bluuebunny/crossref_metadata_2025 huggingface dataset:
Intra- and inter-individual metabolic profiling highlights carnitine and lysophosphatidylcholine pathways as key molecular defects in type-2 diabetes
Authors: Diamanti Klev , Cavalli Marco , Pan Gang , Pereira Maria J , Kumar Chanchal , Skrtic Stanko , Grabherr Manfred , Risérus Ulf , Eriksson Jan W , Komorowski Jan , Wadelius Claes
Published: September 2018

Type-2 diabetes (T2D) mellitus is a complex metabolic disease commonly caused by insulin resistance in several tissues. We performed a matched two-dimensional metabolic screening in tissue samples from a cohort of 43 multi-organ donors. The intra-individual analysis was assessed across five key-metabolic tissues (serum, adipose tissue, liver, pancreatic islets and muscle), and the inter-individual across three different groups reflecting T2D progression. We identified 92 metabolites differing significantly between non-diabetes and T2D subjects. Carnitines were significantly higher in liver, while lysophosphatidylcholines significantly lower in muscle and serum. An investigation of the progression to overt T2D showed that deoxycholic acid glycine conjugate was significantly higher in liver of pre-diabetes samples while additional increase in T2D was insignificant. A subset of lysophosphatidylcholines were significantly lower in the muscle of pre-diabetes subjects. Overall, the analysis of this unique dataset can increase the understanding of the metabolic interplay between organs in the development of T2D.
The Histone Demethylase KDM4D Promotes Hepatic Fibrogenesis by Modulating Toll-Like Receptor 4 Signaling Pathway
Authors: Dong Fangyuan , Jiang Shuheng , Li Jun , Wang Yahui , Zhu Lili , Hu Xiaona , Huang Yiqin , Jiang Xin , Zhou Qi , Zhang Zhigang , Bao Zhijun
Published: September 2018

Accumulating evidence has revealed the pivotal role of epigenetic regulation in the pathogenesis of liver disease. However, the epigenetic mechanism that accounts for hepatic stellate cells (HSCs) activation in liver fibrosis remains largely unknown. In this study, primary HSCs were used to screen the differentially expressed histone H3 lysine methyltransferases and demethylases during HSC activation. KDM4D was identified as a remarkable up-regulated histone H3 demethylase during HSC activation. The overexpression profile of KDM4D was further confirmed in three fibrosis animal models and human fibrotic liver tissues. In vitro genetic silencing of Kdm4d impaired the collagen gel contraction and migration capacity of primary HSCs. In established CCl4-induced mice model, Kdm4d knockdown inhibited fibrosis progression, and promoted fibrosis reversal, with enhanced thinning and splitting of fibrotic septa, as well as a dramatic decrease in collagen area. Whole gene transcriptome analysis showed the regulatory role of KDM4D in Toll-Like Receptor (TLR) signaling pathway. Mechanistically, KDM4D catalyzed histone 3 on lysine 9 (H3K9) di-, and tri-demethylation, which promoted TLR4 expression, and subsequently prompted liver fibrogenesis by activating NF-κB signaling pathways. KDM4D facilitates TLR4 transcription through demethylation of H3K9, thus activating TLR4/NF-κB signaling pathways in HSCs, contributing to HSC activation and collagen crosslinking, further, hepatic fibrosis progression.
An in-depth look at DNA crystals through the prism of molecular dynamics simulations
Authors: Kuzmanic Antonija , Dans Pablo D. , Orozco Modesto
Published: September 2018

X-ray crystallography has been traditionally considered as the primary tool for the determination of biomolecular structures and its derived models are taken as the gold standard in structural biology. However, contacts formed through the crystal lattice are known to affect the structures, especially in the case of small and flexible molecules, like DNA oligos, introducing drastic changes in the structure with respect to the solution phase. Furthermore, it is still unknown why molecules crystallize in certain symmetry groups and how the associated lattice impacts their structure. The role of crystallization additives and whether they are just innocuous and unspecific catalyzers of the crystallization process also remains unclear. On account of a massive computational effort and the use of the latest generation force field, we were able to describe with unprecedented level of detail the nature of intermolecular forces that participate in the stabilization of B-DNA crystals in various symmetry groups and in different solvent environments. We showed that the stability of the crystal lattice and the type of crystallization additives are tightly coupled, and certain symmetry groups are only stable in the presence of a specific crystallization additive (i.e., spermine). Additives and crystal contacts induce small but non-negligible changes in the physical properties of DNA.
Rac1 Activated by DOCK1 in Combination with Rab31 Promotes the Development of Diabetic Retinopathy
Authors: Xie Guijun , Lv Peilin , Li Man , Kong Lingju
Published: September 2018

Background

Diabetic retinopathy (DR) is one of the most common and severe microvascular complications of diabetes. It’s a fundus lesion with specific changes, and its specific molecular mechanism is still unclear.

Methods

All target proteins and markers expression in the study was verified by qPCR and western bloting. The morphology and behavior of human retinal epithelial cells ARPE-19 were analyzed using immunofluorescent and apoptosis detection assays, respectively. And, Small GTPase activity was detected by the GST-pull assay.

Results

We found that DOCK1 showed high expression in high glucose-induced DR. Moreover, its high expression is positively correlated with Rab31 in tissues. DOCK1 promotes the activation of Rac1 and promotes apoptosis of retinal epithelial cells. Rab31 promotes the degradation of TJ proteins by promoting the transport of TJ proteins from the plasma membrane to the endosomes, thereby affecting the tight junctions of epithelial cells. Inhibition of Rac1 activity can effectively reduce cell apoptosis. Similarly, inhibition of Rab31 activity can significantly inhibit the degradation of TJ proteins.

Conclusion

This study based on the high glucose-induced DR cell model reveals the role of two mutually synergistic signaling pathways through the important cytological phenomena of apoptosis and damage of tight junctions. One is the degradation of TJ proteins caused by Rab31-mediated vesicle trafficking, and the other is the apoptosis of retinal epithelial cells mediated by DOCK1-Rac1.
Close proximity interactions support transmission of ESBL-K. pneumoniae but not ESBL-E. coli in healthcare settings
Authors: Duval Audrey , Obadia Thomas , Boëlle Pierre-Yves , Fleury Eric , Herrmann Jean-Louis , Guillemot Didier , Temime Laura , Opatowski Lulla ,   the i-Bird Study group
Published: September 2018

Antibiotic-resistance of hospital-acquired infections is a major public health issue. The worldwide emergence and diffusion of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae, including Escherichia coli (ESBL-EC) and Klebsiella pneumoniae (ESBL-KP), is of particular concern. Preventing their nosocomial spread requires understanding their transmission. Using Close Proximity Interactions (CPIs), measured by wearable sensors, and weekly ESBL-EC– and ESBL-KP–carriage data, we traced their possible transmission paths among 329 patients in a 200-bed long-term care facility over 4 months. Based on phenotypically defined resistance profiles to 12 antibiotics, new bacterial acquisitions were tracked. Extending a previously proposed statistical method, the CPI network’s ability to support observed incident colonization episodes of ESBL-EC and ESBL-KP was tested. Finally, mathematical modeling based on our findings assessed the effect of several infection-control measures. A potential infector was identified in the CPI network for 80% (16/20) of ESBL-KP acquisition episodes. The lengths of CPI paths between ESBL-KP incident cases and their potential infectors were shorter than predicted by chance (P = 0.02), indicating that CPI-network relationships were consistent with dissemination. Potential ESBL-EC infectors were identified for 54% (19/35) of the acquisitions, with longer-than-expected lengths of CPI paths. These contrasting results yielded differing impacts of infection control scenarios, with contact reduction interventions proving less effective for ESBL-EC than for ESBL-KP. These results highlight the widely variable transmission patterns among ESBL-producing Enterobacteriaceae species CPI networks supported ESBL-KP, but not ESBL-EC spread. These outcomes could help design more specific surveillance and control strategies to prevent in-hospital Enterobacteriaceae dissemination.

Author summary

Tracing extended-spectrum β-lactamase (ESBL) dissemination in hospitals is an important step in the fight against the spread of multi-drug resistant bacteria. Indeed, understanding ESBL spreading dynamics will help identify efficient control interventions. In the i-Bird study, patients and hospital staff from a French long-term care facility in France carried a wearable sensor to capture their interactions at less than 1.5 meters, every 30 seconds over a 4-month period. Every week, patients were also swabbed to detect carriage of ESBL-producing Enterobacteriaceae. Based on the analysis of these longitudinal data, this study shows that ESBL-producing Klebsiella pneumoniae (ESBL-KP) mostly spreads during close-proximity interactions between individuals, while this is not the case for ESBL-producing Escherichia coli (ESBL-EC), suggesting that ESBL-KP but not ESBL-EC may be controlled by contact reduction interventions.
A CRISPR/Cas9-generated mutation in the zebrafish orthologue ofPPP2R3Bcauses idiopathic scoliosis
Authors: Seda Marian , Crespo Berta , Corcelli Michelangelo , Osborn Daniel P. , Jenkins Dagan
Published: September 2018

Idiopathic scoliosis (IS) is the deformation and/or abnormal curvature of the spine that develops progressively after birth. It is a very common condition, affecting approximately 4% of the general population, yet the genetic and mechanistic causes of IS are poorly understood. Here, we focus onPPP2R3B, which encodes a protein phosphatase 2A regulatory subunit that has been linked to regulation of autophagy. We found thatPPP2R3Bis expressed at sites of chondrogenesis within human foetuses, including the vertebrae. We also demonstrated prominent expression in myotome and muscle fibres in human foetuses, and zebrafish embryos and adolescents. As there is no rodent orthologue ofPPP2R3B, we used CRIPSR/Cas9-mediated gene-editing to generate a series of frameshift mutations in zebrafishppp2r3b. Adolescent zebrafish that were homozygous for this mutation exhibited a fully penetrant kyphoscoliosis phenotype which became progressively worse over time, mirroring IS in humans. These defects were associated with reduced mineralisation of vertebrae, resembling osteoporosis. Electron microscopy demonstrated abnormal mitochondria adjacent to muscle fibres, suggestive of abnormal mitophagy.
Descriptive analysis in time and space of recorded data for Buruli Ulcer occurrence in Victoria over 22 years
Authors: Avumegah Michael S. , Tay Ee Laine , Alexandersen Soren , Michalski Wojtek P. , O’Brien Daniel P. , Jeanne Isabelle , Athan Eugene
Published: September 2018

Background

Buruli ulcer (BU) is a subcutaneous necrotic infection of the skin caused by Mycobacterium ulcerans. There has been increasing BU incidence in Victoria, Australia. The aim of this study to provide an epidemiological update of BU cases in Victoria to understand the pattern of distribution over time and space and attempt to identify local risk factors.

Methods

A comprehensive descriptive epidemiological analyses were performed on BU notification data from 1994 to 2016. In addition, retrospective temporal, spatial and spatio-temporal analyses were conducted to understand the distribution of cases. Quantum GIS was used to generate maps. Demographic, new housing settlements and historical rainfall data were analysed to assess their effects on BU incidence in Victoria.

Findings

There were a total of 902 patients notified from 1994-2016. The incidence rate was 0.8/100,000 persons in Victoria. Space and time analyses showed that the most likely disease cluster was the Bellarine and Mornington Peninsulas with incidence rate 50 times higher than the State of Victoria rate. Gender was not a risk factor, but age was, with increased susceptibility among the over 60 year old group. There was an unusual high risk in the 15-24 age group in Point Lonsdale. Correlation analyses indicated that increase in population and construction of new settlements might be some of the reasons contributing to the rise in cases in Victoria.

Interpretation

The findings agreed with published works in Australia of the increase in BU cases in Victoria. However, our findings also highlights the endemic nature of cases. The identified spatial disease clusters could be relevant for future environmental sampling studies or screening tests for M. ulcerans exposure.

Author Summary

Buruli ulcer (BU) has been reported in 33 countries, mainly from the Tropics and Sub-tropics. Tropical cases are mainly within the West African region. Australia is the only country outside Africa in the top six highest incidence countries for BU. The exact mode of transmission remains unclear. Disease cases are rising in Australia, especially in Victoria for reasons that remains unclear. We have provided a descriptive epidemiological analyses in space and time of 22 years of recorded data on BU cases in Victoria from 1994 to 2016. We have also discussed demographic and new settlement dynamics over the study period. There were a total of 902 PCR-confirmed BU cases from 245 suburbs. Five suburbs on the Bellarine and Mornington Peninsulas were identified as the most endemic locations in Victoria. Spatial analyses detected a wider disease cluster area on the Peninsulas. We propose environmental sampling for risk factors analyses should focus on the endemic regions and some secondary clusters.
Interphase chromatin as a self-returning random walk: Can DNA fold into liquid trees?
Authors: Huang Kai , Backman Vadim , Szleifer Igal
Published: September 2018

We introduce a self-returning random walk to describe the structure of interphase chromatin. Based on a simple folding algorithm, our de novo model unifies the high contact frequency discovered by genomic techniques, and the high structural heterogeneity revealed by imaging techniques, which two chromatin properties we theoretically prove to be irreconcilable within a fractal polymer framework. Our model provides a holistic view of chromatin folding, in which the topologically associated domains are liquid-tree-like structures, linked and isolated by stretched-out, transcriptionally active DNA to form a secondary structure of chromatin that further folds into a “3D forest” under confinement.
The development of Hong Kong students’ civic attitudes under Chinese sovereignty
Authors: Kennedy Kerry J. , Li Lijuan Joanna , Ng Hoi Yu
Published: September 2018

Purpose

The recent mobilization of many Hong Kong youth to engage in what are regarded as radical political activities is not a new area of investigation. Much has been discussed about this growing political activism and localism often giving an impression that Hong Kong youth are radical and disengaged from China as a nation. Yet little is known about the possible antecedents of such disengagement. The purpose of this paper is to identify whether there is empirical evidence of growth or decline in civic trust and national attitudes amongst Hong Kong young adolescents over the ten-year period from 1999 to 2009.

Design/methodology/approach

In this study latent profile analyses were used to classify cohorts of Hong Kong secondary students according to the levels of their self-reported trust in civic institutions and attitudes toward the nation. The cohorts were separated by a ten-year gap. Comparisons were made across groups and across the ten-year time span, in order to trace changes in civic attitudes of young adolescents following the return of Hong Kong to China in 1997.

Findings

Three distinct groups were identified in both cohorts – Activists, who had negative attitudes to trust and toward the nation, Nationalists who had positive attitudes toward trust and the nation and Moderates who endorsed average responses to the, two variables. The gaps between the groups tended to be greater in the 2009 group compared to the 1999 groups suggesting greater polarization amongst adolescents on these measures.

Originality/value

Young adolescents cannot be assumed to be politically neutral or lacking social values. Citizenship education needs to take this into account so that values can be clarified and major issues can be discussed in a safe and supportive environment.
Perceived interviewee anxiety and performance in telephone interviews
Authors: Jeske Debora , Shultz Kenneth S. , Owen Sarah
Published: September 2018

Purpose

The purpose of this paper is to focus on the role of interviewee anxiety as a predictor of perceived hireability (Study 1, n=82) and job suitability (Study 2, n=74).

Design/methodology/approach

Using an experimental design, participants were randomly allocated to one of two conditions (an audio recording of either a confident or anxious job candidate with identical scripts) and asked to take the role of an interviewer.

Findings

The anxious interviewee (played by an actor) was consistently rated as less hireable (in a combined sample based on Studies and 2), less suitable to the job and received less favorable hiring recommendations (as assessed in Study 2) than the confident interviewee (played by the same actor).

Research limitations/implications

The study was conducted with students who may have less interview experience than experienced interviewers.

Practical implications

The results suggest that anxiety has a negative biasing effect on perceived hireability and job suitability ratings. In other words, the behavioral manipulation of anxiety affects hireability ratings, independent of any subjective assessment of anxiety.

Originality/value

The findings provide evidence of an anxiety bias in telephone interview settings. The results highlight the importance of considering anxiety cues when training employment interviewers.
The role of brokers in a workplace development programme targeting SMEs
Authors: Halvarsson Lundkvist Agneta , Gustavsson Maria
Published: September 2018

Purpose

The purpose of this paper is to investigate the development of a workplace development programme (WPDP) targeting small and medium sized manufacturing enterprises (SMEs) by focussing on the people who acted as brokers providing cross-boundary connections between its collaborating partners.

Design/methodology/approach

The material, from interviews with 32 individuals and 11 meetings, was analysed in a boundary-crossing framework, which provided tools to reveal how the roles of brokers at different levels (operative, strategic and national) of the WPDP affected its development.

Findings

The findings indicate that cross-boundary connections were made by persons who acted as brokers within and between different levels of the WPDP. The brokers who provided cross-boundary connections between different levels of the WPDP were found to play the most important role for the prompt development of the WPDP.

Originality/value

Apart from unique empirical material depicting the development of a collaborative venture between national and regional stakeholders of the manufacturing industry, the value of this study is the attention given to the people behind the policymaking of publicly funded national WPDPs, revealing the complex business of developing policy-driven competence development activities to employees in SMEs.
Usage pattern of e-resources among management students in Nagpur, Maharashtra (India)
Authors: Kumar Vinod , Vandana Vandana , Batra D.K.
Published: September 2018

Purpose

This paper aims to investigate the usage pattern of electronic resources (e-resources) among management graduates. The respondents were asked about the types of e-resources they used, who their influencers were, their preferred place for surfing, the frequency of use, purpose for which they used e-resources, its benefits and the problems they faced while using e-resources. The findings of the study will help in enhancing the usage of e-resources among students who opt for management courses.

Design/methodology/approach

This descriptive research was conducted in Nagpur, Maharashtra (India). Data collected from 150 management students through purposive sampling were analyzed through descriptive statistics, and the responses were presented in tabular form.

Findings

The investigation reveals that students are well aware of e-resources and consider them to be very useful for their academic performance. Interestingly, students are found to be using non-paid resources more than paid ones because of a lack of search skills. Discipline-wise investigation reveals that students from the disciplines of information technology, economics and finance use e-resources more frequently than those studying subjects like marketing, operations and human resource management. Faculty and training have emerged as strong influencers that have persuaded students to use e-resources.

Research limitations/implications

The present study is limited to students studying management courses in Nagpur, Maharashtra (India).

Originality/value

This research will help institutions, librarians and publishers in gaining insight on the utilization patterns of e-resources. The uniqueness of this study lies in the fact that it has analyzed and presented the responses of management students belonging to different disciplines in management studies such as, marketing, finance, human resource management operations, economics and information technology regarding their usage patterns of e-resources.
Emotional intelligence towards entrepreneurial career choice behaviours
Authors: Othman Norasmah , Tengku Muda Tengku Nor Asma Amira
Published: September 2018

Purpose

The purpose of this paper is to assess emotional intelligence levels and their contributions to entrepreneurial career choice behaviours among Malaysian public university students.

Design/methodology/approach

This study surveyed 369 respondents selected from a population of 87,503 Malaysian public university students using stratified and simple random sampling techniques. Respondents were given a three-part questionnaire covering their personal information, their emotional intelligence in terms of self-awareness, emotion management, empathy and social skills and their entrepreneurial career choice behaviours.

Findings

The results indicate that the surveyed students have high levels of self-awareness and empathy, and moderate levels of emotion management and social skills. This indicates that these students are able to manage their emotions in making decisions and consider people’s emotions. The results also indicate that students who were able to manage their negative emotions were more likely to choose an entrepreneurial career.

Research limitations/implications

This study aims to help higher institutions focus on emotional intelligence in the entrepreneurship curriculum to help students recognise their potential in terms of entrepreneurial characteristics and behaviours. Students’ involvement in entrepreneurship can foster economic growth in developing countries. A limitation of this study is that it focuses only on second-year undergraduates from public universities in the Selangor area.

Originality/value

Few studies address emotional intelligence and entrepreneurial career choices among public university students, which this study addresses.
Learning style preferences of undergraduate students
Authors: Yousef Darwish Abdulrahman
Published: September 2018

Purpose

The purpose of this paper is to address the use of Honey and Mumford’s Learning Styles Questionnaire (LSQ) to investigate the learning style preferences of undergraduate students at the American University of Ras Al Khaimah (AURAK) in the United Arab Emirates (UAE) culture. It also investigates whether there are significant differences across the four dimensions of learning styles due to students’ demographics.

Design/methodology/approach

Questionnaires were distributed to a sample of 200 undergraduate students at AURAK in the UAE. The majority of students were Arabic native-speakers. Descriptive statistics were used to present the main characteristics of respondents and the results of the study. The independent samples t-test, Mann–Whitney test and Kurskal–Wallis test were used to find out if there are significant differences across the four dimensions of learning styles due to students’ demographics.

Findings

The results of the study illustrated that undergraduate students at AURAK have preferences for the reflector (15.0), pragmatist (14.2), theorist (13.9) and activist (12.3) learning styles. Moreover, there are only significant differences between Emirati and non-Emirati students across the four learning styles and between single and married students in the theorist learning style.

Research limitations/implications

This study has a number of limitations. First, the findings of the study are based on the data collected from only one university. Second, the sample is limited to undergraduate students and, therefore, it excludes graduate students who might have different experiences. Third, the results are based on a self-reported questionnaire which might affect the reliability of the results. On the other hand, it has a number of implications for educators and students. Educators will benefit from the results of this study in the sense that they need to adopt teaching styles and strategies that match the learning styles of the majority of their students. Students themselves will benefit from knowing their own learning style.

Originality/value

The present study validates a learning style theory developed in a western culture in an Arabic culture.
Electrodermal activity measurement within a qualitative methodology
Authors: Stadler Raphaela , Jepson Allan Stewart , Wood Emma Harriet
Published: September 2018

Purpose

Reflecting, reliving and reforming experiences enhance longer-term effects of travel and tourism, and have been highlighted as an important aspect in determining loyalty, re-visitation and post-consumption satisfaction. The purpose of this paper is to develop new methodological approaches to investigate emotion, memory creation and the resulting psychosocial effects.

Design/methodology/approach

The paper proposes a unique combination of physiological measures and photoelicitation-based discussions within a longitudinal design. A physiological measuring instrument (electrodermal activity [EDA] tracking technology through Empatica E4 wristbands) is utilised to capture the “unadulterated” emotional response both during the experience and in reliving or remembering it. This is combined with post-experience narrative discussion groups using photos and other artefacts to give further understanding of the process of collective memory creation.

Findings

EDA tracking can enhance qualitative research methodologies in three ways: through use as an “artefact” to prompt reflection on feelings, through identifying peaks of emotional response and through highlighting changes in emotional response over time. Empirical evidence from studies into participatory arts events and the potential well-being effects upon women over the age of 70 is presented to illustrate the method.

Originality/value

The artificial environment created using experimental approaches to measure emotions and memory (common in many fields of psychology) has serious limitations. This paper proposes new and more “natural” methods for use in tourism, hospitality and events research, which have the potential to better capture participants’ feelings, behaviours and the meanings they place upon them.
Screen navigation system for visually impaired people
Authors: Ohene-Djan James Francis , Fernando Sandra A.
Published: September 2018

Purpose

The SETUP09 system consists of both navigation and a computer-aided drawing technique for people who are blind and visually impaired (BVI). The purpose of this paper is to address the need for a screen navigation technique, which can facilitate a user’s ability to produce art, and scientific diagrams electronically, by introducing a compass-based screen navigation method.

Design/methodology/approach

BVI computer users were tested using different screen navigation tasks to assess the accuracy and efficiency of this compass-based navigation technique by using a prototype (SETUP09) and tactile paper grid maps.

Findings

The results confirmed that the compass-based navigation facilitates higher accuracy in screen-based moving and location recognition with a noticeable reduction in time and effort.

Research limitations/implications

Improvements such as the addition of a sound layer to the interface, use of hotkeys, braille and user speech inputs are yet to be tested.

Social implications

The current lack of suitable and efficient screen navigation technology is a limiting factor for BVI students and computer users in producing diagrams and drawings. This may place limitations on their career progression and life contentment. It is challenging for a BVI person to draw diagrams and art, which are commonly taught in education or used in industry. The compass-based screen navigation system was developed to address BVI users’ need to be able to create such content.

Originality/value

A compass-based navigation method enables screen navigation through a formal command language and enables intuitive movement to a screen location using matrix-style compass directions with zoom-in and zoom-out capabilities.
A reconsideration of operating-financial leverage tradeoff hypothesis
Authors: Dugan Michael T. , Medcalfe Simon K. , Park Sang Hyun
Published: September 2018

Purpose

This paper aims to attempt to perform a test of the operating leverage-financial leverage tradeoff hypothesis that is more methodologically consistent with the logical framing of the hypothesis appearing in the Mandelker and Rhee (1984) paper.

Design/methodology/approach

The paper uses a sample of firms from the manufacturing industry to estimate their degree of operating leverage and degree of financial leverage coefficients. The switching regression methodology is then used to perform the empirical test of the tradeoff hypothesis.

Findings

The results suggest that firms tradeoff their operating and financial leverage during good economic times, but do not engage in the tradeoff behavior during recessionary times.

Originality/value

This paper refines the empirical testing of the tradeoff hypothesis using the innovative switching regression methodology. The paper also has important implications for the impact of firms’ risk on the capital markets as well as the economy as a whole, and for academic researchers in financial economics examining the relationships between operating and financial leverage and various firm-specific variables.
Enhancement of corrosion resistance of mild steel in NaCl solution with an eco-friendly silane coating containing nanoclay and zinc acetylacetonate
Authors: Taheri M. , Naderi Reza , Mahdavian Mohamad
Published: September 2018

Purpose

This paper aims to enhance the barrier properties and active protection of a water-based silane coating on mild steel through nanoclay and zinc acetylacetonate simultaneously included into the formulation.

Design/methodology/approach

The corrosion protection performance of the silane sol-gel coatings with no additive, zinc acetylacetonate, nanoclay and nanoclay + zinc acetylacetonate was monitored using electrochemical impedance spectroscopy during 5 h of immersion in a sodium chloride solution. Moreover, the surface of coatings was analyzed using a field emission scanning electron microscopy equipped with an energy dispersive X-ray spectrometer (FESEM-EDX) and water contact angle measurements.

Findings

In electrochemical impedance spectroscopy analysis, the impedance at low frequencies, coating resistance and charge transfer resistance were the parameters considered which indicated the superiority of silane coating formulated with both nanoclay and zinc acetylacetonate. According to the results of FESEM/EDX and water contact angle measurements, the superiority was linked with the enhancement in the barrier properties in the presence of nanoclay, as well as function of the corrosion inhibitor at coating–substrate interface.

Originality/value

According to the literature, there is no research conducted to study the impact of the simultaneous use of nanoclay and zinc acetylacetonate on the barrier properties and active protection of an eco-friendly silane sol-gel coating including glycidyloxypropyltrimethoxysilane, tetraethoxysilane and methyltriethoxysilane on mild steel in a sodium chloride solution.
Has International Aid Promoted Economic Growth in Africa?
Authors: Cai Jinyang , Zheng Zuting , Hu Ruifa , Pray Carl E. , Shao Qianqian
Published: September 2018

Using panel data on 47 African countries from 1980–2013, this paper investigates the effects of aid on Africa's economic growth from the perspective of political stability. We find that international aid can promote economic growth in Africa, but the effectiveness of aid depends on countries’ political stability. Further, the intensity of aid affects its effectiveness. When the aid–GDP ratio is between 0 and 69 per cent, aid can promote economic growth in recipient countries, and when this ratio is 27 per cent, the marginal impact of aid on economic growth is maximized. The findings of this paper suggest that providers of aid should avoid providing a substantial amount of aid to countries at risk of political unrest, and they must determine the optimal scale of aid based on the economic development of recipient countries in order to enable aid to generate better results. Recipient countries should maintain social and political stability and ensure that they do not develop an excessive dependence on aid so that they can achieve the self‐sustainable development of their own economies.
Remittances and Food Security in African Countries
Authors: Mabrouk Fatma , Mekni Mohamed Mehdi
Published: September 2018

Over the past decade, the amount of migrant remittances received by developing countries has increased rapidly. Several studies have analysed the impacts on growth, investment, education, and health. However, the effect on food security has not received much attention. This paper contributes to the literature by exploring the linkage between food security and international remittances using panel data during the period of 1990–2013 in African countries. The study employs an econometric model to test the impact of remittances on food security through four channels: availability, access, utilization and stability. Results show a positive link for access, stability and utilization dimensions but a negative link for availability. Relationship between received remittances and the enhancement of food security seems to be mixed.
Asymmetric Price Transmission and Rent‐seeking in Road Fuel Markets: A Comparative Study of South Africa and Selected Eurozone Countries
Authors: Ogbuabor Jonathan E. , Eigbiremolen God'stime O. , Manasseh Charles O. , Mba Ifeoma C.
Published: September 2018

This paper presents the first‐ever analysis of South African and Eurozone road fuel markets for the possibility that firms may be manipulating the tax system to conceal rent‐seeking behavior using the nonlinear ARDL model recently advanced by Shin et al. (). The paper also examines these markets for asymmetric price adjustment following changes in crude oil costs in the aftermath of the 2007–2008 Global Financial Crisis. Monthly data for gasoline, automotive diesel and costs of imported crude oil from November 2004 to August 2016 were used. The results indicate that while the Eurozone road fuel markets are fraught with the problems of long‐run rent‐seeking, rockets and feathers effect, and the possibility that firms may be exploiting the tax system to conceal rent‐seeking behaviors, the South African markets are free from these problems. Even though South Africa and the Eurozone countries have high oil import dependency ratios, this paper shows that government regulatory activities somewhat account for the difference in market outcomes.
Workers’ Remittances and the Dutch‐Disease Argument: Investigating the Relationship in Sub‐Saharan Africa
Authors: Ojapinwa T. V. , Nwokoma N. I.
Published: September 2018

Based on the Salter‐Swan‐Corden‐Dornbusch framework, which argues that capital inflows may appreciate the official exchange rate by aggravating the effects of any previously existing domestic distortions, this paper examines the claim that workers’ remittances cause the Dutch disease in sub‐Saharan Africa (SSA). Specifically, the study investigates whether remittances cause financial overheating and spending effects. The study adopts the dynamic panel instrumental variable system generalized method of moment (IVSGMM). This study finds that although workers’ remittances cause financial overheating, they neither increase general spending nor appreciate the real exchange rate, thereby implying that workers’ remittances do not cause the Dutch disease in SSA from 1996 to 2013. These findings suggest that governments should establish diaspora incentive schemes so as to encourage remitters and recipient households’ to invest productively. Government efforts should be integral at improving the financial education for remitters and the recipient households so as to avoiding channelling overheating effects to spending effects and to the Dutch disease.
Quantitative proteomic analysis of mitochondrial proteins differentially expressed between small cell lung cancer cells and normal human bronchial epithelial cells
Authors: Li Wei , Zhang Wei , Deng Wenjing , Zhong Yujie , Zhang Yonghong , Peng Zhuo , Chen Haijuan , Sun Ruiying , Zhang Xuemei , Yang Shuanying
Published: September 2018

Background

Small cell lung cancer (SCLC) is highly aggressive and is associated with a dismal prognosis. However, there are no clinically recognized biomarkers for early diagnosis. In this study, we used quantitative proteomics to build differential mitochondrial protein profiles that may be used for early diagnosis and investigated the pathogenesis of lung cancer.

Methods

We cultured SCLC cells (NCI‐H446) and normal human bronchial epithelial cells (16‐HBE); mitochondria were extracted and purified using differential and Percoll density gradient centrifugation. Subsequently, we used Western blot analysis to validate mitochondrial purity and labeled proteins/peptides from NCI‐H446 and 16‐HBE cells using relative and absolute quantification of ectopic tags. We then analyzed mixed samples and identified proteins using two‐dimensional liquid chromatography‐tandem mass spectrometry. Additionally, we performed subsequent bioinformatic proteome analyses using the programs ExPASy, GOA, and STRING. Finally, the relationship between ornithine aminotransferase expression and clinicopathological features in lung cancer patients was evaluated using immunohistochemistry.

Results

One hundred and fifty‐three mitochondrial proteins were differentially expressed between 16‐HBE and NCI‐H446 cells. The expression of 30 proteins between 16‐HBE and NCI‐H446 cells increased more than 1.3‐fold. The upregulation of ornithine aminotransferase was associated with pathological grade and clinical tumor node metastasis stage.

Conclusion

Our experiment represented a promising method for building differential mitochondrial protein profiles between NCI‐H446 and 16‐HBE cells. Such analysis may also help to identify novel biomarkers of lung cancer.
Fluid Dynamic Characterization of Transcatheter Aortic Valves Using Particle Image Velocimetry
Authors: Barakat Mohammed , Dvir Danny , Azadani Ali N.
Published: September 2018

Transcatheter aortic valves provide superior systolic hemodynamic performance in terms of valvular pressure gradient and effective orifice area compared with equivalent size surgical bioprostheses. However, in depth investigation of the flow field structures is of interest to examine the flow field characteristics and provide experimental evidence necessary for validation of computational models. The goal of this study was to compare flow field characteristics of the three most commonly used transcatheter and surgical valves using phase‐locked particle image velocimetry (PIV). 26‐mm Edwards SAPIEN 3, 26‐mm Medtronic CoreValve, and 25‐mm Carpentier‐Edwards PERIMOUNT Magna were examined in a pulse duplicator with input parameters matching ISO‐5840, that is, heart rate of 70 beats/min, cardiac output of 5 L/min, and mean aortic pressure of 100 mm Hg. A 2D PIV system was used to obtain flow velocity and viscous shear stress fields during the entire cardiac cycle. In vitro testing showed that the mean transvalvular pressure gradient was lowest for SAPIEN 3, followed by CoreValve, and PERIMOUNT Magna surgical bioprosthesis. In addition, the viscous shear stress magnitude within the jet boundary layer was higher in PERIMOUNT Magna than CoreValve and SAPIEN 3 at the peak of the flow. However, the measured shear stress values were below the known threshold for platelet activation and red blood damage. Therefore, shear‐induced platelet activation is unlikely to take place during systole in the three bioprosthetic heart valves. The PIV measurements can be used for verification and validation of computational simulations.
Maternal risk factor index and cesarean delivery among women with nulliparous, term, singleton, vertex deliveries, Texas, 2015
Authors: Salahuddin Meliha , Mandell Dorothy J. , Lakey David L. , Eppes Catherine S. , Patel Divya A.
Published: September 2018

Background

Cesarean delivery accounts for over one‐third of the ~400 000 annual births in Texas, with first‐time cesarean accounting for 20% of the overall cesareans. We examined associations of maternal medical comorbidities with cesarean delivery among nulliparous, term, singleton, vertex (NTSV) deliveries in Texas.

Methods

Nulliparous, term, singleton, vertex deliveries to women aged 15‐49 years were identified using the 2015 Texas birth file (Center for Health Statistics, Texas Department of State Health Services). A risk factor index was constructed (score range 0‐4), including preexisting/gestational diabetes mellitus, preexisting/gestational hypertension/eclampsia, infertility treatment, smoking during pregnancy, and prepregnancy overweight/obesity, and categorized as 0, 1, 2, and 3+ based on the number of risk factors present. Multivariable logistic regression analyses were conducted to examine associations between the categorized risk factor index and cesarean delivery, overall and by maternal race and ethnicity.

Results

Among the 114 535 NTSV deliveries in Texas in 2015, 27.2% were by cesarean. The most prevalent maternal risk among all deliveries was prepregnancy overweight/obesity (42.4%). The odds of cesarean delivery increased significantly with increasing number of risk factors [one risk factor: 1.72 (95% CI 1.67‐1.78); two risk factors: 2.58 (95% CI 2.46‐2.71); and three or more risk factors: 3.91 (95% CI 3.45‐4.44)].

Discussion

In Texas in 2015, nearly half of NTSV deliveries had at least one maternal risk factor and the odds of cesarean delivery were significantly elevated for women with a higher risk index score. The findings from this study highlight the need for intervening during the preconception and interconception period as intrapartum care practices have an important influence on birth outcomes.
Lower prevalence of subsegmental pulmonary embolism after application of the YEARS diagnostic algorithm
Authors: van der Pol Liselotte M. , Bistervels Ingrid M. , van Mens Thijs E. , van der Hulle Tom , Beenen Ludo F. M. , den Exter Paul L. , Kroft Lucia J. M. , Mairuhu Albert T. A. , Middeldorp Saskia , van Werkhoven Jaap M. , ten Wolde Marije , Huisman Menno V. , Klok Frederikus A.
Published: September 2018

The rate of identified isolated subsegmental pulmonary embolism (ssPE) has doubled with advances in computed tomography pulmonary angiography (CTPA) technology, but its clinical relevance is debated. The YEARS diagnostic algorithm was shown to safely reduce the number of required CTPAs in the diagnostic management of PE. We hypothesized that the higher threshold for performing CTPA in YEARS was associated with a lower prevalence of ssPE compared to the conventional diagnostic algorithm. We compared 2291 consecutive patients with suspected PE managed according to YEARS to 3306 consecutive control patients managed according to the Wells score for the prevalence of isolated ssPE. In the YEARS cohort, 52% were managed without CTPA, 12% had pulmonary embolism (PE) of which 10% were isolated ssPE, and the 3‐month diagnostic failure rate was 0·35%. In the control cohort, 32% were managed without CTPA, 20% had PE of which 16% were isolated ssPE, and the 3‐month failure rate was 0·73%. The isolated ssPE prevalence was significantly lower in YEARS (absolute difference 6·2% (95% confidence interval [CI] 1·4–10), Odds Ratio 0·58 (95% CI 0·37–0·90). In conclusion, YEARS is associated with a lower prevalence of isolated ssPE, due to reduction in CTPAs by the higher D‐dimer threshold. This was however not associated with a higher risk of recurrent VTE during follow‐up.
Pulmonary toxicity in paediatric patients with relapsed or refractory Hodgkin lymphoma receiving brentuximab vedotin
Authors: Faulk Kelly E. , Sopfe Jenna M. , Campbell Kristen , Liptzin Deborah R. , Liu Arthur K. , Franklin Anna R. K. , Cost Carrye R.
Published: September 2018

Brentuximab vedotin (Bv) is becoming increasingly important in the treatment of Hodgkin lymphoma (HL), with improved outcomes and an overall favourable toxicity profile. However, Bv is associated with severe pulmonary toxicity when combined with bleomycin, suggesting that additive toxicity may be an important consideration. Furthermore, little has been published on tolerability in paediatric patients. We retrospectively evaluated the occurrence of pulmonary toxicity of Bv in 19 paediatric and young adult patients with relapsed or refractory HL. Patient characteristics, baseline health status, treatment regimens including cumulative doses of Bv, bleomycin, gemcitabine, radiation and carmustine, and the occurrence of pulmonary toxicity were collected. Seven (36·8%) of the 19 patients were treated with Bv. The odds of pulmonary toxicity were 4·0‐fold higher (95% confidence interval 0·55–29·18) in patients exposed to Bv compared to unexposed patients in univariate analysis (P = 0·17). Similar results were found in multivariable analysis. Pulmonary toxicity occurred frequently in our cohort and was more common in patients who received Bv than in patients who did not receive Bv, although this was not statistically significant. Because patients with HL are exposed to a myriad of therapies with potential for pulmonary toxicity, continuing to evaluate the risk associated with Bv is critical.