bluuebunny/crossref_metadata_2025 huggingface dataset:
High-performance work systems and employee outcomes in Indian call centres: a mediation approach
Authors: Ananthram Subramaniam , Xerri Matthew J. , Teo Stephen T.T. , Connell Julia
Published: May 2018

Purpose

The purpose of this paper is to empirically examine the relationships between high-performance work systems (HPWSs) and four employee outcomes – job satisfaction, employee engagement, presenteeism and well-being – in Indian call centres.

Design/methodology/approach

A path model is developed to investigate the direct and mediation effects between the assessed variables. The study utilised a survey of 250 call centre employees working in five business process management firms based in India.

Findings

The findings indicate that HPWSs have a positive relationship with job satisfaction, engagement and well-being. Job satisfaction also had a positive relationship with engagement and presenteeism, and engagement was positively related to presenteeism and well-being. However, there was no significant direct effect of HPWS on presenteeism. Mediation analysis showed that HPWS has an indirect effect on well-being via engagement and also via job satisfaction and engagement combined.

Research limitations/implications

HPWS significantly increases job satisfaction and employee engagement and indirectly influences employee well-being via these outcomes. However, job satisfaction and employee engagement was also found to increase presenteeism, which, in turn, can reduce employee well-being. These findings contribute to the HPWS theory and the literature on employee well-being, and have implications for HR personnel and call centre management.

Originality/value

Given the well-established challenges with employee retention in Indian call centre environments, one solution may be the adoption of a more strategic approach to HRM using HPWS. Such an approach may enhance employees’ perceptions that HPWS practices would have a positive influence on job satisfaction, employee engagement and employee well-being.
Project management office in non-governmental organizations: anex post factostudy
Authors: Lacruz Adonai , Cunha Everton
Published: May 2018

Purpose

The purpose of this paper is to explore the influence of project management offices (PMO) in non-governmental organizations (NGOs), in fundraising linked to projects, under the theoretical lens of the resource-based view.

Design/methodology/approach

Through a longitudinal analysisex post factostudy in a non-profit civil association, the authors examined by Mann-Whitney’s U tests the results before (2003-2008) and after (2009-2014) PMO implementation, to check if the office moderated the relationship between project management and fundraising for projects.

Findings

Mann-Whitney’s U tests showed that PMO had, in those periods, a statistically significant influence in increasing the number of projects and decreasing the mean value of their budgets (p-value<0.05).

Originality/value

Despite the wide range of studies on the contribution of PMOs to internal project management, there is a lack of empirical evidence on their moderation capacity, especially in NGOs. To fill this research gap, this study investigates the moderating role of PMO in NGOs, by examining their performance on fundraising processes, to contribute to a better understanding of potential PMO effects, particularly as a moderator of the relationship between project management and projects’ fundraising.
Visionary customers: source of long-term competitive advantage
Authors: Wood Robert Chapman
Published: May 2018

Purpose

This case describes how Varian Medical Systems, the successor to one of the pioneers of Silicon Valley, created a business with $11.6 billion in market cap by listening to dreams of its physician customers and their scientist colleagues and finding ways to fulfill them over several decades.

Design/methodology/approach

A key business opportunity that spurred the company was to identify the most perceptive thought-leader customers, then bring them into a long-term, system-building partnership.

Findings

If companies envision the future and work with perceptive, far-sighted customers and others who will benefit from high-value innovation, together they stand a real chance of achieving a desired future.

Practical implications

Establish forums where perceptive, visionary customers meet with executives, marketers and key developers to identify what you should deliver in the immediate future and in years beyond.

Originality/value

The case described the practical steps the company took to implement customer participation in the innovation process over many decades.
Cascading effects of a top predator on intraspecific competition at intermediate and basal trophic levels
Authors: Matassa Catherine M. , Ewanchuk Patrick J. , Trussell Geoffrey C.
Published: May 2018

Predators can impact competition among prey by altering prey density via consumption or by causing prey to modify their traits or foraging behavior. Yet, differences between these two mechanisms may lead to different cascading impacts on lower trophic levels.

Using a crab‐snail‐barnacle rocky intertidal food chain, we tested the effects of predation risk from crabs (top predators) on intraspecific competition among snails (intermediate consumers) and emergent indirect effects on the density of and competition among barnacles (basal resources).

The per capita foraging and growth rates of snails declined with high conspecific density. Predation risk from crabs, which caused even larger reductions in snail foraging and growth, weakened competition among snails, whereas a 45% increase in barnacle density had no detectable effect on snail competition.

Intraspecific competition between barnacles, however, depended on the interactive effects of barnacle density, snail density, and crab predation risk. Barnacles developed hummocking morphologies as they grew and competed for space. Hummock formation (a proxy for competition) increased as a result of either greater initial barnacle density or reduced snail foraging pressure, but these effects depended on predation risk.

The effects of crab predation risk on snail foraging behavior weakened an otherwise strong relationship between barnacle density and hummock development: hummocking increased with barnacle density in the absence of crabs but remained relatively high when crabs were present. In communities with similar final barnacle densities, hummocking was more common in those with crabs than those without crabs.

The extent to which predators can drive trophic cascades by suppressing the foraging rates of their prey is highly context‐dependent: the positive trait‐mediated indirect effect of predators on basal resource abundance is stronger when many prey respond simultaneously to the threat of predation. However, our results demonstrate that top predators can also enhance competition among basal resources even when their indirect effect on resource abundance is relatively weak. Hence, the cascading effects of predators on competition within lower trophic levels may play an important but under‐appreciated role in the dynamics of basal resource populations and the communities they support.

A plain language summary is available for this article.
Estimating external magnetic field differences at high geomagnetic latitudes from a single station
Authors: Beggan Ciarán D. , Billingham Laurence , Clarke Ellen
Published: May 2018

Providing an accurate estimate of the magnetic field on the Earth's surface at a location distant from an observatory has useful scientific and commercial applications, such as in repeat station data reduction, space weather nowcasting or aeromagnetic surveying. While the correlation of measurements between nearby magnetic observatories at low and mid‐latitudes is good, at high geomagnetic latitudes () the external field differences between observatories increase rapidly with distance, even during relatively low magnetic activity. Thus, it is of interest to describe how the differences (or errors) in external magnetic field extrapolation from a single observatory grow with distance from its location. These differences are modulated by local time, seasonal and solar cycle variations, as well as geomagnetic activity, giving a complex temporal and spatial relationship. A straightforward way to describe the differences are via confidence intervals for the extrapolated values with respect to distance. To compute the confidence intervals associated with extrapolation of the external field at varying distances from an observatory, we used 695 station‐years of overlapping minute‐mean data from 37 observatories and variometers at high latitudes from which we removed the main and crustal fields to isolate unmodelled signals. From this data set, the pairwise differences were analysed to quantify the variation during a range of time epochs and separation distances. We estimate the 68.3%, 95.4% and 99.7% confidence levels (equivalent to the 1σ, 2σ and 3σ Gaussian error bounds) from these differences for all components. We find that there is always a small non‐zero bias that we ascribe to instrumentation and local crustal field induction effects. The computed confidence intervals are typically twice as large in the north–south direction compared to the east‐west direction and smaller during the solstice months compared to the equinoxes.
Ultrasound‐guided versus free‐hand fine‐needle aspiration cytology of the parotid gland: A single‐centre, retrospective review
Authors: Hung Dorothy Sze‐Wing , Lai Emily Yat‐Ling
Published: May 2018

Aim

Fine‐needle aspiration cytology (FNAC) is a commonly‐used diagnostic tool to evaluate lesions of the parotid gland. However, ultrasound‐guided FNAC requires expertise, which might not always be immediately available. Free‐hand FNAC can be readily arranged at an outpatient clinic setting, and could shorten waiting time and allow rapid diagnosis of parotid lesions. The aim of our study was to evaluate the accuracy and yield of free‐hand FNAC versus ultrasound‐guided FNAC and its subsequent correlation to the final pathology in order to evaluate its use as a preoperative investigational tool.

Patients and Methods

A retrospective review was carried out for patients who underwent superficial, partial or total parotidectomy at the Queen Elizabeth Hospital by the general surgical team between 1 January 2008 and 31 March 2016. Results for 176 surgeries performed were analysed. In total, 155 cases with preoperative FNAC of the parotid were included in the study.

Results

Ultrasound‐guided FNAC had 100 per cent specificity, whereas free‐hand FNAC had 98.3 per cent specificity for detecting malignancy. Sensitivity was 92.9 per cent in the ultrasound‐guided FNAC group versus 90 per cent in the free‐hand FNAC group. Ultrasound‐guided FNAC offered a preoperative diagnosis as to whether a mass was benign or malignant in 21 out of 75 patients (28 per cent), while free‐hand FNAC was able to do so in 15 out of 80 patients (18.8 per cent). However, this was not statistically significant (P = 0.188).

Conclusion

Overall, both ultrasound‐guided and free‐hand FNAC have high sensitivity and specificity for diagnosing malignancy preoperatively. Free‐hand FNAC does not have a lower yield and was not shown to be statistically inferior to ultrasound‐guided FNAC. Free‐hand FNAC is a good alternative in certain cases where the parotid lesion can be easily accessible.
Discovery of Amadori‐Type Conjugates in a Peptide Maillard Reaction and Their Corresponding Influence on the Formation of Pyrazines
Authors: Zou Tingting , Liu Jianbin , Song Huanlu , Liu Ye
Published: May 2018

Knowledge of the role of peptides in the Maillard reaction is rather limited. In this study, peptide Maillard reaction model systems were established. Volatile and nonvolatile MRPs (Maillard reaction products) were investigated by GC‐O‐MS and LC‐MS. Carbohydrate module labeling (CAMOLA) experiments were performed to elucidate the carbon skeleton of these compounds. Results showed that the peptide reaction system generated more pyrazines than the free amino acid group. Several new Amadori‐type conjugates were identified as novel Maillard reaction products that could greatly influence the formation of pyrazines. Our work suggested anew mechanism involving these Amadori‐type conjugates and subsequent investigation revealed that the conjugates could be important intermediate products in the reaction between dicarbonyl and dipeptide. Our findings demonstrate anew pyrazine generation mechanism in the dipeptide Maillard reaction.

Practical Application

We found that a dipeptide Maillard reaction system generated more pyrazines than a reaction system composed of free amino acids. New cross‐linked peptide‐sugar compounds were identified and found to impact the formation of pyrazines. The results of this study may help in the preparation of thermal reaction flavors using enzymatically hydrolyzed vegetable/animal proteins, which contain a considerable amount of peptides, as one of the major reactants.
Optimization and Scale‐Up Preparation of Egg White Hydrolysate with Angiotensin I Converting Enzyme Inhibitory Activity
Authors: Li Qiyi , Liao Wang , Fan Hongbing , Wu Jianping
Published: May 2018

Angiotensin I converting enzyme (ACE) plays an important role in regulation of blood pressure as it converts angiotensin I into angiotensin II (a potent vasoconstrictor). Food protein‐derived ACE inhibitory peptides have been considered as a safer alternative to antihypertensive drugs. In our previous study, three ACE inhibitory peptides were characterized from egg white ovotransferrin and their antihypertensive activity has been validated in spontaneously hypertensive rats. However, it is too costly to prepare these peptides from purified egg white ovotransferrin. The aims of the study were to determine the feasibility of preparing these peptides using egg white and then to optimize the conditions of preparing egg white hydrolysate. Taguchi's method was used to design experiments for optimization, which was established as follows: substrate %, pH of thermoase, time of thermoase digestion, ratio of pepsin to substrate, pH of pepsin, temperature of pepsin, and time of pepsin digestion were 7.5%, pH 8, 90 min, 1%, pH 2.5, 55 °C, and 180 min, respectively. The ACE inhibitory activity (IC50 value) and peptide yield obtained under optimal condition were 30 ± 2 μg/mL and 77.5% ± 0.3%, respectively, which were comparable to the predicted values. Hydrolysate prepared at 150 L reactor showed comparable activity but low peptide yield. Results of this study demonstrated the feasibility of using egg white protein as the starting material to prepare a functional ingredient with potent ACE inhibitory activity.
Preparation of Novel Iodized Salt with Natural Iodine‐Rich Sources by Spray Drying
Authors: Doh Han Sol , Ko Jung A , Park Hyun Jin
Published: May 2018

Marine products are rich in not only micronutrients but also iodine content. However, the applications of iodine in marine products in the food industry have not been studied extensively. Therefore, in this study, a novel iodized salt was prepared through a simple method for iodine extraction from natural iodine‐rich sources and spray drying. Laminaria ochroleuca (kombu), Porphyra umbilicalis (nori), Undaria pinnatifida (wakame), and Haliotis discus hannai (abalone) were selected as natural iodine‐rich sources. Through hot water extraction, iodine was extracted from the iodine‐rich sources and iodized salt was successfully prepared with extracted iodine and sea salt by spray drying; extraction efficiency varied from 64.88% to 129.67%; yield, 38.45% to 57.09%; loading efficiency, 99.34% to 124.08%. Chemical interactions were assessed using Fourier transform infrared spectroscopy (FT‐IR) and thermal dynamics was evaluated using differential scanning calorimetry (DSC). Morphology of the salt crystals was studied using scanning electron microscopy (SEM). Furthermore, a storage test was performed to investigate iodine loss due to temperature, relative humidity, and oxidation for 10 weeks in harsh condition. On comparing our salt with commercial products, novel iodized salts displayed similar or superior stability. Therefore, the novel iodized salt prepared in this study can be applied in the food industry.

Practical Application

Iodine is essential trace element and plays a key role in our body. Marine products such as Laminaria ochroleuca (Kombu), Porphyra umbilicalis (nori), Undaria pinnatifida (wakame), and Haliotis discus hannai (abalone) are known as iodine rich‐sources. These products have high level of iodine, but iodine in marine products has not been used widely for food industry. Therefore, using iodine in natural sources, novel iodized salt was prepared with simple method (hot water extraction and spray drying). The novel iodized salt prepared in this study can be applied in the food industry.
Analysis and Evaluation of the Characteristic Taste Components in Portobello Mushroom
Authors: Wang Jinbin , Li Wen , Li Zhengpeng , Wu Wenhui , Tang Xueming
Published: May 2018

To identify the characteristic taste components of the common cultivated mushroom (brown; Portobello), Agaricus bisporus, taste components in the stipe and pileus of Portobello mushroom harvested at different growth stages were extracted and identified, and principal component analysis (PCA) and taste active value (TAV) were used to reveal the characteristic taste components during the each of the growth stages of Portobello mushroom. In the stipe and pileus, 20 and 14 different principal taste components were identified, respectively, and they were considered as the principal taste components of Portobello mushroom fruit bodies, which included most amino acids and 5′‐nucleotides. Some taste components that were found at high levels, such as lactic acid and citric acid, were not detected as Portobello mushroom principal taste components through PCA. However, due to their high content, Portobello mushroom could be used as a source of organic acids. The PCA and TAV results revealed that 5′‐GMP, glutamic acid, malic acid, alanine, proline, leucine, and aspartic acid were the characteristic taste components of Portobello mushroom fruit bodies. Portobello mushroom was also found to be rich in protein and amino acids, so it might also be useful in the formulation of nutraceuticals and functional food.

Practical Application

The results in this article could provide a theoretical basis for understanding and regulating the characteristic flavor components synthesis process of Portobello mushroom.
Altering textural properties of fermented milk by using surface‐engineered Lactococcus lactis
Authors: Tarazanova Mariya , Huppertz Thom , Kok Jan , Bachmann Herwig
Published: May 2018

Lactic acid bacteria are widely used for the fermentation of dairy products. While bacterial acidification rates, proteolytic activity and the production of exopolysaccharides are known to influence textural properties of fermented milk products, little is known about the role of the microbial surface on microbe–matrix interactions in dairy products. To investigate how alterations of the bacterial cell surface affect fermented milk properties, 25 isogenic Lactococcus lactis strains that differed with respect to surface charge, hydrophobicity, cell chaining, cell‐clumping, attachment to milk proteins, pili expression and EPS production were used to produce fermented milk. We show that overexpression of pili increases surface hydrophobicity of various strains from 3–19% to 94–99%. A profound effect of different cell surface properties was an altered spatial distribution of the cells in the fermented product. Aggregated cells tightly fill the cavities of the protein matrix, while chaining cells seem to be localized randomly. A positive correlation was found between pili overexpression and viscosity and gel hardness of fermented milk. Gel hardness also positively correlated with clumping of cells in the fermented milk. Viscosity of fermented milk was also higher when it was produced with cells with a chaining phenotype or with cells that overexpress exopolysaccharides. Our results show that alteration of cell surface morphology affects textural parameters of fermented milk and cell localization in the product. This is indicative of a cell surface‐dependent potential of bacterial cells as structure elements in fermented foods.
Non‐small cell lung cancer brain metastasis screening in the era of positron emission tomography‐CT staging: Current practice and outcomes
Authors: Diaz Mauricio E , Debowski Maciej , Hukins Craig , Fielding David , Fong Kwun M , Bettington Catherine S
Published: May 2018

Introduction

Several clinical guidelines indicate that brain metastasis screening (BMS) should be guided by disease stage in non‐small cell lung cancer (NSCLC). We estimate that screening is performed more broadly in practice, and patients undergo brain imaging at considerable cost with questionable benefit. Our aim was to quantify the use and detection rate of BMS in a contemporary cohort staged with 18F‐fluorodeoxyglucose positron emission tomography/computed tomography (PET‐CT).

Methods

We conducted a retrospective review of prospectively collected data from three major lung cancer referral centres in Brisbane between January 2011 and December 2015. Patients included had a new diagnosis of NSCLC and had undergone a PET‐CT to stage extra‐cranial disease. BMS was defined as dedicated brain imaging with contrast‐enhanced computed tomography (CE‐CT) or magnetic resonance (MR), in the absence of clinically apparent neurological deficits.

Results

A total of 1751 eligible cases were identified and of these 718 (41%) underwent BMS. The majority had CE‐CT imaging (n = 703). Asymptomatic brain metastases (BM) were detected in 18 patients (2.5%). Of these patients, 12 had concurrent non‐brain metastases. Only six patients (0.8%) had BM alone. The rate of detection increased with N‐stage (P = 0.02) and overall stage (P < 0.001). It was 0.5%, 1%, 1.6% and 7.3% for stage I, II, III and IV respectively. The overall screening rate increased with T‐stage (P = 0.001), N‐Stage (P < 0.001) and overall stage (P < 0.001).

Conclusions

Non‐small cell lung cancer BMS practices remain at odds with published guidelines. The low number of occult BMs detected supports the existing international recommendations. Rationalising BMS would minimise the burden on patients and the health care system.
Expression of p16INK4a is a biomarker of chondrocyte aging but does not cause osteoarthritis
Authors: Diekman Brian O. , Sessions Garrett A. , Collins John A. , Knecht Anne K. , Strum Susan L. , Mitin Natalia K. , Carlson Cathy S. , Loeser Richard F. , Sharpless Norman E.
Published: May 2018

Cellular senescence drives a functional decline of numerous tissues with aging by limiting regenerative proliferation and/or by producing pro‐inflammatory molecules known as the senescence‐associated secretory phenotype (SASP). The senescence biomarker p16INK4a is a potent inhibitor of the cell cycle but is not essential for SASP production. Thus, it is unclear whether p16INK4a identifies senescence in hyporeplicative cells such as articular chondrocytes and whether p16INK4a contributes to pathologic characteristics of cartilage aging. To address these questions, we examined the role of p16INK4a in murine and human models of chondrocyte aging. We observed that p16INK4a mRNA expression was significantly upregulated with chronological aging in murine cartilage (~50‐fold from 4 to 18 months of age) and in primary human chondrocytes from 57 cadaveric donors (r2 = .27, p < .0001). Human chondrocytes exhibited substantial replicative potential in vitro that depended on the activity of cyclin‐dependent kinases 4 or 6 (CDK4/6), and proliferation was reduced in cells from older donors with increased p16INK4a expression. Moreover, increased chondrocyte p16INK4a expression correlated with several SASP transcripts. Despite the relationship between p16INK4a expression and these features of senescence, somatic inactivation of p16INK4a in chondrocytes of adult mice did not mitigate SASP expression and did not alter the rate of osteoarthritis (OA) with physiological aging or after destabilization of the medial meniscus. These results establish that p16INK4a expression is a biomarker of dysfunctional chondrocytes, but that the effects of chondrocyte senescence on OA are more likely driven by production of SASP molecules than by loss of chondrocyte replicative function.
Restoring mitochondrial DNA copy number preserves mitochondrial function and delays vascular aging in mice
Authors: Foote Kirsty , Reinhold Johannes , Yu Emma P. K. , Figg Nichola L. , Finigan Alison , Murphy Michael P. , Bennett Martin R.
Published: May 2018

Aging is the largest risk factor for cardiovascular disease, yet the molecular mechanisms underlying vascular aging remain unclear. Mitochondrial DNA (mtDNA) damage is linked to aging, but whether mtDNA damage or mitochondrial dysfunction is present and directly promotes vascular aging is unknown. Furthermore, mechanistic studies in mice are severely hampered by long study times and lack of sensitive, repeatable and reproducible parameters of arterial aging at standardized early time points. We examined the time course of multiple invasive and noninvasive arterial physiological parameters and structural changes of arterial aging in mice, how aging affects vessel mitochondrial function, and the effects of gain or loss of mitochondrial function on vascular aging. Vascular aging was first detected by 44 weeks (wk) of age, with reduced carotid compliance and distensibility, increased β‐stiffness index and increased aortic pulse wave velocity (PWV). Aortic collagen content and elastin breaks also increased at 44 wk. Arterial mtDNA copy number (mtCN) and the mtCN‐regulatory proteins TFAM, PGC1α and Twinkle were reduced by 44 wk, associated with reduced mitochondrial respiration. Overexpression of the mitochondrial helicase Twinkle (Tw+) increased mtCN and improved mitochondrial respiration in arteries, and delayed physiological and structural aging in all parameters studied. Conversely, mice with defective mitochondrial polymerase‐gamma (PolG) and reduced mtDNA integrity demonstrated accelerated vascular aging. Our study identifies multiple early and reproducible parameters for assessing vascular aging in mice. Arterial mitochondrial respiration reduces markedly with age, and reduced mtDNA integrity and mitochondrial function directly promote vascular aging.
Prescription opioid use in pregnancy
Authors: Blandthorn Julie , Leung Laura , Loke Yuan , Lloyd‐Jones D. Martyn , Thurman Robin , Bowman Ellen , Bonomo Yvonne
Published: May 2018

Prescription medications, including opioid analgesics, are increasingly prescribed in Australia and internationally. More women are presenting in pregnancy with prescription opioid use which can potentially cause harm to the mother and fetus. This article outlines the different types of prescription opioids, defines how prescription opioid use disorder presents clinically and suggests a rational clinical approach to assess and manage patients in the context of pregnancy and their infants.
Pure laparoscopic hepatectomy with augmented reality‐assisted indocyanine green fluorescence versus open hepatectomy for hepatocellular carcinoma with liver cirrhosis: A propensity analysis at a single center
Authors: Cheung Tan To , Ma Ka Wing , She Wong Hoi , Dai Wing Chiu , Tsang Simon Hing Yin , Chan Albert Chi Yan , Chok Kenneth Siu Ho , Lo Chung Mau
Published: May 2018

Introduction

Laparoscopic hepatectomy is considered an acceptable treatment of choice in selected patients with primary hepatocellular carcinoma (HCC). Whether indocyanine green (ICG) immunofluorescence, a new technology, may improve surgery outcomes has yet to be tested. The aim of the present study was to investigate and compare the effect of ICG fluorescence imaging on the outcomes of pure laparoscopic hepatectomy and open hepatectomy for primary HCC with background cirrhosis.

Methods

From January 2015 to June 2016, 20 patients with HCC and liver cirrhosis underwent laparoscopic hepatectomy with ICG immunofluorescence. The outcomes of pure laparoscopic hepatectomy with ICG immunofluorescence were compared with those of open hepatectomy. To avoid selection bias, patients were propensity score matched in a ratio of 1 : 6, with 20 patients in the laparoscopic group and 120 in the open group.

Results

The laparoscopic group had 20 patients, and the open group had 120 patients. The laparoscopic group had less blood loss (125 vs 450 mL, P < 0.001), a shorter operation time (200 vs 250 min, P = 0.003), and a shorter hospital stay (5 vs 6 days, P < 0.001). The complication rate was 0% in the laparoscopic group compared to 15.0% in the open group (P = 0.135). All patients in the laparoscopic group had negative margin involvement. Four patients (3.3%) in the open resection group had positive margin involvement. Two patients in the ICG immunofluorescence group had additional lesions identified and resected during operation.

Conclusion

Pure laparoscopic hepatectomy with ICG immunofluorescence for primary HCC can be carried out safely with favorable short‐term outcomes even in cirrhotic patients. Better identification of the bile duct structure and better assessment of the tumor resection margin and perfusion are advantages of this new technique.
Working memory dependence of spatial contextual cueing for visual search
Authors: Pollmann Stefan
Published: May 2018

When spatial stimulus configurations repeat in visual search, a search facilitation, resulting in shorter search times, can be observed that is due to incidental learning. This contextual cueing effect appears to be rather implicit, uncorrelated with observers’ explicit memory of display configurations. Nevertheless, as I review here, this search facilitation due to contextual cueing depends on visuospatial working memory resources, and it disappears when visuospatial working memory is loaded by a concurrent delayed match to sample task. However, the search facilitation immediately recovers for displays learnt under visuospatial working memory load when this load is removed in a subsequent test phase. Thus, latent learning of visuospatial configurations does not depend on visuospatial working memory, but the expression of learning, as memory‐guided search in repeated displays, does. This working memory dependence has also consequences for visual search with foveal vision loss, where top‐down controlled visual exploration strategies pose high demands on visuospatial working memory, in this way interfering with memory‐guided search in repeated displays. Converging evidence for the contribution of working memory to contextual cueing comes from neuroimaging data demonstrating that distinct cortical areas along the intraparietal sulcus as well as more ventral parieto‐occipital cortex are jointly activated by visual working memory and contextual cueing.
Arrhythmic hazard map for a 3D whole‐ventricle model under multiple ion channel block
Authors: Okada Jun‐ichi , Yoshinaga Takashi , Kurokawa Junko , Washio Takumi , Furukawa Tetsushi , Sawada Kohei , Sugiura Seiryo , Hisada Toshiaki
Published: May 2018

Background and Purpose

To date, proposed in silico models for preclinical cardiac safety testing are limited in their predictability and usability. We previously reported a multi‐scale heart simulation that accurately predicts arrhythmogenic risk for benchmark drugs.

Experimental Approach

We created a comprehensive hazard map of drug‐induced arrhythmia based on the electrocardiogram (ECG) waveforms simulated under wide range of drug effects using the multi‐scale heart simulator described here, implemented with cell models of human cardiac electrophysiology.

Key Results

A total of 9075 electrocardiograms constitute the five‐dimensional hazard map, with coordinates representing the extent of the block of each of the five ionic currents (rapid delayed rectifier potassium current (IKr), fast (INa) and late (INa,L) components of the sodium current, L‐type calcium current (ICa,L) and slow delayed rectifier current (IKs)), involved in arrhythmogenesis. Results of the evaluation of arrhythmogenic risk based on this hazard map agreed well with the risk assessments reported in the literature. ECG databases also suggested that the interval between the J‐point and the T‐wave peak is a superior index of arrhythmogenicity when compared to the QT interval due to its ability to characterize the multi‐channel effects compared with QT interval.

Conclusion and Implications

Because concentration‐dependent effects on electrocardiograms of any drug can be traced on this map based on in vitro current assay data, its arrhythmogenic risk can be evaluated without performing costly and potentially risky human electrophysiological assays. Hence, the map serves as a novel tool for use in pharmaceutical research and development.
Molecular basis of benzimidazole inhibitors to hepatitis C virus envelope glycoprotein
Authors: Uddin Reaz , Downard Kevin M.
Published: May 2018

The molecular basis for the inhibitory action of a benzimidazole inhibitor compound to hepatitis C virus E1 envelope protein was examined computationally. Structures for the wild‐type E1 protein and seven mutants were modelled using an ab initio protein structure prediction algorithm, and these models were docked with the benzimidazole inhibitor. Top‐ranked conformers for each docked structure were examined in the context of the putative function of the inhibitor that blocks fusion of the envelope protein to the host cells. The results for the wild‐type protein and that for a series of mutants containing reported single, double and triple resistance mutations demonstrate that the inhibitor binds in the vicinity of residue Phe99 (at position 291 in the encoded polyprotein) at the C‐terminal end of a putative fusion domain. In so doing, the compound inhibits the virus from fusing to host cells and blocks viral replication in accord with the results from cell‐based infection studies.
New 1,2,3‐triazole‐based analogues of benznidazole for use against Trypanosoma cruzi infection: In vitro and in vivo evaluations
Authors: Leite Débora Inácio , Fontes Fábio de Vasconcellos , Bastos Monica Macedo , Hoelz Lucas Villas Boas , Bianco Maria da Conceição Avelino Dias , de Oliveira Andressa Paula , da Silva Patricia Bernardino , da Silva Cristiane França , Batista Denise da Gama Jean , da Gama Aline Nefertiti Silva , Peres Raiza Brandão , Villar Jose Daniel Figueroa , Soeiro Maria de Nazaré Correia , Boechat Nubia
Published: May 2018

Chagas disease has spread throughout the world mainly because of the migration of infected individuals. In Brazil, only benznidazole (Bnz) is used; however, it is toxic and not active in the chronic phase, and cases of resistance are described. This work aimed at the synthesis and the trypanocidal evaluation in vitro and in vivo of six new Bnz analogues (3–8). They were designed by exploring the bioisosteric substitution between the amide group contained in Bnz and the 1,2,3‐triazole ring. All the compounds were synthesized in good yields. With the exception of compound 7, the in vitro biological evaluation shows that all Bnz analogues were active against the amastigote form, whereas only compounds 3, 4, 5, and 8 were active against trypomastigote. Compounds 4 and 5 showed the most promising activities in vitro against the form of trypomastigote, being more active than Bnz. In vivo evaluation of compounds, 3–8 showed lower potency and higher toxicity than Bnz. Although the 1,2,3‐triazole ring has been described in the literature as an amide bioisostere, its substitution here has reduced the activity of the compounds and made them more toxic. Thus, further molecular optimization could provide novel therapeutic agents for Chagas’ disease.
HE4 suppresses the expression of osteopontin in mononuclear cells and compromises their cytotoxicity against ovarian cancer cells
Authors: James N E , Cantillo E , Oliver M T , Rowswell-Turner R B , Ribeiro J R , Kim K-K , Chichester C O , DiSilvestro P A , Moore R G , Singh R K , Yano N , Zhao T C
Published: May 2018

Ovarian cancers are known to evade immunosurveillance and to orchestrate a suppressive immune microenvironment. Here we examine the role of human epididymis protein 4 (HE4), an ovarian cancer biomarker, in immune evasion. Through modified subtractive hybridization analyses we have characterized the gene targets of HE4 in human peripheral blood mononuclear cells (PBMCs), and established a preliminary mechanism for HE4-mediated immune failure in ovarian tumours. Upon exposure of purified PMBCs to HE4, osteopontin (OPN) and dual-specificity phosphatase 6 (DUSP6) emerged as the most suppressed and up-regulated genes, respectively. SKOV3 and OVCAR8, human ovarian carcinoma cell lines, exhibited enhanced proliferation in conditioned media from HE4-exposed PBMCs, an effect that was attenuated by the addition of recombinant OPN or OPN-inducible cytokines [interleukin (IL)-12 and interferon (IFN)-Ɣ]. Additionally, upon co-culture with PBMCs, HE4-silenced SKOV3 cells were found to be more susceptible to cytotoxic cell death. The relationship between HE4 and OPN was reinforced further through the analysis of serous ovarian cancer patient samples. In these biopsy specimens, the number of OPN+ T cells correlated positively with progression free survival (PFS) and inversely with serum HE4 level. Taken together, these findings show that HE4 enhances ovarian cancer tumorigenesis by compromising OPN-mediated T cell activation.
Congestion and Distribution of Rents in Wheat Export Sector: A Canada–U.S. Cross‐Border Comparison
Authors: Serfas Devin , Gray Richard , Slade Peter
Published: May 2018

In Canada, average grain freight rates are regulated via the Maximum Revenue Entitlement (MRE), while on the US side of the border grain rates are subject to very little oversight. We use this natural experiment to explore how the MRE regulation has impacted freight rates and the distribution of rents in the wheat supply chain since 2012. On both sides of the border, when large crops have exceeded the short‐term capacity of grain export channels to move the crop, export basis has increased and reduced producer prices. In locations not subject to barge competition, US grain freight rates are higher than Canadian rates and are bid up further during periods of congestion. In Canada, MRE regulation redistributes rents away from railways toward grain companies and producers. These higher grain handling margins have increased the incentives to build additional port terminal capacity in the post‐CWB single desk environment.

Au Canada, les tarifs marchandises moyens des céréales sont règlementés par le Revenu admissible maximal (RAM), tandis qu'aux États‐Unis, les tarifs céréaliers font l'objet de très peu de suivi. Au moyen de cette expérience naturelle, nous explorons l'impact du RAM sur les tarifs marchandises et sur la distribution des rentes dans la chaine d'approvisionnement du blé depuis 2012. Des deux côtés de la frontière, lorsque de vastes cultures ont excédé la capacité à court terme des voies d'exportation céréalières pour distribuer leurs récoltes, le seuil d'exportation augmente et réduit les prix des producteurs. Là où ils ne sont pas assujettis à la compétition de barges, les tarifs marchandises céréaliers américains s'avèrent plus élevés que les tarifs canadiens et se voient encore surenchéris lors de période de congestion. Au Canada, la règlementation du RAM redirige les rentes des compagnies ferroviaires aux entreprises et producteurs céréaliers. Ces marges de manutention plus élevées ont augmenté les incitatifs pour accroître la capacité des ports‐terminaux dans un environnement à pupitre unique, post Commission canadienne du blé.
When predator odour makes groups stronger: effects on behavioural and chemical adaptations in two termite species
Authors: Lucas Christophe , Brossette Lou , Lefloch Lauriane , Dupont Simon , Christidès Jean‐Philippe , Bagnères Anne‐Geneviève
Published: May 2018

1. Being able to detect a predator before any physical contact is crucial for individual survival. Predator presence can be detected thanks to several types of signal, such as chemical cues. Chemical signals are produced by predators for their protection against desiccation, for their communication, or possibly as a side‐effect of their activity. In insects, chemical communication plays a key role in diverse biological processes, including prey‐predator or plant‐insect interactions, courtship behaviour, and kin or species recognition.

2. Cuticular hydrocarbons (CHCs) are specifically involved in recognition processes and social organisation (division of labour, caste ratios) in social insects. Here, the questions raised are whether termites can detect a predator with their cuticular compounds and whether the predator‐produced compounds can influence their prey.

3. The responses of termites Reticulitermes grassei (Clément, 1978) and Reticulitermes flavipes (Kollar, 1837) to the presence of the cuticular compounds produced by a predator, the ant species Lasius niger (Linnaeus, 1758), were investigated. More specifically, the study quantified termite traits such as caste ratios, mortality rates, CHC profile homogeneity and aggressiveness of workers after 2 months' exposure to predator‐produced compounds.

4. The results show that the predator odour did affect the aggressiveness of the native species R. grassei but not of the invasive R. flavipes. The caste ratios and the mortality rates were not affected for both species.

5. Differences between species are discussed around the native or invasive status of each species, along with the role played by chemical cues on behavioural and chemical adaptations.
Beyond the fast–slow continuum: demographic dimensions structuring a tropical tree community
Authors: Rüger Nadja , Comita Liza S. , Condit Richard , Purves Drew , Rosenbaum Benjamin , Visser Marco D. , Wright S.J , Wirth Christian
Published: May 2018

Life‐history theory posits that trade‐offs between demographic rates constrain the range of viable life‐history strategies. For coexisting tropical tree species, the best established demographic trade‐off is the growth‐survival trade‐off. However, we know surprisingly little about co‐variation of growth and survival with measures of reproduction. We analysed demographic rates from seed to adult of 282 co‐occurring tropical tree and shrub species, including measures of reproduction and accounting for ontogeny. Besides the well‐established fast–slow continuum, we identified a second major dimension of demographic variation: a trade‐off between recruitment and seedling performance vs. growth and survival of larger individuals (≥ 1 cm dbh) corresponding to a ‘stature–recruitment’ axis. The two demographic dimensions were almost perfectly aligned with two independent trait dimensions (shade tolerance and size). Our results complement recent analyses of plant life‐history variation at the global scale and reveal that demographic trade‐offs along multiple axes act to structure local communities.
The control of risk hypothesis: reactive vs. proactive antipredator responses and stress‐mediated vs. food‐mediated costs of response
Authors: Creel Scott
Published: May 2018

Inducible defences against predators evolve because they reduce the rate of direct predation, but this benefit is offset by the cost (if any) of defence. If antipredator responses carry costs, the effect of predators on their prey is partitioned into two components, direct killing and risk effects. There is considerable uncertainty about the strength of risk effects, the factors that affect their strength, and the mechanisms that underlie them. In some cases, antipredator responses are associated with a glucocorticoid stress response, and in other cases they are associated with trade‐offs between food and safety, but there is no general theory to explain this variation. Here, I develop the control of risk (COR) hypothesis, predicting that proactive responses to predictable and controllable aspects of risk will generally have food‐mediated costs, while reactive responses to unpredictable or uncontrollable aspects of predation risk will generally have stress‐mediated costs. The hypothesis is grounded in laboratory studies of neuroendocrine stressors and field studies of food‐safety trade‐offs. Strong tests of the COR hypothesis will require more studies of responses to natural variation in predation risk and the physiological consequences of these responses, but its explanatory power can be illustrated with existing case studies.
Ecological genomics predicts climate vulnerability in an endangered southwestern songbird
Authors: Ruegg Kristen , Bay Rachael A. , Anderson Eric C. , Saracco James F. , Harrigan Ryan J. , Whitfield Mary , Paxton Eben H. , Smith Thomas B.
Published: May 2018

Few regions have been more severely impacted by climate change in the USA than the Desert Southwest. Here, we use ecological genomics to assess the potential for adaptation to rising global temperatures in a widespread songbird, the willow flycatcher (Empidonax traillii), and find the endangered desert southwestern subspecies (E. t. extimus) most vulnerable to future climate change. Highly significant correlations between present abundance and estimates of genomic vulnerability – the mismatch between current and predicted future genotype–environment relationships – indicate small, fragmented populations of the southwestern willow flycatcher will have to adapt most to keep pace with climate change. Links between climate‐associated genotypes and genes important to thermal tolerance in birds provide a potential mechanism for adaptation to temperature extremes. Our results demonstrate that the incorporation of genotype–environment relationships into landscape‐scale models of climate vulnerability can facilitate more precise predictions of climate impacts and help guide conservation in threatened and endangered groups.
Non‐invasive brain stimulation for fine motor improvement after stroke: a meta‐analysis
Authors: O'Brien A. T. , Bertolucci F. , Torrealba‐Acosta G. , Huerta R. , Fregni F. , Thibaut A.
Published: May 2018

The aim of this study was to determine whether non‐invasive brain stimulation (NIBS) techniques improve fine motor performance in stroke. We searched PubMed, EMBASE, Web of Science, SciELO and OpenGrey for randomized clinical trials on NIBS for fine motor performance in stroke patients and healthy participants. We computed Hedges’ g for active and sham groups, pooled data as random‐effects models and performed sensitivity analysis on chronicity, montage, frequency of stimulation and risk of bias. Twenty‐nine studies (351 patients and 152 healthy subjects) were reviewed. Effect sizes in stroke populations for transcranial direct current stimulation and repeated transcranial magnetic stimulation were 0.31 [95% confidence interval (CI), 0.08–0.55; P = 0.010; Tau2, 0.09; I2, 34%; Q, 18.23; P = 0.110] and 0.46 (95% CI, 0.00–0.92; P = 0.05; Tau2, 0.38; I2, 67%; Q, 30.45; P = 0.007). The effect size of non‐dominant healthy hemisphere transcranial direct current stimulation on non‐dominant hand function was 1.25 (95% CI, 0.09–2.41; P = 0.04; Tau2, 1.26; I2, 93%; Q, 40.27; P < 0.001). Our results show that NIBS is associated with gains in fine motor performance in chronic stroke patients and healthy subjects. This supports the effects of NIBS on motor learning and encourages investigation to optimize their effects in clinical and research settings.