bluuebunny/crossref_metadata_2025_split huggingface dataset:
Untangling climate and water chemistry to predict changes in freshwater macrophyte distributions
Authors: Sleith Robin S. , Wehr John D. , Karol Kenneth G. 
Published: February 2018

AbstractForecasting changes in the distributions of macrophytes is essential to understanding how aquatic ecosystems will respond to climate and environmental changes. Previous work in aquatic ecosystems has used climate data at large scales and chemistry data at small scales; the consequence of using these different data types has not been evaluated. This study combines a survey of macrophyte diversity and water chemistry measurements at a large regional scale to demonstrate the feasibility and necessity of including ecological measurements, in addition to climate data, in species distribution models of aquatic macrophytes. A survey of 740 water bodies stratified across 327,000 square kilometers was conducted to document Characeae (green macroalgae) species occurrence and water chemistry data. Chemistry variables and climate data were used separately and in concert to develop species distribution models for ten species across the study area. The impacts of future environmental changes on species distributions were modeled using a range of global climate models (GCMs), representative concentration pathways (RCPs), and pollution scenarios. Models developed with chemistry variables generally gave the most accurate predictions of species distributions when compared with those using climate variables. Calcium and conductivity had the highest total relative contribution to models across all species. Habitat changes were most pronounced in scenarios with increased road salt and deicer influences, with two species predicted to increase in range by >50% and four species predicted to decrease in range by >50%. Species of Characeae have distinct habitat ranges that closely follow spatial patterns of water chemistry. Species distribution models built with climate data alone were insufficient to predict changes in distributions in the study area. The development and implementation of standardized, large‐scale water chemistry databases will aid predictions of habitat changes for aquatic ecosystems.
Spatial correlations between browsing on balsam fir by white‐tailed deer and the nutritional value of neighboring winter forage
Authors: Champagne Emilie , Moore Ben D. , Côté Steeve D. , Tremblay Jean‐Pierre 
Published: February 2018

AbstractAssociational effects, that is, the influence of neighboring plants on herbivory suffered by a plant, are an outcome of forage selection. Although forage selection is a hierarchical process, few studies have investigated associational effects at multiple spatial scales. Because the nutritional quality of plants can be spatially structured, it might differently influence associational effects across multiple scales. Our objective was to determine the radius of influence of neighbor density and nutritional quality on balsam fir (Abies balsamea) herbivory by white‐tailed deer (Odocoileus virginianus) in winter. We quantified browsing rates on fir and the density and quality of neighboring trees in a series of 10‐year‐old cutovers on Anticosti Island (Canada). We used cross‐correlations to investigate relationships between browsing rates and the density and nutritional quality of neighboring trees at distances up to 1,000 m. Balsam fir and white spruce (Picea glauca) fiber content and dry matterin vitrotrue digestibility were correlated with fir browsing rate at the finest extra‐patch scale (across distance of up to 50 m) and between cutover areas (300–400 m). These correlations suggest associational effects, that is, low nutritional quality of neighbors reduces the likelihood of fir herbivory (associational defense). Our results may indicate associational effects mediated by intraspecific variation in plant quality and suggest that these effects could occur at scales from tens to hundreds of meters. Understanding associational effects could inform strategies for restoration or conservation; for example, planting of fir among existing natural regeneration could be concentrated in areas of low nutritional quality.
Mechanisms of CD8+ T cell‐mediated suppression of HIV/SIV replication
Authors: McBrien Julia Bergild , Kumar Nitasha A. , Silvestri Guido 
Published: February 2018

AbstractIn this article, we summarize the role of CD8+ T cells during natural and antiretroviral therapy (ART)‐treated HIV and SIV infections, discuss the mechanisms responsible for their suppressive activity, and review the rationale for CD8+ T cell‐based HIV cure strategies. Evidence suggests that CD8+ T cells are involved in the control of virus replication during HIV and SIV infections. During early HIV infection, the cytolytic activity of CD8+ T cells is responsible for control of viremia. However, it has been proposed that CD8+ T cells also use non‐cytolytic mechanisms to control SIV infection. More recently, CD8+ T cells were shown to be required to fully suppress virus production in ART‐treated SIV‐infected macaques, suggesting that CD8+ T cells are involved in the control of virus transcription in latently infected cells that persist under ART. A better understanding of the complex antiviral activities of CD8+ T cells during HIV/SIV infection will pave the way for immune interventions aimed at harnessing these functions to target the HIV reservoir.
Psychological factors not strength deficits are associated with severity of gluteal tendinopathy: A cross‐sectional study
Authors: Plinsinga M.L. , Coombes B.K. , Mellor R. , Nicolson P. , Grimaldi A. , Hodges P. , Bennell K. , Vicenzino B. 
Published: February 2018

AbstractBackgroundGluteal tendinopathy is the most common lower limb tendinopathy presenting to general practice. It has a high prevalence amongst middle‐aged women and impacts on daily activities, work participation and quality of life. The aim was to compare physical and psychological characteristics between subgroups of severity of pain and disability.MethodsA multicentre cross‐sectional cohort of 204 participants (mean age 55 years, 82% female) who had a clinical diagnosis of gluteal tendinopathy with magnetic resonance imaging confirmation were assessed. A range of physical and psychosocial characteristics were recorded. Pain and disability were measured with the VISA‐G questionnaire. A cluster analysis was used to identify mild, moderate and severe subgroups based on total VISA‐G scores. Between‐group differences were then evaluated with a MANCOVA, including sex and study site as covariates, followed by a Bonferroni post hoc test. Significance was set at 0.05.ResultsThere were significantly higher pain catastrophizing and depression scores in the more severe subgroups. Lower pain self‐efficacy scores were found in the severe group compared to the moderate and mild groups. Greater waist girth and body mass index (BMI), lower activity levels and poorer quality of life were reported in the severe group compared to the mild group. Hip abductor muscle strength and hip circumference did not differ between subgroups of severity.ConclusionsIndividuals with severe gluteal tendinopathy present with psychological distress, poorer quality of life, greater BMI and waist girth. Given these features, the consideration of psychological factors in more severe patients may be important to optimize patient outcomes and reduce healthcare utilization.SignificancePatients with severe gluteal tendinopathy exhibit greater psychological distress, poorer quality of life and greater waist girth and BMI when compared to less severe cases. This implies that clinicians ought to consider psychological factors in the management of more severe gluteal tendinopathy.
Uptake and metabolism of the antidepressants sertraline, clomipramine, and trazodone in a garden cress (Lepidium sativum) model
Authors: Reichl Bernd , Himmelsbach Markus , Emhofer Lisa , Klampfl Christian W. , Buchberger Wolfgang 
Published: February 2018

AbstractEnvironmental contamination with pharmaceuticals has received growing attention in recent years. Several studies describe the presence of traces of drugs in water bodies and soils and their impacts on nontarget organisms including plants. Due to these facts investigations of the uptake and metabolism of pharmaceuticals in organisms is an emerging research area. The present study demonstrates the analysis of three selected antidepressants (sertraline, clomipramine, and trazodone) as well as metabolites and transformation products in a cress model (Lepidium sativum). Cress was treated with tap water containing 10 mg/L of the parent drugs. Employing an analytical approach based on high performance liquid chromatography coupled with quadrupole time of flight or Orbitrap mass spectrometry in MS and MS² modes, in total 14 substances were identified in the cress extracts. All three parent drugs were taken up by the cress and translocated from the roots to the leaves in specific patterns. In addition to this, eleven metabolite species were identified. They were generated by hydroxylation, demethylation, conjugation with amino acids, or combinations of these mechanisms. Finally, the inclusion of control cultures in the experimental setup allowed for a differentiation of “true” metabolites generated by the cress and transformation products generated by plant‐independent mechanisms.
Investigation of pumping mechanism for non‐Newtonian blood flow with AC electrothermal forces in a microchannel by hybrid boundary element method and immersed boundary‐lattice Boltzmann method
Authors: Ren Qinlong 
Published: February 2018

AbstractEfficient pumping of blood flow in a microfluidic device is essential for rapid detection of bacterial bloodstream infections (BSI) using alternating current (AC) electrokinetics. Compared with AC electro‐osmosis (ACEO) phenomenon, the advantage of AC electrothermal (ACET) mechanism is its capability of pumping biofluids with high electrical conductivities at a relatively high AC voltage frequency. In the current work, the microfluidic pumping of non‐Newtonian blood flow using ACET forces is investigated in detail by modeling its multi‐physics process with hybrid boundary element method (BEM) and immersed boundary‐lattice Boltzmann method (IB‐LBM). The Carreau–Yasuda model is used to simulate the realistic rheological behavior of blood flow. The ACET pumping efficiency of blood flow is studied in terms of different AC voltage magnitudes and frequencies, thermal boundary conditions of electrodes, electrode configurations, channel height, and the channel length per electrode pair. Besides, the effect of rheological behavior on the blood flow velocity is theoretically analyzed by comparing with the Newtonian fluid flow using scaling law analysis under the same physical conditions. The results indicate that the rheological behavior of blood flow and its frequency‐dependent dielectric property make the pumping phenomenon of blood flow different from that of the common Newtonian aqueous solutions. It is also demonstrated that using a thermally insulated electrode could enhance the pumping efficiency dramatically. Besides, the results conclude that increasing the AC voltage magnitude is a more economical pumping approach than adding the number of electrodes with the same energy consumption when the Joule heating effect is acceptable.
Conceptual design of a new SF6 abatement technology using a multi‐bed series reactor for the production of valuable chemicals free of toxic wastes
Authors: Lee Boreum , Kim Sehwa , Song Jiseon , Ryi Shin‐Kun , Lim Hankwon 
Published: February 2018

AbstractConceptual design using multi‐bed series reactors consisting of catalysts and adsorbent beds was performed for a new SF6 abatement and utilization technology free of toxic chemicals to reduce SF6 emissions and produce valuable products like CaF2 and CaSO4 simultaneously. With process simulation studies using Aspen HYSYS®, comparative studies for a single‐bed reactor (SR‐1), a two‐bed series reactor (SR‐2), and a three‐bed series reactor (SR‐3) revealed that more CaF2 and CaSO4 were produced in multi‐bed series reactors compared to a SR‐1 (SR‐3 > SR‐2 > SR‐1) possibly due to sorption‐enhanced hydrolysis. In addition, lower operating temperatures were observed in multi‐bed series reactors (TSR1 > TSR2 > TSR3) showing the positive effect of using multi‐bed series reactors for a simultaneous SF6 abatement and utilization technology.
Male-biased gene expression resolves sexual conflict through the evolution of sex-specific genetic architecture
Authors: Wright Alison E. , Fumagalli Matteo , Cooney Christopher R. , Bloch Natasha I. , Vieira Filipe G. , Buechel Severine D. , Kolm Niclas , Mank Judith E. 
Published: February 2018

AbstractMany genes are subject to contradictory selection pressures in males and females, and balancing selection resulting from sexual conflict has the potential to substantially increase standing genetic diversity in populations and thereby act as an important force in adaptation. However, the underlying causes of sexual conflict, and the potential for resolution, remains hotly debated. Using transcriptome-resequencing data from male and female guppies, we use a novel approach, combining patterns of genetic diversity and intersexual divergence in allele frequency, to distinguish the different scenarios that give rise to sexual conflict, and how this conflict may be resolved through regulatory evolution. We show that reproductive fitness is the main source of sexual conflict, and this is resolved via the evolution of male-biased expression. Furthermore, resolution of sexual conflict produces significant differences in genetic architecture between males and females, which in turn lead to specific alleles influencing sex-specific viability. Together, our findings suggest an important role for sexual conflict in shaping broad patterns of genome diversity, and show that regulatory evolution is a rapid and efficient route to the resolution of conflict.
An analytic approach for interpretable predictive models in high‐dimensional data in the presence of interactions with exposures
Authors: Bhatnagar Sahir Rai , Yang Yi , Khundrakpam Budhachandra , Evans Alan C. , Blanchette Mathieu , Bouchard Luigi , Greenwood Celia M.T. 
Published: February 2018

ABSTRACTPredicting a phenotype and understanding which variables improve that prediction are two very challenging and overlapping problems in the analysis of high‐dimensional (HD) data such as those arising from genomic and brain imaging studies. It is often believed that the number of truly important predictors is small relative to the total number of variables, making computational approaches to variable selection and dimension reduction extremely important. To reduce dimensionality, commonly used two‐step methods first cluster the data in some way, and build models using cluster summaries to predict the phenotype. It is known that important exposure variables can alter correlation patterns between clusters of HD variables, that is, alter network properties of the variables. However, it is not well understood whether such altered clustering is informative in prediction. Here, assuming there is a binary exposure with such network‐altering effects, we explore whether the use of exposure‐dependent clustering relationships in dimension reduction can improve predictive modeling in a two‐step framework. Hence, we propose a modeling framework called ECLUST to test this hypothesis, and evaluate its performance through extensive simulations. With ECLUST, we found improved prediction and variable selection performance compared to methods that do not consider the environment in the clustering step, or to methods that use the original data as features. We further illustrate this modeling framework through the analysis of three data sets from very different fields, each with HD data, a binary exposure, and a phenotype of interest. Our method is available in the eclust CRAN package.
A test for gene–environment interaction in the presence of measurement error in the environmental variable
Authors: Aschard Hugues , Spiegelman Donna , Laville Vincent , Kraft Pete , Wang Molin 
Published: February 2018

AbstractThe identification of gene–environment interactions in relation to risk of human diseases has been challenging. One difficulty has been that measurement error in the exposure can lead to massive reductions in the power of the test, as well as in bias toward the null in the interaction effect estimates. Leveraging previous work on linear discriminant analysis, we develop a new test of interaction between genetic variants and a continuous exposure that mitigates these detrimental impacts of exposure measurement error in ExG testing by reversing the role of exposure and the diseases status in the fitted model, thus transforming the analysis to standard linear regression. Through simulation studies, we show that the proposed approach is valid in the presence of classical exposure measurement error as well as when there is correlation between the exposure and the genetic variant. Simulations also demonstrated that the reverse test has greater power compared to logistic regression. Finally, we confirmed that our approach eliminates bias from exposure measurement error in estimation. Computing times are reduced by as much as fivefold in this new approach. For illustrative purposes, we applied the new approach to an ExGWAS study of interactions with alcohol and body mass index among 1,145 cases with invasive breast cancer and 1,142 controls from the Cancer Genetic Markers of Susceptibility study.
Astrocyte disruption of neurovascular communication is linked to cortical damage in an animal model of multiple sclerosis
Authors: Eilam Raya , Segal Menahem , Malach Rafael , Sela Michael , Arnon Ruth , Aharoni Rina 
Published: February 2018

AbstractTo elucidate mechanisms contributing to cortical pathology in multiple sclerosis (MS), we investigated neurovascular aberrations, in particular the association of astrocytes with cortical neurons and blood vessels, in mice induced with experimental autoimmune encephalomyelitis (EAE). Blood–brain barrier (BBB) dysfunction was evident by leakage of the tracer sodium fluorescein, along with reduced expression of claudin‐5 by endothelial cells and desmin by pericytes. Immunohistological and ultrastructural analyses revealed detachment of the astroglial cell bodies from the blood vessels and loss of their connections with both the blood vessels and the neuronal synapses. Furthermore, examination of individual astrocytic processes at cortical layer IV, where well‐defined neuronal columns (barrels) are linked to functional properties, revealed loss of astrocytic confinement to the functional neuronal boundaries. Thus, in contrast to the highly modulated patches of astrocyte processes in naïve mice overlapping the barrel cores, in EAE‐mice process distribution was uniform ignoring the barrel boundaries. These aberrations are attributed to the surrounding inflammation, indicated by T‐cells presence in the cortex as well as in the subcortical white matter and the meninges. Immunomodulatory treatment with glatiramer acetate partially abrogated the neurovascular damage. These combined findings indicate that under inflammatory conditions, activated perivascular astrocytes fail in neuro‐hemodynamic coupling, resulting in obstructed cross‐talk between the blood vessels and the neurons. We propose that loss of cortical astrocytic regulation and fine‐tuning between the blood supply and the neuronal needs contributes to the neurological impairment and cognitive decline occurring in EAE/MS as well as to the disease progression.
Asymmetric, nano‐textured surfaces influence neuron viability and polarity
Authors: Belu Andreea , Yilmaz Mehmet , Neumann Elmar , Offenhäusser Andreas , Demirel Gokhan , Mayer Dirk 
Published: February 2018

AbstractThree dimensional, nanostructured surfaces have attracted considerable attention in biomedical research since they have proven to represent a powerful platform to influence cell fate. In particular, nanorods and nanopillars possess great potential for the control of cell adhesion and differentiation, gene and biomolecule delivery, optical and electrical stimulation and recording, as well as cell patterning. Here, we investigate the influence of asymmetric poly(dichloro‐p‐xylene) (PPX) columnar films on the adhesion and maturation of cortical neurons. We show that nanostructured films with dense, inclined polymer columns can support viable primary neuronal culture. The cell‐nanostructure interface is characterized showing a minimal cell penetration but strong adhesion on the surface. Moreover, we quantify the influence of the nano‐textured surface on the neural development (soma size, neuritogenesis, and polarity) in comparison to a planar PPX sample. We demonstrate that the nanostructures facilitates an enhancement in neurite branching as well as elongation of axons and growth cones. Furthermore, we show for the first time that the asymmetric orientation of polymeric nanocolumns strongly influences the initiation direction of the axon formation. These results evidence that 3D nano‐topographies can significantly change neural development and can be used to engineer axon elongation. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1634–1645, 2018.
Development of zwitterionic sulfobetaine block copolymer conjugation strategies for reduced platelet deposition in respiratory assist devices
Authors: Malkin Alexander D. , Ye Sang‐Ho , Lee Evan J. , Yang Xiguang , Zhu Yang , Gamble Lara J. , Federspiel William J. , Wagner William R. 
Published: February 2018

AbstractRespiratory assist devices, that utilize ∼2 m2 of hollow fiber membranes (HFMs) to achieve desired gas transfer rates, have been limited in their adoption due to such blood biocompatibility limitations. This study reports two techniques for the functionalization and subsequent conjugation of zwitterionic sulfobetaine (SB) block copolymers to polymethylpentene (PMP) HFM surfaces with the intention of reducing thrombus formation in respiratory assist devices. Amine or hydroxyl functionalization of PMP HFMs (PMP‐A or PMP‐H) was accomplished using plasma‐enhanced chemical vapor deposition. The generated functional groups were conjugated to low molecular weight SB block copolymers with N‐hydroxysuccinimide ester or siloxane groups (SBNHS or SBNHSi) that were synthesized using reversible addition fragmentation chain transfer polymerization. The modified HFMs (PMP‐A‐SBNHS or PMP‐H‐SBNHSi) showed 80–95% reduction in platelet deposition from whole ovine blood, stability under the fluid shear of anticipated operating conditions, and uninhibited gas exchange performance relative to non‐modified HFMs (PMP‐C). Additionally, the functionalization and SBNHSi conjugation technique was shown to reduce platelet deposition on polycarbonate and poly(vinyl chloride), two other materials commonly found in extracorporeal circuits. The observed thromboresistance and stability of the SB modified surfaces, without degradation of HFM gas transfer performance, indicate that this approach is promising for longer term pre‐clinical testing in respiratory assist devices and may ultimately allow for the reduction of anticoagulation levels in patients being supported for extended periods. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2681–2692, 2018.