quantitative real‐time PCR. The serum PNX concentrations were also estimated with ELISA technique. The hypothalamic, hypophyseal and especially ovarian levels of SMIM20 mRNA were increased after both buserelin and cetrorelix administration. The GPR173 expressions were in turn decreased in the hypothalamus and pituitary. Treatment with the GnRH analogues led to the modulation of SMIM20/phoenixin and GPR173 mRNA expression in the female rat hypothalamic–pituitary–gonadal axis. By identifying buserelin and cetrorelix as novel modulators of phoenixin signalling in the animal HPG axis, these results cast new light on the GnRH analogues mode of action and contribute to a better understanding of the mechanisms responsible for the hormonal control of reproduction.