bluuebunny/crossref_metadata_2025_split huggingface dataset:
Subphase Material Stabilizes Films of Pulmonary Surfactant
Authors: Andreev K. , Martynowycz M. W. , Kuzmenko I. , Bu W. , Hall S. B. , Gidalevitz D. 
Published: February 2020

ABSTRACTWhen compressed by the shrinking alveolar surface area during exhalation, films of pulmonary surfactantin situreduce surface tension to levels, at which surfactant monolayers collapse from the surfacein vitro. Vesicles of pulmonary surfactant added below these monolayers slow collapse. X-ray scattering here determined the structural changes that improve stability. Grazing incidence X-ray diffraction on monolayers of extracted calf surfactant detected an ordered phase. Mixtures of dipalmitoyl phosphatidylcholine and cholesterol, but not the phospholipid alone, mimic that structure. At concentrations that stabilize the monolayers, vesicles in the subphase had no effect on the unit cell, and the film remained monomolecular. The added vesicles, however, produced a concentration-dependent increase in the diffracted intensity. These results suggest that the enhanced resistance to collapse results from components of an ordered interfacial phase which partition from subphase to the surface, increasing the area of the ordered structure.SIGNIFICANCELow alveolar surface tensions are essential for maintaining the integrity of the pulmonary air-sacks during normal breathing. Films of pulmonary surfactant cause the low tensions. The interfacial structures required for the low surface tensions remain uncertain. These studies used X-ray scattering to determine the initial structure of pulmonary surfactant monolayers, and to establish how vesicles of pulmonary surfactant enhance the ability of those initial monolayers to sustain low tensions. The initial monolayers contained ordered structures that differ from the crystalline forms widely speculated to occur in alveolar films. The added vesicles had no effect on the local structure of the initial monolayer, but substantially increased the area of the ordered regions. This structural change reasonably explains the functional improvement.
Genome wide-association study identifies novel loci in the Primary Open-Angle African American Glaucoma Genetics (POAAGG) study
Authors: Gudiseva Harini V. , Verma Shefali Setia , Chavali Venkata R. M. , Salowe Rebecca J. , Lucas Anastasia , Collins David W. , Rathi Sonika , He Jie , Lee Roy , Merriam Sayaka , Bowman Anita S. , McHugh Caitlin P. , Zody Michael C. , Pistilli Maxwell , Khachataryan Naira , Daniel Ebenezer , Murphy Windell , Weiner Mark , Henderer Jeffrey , Ross Ahmara , Cui Qi N. , Addis Victoria , Lehman Amanda , Miller-Ellis Eydie , Sankar Prithvi S. , Varma Rohit , Williams Scott M. , Ying Gui-shuang , Moore Jason H. , Ritchie Marylyn D. , O’Brien Joan M. 
Published: February 2020

AbstractPrimary open-angle glaucoma (POAG), the leading cause of irreversible blindness worldwide, disproportionately affects African Americans. Large-scale POAG genetic studies have focused on individuals of European and Asian ancestry, limiting our understanding of disease biology. Here we report genetic analysis of the largest-ever deeply phenotyped African American population (n=5950), identifying a novel POAG-associated SNP on chromosome 11 near theTRIM66gene (rs112369934). POAG trait association also implicated SNPs in genes involved in trabecular meshwork homeostasis and retinal ganglion cell maintenance. These new loci deepen our understanding of the pathophysiology of POAG in African Americans.
Dynamic modulation of glucose utilisation by glucocorticoid rhythms in health and disease
Authors: Zavala Eder , Gil-Gómez Carlos A. , Wedgwood Kyle C. A. , Burgess Romana , Tsaneva-Atanasova Krasimira , Herrera-Valdez Marco A. 
Published: February 2020

AbstractA systems level coordination of physiological rhythms is essential to sustain healthy states, especially in the face of stimuli that may disrupt such rhythms. The timing of meals, medication and chronic stress can profoundly influence metabolism, which depends on the dynamic interactions between glucose, insulin and cortisol. Although the metabolic and stress endocrine axes are simultaneously disrupted in many diseases, a theoretical framework to understand how chronodisruption leads to disease is lacking. By developing a mathematical model of glucose utilisation that accounts for the antagonism between insulin and cortisol, we investigate the dynamic effects of glucose boluses under normal and disrupted cortisol rhythms, including the effects of cortisol agonists and antagonists. We also predict how cortisol rhythms modulate circadian responses to oral glucose diagnostic tests, and analyse the disruptions caused by hypercortisolism. Finally, we predict the mechanisms leading to type 2 diabetes in patients with normal and excess cortisol.
Amalgams: data-driven amalgamation for the reference-free dimensionality reduction of zero-laden compositional data
Authors: Quinn Thomas P. , Erb Ionas 
Published: February 2020

AbstractIn the health sciences, many data sets produced by next-generation sequencing (NGS) only contain relative information because of biological and technical factors that limit the total number of nucleotides observed for a given sample. As mutually dependent elements, it is not possible to interpret any component in isolation, at least without normalization. The field of compositional data analysis (CoDA) has emerged with alternative methods for relative data based on log-ratio transforms. However, NGS data often contain many more features than samples, and thus require creative new ways to reduce the dimensionality of the data without sacrificing interpretability. The summation of parts, called amalgamation, is a practical way of reducing dimensionality, but can introduce a non-linear distortion to the data. We exploit this non-linearity to propose a powerful yet interpretable dimension reduction method. In this report, we present data-driven amalgamation as a new method and conceptual framework for reducing the dimensionality of compositional data. Unlike expert-driven amalgamation which requires prior domain knowledge, our data-driven amalgamation method uses a genetic algorithm to answer the question, “What is the best way to amalgamate the data to achieve the user-defined objective?”. We present a user-friendly R package, called amalgam, that can quickly find the optimal amalgamation to (a) preserve the distance between samples, or (b) classify samples as diseased or not. Our benchmark on 13 real data sets confirm that these amalgamations compete with the state-of-the-art unsupervised and supervised dimension reduction methods in terms of performance, but result in new variables that are much easier to understand: they are groups of features added together.
Prefrontal responses during proactive and reactive inhibition are differentially impacted by stress in anorexia and bulimia nervosa
Authors: Westwater Margaret L. , Mancini Flavia , Gorka Adam X. , Shapleske Jane , Serfontein Jaco , Grillon Christian , Ernst Monique , Ziauddeen Hisham , Fletcher Paul C. 
Published: February 2020

AbstractBackgroundBinge-eating is a distressing, transdiagnostic eating disorder symptom associated with impulsivity, particularly in negative mood states. Neuroimaging studies of bulimia nervosa (BN) report reduced activity in fronto-striatal regions implicated in self-regulatory control. However, it remains unknown if negative affective states, including stress, impair self-regulation, and, if so, whether such self-regulatory deficits generalize to binge-eating in underweight individuals (i.e., the bingeing/purging subtype of anorexia nervosa; AN-BP).MethodsWe determined the effect of acute stress on inhibitory control in 85 women (33 BN, 22 AN-BP, 30 matched controls). Participants underwent repeated functional MRI scanning, during performance of the stop-signal anticipation task, a validated measure of proactive (i.e., anticipation of stopping) and reactive (outright stopping) inhibition. Neural and behavioral responses to induced, psychological stress and a control task were evaluated on two separate days.ResultsWomen with BN had reduced proactive inhibition while prefrontal responses were increased in both AN-BP and BN. Reactive inhibition was neurally and behaviorally intact in both diagnostic groups. Both AN-BP and BN groups showed distinct, stress-induced changes in prefrontal activity during both proactive and reactive inhibition. However, task performance was not significantly affected by stress.ConclusionsThese findings offer novel evidence of reduced proactive inhibition in BN, yet inhibitory control deficits did not generalize to AN-BP. While both groups showed altered neural responses during inhibition following stress, neither group demonstrated stress-induced performance deficits. As such, our findings counsel against a simplistic, stress-induced failure of regulation as a holistic explanation for binge-eating in these conditions.
Microbiome shifts associated with the introduction of wild Atlantic horseshoe crabs (Limulus polyphemus) into a touch-tank exhibit
Authors: Friel Ariel D. , Neiswenter Sean A. , Seymour Cale O. , Bali Lauren Rose , McNamara Ginger , Leija Fabian , Jewell Jack , Hedlund Brian P. 
Published: February 2020

AbstractThe Atlantic horseshoe crab (Limulus polyphemus) is a common marine aquarium species and model organism for research. There is potential monetary and conservation value in developing a stable captive population of horseshoe crabs, however, one major impediment to achieving captivity is a lack of knowledge regarding captive diseases. We utilized 16S rRNA gene amplicon sequencing to track changes in the microbiomes of four body locations in three wild-caught (tracked over 14 months in captivity) and three tank-acclimated (>2 years in captivity) adultL. polyphemusin a touch tank at Shark Reef Aquarium at Mandalay Bay in Las Vegas, NV. The wild population hosted diverse and distinct microbiomes on the carapace (737 amplicon sequence variants or ASVs), cloaca (1078 ASVs), gills (941 ASVs), and oral cavity (1193 ASVs), which were dominated by classesGammaproteobacteria,Bacteroidia, andAlphaproteobacteria. A rapid decline in richness across all body locations was observed within 1 month of captivity, with tank-acclimated (>2 years) animals having <5% of the initial microbiome richness and a nearly completely restructured microbial community. The carapace, oral cavity, and gills of the tank-acclimated animals hosted abundant populations ofAeromonas(>60%) andPseudomonas(>20%), both of which are known opportunistic pathogens of aquatic animals and can express chitinases, providing a plausible mechanism for the development of the carapace lesion pathology observed in this and other studies. These results provide an important baseline on the microbiomes of both wild and tank-acclimated horseshoe crabs and underscore the need to continue to investigate how native microbial populations may protect animals from pathogens.
In vivoFeedback Control of an Antithetic Molecular-Titration Motif inEscherichia coliusing Microfluidics
Authors: Shannon B. , Zamora-Chimal C.G. , Postiglione L. , Salzano D. , Grierson C. , Marucci L. , Savery N.J. , di Bernardo M. 
Published: February 2020

SummaryWe study bothin silicoandin vivothe real-time feedback control of a molecular titration motif that has been earmarked as a fundamental component of antithetic and multicellular feedback control schemes inE. coli. We show that an external feedback control strategy can successfully regulate the average fluorescence output of a bacterial cell population to a desired constant level in real-time. We also providein silicoevidence that the same strategy can be used to track a time-varying reference signal where the set-point is switched to a different value halfway through the experiment. We use the experimental data to refine and parameterize anin silicomodel of the motif that can be used as an error computation module in future embedded or multicellular control experiments.
Alternative splicing of COQ-2 determines the choice between ubiquinone and rhodoquinone biosynthesis in helminths
Authors: Tan June H. , Lautens Margot , Romanelli-Cedrez Laura , Wang Jianbin , Schertzberg Michael R. , Reinl Samantha R. , Davis Richard E. , Shepherd Jennifer N. , Fraser Andrew G. , Salinas Gustavo 
Published: February 2020

AbstractParasitic helminths use two benzoquinones as electron carriers in the electron transport chain. In aerobic environments they use ubiquinone (UQ) but in anaerobic environments inside the host, they require rhodoquinone (RQ) and greatly increase RQ levels. The switch to RQ synthesis is driven by substrate selection by the polyprenyltransferase COQ-2 but the mechanisms underlying this substrate choice are unknown. We found that helminths make twocoq-2isoforms,coq-2aandcoq-2e, by alternative splicing. COQ-2a is homologous to COQ2 from other eukaryotes but the COQ-2e-specific exon is only found in species that make RQ and its inclusion changes the enzyme core. We show COQ-2e is required for RQ synthesis and for survival in cyanide inC. elegans. Crucially, we see a switch from COQ-2a to COQ-2e as parasites transition into anaerobic environments. We conclude that under anaerobic conditions helminths switch from UQ to RQ synthesis via alternative splicing ofcoq-2.
A simplified approach to understanding customer support and help during self-service encounters
Authors: van Tonder Estelle , Saunders Stephen G. , de Beer Leon T. 
Published: February 2020

PurposeIn the absence of direct employee involvement, customers sharing knowledge and know-how with other customers during self-service encounters is key for promoting service quality. This study assessed the extent to which customer support and help during self-service encounters could simply be explained by multiple motivations of the social exchange theory.Design/methodology/approachA survey approach was followed. The model was tested among 258 electronic banking customers in South Africa and later cross-validated among 253 electronic banking customers in Australia. Multi-group confirmatory factor analysis with country as the grouping variable, latent variable modelling and indirect tests were performed to assess interrelationships among diverse factors that may contribute to customer support and help during self-service encounters, as accounted for by motivations of the social exchange theory.FindingsAdequate model fit was obtained for the combined structural model, which was based on the invariant model. Value contribution and competence affirmation, pleasure derived from helping, reciprocity and reputation enhancement are relevant motivations of the social exchange theory that may impact customer support and help through knowledge sharing.Research implicationsThe study provides a simplified and more cohesive explanation of customers' motivations for engaging in customer support and helping behaviours during self-service encounters.Practical implicationsService providers seeking guidance on knowledge sharing among customers, which may lead to greater service quality, should benefit from this research.Originality/valueThe findings contribute to greater understanding of social exchanges by customers who provide support and help to other customers during self-service encounters, and that ultimately may affect service quality.
Home intelligent lighting control system based on wireless sensor
Authors: Wang Lianyu 
Published: February 2020

Purpose
Intelligent lighting control system can control lights to go off when people leave, which has been widely concerned by researchers.

Design/methodology/approach
In this study, an intelligent lighting control system based on wireless sensor network was designed. First, the hardware and software designs of the system were described briefly. Then, the lighting control algorithm was analyzed emphatically. Considering the illumination and uniformity of light, an intelligent lighting control algorithm based on gradient descent was designed.

Findings
In the system test, it was found that the system had a good through-wall communication function, and the communication distance could fully meet the system requirements and run normally. In the test of the lighting control algorithm, it was found that the user’s satisfaction on uniformity in different scenarios was close to 1, and the satisfaction on illumination could also meet the user’s needs, which verified the reliability of the lighting control algorithm.

Originality/value
This study provides some theoretical supports for the better application of wireless sensor network in intelligent light control system, which is conducive to the further development of light control system.
Endogenous growth, human capital and the dynamic costs of recessions
Authors: Roufagalas John , Orlov Alexei G. 
Published: February 2020

PurposeThe purpose of the paper is twofold: to construct and analyze a novel endogenous growth model, in which unbounded growth is possible without the need to assume increasing returns to scale, and to use the model to estimate the long-run (or dynamic) costs of recessions.Design/methodology/approachIn the proposed model, endogenous technology and human capital accumulation serve as the “twin engines of growth.” Simulations are used to derive growth rates consistent with long-term experience of developed countries, to understand better the differences between balanced growth and unbounded growth and to provide an estimate of the dynamic costs of capacity utilization shocks that produce business cycle-like behavior.FindingsConservative calculations show that the costs of the capacity shocks can be large – about 1.5 percent of the present value of output over a 100-period horizon. The theoretical model also suggests that differences in the technology production and human capital accumulation functions, possibly due to differing institutions, may help explain diverse growth experiences.Originality/valueThe paper, for first time, combines two strands of the economic growth theory – endogenous technology and endogenous human capital production – into a single model. It uses the implications of the model to argue, through simulations, that the benefits of counter-cyclical policies are potentially large in the long run.
Do global sentiment shocks spillover towards emerging and frontier markets?
Authors: Rehman Mobeen Ur , Apergis Nicholas 
Published: February 2020

PurposeThis study aims to investigate the impact of sentiment shocks based on US investor sentiments, bearish and bullish market conditions. Earlier studies, though very few, only consider the effect of investor sentiments on stock returns of emerging frontier Asian (EFA) markets.Design/methodology/approachThis study uses the application of regime switching model because of its capability to explore time-varying causality across different regimes unlike traditional linear models. The Markov regime switching model uses regime switching probabilities for capturing the potential asymmetries or non-linearity in a model, in this study’s case, thereby adjusting investor sentiments shocks to stock market returns.FindingsThe results of the Markov regime switching method suggests that US sentiment, bullish and bearish market shocks act as a main contributors for inducing variation in EFA stock market returns. The study’s non-parametric robustness results highlight an asymmetric relationship across the mean series, whereas a symmetric relationship across variance series. The study also reports Thailand as the most sensitive market to global sentiment shocks.Research limitations/implicationsThe sensitivity of the EFA markets to these global sentiment shocks highlights their sensitivity and implications for investors relying merely on returns correlation and spillover. These findings also suggest that spillover from developed to emerging and frontier equity markets only in the form of returns following traditional linear models may not be appropriate.Practical implicationsThis paper supports the behavioral aspect of investors and resultant spillover from developed market sentiments to emerging and frontier market returns across international equity markets offering more rational justification for an irrational behavior.Originality/valueThe study’s motivation to use the application of regime switching models is because of its capability to explore time-varying causality across different regimes unlike traditional linear models. The Markov regime switching model uses regime switching probabilities for capturing the potential asymmetries or non-linearity in a model, in the study’s case, thereby adjusting investor sentiments shocks to stock market returns. It is also useful of the adjustment attributable to exogenous events.
A win-win situation for both managers and shareholders
Authors: Ramachandran Jayalakshmy , Alam Nafis , Goh Chea Ei 
Published: February 2020

PurposeTo examine the impact of corporate governance on Cost of Capital (COC) and financial distress in the ASEAN countries.Design/methodology/approachWe compiled a list of the 50 largest publicly listed firms by market capitalization in each of the following five East Asian countries, namely Malaysia, Singapore, Thailand, the Philippines, and Indonesia. Furthermore, we then divided the five countries into two distinctive categories – (i) Malaysia and Singapore (Common Law/strong legal protection countries) and (ii) Thailand, the Philippines, and Indonesia (Civil Law/weak legal protection countries). The annual data is collected for the time period ranging from 2006 to 2015, allowing a total observation of 1,317 firm years.FindingsOverall, the paper supports the findings of many researchers that Board independence, promulgating good corporate governance, leads to better access to capital at lower cost, thus providing growth opportunities for ASEAN region. Taking lead from Simpson and Gleason (1999) and similar, we emphasize that during financial distress CEO duality will strengthen control systems and reduce internal discord in ASEAN firms.Originality/valueThe paper is one of the niche studies that has incorporated the difference between civil and common law rule in the study of corporate governance and its impact on financial measures of firms' in the ASEAN countries.
A numerical study on deblending of land simultaneous shooting acquisition data via rank‐reduction filtering and signal enhancement applications
Authors: Jeong Woodon , Tsingas Constantinos , Almubarak Mohammed S. 
Published: February 2020

ABSTRACTWe propose a workflow of deblending methodology comprised of rank‐reduction filtering followed by a signal enhancing process. This methodology can be used to preserve coherent subsurface reflections and at the same time to remove incoherent and interference noise. In pseudo‐deblended data, the blending noise exhibits coherent events, whereas in any other data domain (i.e. common receiver, common midpoint and common offset), it appears incoherent and is regarded as an outlier. In order to perform signal deblending, a robust implementation of rank‐reduction filtering is employed to eliminate the blending noise and is referred to as a joint sparse and low‐rank approximation. Deblending via rank‐reduction filtering gives a reasonable result with a sufficient signal‐to‐noise ratio. However, for land data acquired using unconstrained simultaneous shooting, rank‐reduction–based deblending applications alone do not completely attenuate the interference noise. A considerable amount of signal leakage is observed in the residual component, which can affect further data processing and analyses. In this study, we propose a deblending workflow via a rank‐reduction filter followed by post‐processing steps comprising a nonlinear masking filter and a local orthogonalization weight application. Although each application shows a few footprints of leaked signal energy, the proposed combined workflow restores the signal energy from the residual component achieving significantly signal‐to‐noise ratio enhancement. These hierarchical schemes are applied on land simultaneous shooting acquisition data sets and produced cleaner and reliable deblended data ready for further data processing.