bluuebunny/crossref_metadata_2025_split huggingface dataset:
Eddy covariance captures four‐phase crassulacean acid metabolism (CAM) gas exchange signature in Agave
Authors: Owen Nick A. , Choncubhair Órlaith Ní , Males Jamie , del Real Laborde José Ignacio , Rubio‐Cortés Ramón , Griffiths Howard , Lanigan Gary 
Published: July 2015

AbstractMass and energy fluxes were measured over a field of Agave tequilana in Mexico using eddy covariance (EC) methodology. Data were gathered over 252 d, including the transition from wet to dry periods. Net ecosystem exchanges (FN,EC) displayed a crassulacean acid metabolism (CAM) rhythm that alternated from CO2 sink at night to CO2 source during the day, and partitioned canopy fluxes (FA,EC) showed a characteristic four‐phase CO2 exchange pattern. Results were cross‐validated against diel changes in titratable acidity, leaf‐unfurling rates, energy exchange fluxes and reported biomass yields. Projected carbon balance (g C m−2 year−1, mean ± 95% confidence interval) indicated the site was a net sink of −333 ± 24, of which contributions from soil respiration were +692 ± 7, and FA,EC was −1025 ± 25. EC estimated biomass yield was 20.1 Mg (dry) ha−1 year−1. Average integrated daily FA,EC was −234 ± 5 mmol CO2 m−2 d−1 and persisted almost unchanged after 70 d of drought conditions. Regression analyses were performed on the EC data to identify the best environmental predictors of FA. Results suggest that the carbon acquisition strategy of Agave offers productivity and drought resilience advantages over conventional semi‐arid C3 and C4 bioenergy candidates.
Leaf size serves as a proxy for xylem vulnerability to cavitation in plantation trees
Authors: Schreiber Stefan G. , Hacke Uwe G. , Chamberland Sabrina , Lowe Christopher W. , Kamelchuk David , Bräutigam Katharina , Campbell Malcolm M. , Thomas Barb R. 
Published: July 2015

AbstractHybrid poplars are an important renewable forest resource known for their high productivity. At the same time, they are highly vulnerable to water stress. Identifying traits that can serve as indicators for growth performance remains an important task, particularly under field conditions. Understanding which trait combinations translate to improved productivity is key in order to satisfy the demand for poplar wood in an uncertain future climate. In this study, we compared hydraulic and leaf traits among five hybrid poplar clones at 10 plantations in central Alberta. We also assessed the variation of these traits between 2‐ to 3‐year‐old branches from the lower to mid‐crown and current‐year long shoots from the mid to upper crown. Our results showed that (1) hybrid poplars differed in key hydraulic parameters between branch type, (2) variation of hydraulic traits among clones was relatively large for some clones and less for others, and (3) strong relationships between measured hydraulic traits, such as vessel diameter, cavitation resistance, xylem‐specific and leaf‐specific conductivity and leaf area, were observed. Our results suggest that leaf size could serve as an additional screening tool when selecting for drought‐tolerant genotypes in forest management and tree improvement programmes.
Bark water uptake promotes localized hydraulic recovery in coastal redwood crown
Authors: Mason Earles J. , Sperling Or , Silva Lucas C. R. , McElrone Andrew J. , Brodersen Craig R. , North Malcolm P. , Zwieniecki Maciej A. 
Published: July 2015

AbstractCoastal redwood (Sequoia sempervirens), the world's tallest tree species, rehydrates leaves via foliar water uptake during fog/rain events. Here we examine if bark also permits water uptake in redwood branches, exploring potential flow mechanisms and biological significance. Using isotopic labelling and microCT imaging, we observed that water entered the xylem via bark and reduced tracheid embolization. Moreover, prolonged bark wetting (16 h) partially restored xylem hydraulic conductivity in isolated branch segments and whole branches. Partial hydraulic recovery coincided with an increase in branch water potential from about −5.5 ± 0.4 to −4.2 ± 0.3 MPa, suggesting localized recovery and possibly hydraulic isolation. As bark water uptake rate correlated with xylem osmotic potential (R2 = 0.88), we suspect a symplastic role in transferring water from bark to xylem. Using historical weather data from typical redwood habitat, we estimated that bark and leaves are wet more than 1000 h per year on average, with over 30 events being sufficiently long (>24 h) to allow for bark‐assisted hydraulic recovery. The capacity to uptake biologically meaningful volumes of water via bark and leaves for localized hydraulic recovery throughout the crown during rain/fog events might be physiologically advantageous, allowing for relatively constant transpiration.
Preparation of Silver Carbonate and its Application as Visible Light‐driven Photocatalyst Without Sacrificial Reagent
Authors: Jiang Wei , Zeng Ya , Wang Xiaoyan , Yue Xiaoning , Yuan Shaojun , Lu Houfang , Liang Bin 
Published: July 2015

AbstractVisible light‐driven photocatalyst is the current research focus and silver oxyacid salts with p‐block elements are the promising candidates. In this research, Ag2CO3 was prepared by a facile precipitation method and used to degrade the pollutants from waters. The results revealed that the silver carbonate with monoclinic structure quickly decomposed methyl orange and rhodamine B in less than 15 min under visible light irradiation. When it was recycled six times, the degradation of methyl orange still can reach 87% after 30 min. The calculated band gap of Ag2CO3 was 2.312 eV with Valence band edge potential of 2.685 eV and Conduction band 0.373 eV vs NHE, which endowed the excellent photo‐oxidation ability of silver carbonate. Photogenerated holes and ozone anion radicals were the primary active species in the photo‐oxidization degradation of dye. The generation of metallic silver resulted from photocorrosion and the consequent reduction in the ozone anion radical amount led to the performance degradation of Ag2CO3. The simple preparation method and high photocatalytic performance of Ag2CO3 increases its prospect of application in future.
Getting People to Behave: Research Lessons for Policy Makers
Authors: Weaver R. Kent 
Published: July 2015

AbstractMany government policies attempt to change the behavior of individuals and businesses. This article argues that policy makers and administrators should (1) think comprehensively about the barriers that may keep target populations from complying with government policies, (2) match policy instruments to the most important barriers that inhibit compliance, and (3) take into account heterogeneity within the target population. Relatively nonintrusive strategies such as social marketing, providing resources to targets to help them comply, and manipulating options and defaults (choice architecture) are politically attractive but unlikely to secure compliance when incentives for noncompliance are high. Based on the three basic principles outlined in the article, the author recommends strategies to increase compliance, including the use of leverage points and secondary targets, adjusting for unanticipated behavioral responses, and employing long‐term, multiphase strategic management of behavior change initiatives.
Retracted: KATP channels in the nodose ganglia mediate the orexigenic actions of ghrelin
Authors: Grabauskas Gintautas , Wu Xiaoyin , Lu Yuanxu , Heldsinger Andrea , Song Il , Zhou Shi‐Yi , Owyang Chung 
Published: July 2015

Key points
Ghrelin, a hunger signalling peptide derived from the peripheral tissues, overcomes the satiety signals evoked by anorexigenic molecules, such as cholecystokinin (CCK) and leptin, to stimulate feeding.
Using in vivo and in vitro electrophysiological techniques, we show that ghrelin hyperpolarizes neurons and inhibits currents evoked by leptin and CCK‐8.
Administering a KATP channel antagonist or silencing Kir6.2, a major subunit of the KATP channel, abolished ghrelin inhibition.
The inhibitory actions of ghrelin were also abolished by treating the vagal ganglia neurons with pertussis toxin, as well as phosphatidylinositol 3‐kinase (PI3K) or extracellular signal‐regulated kinase 1 and 2 (Erk1/2) small interfering RNA.
Feeding experiments showed that silencing Kir6.2 in the vagal ganglia abolished the orexigenic actions of ghrelin.
These data indicate that ghrelin modulates vagal ganglia neuron excitability by activating KATP conductance via the growth hormone secretagogue receptor subtype 1a–Gαi–PI3K–Erk1/2–KATP pathway.
This provides a mechanism to explain the actions of ghrelin with respect to overcoming anorexigenic signals that act via the vagal afferent pathways.
AbstractGhrelin is the only known hunger signal derived from the peripheral tissues. Ghrelin overcomes the satiety signals evoked by anorexigenic molecules, such as cholecystokinin (CCK) and leptin, to stimulate feeding. The mechanisms by which ghrelin reduces the sensory signals evoked by anorexigenic hormones, which act via the vagus nerve to stimulate feeding, are unknown. Patch clamp recordings of isolated rat vagal neurons show that ghrelin hyperpolarizes neurons by activating K+ conductance. Administering a KATP channel antagonist or silencing Kir6.2, a major subunit of the KATP channel, abolished ghrelin inhibition in vitro and in vivo. Patch clamp studies show that ghrelin inhibits currents evoked by leptin and CCK‐8, which operate through independent ionic channels. The inhibitory actions of ghrelin were abolished by treating the vagal ganglia neurons with pertussis toxin, as well as phosphatidylinositol 3‐kinase (PI3K) or extracellular signal‐regulated kinase 1 and 2 (Erk1/2) small interfering RNA. In vivo gene silencing of PI3K and Erk1/2 in the nodose ganglia prevented ghrelin inhibition of leptin‐ or CCK‐8‐evoked vagal firing. Feeding experiments showed that silencing Kir6.2 in the vagal ganglia abolished the orexigenic actions of ghrelin. These data indicate that ghrelin modulates vagal ganglia neuron excitability by activating KATP conductance via the growth hormone secretagogue receptor subtype 1a–Gαi–PI3K–Erk1/2–KATP pathway. The resulting hyperpolarization renders the neurons less responsive to signals evoked by anorexigenic hormones. This provides a mechanism to explain the actions of ghrelin with respect to overcoming anorexigenic signals that act via the vagal afferent pathways.
μ opioid receptor activation hyperpolarizes respiratory‐controlling Kölliker–Fuse neurons and suppresses post‐inspiratory drive
Authors: Levitt Erica S. , Abdala Ana P. , Paton Julian F. R. , Bissonnette John M. , Williams John T. 
Published: July 2015

Key points
In addition to reductions in respiratory rate, opioids also cause aspiration and difficulty swallowing, indicating impairment of the upper airways. The Kölliker–Fuse (KF) maintains upper airway patency and a normal respiratory pattern.
In this study, activation of μ opioid receptors in the KF reduced respiratory frequency and tidal volume in anaesthetized rats.
Nerve recordings in an in situ preparation showed that activation of μ opioid receptors in the KF eliminated the post‐inspiration phase of the respiratory cycle.
In brain slices, μ opioid agonists hyperpolarized a distinct population (61%) of KF neurons by activation of an inwardly rectifying potassium conductance.
These results suggest that KF neurons that are hyperpolarized by opioids could contribute to opioid‐induced respiratory disturbances, particularly the impairment of upper airways.
AbstractOpioid‐induced respiratory effects include aspiration and difficulty swallowing, suggesting impairment of the upper airways. The pontine Kölliker–Fuse nucleus (KF) controls upper airway patency and regulates respiration, in particular the inspiratory/expiratory phase transition. Given the importance of the KF in coordinating respiratory pattern, the mechanisms of μ opioid receptor activation in this nucleus were investigated at the systems and cellular level. In anaesthetized, vagi‐intact rats, injection of opioid agonists DAMGO or [Met5]enkephalin (ME) into the KF reduced respiratory frequency and amplitude. The μ opioid agonist DAMGO applied directly into the KF of the in situ arterially perfused working heart–brainstem preparation of rat resulted in robust apneusis (lengthened low amplitude inspiration due to loss of post‐inspiratory drive) that was rapidly reversed by the opioid antagonist naloxone. In brain slice preparations, activation of μ opioid receptors on KF neurons hyperpolarized a distinct population (61%) of neurons. As expected, the opioid‐induced hyperpolarization reduced the excitability of the neuron in response to either current injection or local application of glutamate. In voltage‐clamp recordings the outward current produced by the opioid agonist ME was concentration dependent, reversed at the potassium equilibrium potential and was blocked by BaCl2, characteristics of a G protein‐coupled inwardly rectifying potassium (GIRK) conductance. The clinically used drug morphine produced an outward current in KF neurons with similar potency to morphine‐mediated currents in locus coeruleus brain slice preparations. Thus, the population of KF neurons that are hyperpolarized by μ opioid agonists are likely mediators of the opioid‐induced loss of post‐inspiration and induction of apneusis.
Accurate and representative decoding of the neural drive to muscles in humans with multi‐channel intramuscular thin‐film electrodes
Authors: Muceli Silvia , Poppendieck Wigand , Negro Francesco , Yoshida Ken , Hoffmann Klaus P. , Butler Jane E. , Gandevia Simon C. , Farina Dario 
Published: July 2015

Key points
Intramuscular electrodes developed over the past 80 years can record the concurrent activity of only a few motor units active during a muscle contraction.
We designed, produced and tested a novel multi‐channel intramuscular wire electrode that allows in vivo concurrent recordings of a substantially greater number of motor units than with conventional methods.
The electrode has been extensively tested in deep and superficial human muscles.
The performed tests indicate the applicability of the proposed technology in a variety of conditions.
The electrode represents an important novel technology that opens new avenues in the study of the neural control of muscles in humans.
AbstractWe describe the design, fabrication and testing of a novel multi‐channel thin‐film electrode for detection of the output of motoneurones in vivo and in humans, through muscle signals. The structure includes a linear array of 16 detection sites that can sample intramuscular electromyographic activity from the entire muscle cross‐section. The structure was tested in two superficial muscles (the abductor digiti minimi (ADM) and the tibialis anterior (TA)) and a deep muscle (the genioglossus (GG)) during contractions at various forces. Moreover, surface electromyogram (EMG) signals were concurrently detected from the TA muscle with a grid of 64 electrodes. Surface and intramuscular signals were decomposed into the constituent motor unit (MU) action potential trains. With the intramuscular electrode, up to 31 MUs were identified from the ADM muscle during an isometric contraction at 15% of the maximal force (MVC) and 50 MUs were identified for a 30% MVC contraction of TA. The new electrode detects different sources from a surface EMG system, as only one MU spike train was found to be common in the decomposition of the intramuscular and surface signals acquired from the TA. The system also allowed access to the GG muscle, which cannot be analysed with surface EMG, with successful identification of MU activity. With respect to classic detection systems, the presented thin‐film structure enables recording from large populations of active MUs of deep and superficial muscles and thus can provide a faithful representation of the neural drive sent to a muscle.
Ageing induced vascular smooth muscle cell senescence in atherosclerosis
Authors: Uryga Anna K. , Bennett Martin R. 
Published: July 2015

AbstractAtherosclerosis is a disease of ageing in that its incidence and prevalence increase with age. However, atherosclerosis is also associated with biological ageing, manifest by a number of typical hallmarks of ageing in the atherosclerotic plaque. Thus, accelerated biological ageing may be superimposed on the effects of chronological ageing in atherosclerosis. Tissue ageing is seen in all cells that comprise the plaque, but particularly in vascular smooth muscle cells (VSMCs). Hallmarks of ageing include evidence of cell senescence, DNA damage (including telomere attrition), mitochondrial dysfunction, a pro‐inflammatory secretory phenotype, defects in proteostasis, epigenetic changes, deregulated nutrient sensing, and exhaustion of progenitor cells. In this model, initial damage to DNA (genomic, telomeric, mitochondrial and epigenetic changes) results in a number of cellular responses (cellular senescence, deregulated nutrient sensing and defects in proteostasis). Ultimately, ongoing damage and attempts at repair by continued proliferation overwhelm reparative capacity, causing loss of specialised cell functions, cell death and inflammation. This review summarises the evidence for accelerated biological ageing in atherosclerosis, the functional consequences of cell ageing on cells comprising the plaque, and the causal role that VSMC senescence plays in atherogenesis.
image
Analysis of the Efficiency of Hydroerosive Grinding Without Renewal of Abrasive Particles
Authors: Della Roverys Coseglio Mario Sergio , Portela Moreira Pâmela , Leonardo Procópio Henrique , Pintaude Giuseppe 
Published: July 2015

Abstract
Hydroerosive grinding is used as a finishing and inlet rounding operation of diesel nozzles to improve the engine performance. A mixture of hard particles suspended in a carrier fluid circulates through the injection holes to remove material until the required flow condition is achieved, although the time to reach this specification increases with time. The aim of this study is to analyze the process efficiency without renewal of solid particles. Results show that the removal efficiency decreased 20% after 150 hrs and this significant loss can be attributed to hydrodynamic interactions, particle size distribution change, and fluid viscosity reduction.
Effect of Oxidation Chemistry of Supercritical Water on Stress Corrosion Cracking of Austenitic Steels
Authors: Gong Bin , Huang Yanping , Jiang E. , Zhao Yongfu , Liu Weiwei , Zhou Zhiru 
Published: July 2015

Austenitic steel is a candidate material for supercritical water-cooled reactor (SCWR). This study is to investigate the stress corrosion cracking (SCC) behavior of HR3C under the effect of supercritical water chemistry. A transition phenomenon of the water parameters was monitored during a pseudocritical region by water quality experiments at 650°C and 30 MPa. The stress–strain curves and fracture time of HR3C were obtained by slow strain rate tensile (SSRT) tests in the supercritical water at 620°C and 25 MPa. The concentration of the dissolved oxygen (DO) was 200–1000  μg/kg, and the strain rate was 7.5×10−7/s. The recent results showed that the failure mode was dominated by intergranular brittle fracture. The relations of the oxygen concentration and the fracture time were nonlinear. 200–500  μg/kg of oxygen accelerated the cracking, but a longer fracture time was measured when the oxygen concentration was increased to 1000  μg/kg. Chromium depletion occurred in the oxide layer at the tip of cracks. Grain size increased and chain-precipitated phases were observed in the fractured specimens. These characteristics were considered to contribute to the intergranular SCC.
The Endoplasmic Reticulum Stress Sensor Inositol-Requiring Enzyme 1α Augments Bacterial Killing through Sustained Oxidant Production
Authors: Abuaita Basel H. , Burkholder Kristin M. , Boles Blaise R. , O’Riordan Mary X. 
Published: July 2015

ABSTRACT

Bacterial infection can trigger cellular stress programs, such as the unfolded protein response (UPR), which occurs when misfolded proteins accumulate within the endoplasmic reticulum (ER). Here, we used the human pathogen methicillin-resistant
Staphylococcus aureus
(MRSA) as an infection model to probe how ER stress promotes antimicrobial function. MRSA infection activated the most highly conserved unfolded protein response sensor, inositol-requiring enzyme 1α (IRE1α), which was necessary for robust bacterial killing
in vitro
and
in vivo
. The macrophage IRE1-dependent bactericidal activity required reactive oxygen species (ROS). Viable MRSA cells excluded ROS from the nascent phagosome and strongly triggered IRE1 activation, leading to sustained generation of ROS that were largely Nox2 independent. In contrast, dead MRSA showed early colocalization with ROS but was a poor activator of IRE1 and did not trigger sustained ROS generation. The global ROS stimulated by IRE1 signaling was necessary, but not sufficient, for MRSA killing, which also required the ER resident SNARE Sec22B for accumulation of ROS in the phagosomal compartment. Taken together, these results suggest that IRE1-mediated persistent ROS generation might act as a fail-safe mechanism to kill bacterial pathogens that evade the initial macrophage oxidative burst.

IMPORTANCE
Cellular stress programs have been implicated as important components of the innate immune response to infection. The role of the IRE1 pathway of the ER stress response in immune secretory functions, such as antibody production, is well established, but its contribution to innate immunity is less well defined. Here, we show that infection of macrophages with viable MRSA induces IRE1 activation, leading to bacterial killing. IRE1-dependent bactericidal activity required generation of reactive oxygen species in a sustained manner over hours of infection. The SNARE protein Sec22B, which was previously demonstrated to control ER-phagosome trafficking, was dispensable for IRE1-driven global ROS production but necessary for late ROS accumulation in bacteria-containing phagosomes. Our study highlights a key role for IRE1 in promoting macrophage bactericidal capacity and reveals a fail-safe mechanism that leads to the concentration of antimicrobial effector molecules in the macrophage phagosome.