Sample records for accumulating evidence demonstrates

  1. Evidence accumulation as a model for lexical selection.

    PubMed

    Anders, R; Riès, S; van Maanen, L; Alario, F X

    2015-11-01

    We propose and demonstrate evidence accumulation as a plausible theoretical and/or empirical model for the lexical selection process of lexical retrieval. A number of current psycholinguistic theories consider lexical selection as a process related to selecting a lexical target from a number of alternatives, which each have varying activations (or signal supports), that are largely resultant of an initial stimulus recognition. We thoroughly present a case for how such a process may be theoretically explained by the evidence accumulation paradigm, and we demonstrate how this paradigm can be directly related or combined with conventional psycholinguistic theory and their simulatory instantiations (generally, neural network models). Then with a demonstrative application on a large new real data set, we establish how the empirical evidence accumulation approach is able to provide parameter results that are informative to leading psycholinguistic theory, and that motivate future theoretical development. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Discriminating evidence accumulation from urgency signals in speeded decision making.

    PubMed

    Hawkins, Guy E; Wagenmakers, Eric-Jan; Ratcliff, Roger; Brown, Scott D

    2015-07-01

    The dominant theoretical paradigm in explaining decision making throughout both neuroscience and cognitive science is known as “evidence accumulation”--The core idea being that decisions are reached by a gradual accumulation of noisy information. Although this notion has been supported by hundreds of experiments over decades of study, a recent theory proposes that the fundamental assumption of evidence accumulation requires revision. The "urgency gating" model assumes decisions are made without accumulating evidence, using only moment-by-moment information. Under this assumption, the successful history of evidence accumulation models is explained by asserting that the two models are mathematically identical in standard experimental procedures. We demonstrate that this proof of equivalence is incorrect, and that the models are not identical, even when both models are augmented with realistic extra assumptions. We also demonstrate that the two models can be perfectly distinguished in realistic simulated experimental designs, and in two real data sets; the evidence accumulation model provided the best account for one data set, and the urgency gating model for the other. A positive outcome is that the opposing modeling approaches can be fruitfully investigated without wholesale change to the standard experimental paradigms. We conclude that future research must establish whether the urgency gating model enjoys the same empirical support in the standard experimental paradigms that evidence accumulation models have gathered over decades of study. Copyright © 2015 the American Physiological Society.

  3. An evidence accumulation model for conflict detection performance in a simulated air traffic control task.

    PubMed

    Neal, Andrew; Kwantes, Peter J

    2009-04-01

    The aim of this article is to develop a formal model of conflict detection performance. Our model assumes that participants iteratively sample evidence regarding the state of the world and accumulate it over time. A decision is made when the evidence reaches a threshold that changes over time in response to the increasing urgency of the task. Two experiments were conducted to examine the effects of conflict geometry and timing on response proportions and response time. The model is able to predict the observed pattern of response times, including a nonmonotonic relationship between distance at point of closest approach and response time, as well as effects of angle of approach and relative velocity. The results demonstrate that evidence accumulation models provide a good account of performance on a conflict detection task. Evidence accumulation models are a form of dynamic signal detection theory, allowing for the analysis of response times as well as response proportions, and can be used for simulating human performance on dynamic decision tasks.

  4. Sequential biases in accumulating evidence

    PubMed Central

    Huggins, Richard; Dogo, Samson Henry

    2015-01-01

    Whilst it is common in clinical trials to use the results of tests at one phase to decide whether to continue to the next phase and to subsequently design the next phase, we show that this can lead to biased results in evidence synthesis. Two new kinds of bias associated with accumulating evidence, termed ‘sequential decision bias’ and ‘sequential design bias’, are identified. Both kinds of bias are the result of making decisions on the usefulness of a new study, or its design, based on the previous studies. Sequential decision bias is determined by the correlation between the value of the current estimated effect and the probability of conducting an additional study. Sequential design bias arises from using the estimated value instead of the clinically relevant value of an effect in sample size calculations. We considered both the fixed‐effect and the random‐effects models of meta‐analysis and demonstrated analytically and by simulations that in both settings the problems due to sequential biases are apparent. According to our simulations, the sequential biases increase with increased heterogeneity. Minimisation of sequential biases arises as a new and important research area necessary for successful evidence‐based approaches to the development of science. © 2015 The Authors. Research Synthesis Methods Published by John Wiley & Sons Ltd. PMID:26626562

  5. Evidence accumulation detected in BOLD signal using slow perceptual decision making.

    PubMed

    Krueger, Paul M; van Vugt, Marieke K; Simen, Patrick; Nystrom, Leigh; Holmes, Philip; Cohen, Jonathan D

    2017-04-01

    We assessed whether evidence accumulation could be observed in the BOLD signal during perceptual decision making. This presents a challenge since the hemodynamic response is slow, while perceptual decisions are typically fast. Guided by theoretical predictions of the drift diffusion model, we slowed down decisions by penalizing participants for incorrect responses. Second, we distinguished BOLD activity related to stimulus detection (modeled using a boxcar) from activity related to integration (modeled using a ramp) by minimizing the collinearity of GLM regressors. This was achieved by dissecting a boxcar into its two most orthogonal components: an "up-ramp" and a "down-ramp." Third, we used a control condition in which stimuli and responses were similar to the experimental condition, but that did not engage evidence accumulation of the stimuli. The results revealed an absence of areas in parietal cortex that have been proposed to drive perceptual decision making but have recently come into question; and newly identified regions that are candidates for involvement in evidence accumulation. Previous fMRI studies have either used fast perceptual decision making, which precludes the measurement of evidence accumulation, or slowed down responses by gradually revealing stimuli. The latter approach confounds perceptual detection with evidence accumulation because accumulation is constrained by perceptual input. We slowed down the decision making process itself while leaving perceptual information intact. This provided a more sensitive and selective observation of brain regions associated with the evidence accumulation processes underlying perceptual decision making than previous methods. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Evidence Accumulator or Decision Threshold – Which Cortical Mechanism are We Observing?

    PubMed Central

    Simen, Patrick

    2012-01-01

    Most psychological models of perceptual decision making are of the accumulation-to-threshold variety. The neural basis of accumulation in parietal and prefrontal cortex is therefore a topic of great interest in neuroscience. In contrast, threshold mechanisms have received less attention, and their neural basis has usually been sought in subcortical structures. Here I analyze a model of a decision threshold that can be implemented in the same cortical areas as evidence accumulators, and whose behavior bears on two open questions in decision neuroscience: (1) When ramping activity is observed in a brain region during decision making, does it reflect evidence accumulation? (2) Are changes in speed-accuracy tradeoffs and response biases more likely to be achieved by changes in thresholds, or in accumulation rates and starting points? The analysis suggests that task-modulated ramping activity, by itself, is weak evidence that a brain area mediates evidence accumulation as opposed to threshold readout; and that signs of modulated accumulation are as likely to indicate threshold adaptation as adaptation of starting points and accumulation rates. These conclusions imply that how thresholds are modeled can dramatically impact accumulator-based interpretations of this data. PMID:22737136

  7. Normative evidence accumulation in unpredictable environments

    PubMed Central

    Glaze, Christopher M; Kable, Joseph W; Gold, Joshua I

    2015-01-01

    In our dynamic world, decisions about noisy stimuli can require temporal accumulation of evidence to identify steady signals, differentiation to detect unpredictable changes in those signals, or both. Normative models can account for learning in these environments but have not yet been applied to faster decision processes. We present a novel, normative formulation of adaptive learning models that forms decisions by acting as a leaky accumulator with non-absorbing bounds. These dynamics, derived for both discrete and continuous cases, depend on the expected rate of change of the statistics of the evidence and balance signal identification and change detection. We found that, for two different tasks, human subjects learned these expectations, albeit imperfectly, then used them to make decisions in accordance with the normative model. The results represent a unified, empirically supported account of decision-making in unpredictable environments that provides new insights into the expectation-driven dynamics of the underlying neural signals. DOI: http://dx.doi.org/10.7554/eLife.08825.001 PMID:26322383

  8. Conscious and Nonconscious Processes:Distinct Forms of Evidence Accumulation?

    NASA Astrophysics Data System (ADS)

    Dehaene, Stanislas

    Among the many brain events evoked by a visual stimulus, which ones are associated specifically with conscious perception, and which merely reflect nonconscious processing? Understanding the neuronal mechanisms of consciousness is a major challenge for cognitive neuroscience. Recently, progress has been achieved by contrasting behavior and brain activation in minimally different experimental conditions, one of which leads to conscious perception whereas the other does not. This chapter reviews briefly this line of research and speculates on its theoretical interpretation. I propose to draw links between evidence accumulation models, which are highly successful in capturing elementary psychophysical decisions, and the conscious/nonconscious dichotomy. In this framework, conscious access would correspond to the crossing of a threshold in evidence accumulation within a distributed global workspace, a set of recurrently connected neurons with long axons that is able to integrate and broadcast back evidence from multiple brain processors. During nonconscious processing, evidence would be accumulated locally within specialized subcircuits, but would fail to reach the threshold needed for global ignition and, therefore, conscious reportability.

  9. Accumulation of evidence during sequential decision making: the importance of top-down factors.

    PubMed

    de Lange, Floris P; Jensen, Ole; Dehaene, Stanislas

    2010-01-13

    In the last decade, great progress has been made in characterizing the accumulation of neural information during simple unitary perceptual decisions. However, much less is known about how sequentially presented evidence is integrated over time for successful decision making. The aim of this study was to study the mechanisms of sequential decision making in humans. In a magnetoencephalography (MEG) study, we presented healthy volunteers with sequences of centrally presented arrows. Sequence length varied between one and five arrows, and the accumulated directions of the arrows informed the subject about which hand to use for a button press at the end of the sequence (e.g., LRLRR should result in a right-hand press). Mathematical modeling suggested that nonlinear accumulation was the rational strategy for performing this task in the presence of no or little noise, whereas quasilinear accumulation was optimal in the presence of substantial noise. MEG recordings showed a correlate of evidence integration over parietal and central cortex that was inversely related to the amount of accumulated evidence (i.e., when more evidence was accumulated, neural activity for new stimuli was attenuated). This modulation of activity likely reflects a top-down influence on sensory processing, effectively constraining the influence of sensory information on the decision variable over time. The results indicate that, when making decisions on the basis of sequential information, the human nervous system integrates evidence in a nonlinear manner, using the amount of previously accumulated information to constrain the accumulation of additional evidence.

  10. Evidence Accumulation and Choice Maintenance Are Dissociated in Human Perceptual Decision Making

    PubMed Central

    Pedersen, Mads Lund; Endestad, Tor; Biele, Guido

    2015-01-01

    Perceptual decision making in monkeys relies on decision neurons, which accumulate evidence and maintain choices until a response is given. In humans, several brain regions have been proposed to accumulate evidence, but it is unknown if these regions also maintain choices. To test if accumulator regions in humans also maintain decisions we compared delayed and self-paced responses during a face/house discrimination decision making task. Computational modeling and fMRI results revealed dissociated processes of evidence accumulation and decision maintenance, with potential accumulator activations found in the dorsomedial prefrontal cortex, right inferior frontal gyrus and bilateral insula. Potential maintenance activation spanned the frontal pole, temporal gyri, precuneus and the lateral occipital and frontal orbital cortices. Results of a quantitative reverse inference meta-analysis performed to differentiate the functions associated with the identified regions did not narrow down potential accumulation regions, but suggested that response-maintenance might rely on a verbalization of the response. PMID:26510176

  11. Active inference, evidence accumulation and the urn task

    PubMed Central

    FitzGerald, Thomas HB; Schwartenbeck, Philipp; Moutoussis, Michael; Dolan, Raymond J; Friston, Karl

    2015-01-01

    Deciding how much evidence to accumulate before making a decision is a problem we and other animals often face, but one which is not completely understood. This issue is particularly important because a tendency to sample less information (often known as reflection impulsivity) is a feature in several psychopathologies, such as psychosis. A formal understanding information sampling may therefore clarify the computational anatomy of psychopathology. In this theoretical paper, we consider evidence accumulation in terms of active (Bayesian) inference using a generic model of Markov decision processes. Here, agents are equipped with beliefs about their own behaviour – in this case, that they will make informed decisions. Normative decision-making is then modelled using variational Bayes to minimise surprise about choice outcomes. Under this scheme, different facets of belief updating map naturally onto the functional anatomy of the brain (at least at a heuristic level). Of particular interest is the key role played by the expected precision of beliefs about control, which we have previously suggested may be encoded by dopaminergic neurons in the midbrain. We show that manipulating expected precision strongly affects how much information an agent characteristically samples, and thus provides a possible link between impulsivity and dopaminergic dysfunction. Our study therefore represents a step towards understanding evidence accumulation in terms of neurobiologically plausible Bayesian inference, and may cast light on why this process is disordered in psychopathology. PMID:25514108

  12. Content-specific evidence accumulation in inferior temporal cortex during perceptual decision-making

    PubMed Central

    Tremel, Joshua J.; Wheeler, Mark E.

    2015-01-01

    During a perceptual decision, neuronal activity can change as a function of time-integrated evidence. Such neurons may serve as decision variables, signaling a choice when activity reaches a boundary. Because the signals occur on a millisecond timescale, translating to human decision-making using functional neuroimaging has been challenging. Previous neuroimaging work in humans has identified patterns of neural activity consistent with an accumulation account. However, the degree to which the accumulating neuroimaging signals reflect specific sources of perceptual evidence is unknown. Using an extended face/house discrimination task in conjunction with cognitive modeling, we tested whether accumulation signals, as measured using functional magnetic resonance imaging (fMRI), are stimulus-specific. Accumulation signals were defined as a change in the slope of the rising edge of activation corresponding with response time (RT), with higher slopes associated with faster RTs. Consistent with an accumulation account, fMRI activity in face- and house-selective regions in the inferior temporal cortex increased at a rate proportional to decision time in favor of the preferred stimulus. This finding indicates that stimulus-specific regions perform an evidence integrative function during goal-directed behavior and that different sources of evidence accumulate separately. We also assessed the decision-related function of other regions throughout the brain and found that several regions were consistent with classifications from prior work, suggesting a degree of domain generality in decision processing. Taken together, these results provide support for an integration-to-boundary decision mechanism and highlight possible roles of both domain-specific and domain-general regions in decision evidence evaluation. PMID:25562821

  13. The nitrogen legacy: emerging evidence of nitrogen accumulation in anthropogenic landscapes

    NASA Astrophysics Data System (ADS)

    Van Meter, K. J.; Basu, N. B.; Veenstra, J. J.; Burras, C. L.

    2016-03-01

    Watershed and global-scale nitrogen (N) budgets indicate that the majority of the N surplus in anthropogenic landscapes does not reach the coastal oceans. While there is general consensus that this ‘missing’ N either exits the landscape via denitrification or is retained within watersheds as nitrate or organic N, the relative magnitudes of these pools and fluxes are subject to considerable uncertainty. Our study, for the first time, provides direct, large-scale evidence of N accumulation in the root zones of agricultural soils that may account for much of the ‘missing N’ identified in mass balance studies. We analyzed long-term soil data (1957-2010) from 2069 sites throughout the Mississippi River Basin (MRB) to reveal N accumulation in cropland of 25-70 kg ha-1 yr-1, a total of 3.8 ± 1.8 Mt yr-1 at the watershed scale. We then developed a simple modeling framework to capture N depletion and accumulation dynamics under intensive agriculture. Using the model, we show that the observed accumulation of soil organic N (SON) in the MRB over a 30 year period (142 Tg N) would lead to a biogeochemical lag time of 35 years for 99% of legacy SON, even with complete cessation of fertilizer application. By demonstrating that agricultural soils can act as a net N sink, the present work makes a critical contribution towards the closing of watershed N budgets.

  14. Distinct effects of prefrontal and parietal cortex inactivations on an accumulation of evidence task in the rat

    PubMed Central

    Erlich, Jeffrey C; Brunton, Bingni W; Duan, Chunyu A; Hanks, Timothy D; Brody, Carlos D

    2015-01-01

    Numerous brain regions have been shown to have neural correlates of gradually accumulating evidence for decision-making, but the causal roles of these regions in decisions driven by accumulation of evidence have yet to be determined. Here, in rats performing an auditory evidence accumulation task, we inactivated the frontal orienting fields (FOF) and posterior parietal cortex (PPC), two rat cortical regions that have neural correlates of accumulating evidence and that have been proposed as central to decision-making. We used a detailed model of the decision process to analyze the effect of inactivations. Inactivation of the FOF induced substantial performance impairments that were quantitatively best described as an impairment in the output pathway of an evidence accumulator with a long integration time constant (>240 ms). In contrast, we found a minimal role for PPC in decisions guided by accumulating auditory evidence, even while finding a strong role for PPC in internally-guided decisions. DOI: http://dx.doi.org/10.7554/eLife.05457.001 PMID:25869470

  15. Perception as Evidence Accumulation and Bayesian Inference: Insights from Masked Priming

    ERIC Educational Resources Information Center

    Norris, Dennis; Kinoshita, Sachiko

    2008-01-01

    The authors argue that perception is Bayesian inference based on accumulation of noisy evidence and that, in masked priming, the perceptual system is tricked into treating the prime and the target as a single object. Of the 2 algorithms considered for formalizing how the evidence sampled from a prime and target is combined, only 1 was shown to be…

  16. Evidence accumulation in obsessive-compulsive disorder: the role of uncertainty and monetary reward on perceptual decision-making thresholds.

    PubMed

    Banca, Paula; Vestergaard, Martin D; Rankov, Vladan; Baek, Kwangyeol; Mitchell, Simon; Lapa, Tatyana; Castelo-Branco, Miguel; Voon, Valerie

    2015-03-13

    The compulsive behaviour underlying obsessive-compulsive disorder (OCD) may be related to abnormalities in decision-making. The inability to commit to ultimate decisions, for example, patients unable to decide whether their hands are sufficiently clean, may reflect failures in accumulating sufficient evidence before a decision. Here we investigate the process of evidence accumulation in OCD in perceptual discrimination, hypothesizing enhanced evidence accumulation relative to healthy volunteers. Twenty-eight OCD patients and thirty-five controls were tested with a low-level visual perceptual task (random-dot-motion task, RDMT) and two response conflict control tasks. Regression analysis across different motion coherence levels and Hierarchical Drift Diffusion Modelling (HDDM) were used to characterize response strategies between groups in the RDMT. Patients required more evidence under high uncertainty perceptual contexts, as indexed by longer response time and higher decision boundaries. HDDM, which defines a decision when accumulated noisy evidence reaches a decision boundary, further showed slower drift rate towards the decision boundary reflecting poorer quality of evidence entering the decision process in patients under low uncertainty. With monetary incentives emphasizing speed and penalty for slower responses, patients decreased the decision thresholds relative to controls, accumulating less evidence in low uncertainty. These findings were unrelated to visual perceptual deficits and response conflict. This study provides evidence for impaired decision-formation processes in OCD, with a differential influence of high and low uncertainty contexts on evidence accumulation (decision threshold) and on the quality of evidence gathered (drift rates). It further emphasizes that OCD patients are sensitive to monetary incentives heightening speed in the speed-accuracy tradeoff, improving evidence accumulation.

  17. What is value—accumulated reward or evidence?

    PubMed Central

    Friston, Karl; Adams, Rick; Montague, Read

    2012-01-01

    Why are you reading this abstract? In some sense, your answer will cast the exercise as valuable—but what is value? In what follows, we suggest that value is evidence or, more exactly, log Bayesian evidence. This implies that a sufficient explanation for valuable behavior is the accumulation of evidence for internal models of our world. This contrasts with normative models of optimal control and reinforcement learning, which assume the existence of a value function that explains behavior, where (somewhat tautologically) behavior maximizes value. In this paper, we consider an alternative formulation—active inference—that replaces policies in normative models with prior beliefs about the (future) states agents should occupy. This enables optimal behavior to be cast purely in terms of inference: where agents sample their sensorium to maximize the evidence for their generative model of hidden states in the world, and minimize their uncertainty about those states. Crucially, this formulation resolves the tautology inherent in normative models and allows one to consider how prior beliefs are themselves optimized in a hierarchical setting. We illustrate these points by showing that any optimal policy can be specified with prior beliefs in the context of Bayesian inference. We then show how these prior beliefs are themselves prescribed by an imperative to minimize uncertainty. This formulation explains the saccadic eye movements required to read this text and defines the value of the visual sensations you are soliciting. PMID:23133414

  18. Neural chronometry and coherency across speed-accuracy demands reveal lack of homomorphism between computational and neural mechanisms of evidence accumulation.

    PubMed

    Heitz, Richard P; Schall, Jeffrey D

    2013-10-19

    The stochastic accumulation framework provides a mechanistic, quantitative account of perceptual decision-making and how task performance changes with experimental manipulations. Importantly, it provides an elegant account of the speed-accuracy trade-off (SAT), which has long been the litmus test for decision models, and also mimics the activity of single neurons in several key respects. Recently, we developed a paradigm whereby macaque monkeys trade speed for accuracy on cue during visual search task. Single-unit activity in frontal eye field (FEF) was not homomorphic with the architecture of models, demonstrating that stochastic accumulators are an incomplete description of neural activity under SAT. This paper summarizes and extends this work, further demonstrating that the SAT leads to extensive, widespread changes in brain activity never before predicted. We will begin by reviewing our recently published work that establishes how spiking activity in FEF accomplishes SAT. Next, we provide two important extensions of this work. First, we report a new chronometric analysis suggesting that increases in perceptual gain with speed stress are evident in FEF synaptic input, implicating afferent sensory-processing sources. Second, we report a new analysis demonstrating selective influence of SAT on frequency coupling between FEF neurons and local field potentials. None of these observations correspond to the mechanics of current accumulator models.

  19. An Accumulation-of-Evidence Task Using Visual Pulses for Mice Navigating in Virtual Reality

    PubMed Central

    Pinto, Lucas; Koay, Sue A.; Engelhard, Ben; Yoon, Alice M.; Deverett, Ben; Thiberge, Stephan Y.; Witten, Ilana B.; Tank, David W.; Brody, Carlos D.

    2018-01-01

    The gradual accumulation of sensory evidence is a crucial component of perceptual decision making, but its neural mechanisms are still poorly understood. Given the wide availability of genetic and optical tools for mice, they can be useful model organisms for the study of these phenomena; however, behavioral tools are largely lacking. Here, we describe a new evidence-accumulation task for head-fixed mice navigating in a virtual reality (VR) environment. As they navigate down the stem of a virtual T-maze, they see brief pulses of visual evidence on either side, and retrieve a reward on the arm with the highest number of pulses. The pulses occur randomly with Poisson statistics, yielding a diverse yet well-controlled stimulus set, making the data conducive to a variety of computational approaches. A large number of mice of different genotypes were able to learn and consistently perform the task, at levels similar to rats in analogous tasks. They are sensitive to side differences of a single pulse, and their memory of the cues is stable over time. Moreover, using non-parametric as well as modeling approaches, we show that the mice indeed accumulate evidence: they use multiple pulses of evidence from throughout the cue region of the maze to make their decision, albeit with a small overweighting of earlier cues, and their performance is affected by the magnitude but not the duration of evidence. Additionally, analysis of the mice's running patterns revealed that trajectories are fairly stereotyped yet modulated by the amount of sensory evidence, suggesting that the navigational component of this task may provide a continuous readout correlated to the underlying cognitive variables. Our task, which can be readily integrated with state-of-the-art techniques, is thus a valuable tool to study the circuit mechanisms and dynamics underlying perceptual decision making, particularly under more complex behavioral contexts. PMID:29559900

  20. Dopamine Modulates the Efficiency of Sensory Evidence Accumulation During Perceptual Decision Making.

    PubMed

    Beste, Christian; Adelhöfer, Nico; Gohil, Krutika; Passow, Susanne; Roessner, Veit; Li, Shu-Chen

    2018-04-02

    Perceptual decision making is the process through which available sensory information is gathered and processed to guide our choices. However, the neuropsychopharmacological basis of this important cognitive function is largely elusive. Yet, theoretical considerations suggest that the dopaminergic system may play an important role. In a double-blind, randomized, placebo-controlled study design, we examined the effect of methylphenidate in 2 dosages (0.25 mg/kg and 0.5 mg/kg body weight) in separate groups of healthy young adults. We used a moving dots task in which the coherency of the direction of moving dots stimuli was manipulated in 3 levels (5%, 15%, and 35%). Drift diffusion modelling was applied to behavioral data to capture subprocesses of perceptual decision making. The findings show that only the drift rate (v), reflecting the efficiency of sensory evidence accumulation, but not the decision criterion threshold (a) or the duration of nondecisional processes (Ter), is affected by methylphenidate vs placebo administration. Compared with placebo, administering 0.25 mg/kg methylphenidate increased v, but only in the 35% coherence condition. Administering 0.5 mg/kg methylphenidate did not induce modulations. The data suggest that dopamine selectively modulates the efficacy of evidence accumulation during perceptual decision making. This modulation depends on 2 factors: (1) the degree to which the dopaminergic system is modulated using methylphenidate (i.e., methylphenidate dosage) and (2) the signal-to-noise ratio of the visual information. Dopamine affects sensory evidence accumulation only when dopamine concentration is not shifted beyond an optimal level and the incoming information is less noisy.

  1. Accumulating Evidence and Research Organization (AERO) model: a new tool for representing, analyzing, and planning a translational research program.

    PubMed

    Hey, Spencer Phillips; Heilig, Charles M; Weijer, Charles

    2013-05-30

    Maximizing efficiency in drug development is important for drug developers, policymakers, and human subjects. Limited funds and the ethical imperative of risk minimization demand that researchers maximize the knowledge gained per patient-subject enrolled. Yet, despite a common perception that the current system of drug development is beset by inefficiencies, there remain few approaches for systematically representing, analyzing, and communicating the efficiency and coordination of the research enterprise. In this paper, we present the first steps toward developing such an approach: a graph-theoretic tool for representing the Accumulating Evidence and Research Organization (AERO) across a translational trajectory. This initial version of the AERO model focuses on elucidating two dimensions of robustness: (1) the consistency of results among studies with an identical or similar outcome metric; and (2) the concordance of results among studies with qualitatively different outcome metrics. The visual structure of the model is a directed acyclic graph, designed to capture these two dimensions of robustness and their relationship to three basic questions that underlie the planning of a translational research program: What is the accumulating state of total evidence? What has been the translational trajectory? What studies should be done next? We demonstrate the utility of the AERO model with an application to a case study involving the antibacterial agent, moxifloxacin, for the treatment of drug-susceptible tuberculosis. We then consider some possible elaborations for the AERO model and propose a number of ways in which the tool could be used to enhance the planning, reporting, and analysis of clinical trials. The AERO model provides an immediate visual representation of the number of studies done at any stage of research, depicting both the robustness of evidence and the relationship of each study to the larger translational trajectory. In so doing, it makes some of the

  2. Evidence for gas accumulation associated with diapirism and gas hydrates at the head of the Cape Fear Slide

    USGS Publications Warehouse

    Schmuck, E.A.; Paull, C.K.

    1993-01-01

    Single-channel seismic reflection profiles show evidence for areas of significant gas accumulation at the head of the Cape Fear Slide on the continental rise oft North Carolina. Gas accumulation appears to occur beneath a gas hydrate seal in landward-dipping strata and in domed strata associated with diapirism. In addition, gas venting may have occurred near diapirs located at the head of the slide.

  3. Evidence for gas accumulation associated with diapirism and gas hydrates at the head of the Cape Fear Slide

    USGS Publications Warehouse

    Schmuck, E.A.; Paull, C.K.

    1993-01-01

    Single-channel seismic reflection profiles show evidence for areas of significant gas accumulation at the head of the Cape Fear Slide on the continental rise off North Carolina. Gas accumulation appears to occur beneath a gas hydrate seal in landward-dipping strata and in domed strata associated with diapirism. In addition, gas venting may have occurred near diapirs located at the head of the slide. ?? 1993 Springer-Verlag.

  4. Rapid temporal accumulation in spider fear: Evidence from hierarchical drift diffusion modelling.

    PubMed

    Tipples, Jason

    2015-12-01

    Fear can distort sense of time--making time seem slow or even stand still. Here, I used hierarchical drift diffusion modeling (HDDM; Vandekerckhove, Tuerlinckx, & Lee, 2008, 2011; Wiecki, Sofer, & Frank, 2013) to test the idea that temporal accumulation speeds up during fear. Eighteen high fearful and 23 low fearful participants judged the duration of both feared stimuli (spiders) and nonfeared stimuli (birds) in a temporal bisection task. The drift diffusion modeling results support the main hypothesis. In high but not low fearful individuals, evidence accumulated more rapidly toward a long duration decision-drift rates were higher-for spiders compared with birds. This result and further insights into how fear affects time perception would not have been possible on the basis of analyses of choice proportion data alone. Further results were interpreted in the context of a recent 2-stage model of time perception (Balcı & Simen, 2014). The results highlight the usefulness of diffusion modeling to test process-based explanations of disordered cognition in emotional disorders. (c) 2015 APA, all rights reserved).

  5. Evidence Accumulation and Change Rate Inference in Dynamic Environments.

    PubMed

    Radillo, Adrian E; Veliz-Cuba, Alan; Josić, Krešimir; Kilpatrick, Zachary P

    2017-06-01

    In a constantly changing world, animals must account for environmental volatility when making decisions. To appropriately discount older, irrelevant information, they need to learn the rate at which the environment changes. We develop an ideal observer model capable of inferring the present state of the environment along with its rate of change. Key to this computation is an update of the posterior probability of all possible change point counts. This computation can be challenging, as the number of possibilities grows rapidly with time. However, we show how the computations can be simplified in the continuum limit by a moment closure approximation. The resulting low-dimensional system can be used to infer the environmental state and change rate with accuracy comparable to the ideal observer. The approximate computations can be performed by a neural network model via a rate-correlation-based plasticity rule. We thus show how optimal observers accumulate evidence in changing environments and map this computation to reduced models that perform inference using plausible neural mechanisms.

  6. RELATING ACCUMULATOR MODEL PARAMETERS AND NEURAL DYNAMICS

    PubMed Central

    Purcell, Braden A.; Palmeri, Thomas J.

    2016-01-01

    Accumulator models explain decision-making as an accumulation of evidence to a response threshold. Specific model parameters are associated with specific model mechanisms, such as the time when accumulation begins, the average rate of evidence accumulation, and the threshold. These mechanisms determine both the within-trial dynamics of evidence accumulation and the predicted behavior. Cognitive modelers usually infer what mechanisms vary during decision-making by seeing what parameters vary when a model is fitted to observed behavior. The recent identification of neural activity with evidence accumulation suggests that it may be possible to directly infer what mechanisms vary from an analysis of how neural dynamics vary. However, evidence accumulation is often noisy, and noise complicates the relationship between accumulator dynamics and the underlying mechanisms leading to those dynamics. To understand what kinds of inferences can be made about decision-making mechanisms based on measures of neural dynamics, we measured simulated accumulator model dynamics while systematically varying model parameters. In some cases, decision- making mechanisms can be directly inferred from dynamics, allowing us to distinguish between models that make identical behavioral predictions. In other cases, however, different parameterized mechanisms produce surprisingly similar dynamics, limiting the inferences that can be made based on measuring dynamics alone. Analyzing neural dynamics can provide a powerful tool to resolve model mimicry at the behavioral level, but we caution against drawing inferences based solely on neural analyses. Instead, simultaneous modeling of behavior and neural dynamics provides the most powerful approach to understand decision-making and likely other aspects of cognition and perception. PMID:28392584

  7. Visuospatial Asymmetries Arise from Differences in the Onset Time of Perceptual Evidence Accumulation.

    PubMed

    Newman, Daniel P; Loughnane, Gerard M; Kelly, Simon P; O'Connell, Redmond G; Bellgrove, Mark A

    2017-03-22

    Healthy subjects tend to exhibit a bias of visual attention whereby left hemifield stimuli are processed more quickly and accurately than stimuli appearing in the right hemifield. It has long been held that this phenomenon arises from the dominant role of the right cerebral hemisphere in regulating attention. However, methods that would enable more precise understanding of the mechanisms underpinning visuospatial bias have remained elusive. We sought to finely trace the temporal evolution of spatial biases by leveraging a novel bilateral dot motion detection paradigm. In combination with electroencephalography, this paradigm enables researchers to isolate discrete neural signals reflecting the key neural processes needed for making these detection decisions. These include signals for spatial attention, early target selection, evidence accumulation, and motor preparation. Using this method, we established that three key neural markers accounted for unique between-subject variation in visuospatial bias: hemispheric asymmetry in posterior α power measured before target onset, which is related to the distribution of preparatory attention across the visual field; asymmetry in the peak latency of the early N2c target-selection signal; and, finally, asymmetry in the onset time of the subsequent neural evidence-accumulation process with earlier onsets for left hemifield targets. Our development of a single paradigm to dissociate distinct processing components that track the temporal evolution of spatial biases not only advances our understanding of the neural mechanisms underpinning normal visuospatial attention bias, but may also in the future aid differential diagnoses in disorders of spatial attention. SIGNIFICANCE STATEMENT The significance of this research is twofold. First, it shows that individual differences in how humans direct their attention between left and right space reflects physiological differences in how early the brain starts to accumulate evidence for

  8. Molecular chaperone accumulation as a function of stress evidences adaptation to high hydrostatic pressure in the piezophilic archaeon Thermococcus barophilus.

    PubMed

    Cario, Anaïs; Jebbar, Mohamed; Thiel, Axel; Kervarec, Nelly; Oger, Phil M

    2016-07-05

    The accumulation of mannosyl-glycerate (MG), the salinity stress response osmolyte of Thermococcales, was investigated as a function of hydrostatic pressure in Thermococcus barophilus strain MP, a hyperthermophilic, piezophilic archaeon isolated from the Snake Pit site (MAR), which grows optimally at 40 MPa. Strain MP accumulated MG primarily in response to salinity stress, but in contrast to other Thermococcales, MG was also accumulated in response to thermal stress. MG accumulation peaked for combined stresses. The accumulation of MG was drastically increased under sub-optimal hydrostatic pressure conditions, demonstrating that low pressure is perceived as a stress in this piezophile, and that the proteome of T. barophilus is low-pressure sensitive. MG accumulation was strongly reduced under supra-optimal pressure conditions clearly demonstrating the structural adaptation of this proteome to high hydrostatic pressure. The lack of MG synthesis only slightly altered the growth characteristics of two different MG synthesis deletion mutants. No shift to other osmolytes was observed. Altogether our observations suggest that the salinity stress response in T. barophilus is not essential and may be under negative selective pressure, similarly to what has been observed for its thermal stress response.

  9. Molecular chaperone accumulation as a function of stress evidences adaptation to high hydrostatic pressure in the piezophilic archaeon Thermococcus barophilus

    PubMed Central

    Cario, Anaïs; Jebbar, Mohamed; Thiel, Axel; Kervarec, Nelly; Oger, Phil M.

    2016-01-01

    The accumulation of mannosyl-glycerate (MG), the salinity stress response osmolyte of Thermococcales, was investigated as a function of hydrostatic pressure in Thermococcus barophilus strain MP, a hyperthermophilic, piezophilic archaeon isolated from the Snake Pit site (MAR), which grows optimally at 40 MPa. Strain MP accumulated MG primarily in response to salinity stress, but in contrast to other Thermococcales, MG was also accumulated in response to thermal stress. MG accumulation peaked for combined stresses. The accumulation of MG was drastically increased under sub-optimal hydrostatic pressure conditions, demonstrating that low pressure is perceived as a stress in this piezophile, and that the proteome of T. barophilus is low-pressure sensitive. MG accumulation was strongly reduced under supra-optimal pressure conditions clearly demonstrating the structural adaptation of this proteome to high hydrostatic pressure. The lack of MG synthesis only slightly altered the growth characteristics of two different MG synthesis deletion mutants. No shift to other osmolytes was observed. Altogether our observations suggest that the salinity stress response in T. barophilus is not essential and may be under negative selective pressure, similarly to what has been observed for its thermal stress response. PMID:27378270

  10. XFM demonstrates preferential accumulation of a vanadyl-based MRI contrast agent in murine colonic tumors

    PubMed Central

    Mustafi, Devkumar; Ward, Jesse; Dougherty, Urszula; Bissonnette, Marc; Hart, John; Vogt, Stefan; Karczmar, Gregory S.

    2016-01-01

    Contrast agents that specifically enhance cancers on MRI would allow earlier detection. Vanadyl-based chelates (VCs) selectively enhance rodent cancers on MRI, suggesting selective uptake of VCs by cancers. Here we report X-ray fluorescence microscopy (XFM) of VC uptake by murine colon cancer. Colonic tumors in mice treated with azoxymethane/dextran sulfate sodium were identified by MRI. Then a gadolinium-based contrast agent and a VC were injected I.V.; mice were sacrificed and colons sectioned. VC distribution was sampled at 120 minutes after injection to evaluate the long term accumulation. Gadolinium distribution was sampled at 10 minutes after injection due to its rapid washout. XFM was performed on 72 regions of normal and cancerous colon from 5 normal mice and 4 cancer-bearing mice. XFM showed that all gadolinium was extracellular with similar concentrations in colon cancers and normal colon. In contrast, the average VC concentration was 2-fold higher in cancers vs. normal tissue (p<0.002). Cancers also contained numerous ‘hot spots’ with intracellular VC concentrations 6-fold higher than the concentration in normal colon (p<0.0001). No ‘hot spots’ were detected in normal colon. This is the first direct demonstration that VCs selectively accumulate in cancer cells, and thus may improve cancer detection. PMID:25813904

  11. Ultrastructural and clinical evidence of subretinal debris accumulation in type 2 macular telangiectasia.

    PubMed

    Cherepanoff, Svetlana; Killingsworth, Murray C; Zhu, Meidong; Nolan, Timothy; Hunyor, Alex P; Young, Stephanie H; Hageman, Gregory S; Gillies, Mark C

    2012-11-01

    To describe subretinal debris found on ultrastructural examination in an eye with macular telangiectasia (MacTel) type 2 and on optical coherence tomography (OCT) in a subset of patients with MacTel type 2. Blocks from the mid-periphery and temporal perifovea of an eye with clinically documented MacTel type 2 were examined with electron microscopy (EM). Cases came from the Sydney centre of the MacTel project and the practices of the authors. On EM examination, subretinal debris was found in the perifovea with accumulation of degenerate photoreceptor elements in the subretinal space. Despite the substantial subretinal debris, there was minimal retinal pigment epithelial (RPE) reaction. Focal defects were seen in the inner limiting membrane in the perifovea. Of the 65 Sydney MacTel project participants, three (5%) had prominent yellow material at the fovea. OCT revealed smooth mounds between the RPE and the ellipsoid region. The material was hyperautofluorescent. This study suggests that subretinal accumulation of photoreceptor debris may be a feature of MacTel type 2. Ultrastructural and OCT evidence of disease beyond the vasculature, involving photoreceptors and Muller cells, is presented.

  12. Accumulator and random-walk models of psychophysical discrimination: a counter-evaluation.

    PubMed

    Vickers, D; Smith, P

    1985-01-01

    In a recent assessment of models of psychophysical discrimination, Heath criticises the accumulator model for its reliance on computer simulation and qualitative evidence, and contrasts it unfavourably with a modified random-walk model, which yields exact predictions, is susceptible to critical test, and is provided with simple parameter-estimation techniques. A counter-evaluation is presented, in which the approximations employed in the modified random-walk analysis are demonstrated to be seriously inaccurate, the resulting parameter estimates to be artefactually determined, and the proposed test not critical. It is pointed out that Heath's specific application of the model is not legitimate, his data treatment inappropriate, and his hypothesis concerning confidence inconsistent with experimental results. Evidence from adaptive performance changes is presented which shows that the necessary assumptions for quantitative analysis in terms of the modified random-walk model are not satisfied, and that the model can be reconciled with data at the qualitative level only by making it virtually indistinguishable from an accumulator process. A procedure for deriving exact predictions for an accumulator process is outlined.

  13. Pulmonary accumulation of polymorphonuclear leukocytes in the adult respiratory distress syndrome

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Powe, J.E.; Short, A.; Sibbald, W.J.

    1982-11-01

    The polymorphonuclear leukocyte (PMN) plays an integral role in the development of permeability pulmonary edema associated with the adult respiratory distress syndrome (ARDS). This report describes 3 patients with ARDS secondary to systemic sepsis who demonstrated an abnormal diffuse accumulation of Indium (/sup 111/In)-labeled PMNs in their lungs, without concomitant clinical or laboratory evidence of a primary chest infection. In one patient, the accumulation of the pulmonary activity during an initial pass suggested that this observation was related to diffuse leukoaggregation within the pulmonary microvasculature. A 4th patient with ARDS was on high-dose corticosteroids at the time of a similarmore » study, and showed no pulmonary accumulation of PMNs, suggesting a possible reason for the reported beneficial effect of corticosteroids in human ARDS.« less

  14. Disease-associated protein seeding suggests a dissociation between misfolded protein accumulation and neurodegeneration in prion disease

    PubMed Central

    Alibhai, James; Diack, Abigail; Manson, Jean

    2017-01-01

    ABSTRACT Chronic neurodegenerative diseases, such as prion diseases or Alzheimer's disease, are associated with progressive accumulation of host proteins which misfold and aggregate. Neurodegeneration is restricted to specific neuronal populations which show clear accumulation of misfolded proteins, whilst neighbouring neurons remain unaffected. Such data raise interesting questions about the vulnerability of specific neuronal populations to neurodegeneration and much research has concentrated only on the mechanisms of neurodegeneration in afflicted neuronal populations. An alternative, undervalued and almost completely unstudied question however is how and why neuronal populations are resilient to neurodegeneration. One potential answer is unaffected regions do not accumulate misfolded proteins, thus mechanisms of neurodegeneration do not become activated. In this perspectives, we discuss novel data from our laboratories which demonstrate that misfolded proteins do accumulate in regions of the brain which do not show evidence of neurodegeneration and further evidence that microglial responses may define the severity of neurodegeneration. PMID:29023184

  15. Accelerated Mutation Accumulation in Asexual Lineages of a Freshwater Snail

    PubMed Central

    Neiman, Maurine; Hehman, Gery; Miller, Joseph T.; Logsdon, John M.; Taylor, Douglas R.

    2010-01-01

    Sexual reproduction is both extremely costly and widespread relative to asexual reproduction, meaning that it must also confer profound advantages in order to persist. One theorized benefit of sex is that it facilitates the clearance of harmful mutations, which would accumulate more rapidly in the absence of recombination. The extent to which ineffective purifying selection and mutation accumulation are direct consequences of asexuality and whether the accelerated buildup of harmful mutations in asexuals can occur rapidly enough to maintain sex within natural populations, however, remain as open questions. We addressed key components of these questions by estimating the rate of mutation accumulation in the mitochondrial genomes of multiple sexual and asexual representatives of Potamopyrgus antipodarum, a New Zealand snail characterized by mixed sexual/asexual populations. We found that increased mutation accumulation is associated with asexuality and occurs rapidly enough to be detected in recently derived asexual lineages of P. antipodarum. Our results demonstrate that increased mutation accumulation in asexuals can differentially affect coexisting and ecologically similar sexual and asexual lineages. The accelerated rate of mutation accumulation observed in asexual P. antipodarum provides some of the most direct evidence to date for a link between asexuality and mutation accumulation and implies that mutational buildup could be rapid enough to contribute to the short-term evolutionary mechanisms that favor sexual reproduction. PMID:19995828

  16. Everything should be as simple as possible, but no simpler: towards a protocol for accumulating evidence regarding the active content of health behaviour change interventions.

    PubMed

    Peters, Gjalt-Jorn Ygram; de Bruin, Marijn; Crutzen, Rik

    2015-01-01

    There is a need to consolidate the evidence base underlying our toolbox of methods of behaviour change. Recent efforts to this effect have conducted meta-regressions on evaluations of behaviour change interventions, deriving each method's effectiveness from its association to intervention effect size. However, there are a range of issues that raise concern about whether this approach is actually furthering or instead obstructing the advancement of health psychology theories and the quality of health behaviour change interventions. Using examples from theory, the literature and data from previous meta-analyses, these concerns and their implications are explained and illustrated. An iterative protocol for evidence base accumulation is proposed that integrates evidence derived from both experimental and applied behaviour change research, and combines theory development in experimental settings with theory testing in applied real-life settings. As evidence gathered in this manner accumulates, a cumulative science of behaviour change can develop.

  17. Everything should be as simple as possible, but no simpler: towards a protocol for accumulating evidence regarding the active content of health behaviour change interventions

    PubMed Central

    Peters, Gjalt-Jorn Ygram; de Bruin, Marijn; Crutzen, Rik

    2015-01-01

    There is a need to consolidate the evidence base underlying our toolbox of methods of behaviour change. Recent efforts to this effect have conducted meta-regressions on evaluations of behaviour change interventions, deriving each method's effectiveness from its association to intervention effect size. However, there are a range of issues that raise concern about whether this approach is actually furthering or instead obstructing the advancement of health psychology theories and the quality of health behaviour change interventions. Using examples from theory, the literature and data from previous meta-analyses, these concerns and their implications are explained and illustrated. An iterative protocol for evidence base accumulation is proposed that integrates evidence derived from both experimental and applied behaviour change research, and combines theory development in experimental settings with theory testing in applied real-life settings. As evidence gathered in this manner accumulates, a cumulative science of behaviour change can develop. PMID:25793484

  18. The ecological impacts of marine debris: unraveling the demonstrated evidence from what is perceived.

    PubMed

    Rochman, Chelsea M; Browne, Mark Anthony; Underwood, A J; van Franeker, Jan A; Thompson, Richard C; Amaral-Zettler, Linda A

    2016-02-01

    Anthropogenic debris contaminates marine habitats globally, leading to several perceived ecological impacts. Here, we critically and systematically review the literature regarding impacts of debris from several scientific fields to understand the weight of evidence regarding the ecological impacts of marine debris. We quantified perceived and demonstrated impacts across several levels of biological organization that make up the ecosystem and found 366 perceived threats of debris across all levels. Two hundred and ninety-six of these perceived threats were tested, 83% of which were demonstrated. The majority (82%) of demonstrated impacts were due to plastic, relative to other materials (e.g., metals, glass) and largely (89%) at suborganismal levels (e.g., molecular, cellular, tissue). The remaining impacts, demonstrated at higher levels of organization (i.e., death to individual organisms, changes in assemblages), were largely due to plastic marine debris (> 1 mm; e.g., rope, straws, and fragments). Thus, we show evidence of ecological impacts from marine debris, but conclude that the quantity and quality of research requires improvement to allow the risk of ecological impacts of marine debris to be determined with precision. Still, our systematic review suggests that sufficient evidence exists for decision makers to begin to mitigate problematic plastic debris now, to avoid risk of irreversible harm.

  19. Accumulate-Repeat-Accumulate-Accumulate-Codes

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Sam; Thorpe, Jeremy

    2004-01-01

    Inspired by recently proposed Accumulate-Repeat-Accumulate (ARA) codes [15], in this paper we propose a channel coding scheme called Accumulate-Repeat-Accumulate-Accumulate (ARAA) codes. These codes can be seen as serial turbo-like codes or as a subclass of Low Density Parity Check (LDPC) codes, and they have a projected graph or protograph representation; this allows for a high-speed iterative decoder implementation using belief propagation. An ARAA code can be viewed as a precoded Repeat-and-Accumulate (RA) code with puncturing in concatenation with another accumulator, where simply an accumulator is chosen as the precoder; thus ARAA codes have a very fast encoder structure. Using density evolution on their associated protographs, we find examples of rate-lJ2 ARAA codes with maximum variable node degree 4 for which a minimum bit-SNR as low as 0.21 dB from the channel capacity limit can be achieved as the block size goes to infinity. Such a low threshold cannot be achieved by RA or Irregular RA (IRA) or unstructured irregular LDPC codes with the same constraint on the maximum variable node degree. Furthermore by puncturing the accumulators we can construct families of higher rate ARAA codes with thresholds that stay close to their respective channel capacity thresholds uniformly. Iterative decoding simulation results show comparable performance with the best-known LDPC codes but with very low error floor even at moderate block sizes.

  20. Bayes factors for the linear ballistic accumulator model of decision-making.

    PubMed

    Evans, Nathan J; Brown, Scott D

    2018-04-01

    Evidence accumulation models of decision-making have led to advances in several different areas of psychology. These models provide a way to integrate response time and accuracy data, and to describe performance in terms of latent cognitive processes. Testing important psychological hypotheses using cognitive models requires a method to make inferences about different versions of the models which assume different parameters to cause observed effects. The task of model-based inference using noisy data is difficult, and has proven especially problematic with current model selection methods based on parameter estimation. We provide a method for computing Bayes factors through Monte-Carlo integration for the linear ballistic accumulator (LBA; Brown and Heathcote, 2008), a widely used evidence accumulation model. Bayes factors are used frequently for inference with simpler statistical models, and they do not require parameter estimation. In order to overcome the computational burden of estimating Bayes factors via brute force integration, we exploit general purpose graphical processing units; we provide free code for this. This approach allows estimation of Bayes factors via Monte-Carlo integration within a practical time frame. We demonstrate the method using both simulated and real data. We investigate the stability of the Monte-Carlo approximation, and the LBA's inferential properties, in simulation studies.

  1. Accumulate-Repeat-Accumulate-Accumulate Codes

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Samuel; Thorpe, Jeremy

    2007-01-01

    Accumulate-repeat-accumulate-accumulate (ARAA) codes have been proposed, inspired by the recently proposed accumulate-repeat-accumulate (ARA) codes. These are error-correcting codes suitable for use in a variety of wireless data-communication systems that include noisy channels. ARAA codes can be regarded as serial turbolike codes or as a subclass of low-density parity-check (LDPC) codes, and, like ARA codes they have projected graph or protograph representations; these characteristics make it possible to design high-speed iterative decoders that utilize belief-propagation algorithms. The objective in proposing ARAA codes as a subclass of ARA codes was to enhance the error-floor performance of ARA codes while maintaining simple encoding structures and low maximum variable node degree.

  2. Using Time-Varying Evidence to Test Models of Decision Dynamics: Bounded Diffusion vs. the Leaky Competing Accumulator Model

    PubMed Central

    Tsetsos, Konstantinos; Gao, Juan; McClelland, James L.; Usher, Marius

    2012-01-01

    When people make decisions, do they give equal weight to evidence arriving at different times? A recent study (Kiani et al., 2008) using brief motion pulses (superimposed on a random moving dot display) reported a primacy effect: pulses presented early in a motion observation period had a stronger impact than pulses presented later. This observation was interpreted as supporting the bounded diffusion (BD) model and ruling out models in which evidence accumulation is subject to leakage or decay of early-arriving information. We use motion pulses and other manipulations of the timing of the perceptual evidence in new experiments and simulations that support the leaky competing accumulator (LCA) model as an alternative to the BD model. While the LCA does include leakage, we show that it can exhibit primacy as a result of competition between alternatives (implemented via mutual inhibition), when the inhibition is strong relative to the leak. Our experiments replicate the primacy effect when participants must be prepared to respond quickly at the end of a motion observation period. With less time pressure, however, the primacy effect is much weaker. For 2 (out of 10) participants, a primacy bias observed in trials where the motion observation period is short becomes weaker or reverses (becoming a recency effect) as the observation period lengthens. Our simulation studies show that primacy is equally consistent with the LCA or with BD. The transition from primacy-to-recency can also be captured by the LCA but not by BD. Individual differences and relations between the LCA and other models are discussed. PMID:22701399

  3. Evidence accumulation in decision making: unifying the "take the best" and the "rational" models.

    PubMed

    Lee, Michael D; Cummins, Tarrant D R

    2004-04-01

    An evidence accumulation model of forced-choice decision making is proposed to unify the fast and frugal take the best (TTB) model and the alternative rational (RAT) model with which it is usually contrasted. The basic idea is to treat the TTB model as a sequential-sampling process that terminates as soon as any evidence in favor of a decision is found and the rational approach as a sequential-sampling process that terminates only when all available information has been assessed. The unified TTB and RAT models were tested in an experiment in which participants learned to make correct judgments for a set of real-world stimuli on the basis of feedback, and were then asked to make additional judgments without feedback for cases in which the TTB and the rational models made different predictions. The results show that, in both experiments, there was strong intraparticipant consistency in the use of either the TTB or the rational model but large interparticipant differences in which model was used. The unified model is shown to be able to capture the differences in decision making across participants in an interpretable way and is preferred by the minimum description length model selection criterion.

  4. Memory Accumulation Mechanisms in Human Cortex Are Independent of Motor Intentions

    PubMed Central

    Tosoni, Annalisa; Mignogna, Valeria; McAvoy, Mark P.; Shulman, Gordon L.; Corbetta, Maurizio; Romani, Gian Luca

    2014-01-01

    Previous studies on perceptual decision-making have often emphasized a tight link between decisions and motor intentions. Human decisions, however, also depend on memories or experiences that are not closely tied to specific motor responses. Recent neuroimaging findings have suggested that, during episodic retrieval, parietal activity reflects the accumulation of evidence for memory decisions. It is currently unknown, however, whether these evidence accumulation signals are functionally linked to signals for motor intentions coded in frontoparietal regions and whether activity in the putative memory accumulator tracks the amount of evidence for only previous experience, as reflected in “old” reports, or for both old and new decisions, as reflected in the accuracy of memory judgments. Here, human participants used saccadic-eye and hand-pointing movements to report recognition judgments on pictures defined by different degrees of evidence for old or new decisions. A set of cortical regions, including the middle intraparietal sulcus, showed a monotonic variation of the fMRI BOLD signal that scaled with perceived memory strength (older > newer), compatible with an asymmetrical memory accumulator. Another set, including the hippocampus and the angular gyrus, showed a nonmonotonic response profile tracking memory accuracy (higher > lower evidence), compatible with a symmetrical accumulator. In contrast, eye and hand effector-specific regions in frontoparietal cortex tracked motor intentions but were not modulated by the amount of evidence for the effector outcome. We conclude that item recognition decisions are supported by a combination of symmetrical and asymmetrical accumulation signals largely segregated from motor intentions. PMID:24828652

  5. Strain accumulation and rotation in the Eastern California Shear Zone

    USGS Publications Warehouse

    Savage, J.C.; Gan, Weijun; Svarc, J.L.

    2001-01-01

    Although the Eastern California Shear Zone (ECSZ) (strike ???N25??W) does not quite coincide with a small circle drawn about the Pacific-North America pole of rotation, trilateration and GPS measurements demonstrate that the motion within the zone corresponds to right-lateral simple shear across a vertical plane (strike N33??W??5??) roughly parallel to the tangent to that local small circle (strike ???N40??W). If the simple shear is released by slip on faults subparallel to the shear zone, the accumulated rotation is also released, leaving no secular rotation. South of the Garlock fault the principal faults (e.g., Calico-Blackwater fault) strike ???N40??W, close enough to the strike of the vertical plane across which maximum right-lateral shear accumulates to almost wholly accommodate that accumulation of both strain and rotation by right-lateral slip. North of the Garlock fault dip slip as well as strike slip on the principal faults (strike ???N20??W) is required to accommodate the simple shear accumulation. In both cases the accumulated rotation is released with the shear strain. The Garlock fault, which transects the ECSZ, is not offset by north-northwest striking faults nor, despite geological evidence for long-term left-lateral slip, does it appear at the present time to be accumulating left-lateral simple shear strain across the fault due to slip at depth. Rather the motion is explained by right-lateral simple shear across the orthogonal ECSZ. Left-lateral slip on the Garlock fault will release the shear strain accumulating there but would augment the accumulating rotation, resulting in a secular clockwise rotation rate ???80 nrad yr-1 (4.6?? Myr-1).

  6. Accumulating Evidence for a Drug–Drug Interaction Between Methotrexate and Proton Pump Inhibitors

    PubMed Central

    Mackey, Ann Corken; Kluetz, Paul; Jappar, Dilara; Korvick, Joyce

    2012-01-01

    Background. A number of medications are known to interact with methotrexate through various mechanisms. The aim of this article is to apprise practitioners of a new labeling change based on the accumulating evidence for a possible drug–drug interaction between methotrexate (primarily at high doses) and proton pump inhibitors (PPIs). Methods. The U.S. Food and Drug Administration (FDA) Adverse Event Reporting System (AERS) database of spontaneous adverse event reports and the published literature were searched for cases reporting an interaction between methotrexate and PPIs. Results. A search of the AERS database and existing literature found several individual case reports of drug–drug interactions and three additional supportive studies that suggest potential underlying mechanisms for the interaction. Conclusion. There is evidence to suggest that concomitant use of methotrexate (primarily at high doses) with PPIs such as omeprazole, esomeprazole, and pantoprazole may decrease methotrexate clearance, leading to elevated serum levels of methotrexate and/or its metabolite hydroxymethotrexate, possibly leading to methotrexate toxicities. In several case reports, no methotrexate toxicity was found when a histamine H2 blocker was substituted for a PPI. Based on the reviewed data, the FDA updated the methotrexate label to include the possible drug–drug interaction between high-dose methotrexate and PPIs. Physicians should be alerted to this potential drug–drug interaction in patients receiving concomitant high-dose methotrexate and PPIs. PMID:22477728

  7. The influence of large wood accumulations on riparian seed bank diversity

    NASA Astrophysics Data System (ADS)

    Osei, N. A.

    2012-04-01

    Little is known about the structure and complexity of seed bank within the riparian corridor and the how large wood accumulations contribute to riparian seed bank diversity. This study aimed to examine and quantify seed bank assemblage and diversity along the undisturbed riparian corridor of the Highland Water, a second order lowland stream draining the New Forest. Seed bank samples were collected from five riparian corridor microhabitats namely mid-channel bars, floodplains, bare banks, banks adjacent large wood accumulations and within large wood accumulations that differed in their hydrologic connectivity with the river. Descriptive statistics and ordination methods applied to the floristic and sediment data sets indicates that sediment organic matter content, species richness and proportions of functional types distinctly differed among the riparian microhabitats types but there was no difference in viable seed densities. Banks adjacent large wood accumulations were the most floristically diverse and rich in organic matter with mid-channel bars exhibiting the reverse. This was due to the ability of large wood accumulations to buffer varying magnitudes of physical gradients and sort seeds and sediments, therefore altering the character of bare banks. This study not only strengthen the evidence that riparian corridors exhibit elevated spatial sediment and vegetation heterogeneity but also demonstrates the importance of large wood accumulation as habitat modifiers, ecosystem engineers and conservation sink for moisture, organic matter and seeds, resources essential for riparian vegetation conservation, recovery and restoration efforts.

  8. Accumulate repeat accumulate codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, A.; Divsalar, D.; Yao, K.

    2004-01-01

    In this paper we propose an innovative channel coding scheme called Accumulate Repeat Accumulate codes. This class of codes can be viewed as trubo-like codes, namely a double serial concatenation of a rate-1 accumulator as an outer code, a regular or irregular repetition as a middle code, and a punctured accumulator as an inner code.

  9. 8 CFR 1245.22 - Evidence to demonstrate an alien's physical presence in the United States on a specific date.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Evidence to demonstrate an alien's physical... OFFICE FOR IMMIGRATION REVIEW, DEPARTMENT OF JUSTICE IMMIGRATION REGULATIONS ADJUSTMENT OF STATUS TO THAT OF PERSON ADMITTED FOR PERMANENT RESIDENCE § 1245.22 Evidence to demonstrate an alien's physical...

  10. Hydroxynonenal-generated crosslinking fluorophore accumulation in Alzheimer disease reveals a dichotomy of protein turnover.

    PubMed

    Zhu, Xiongwei; Castellani, Rudy J; Moreira, Paula I; Aliev, Gjumrakch; Shenk, Justin C; Siedlak, Sandra L; Harris, Peggy L R; Fujioka, Hisashi; Sayre, Lawrence M; Szweda, Pamela A; Szweda, Luke I; Smith, Mark A; Perry, George

    2012-02-01

    Lipid peroxidation generates reactive aldehydes, most notably hydroxynonenal (HNE), which covalently bind amino acid residue side chains leading to protein inactivation and insolubility. Specific adducts of lipid peroxidation have been demonstrated in intimate association with the pathological lesions of Alzheimer disease (AD), suggesting that oxidative stress is a major component of AD pathogenesis. Some HNE-protein products result in protein crosslinking through a fluorescent compound similar to lipofuscin, linking lipid peroxidation and the lipofuscin accumulation that commonly occurs in post-mitotic cells such as neurons. In this study, brain tissue from AD and control patients was examined by immunocytochemistry and immunoelectron microscopy for evidence of HNE-crosslinking modifications of the type that should accumulate in the lipofuscin pathway. Strong labeling of granulovacuolar degeneration (GVD) and Hirano bodies was noted but lipofuscin did not contain this specific HNE-fluorophore. These findings directly implicate lipid crosslinking peroxidation products as accumulating not in the lesions or the lipofuscin pathways, but instead in a distinct pathway, GVD, that accumulates cytosolic proteins. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. 8 CFR 1245.22 - Evidence to demonstrate an alien's physical presence in the United States on a specific date.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 8 Aliens and Nationality 1 2011-01-01 2011-01-01 false Evidence to demonstrate an alien's physical presence in the United States on a specific date. 1245.22 Section 1245.22 Aliens and Nationality EXECUTIVE... OF PERSON ADMITTED FOR PERMANENT RESIDENCE § 1245.22 Evidence to demonstrate an alien's physical...

  12. 8 CFR 1245.22 - Evidence to demonstrate an alien's physical presence in the United States on a specific date.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 8 Aliens and Nationality 1 2012-01-01 2012-01-01 false Evidence to demonstrate an alien's physical presence in the United States on a specific date. 1245.22 Section 1245.22 Aliens and Nationality EXECUTIVE... OF PERSON ADMITTED FOR PERMANENT RESIDENCE § 1245.22 Evidence to demonstrate an alien's physical...

  13. 8 CFR 1245.22 - Evidence to demonstrate an alien's physical presence in the United States on a specific date.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 8 Aliens and Nationality 1 2013-01-01 2013-01-01 false Evidence to demonstrate an alien's physical presence in the United States on a specific date. 1245.22 Section 1245.22 Aliens and Nationality EXECUTIVE... OF PERSON ADMITTED FOR PERMANENT RESIDENCE § 1245.22 Evidence to demonstrate an alien's physical...

  14. 8 CFR 1245.22 - Evidence to demonstrate an alien's physical presence in the United States on a specific date.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 8 Aliens and Nationality 1 2014-01-01 2014-01-01 false Evidence to demonstrate an alien's physical presence in the United States on a specific date. 1245.22 Section 1245.22 Aliens and Nationality EXECUTIVE... OF PERSON ADMITTED FOR PERMANENT RESIDENCE § 1245.22 Evidence to demonstrate an alien's physical...

  15. 8 CFR 245.22 - Evidence to demonstrate an alien's physical presence in the United States on a specific date.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 8 Aliens and Nationality 1 2011-01-01 2011-01-01 false Evidence to demonstrate an alien's physical presence in the United States on a specific date. 245.22 Section 245.22 Aliens and Nationality DEPARTMENT... PERMANENT RESIDENCE § 245.22 Evidence to demonstrate an alien's physical presence in the United States on a...

  16. 8 CFR 245.22 - Evidence to demonstrate an alien's physical presence in the United States on a specific date.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 8 Aliens and Nationality 1 2012-01-01 2012-01-01 false Evidence to demonstrate an alien's physical presence in the United States on a specific date. 245.22 Section 245.22 Aliens and Nationality DEPARTMENT... PERMANENT RESIDENCE § 245.22 Evidence to demonstrate an alien's physical presence in the United States on a...

  17. 8 CFR 245.22 - Evidence to demonstrate an alien's physical presence in the United States on a specific date.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 8 Aliens and Nationality 1 2014-01-01 2014-01-01 false Evidence to demonstrate an alien's physical presence in the United States on a specific date. 245.22 Section 245.22 Aliens and Nationality DEPARTMENT... PERMANENT RESIDENCE § 245.22 Evidence to demonstrate an alien's physical presence in the United States on a...

  18. 8 CFR 245.22 - Evidence to demonstrate an alien's physical presence in the United States on a specific date.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 8 Aliens and Nationality 1 2013-01-01 2013-01-01 false Evidence to demonstrate an alien's physical presence in the United States on a specific date. 245.22 Section 245.22 Aliens and Nationality DEPARTMENT... PERMANENT RESIDENCE § 245.22 Evidence to demonstrate an alien's physical presence in the United States on a...

  19. Ecological strategies of Al-accumulating and non-accumulating functional groups from the cerrado sensu stricto.

    PubMed

    Souza, Marcelo C de; Bueno, Paula C P; Morellato, Leonor P C; Habermann, Gustavo

    2015-01-01

    The cerrado's flora comprises aluminum-(Al) accumulating and non-accumulating plants, which coexist on acidic and Al-rich soils with low fertility. Despite their existence, the ecological importance or biological strategies of these functional groups have been little explored. We evaluated the leaf flushing patterns of both groups throughout a year; leaf concentrations of N, P, K, Ca, Mg, S, Al, total flavonoids and polyphenols; as well as the specific leaf area (SLA) on young and mature leaves within and between the groups. In Al-accumulating plants, leaf flushed throughout the year, mainly in May and September; for non-accumulating plants, leaf flushing peaked at the dry-wet seasons transition. However, these behaviors could not be associated with strategies for building up concentrations of defense compounds in leaves of any functional groups. Al-accumulating plants showed low leaf nutrient concentrations, while non-accumulating plants accumulated more macronutrients and produced leaves with high SLA since the juvenile leaf phase. This demonstrates that the increase in SLA is slower in Al-accumulating plants that are likely to achieve SLA values comparable to the rest of the plant community only in the wet season, when sunlight capture is important for the growth of new branches.

  20. Crustal strain accumulation on Southern Basin and Range Province faults modulated by distant plate boundary earthquakes? Evidence from geodesy, seismic imaging, and paleoseismology

    NASA Astrophysics Data System (ADS)

    Bennett, R. A.; Shirzaei, M.; Broermann, J.; Spinler, J. C.; Holland, A. A.; Pearthree, P.

    2014-12-01

    GPS in Arizona reveals a change in the pattern of crustal strain accumulation in 2010 and based on viscoelastic modeling appears to be associated with the distant M7.2 El Mayor-Cucapah (EMC) earthquake in Baja California, Mexico. GPS data collected between 1999 and 2009 near the Santa Rita normal fault in SE Arizona reveal a narrow zone of crustal deformation coincident with the fault trace, delineated by W-NW facing Pleistocene fault scarps of heights 1 to 7 m. The apparent deformation zone is also seen in a preliminary InSAR interferogram. Total motion across the zone inferred using an elastic block model constrained by the pre-2010 GPS measurements is ~1 mm/yr in a sense consistent with normal fault motion. However, continuous GPS measurements throughout Arizona reveal pronounced changes in crustal velocity following the EMC earthquake, such that the relative motion across the Santa Rita fault post-2010 is negligible. Paleoseismic evidence indicates that mapped Santa Rita fault scarps were formed by two or more large magnitude (M6.7 to M7.6) surface rupturing normal-faulting earthquakes 60 to 100 kyrs ago. Seismic refraction and reflection data constrained by deep (~800 m) well log data provide evidence of progressive, possibly intermittent, displacement on the fault through time. The rate of strain accumulation observed geodetically prior to 2010, if constant over the past 60 to 100 kyrs, would imply an untenable minimum slip rate deficit of 60 to 100 m since the most recent earthquake. One explanation for the available geodetic, seismic, and paleoseismic evidence is that strain accumulation is modulated by viscoelastic relaxation associated with frequent large magnitude earthquakes in the Salton Trough region, episodically inhibiting the accumulation of elastic strain required to generate large earthquakes on the Santa Rita and possibly other faults in the Southern Basin and Range. An important question is thus for how long the postseismic velocity changes

  1. Evidence that the Great Pacific Garbage Patch is rapidly accumulating plastic.

    PubMed

    Lebreton, L; Slat, B; Ferrari, F; Sainte-Rose, B; Aitken, J; Marthouse, R; Hajbane, S; Cunsolo, S; Schwarz, A; Levivier, A; Noble, K; Debeljak, P; Maral, H; Schoeneich-Argent, R; Brambini, R; Reisser, J

    2018-03-22

    Ocean plastic can persist in sea surface waters, eventually accumulating in remote areas of the world's oceans. Here we characterise and quantify a major ocean plastic accumulation zone formed in subtropical waters between California and Hawaii: The Great Pacific Garbage Patch (GPGP). Our model, calibrated with data from multi-vessel and aircraft surveys, predicted at least 79 (45-129) thousand tonnes of ocean plastic are floating inside an area of 1.6 million km 2 ; a figure four to sixteen times higher than previously reported. We explain this difference through the use of more robust methods to quantify larger debris. Over three-quarters of the GPGP mass was carried by debris larger than 5 cm and at least 46% was comprised of fishing nets. Microplastics accounted for 8% of the total mass but 94% of the estimated 1.8 (1.1-3.6) trillion pieces floating in the area. Plastic collected during our study has specific characteristics such as small surface-to-volume ratio, indicating that only certain types of debris have the capacity to persist and accumulate at the surface of the GPGP. Finally, our results suggest that ocean plastic pollution within the GPGP is increasing exponentially and at a faster rate than in surrounding waters.

  2. Exercise decreases CLK2 in the liver of obese mice and prevents hepatic fat accumulation.

    PubMed

    Muñoz, Vitor R; Gaspar, Rafael C; Kuga, Gabriel K; Nakandakari, Susana C B R; Baptista, Igor L; Mekary, Rania A; da Silva, Adelino S R; de Moura, Leandro P; Ropelle, Eduardo R; Cintra, Dennys E; Pauli, José R

    2018-03-25

    The accumulation of fatty acids in the liver associated with obesity condition is also known as nonalcoholic fatty liver disease (NAFLD). The impaired fat oxidation in obesity condition leads to increased hepatic fat accumulation and increased metabolic syndrome risk. On the other hand, physical exercise has been demonstrated as a potent strategy in the prevention of NAFLD. Also, these beneficial effects of exercise occur through different mechanisms. Recently, the Cdc2-like kinase (CLK2) protein was associated with the suppression of fatty acid oxidation and hepatic ketogenesis. Thus, obese animals demonstrated elevated levels of hepatic CLK2 and decreased fat acid oxidation. Here, we explored the effects of chronic physical exercise in the hepatic metabolism of obese mice. Swiss mice were distributed in Lean, Obese (fed with high-fat diet during 16 weeks) and Trained Obese group (fed with high-fat diet during 16 weeks and exercised (at 60% exhaustion velocity during 1 h/5 days/week) during 8 weeks. In our results, the obese animals showed insulin resistance, increased hepatic CLK2 content and increased hepatic fat accumulation compared to the Lean group. Otherwise, the chronic physical exercise improved insulin resistance state, prevented the increased CLK2 in the liver and attenuated hepatic fat accumulation. In summary, these data reveal a new protein involved in the prevention of hepatic fat accumulation after chronic physical exercise. More studies can evidence the negative role of CLK2 in the control of liver metabolism, contributing to the improvement of insulin resistance, obesity, and type 2 diabetes. © 2018 Wiley Periodicals, Inc.

  3. Demonstrating PQS Effectiveness and Driving Continual Improvement: Evidence-Based Risk Reduction.

    PubMed

    Ramnarine, Emma; O'Donnell, Kevin

    2018-04-18

    Product knowledge grows and evolves during the life of a product. In order to maintain a state of control and deliver product with consistent quality throughout its commercial life, continuous improvement and product lifecycle management become essential. The practical link between product and process knowledge, risk-based control strategies, and continual improvement and innovation can be made stronger through evidence-based risk reduction. Regulatory relief and flexibility in post approval change management and overall product lifecycle management will only be possible with effective application of science and risk-based concepts and demonstrated effectiveness of the PQS in assuring a state of control. Copyright © 2018, Parenteral Drug Association.

  4. Accumulation of senescent cells in mitotic tissue of aging primates.

    PubMed

    Jeyapalan, Jessie C; Ferreira, Mark; Sedivy, John M; Herbig, Utz

    2007-01-01

    Cellular senescence, a stress induced growth arrest of somatic cells, was first documented in cell cultures over 40 years ago, however its physiological significance has only recently been demonstrated. Using novel biomarkers of cellular senescence we examined whether senescent cells accumulate in tissues from baboons of ages encompassing the entire lifespan of this species. We show that dermal fibroblasts, displaying markers of senescence such as telomere damage, active checkpoint kinase ATM, high levels of heterochromatin proteins and elevated levels of p16, accumulate in skin biopsies from baboons with advancing age. The number of dermal fibroblasts containing damaged telomeres reaches a value of over 15% of total fibroblasts, whereas 80% of cells contain high levels of the heterochromatin protein HIRA. In skeletal muscle, a postmitotic tissue, only a small percentage of myonuclei containing damaged telomeres were detected regardless of animal age. The presence of senescent cells in mitotic tissues might therefore be a contributing factor to aging and age related pathology and provides further evidence that cellular senescence is a physiological event.

  5. Accumulation of Senescent Cells in Mitotic Tissue of Aging Primates

    PubMed Central

    Jeyapalan, Jessie C.; Ferreira, Mark; Sedivy, John M.; Herbig, Utz

    2013-01-01

    Cellular senescence, a stress induced growth arrest of somatic cells, was first documented in cell cultures over forty years ago, however its physiological significance has only recently been demonstrated. Using novel biomarkers of cellular senescence we examined whether senescent cells accumulate in tissues from baboons of ages encompassing the entire lifespan of this species. We show that dermal fibroblasts, displaying markers of senescence such as telomere damage, active checkpoint kinase ATM, high levels of heterochromatin proteins and elevated levels of p16, accumulate in skin biopsies from baboons with advancing age. The number of dermal fibroblasts containing damaged telomeres reaches a value of over 15% of total fibroblasts, whereas 80% of cells contain high levels of the heterochromatin protein HIRA. In skeletal muscle, a postmitotic tissue, only a small percentage of myonuclei containing damaged telomeres were detected regardless of animal age. The presence of senescent cells in mitotic tissues might therefore be a contributing factor to aging and age related pathology and provides further evidence that cellular senescence is a physiological event. PMID:17116315

  6. Accumulate repeat accumulate codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    In this paper we propose an innovative channel coding scheme called 'Accumulate Repeat Accumulate codes' (ARA). This class of codes can be viewed as serial turbo-like codes, or as a subclass of Low Density Parity Check (LDPC) codes, thus belief propagation can be used for iterative decoding of ARA codes on a graph. The structure of encoder for this class can be viewed as precoded Repeat Accumulate (RA) code or as precoded Irregular Repeat Accumulate (IRA) code, where simply an accumulator is chosen as a precoder. Thus ARA codes have simple, and very fast encoder structure when they representing LDPC codes. Based on density evolution for LDPC codes through some examples for ARA codes, we show that for maximum variable node degree 5 a minimum bit SNR as low as 0.08 dB from channel capacity for rate 1/2 can be achieved as the block size goes to infinity. Thus based on fixed low maximum variable node degree, its threshold outperforms not only the RA and IRA codes but also the best known LDPC codes with the dame maximum node degree. Furthermore by puncturing the accumulators any desired high rate codes close to code rate 1 can be obtained with thresholds that stay close to the channel capacity thresholds uniformly. Iterative decoding simulation results are provided. The ARA codes also have projected graph or protograph representation that allows for high speed decoder implementation.

  7. A model for evidence accumulation in the lexical decision task.

    PubMed

    Wagenmakers, Eric-Jan; Steyvers, Mark; Raaijmakers, Jeroen G W; Shiffrin, Richard M; van Rijn, Hedderik; Zeelenberg, René

    2004-05-01

    We present a new model for lexical decision, REM-LD, that is based on REM theory (e.g., ). REM-LD uses a principled (i.e., Bayes' rule) decision process that simultaneously considers the diagnosticity of the evidence for the 'WORD' response and the 'NONWORD' response. The model calculates the odds ratio that the presented stimulus is a word or a nonword by averaging likelihood ratios for lexical entries from a small neighborhood of similar words. We report two experiments that used a signal-to-respond paradigm to obtain information about the time course of lexical processing. Experiment 1 verified the prediction of the model that the frequency of the word stimuli affects performance for nonword stimuli. Experiment 2 was done to study the effects of nonword lexicality, word frequency, and repetition priming and to demonstrate how REM-LD can account for the observed results. We discuss how REM-LD could be extended to account for effects of phonology such as the pseudohomophone effect, and how REM-LD can predict response times in the traditional 'respond-when-ready' paradigm.

  8. Accumulation of 5-Oxoproline in Mouse Tissues After Inhibition of 5-Oxoprolinase and Administration of Amino Acids: Evidence for Function of the γ-Glutamyl Cycle*

    PubMed Central

    Van Der Werf, Paul; Stephani, Ralph A.; Meister, Alton

    1974-01-01

    5-Oxoprolinase catalyzes the conversion of 5-oxo-L-proline (L-pyroglutamate, L-2-pyrrolidone-5-carboxylate) to L-glutamate with concomitant stoichiometric cleavage of ATP to ADP and inorganic orthophosphate. In this reaction, a step in the γ-glutamyl cycle, 5-oxoproline (formed by the action of γ-glutamylcyclotransferase on γ-glutamyl amino acids, which are in turn formed by transpeptidation of amino acids with glutathione), is made available for glutathione synthesis. When mice are injected with L-2-imidazolidone-4-carboxylate, a competitive inhibitor of 5-oxoprolinase, they accumulate 5-oxoproline in their tissues (kidney, liver, brain, and eye) and excrete it in the urine. Mice given the inhibitor together with one of several L-amino acids accumulate and excrete much more 5-oxoproline than when they are given the inhibitor alone. Such augmentation of 5-oxoproline accumulation offers evidence for the function of the γ-glutamyl cycle in vivo and supports the view that 5-oxoproline is a quantitatively significant metabolite. Images PMID:4151516

  9. Suppression of glycolate oxidase causes glyoxylate accumulation that inhibits photosynthesis through deactivating Rubisco in rice.

    PubMed

    Lu, Yusheng; Li, Yong; Yang, Qiaosong; Zhang, Zhisheng; Chen, Yan; Zhang, Sheng; Peng, Xin-Xiang

    2014-03-01

    Glycolate oxidase (GLO) is a key enzyme for photorespiration in plants. Previous studies have demonstrated that suppression of GLO causes photosynthetic inhibition, and the accumulated glycolate with the deactivated Rubisco is likely involved in the regulation. Using isolated Rubisco and chloroplasts, it has been found that only glyoxylate can effectively inactivate Rubisco and meanwhile inhibit photosynthesis, but little in vivo evidence has been acquired and reported. In this study, we have generated the transgenic rice (Oryza sativa) plants with GLO being constitutively silenced, and conducted the physiological and biochemical analyses on these plants to explore the regulatory mechanism. When GLO was downregulated, the net photosynthetic rate (Pn) was reduced and the plant growth was correspondingly stunted. Surprisingly, glyoxylate, as a product of the GLO catalysis, was accumulated in response to the GLO suppression, like its substrate glycolate. Furthermore, the glyoxylate content was found to be inversely proportional to the Pn while the Pn is directly proportional to the Rubisco activation state in the GLO-suppressed plants. A mathematical fitting equation using least square method also demonstrated that the Rubisco activation state was inversely proportional to the glyoxylate content. Despite that the further analyses we have conducted failed to reveal how glyoxylate was accumulated in response to the GLO suppression, the current results do strongly suggest that there may exist an unidentified, alternative pathway to produce glyoxylate, and that the accumulated glyoxylate inhibits photosynthesis by deactivating Rubisco, and causes the photorespiratory phenotype in the GLO-suppressed rice plants. © 2013 Scandinavian Plant Physiology Society.

  10. Coordinated within-trial dynamics of low-frequency neural rhythms controls evidence accumulation.

    PubMed

    Werkle-Bergner, Markus; Grandy, Thomas H; Chicherio, Christian; Schmiedek, Florian; Lövdén, Martin; Lindenberger, Ulman

    2014-06-18

    Higher cognitive functions, such as human perceptual decision making, require information processing and transmission across wide-spread cortical networks. Temporally synchronized neural firing patterns are advantageous for efficiently representing and transmitting information within and between assemblies. Computational, empirical, and conceptual considerations all lead to the expectation that the informational redundancy of neural firing rates is positively related to their synchronization. Recent theorizing and initial evidence also suggest that the coding of stimulus characteristics and their integration with behavioral goal states require neural interactions across a hierarchy of timescales. However, most studies thus have focused on neural activity in a single frequency range or on a restricted set of brain regions. Here we provide evidence for cooperative spatiotemporal dynamics of slow and fast EEG signals during perceptual decision making at the single-trial level. Participants performed three masked two-choice decision tasks, one each with numerical, verbal, or figural content. Decrements in posterior α power (8-14 Hz) were paralleled by increments in high-frequency (>30 Hz) signal entropy in trials demanding active sensory processing. Simultaneously, frontocentral θ power (4-7 Hz) increased, indicating evidence integration. The coordinated α/θ dynamics were tightly linked to decision speed and remarkably similar across tasks, suggesting a domain-general mechanism. In sum, we demonstrate an inverse association between decision-related changes in widespread low-frequency power and local high-frequency entropy. The cooperation among mechanisms captured by these changes enhances the informational density of neural response patterns and qualifies as a neural coding system in the service of perceptual decision making. Copyright © 2014 the authors 0270-6474/14/348519-10$15.00/0.

  11. Understanding reduced inorganic mercury accumulation in rice following selenium application: Selenium application routes, speciation and doses.

    PubMed

    Tang, Wenli; Dang, Fei; Evans, Douglas; Zhong, Huan; Xiao, Lin

    2017-02-01

    Selenium (Se) has recently been demonstrated to reduce inorganic mercury (IHg) accumulation in rice plants, while its mechanism is far from clear. Here, we aimed at exploring the potential effects of Se application routes (soil or foliar application with Se), speciation (selenite and selenate), and doses on IHg-Se antagonistic interactions in soil-rice systems. Results of our pot experiments indicated that soil application but not foliar application could evidently reduce tissue IHg concentrations (root: 0-48%, straw: 15-58%, and brown rice: 26-74%), although both application routes resulted in comparable Se accumulation in aboveground tissues. Meanwhile, IHg distribution in root generally increased with amended Se doses in soil, suggesting antagonistic interactions between IHg and Se in root. These results provided initial evidence that IHg-Se interactions in the rhizosphere (i.e., soil or rice root), instead of those in the aboveground tissues, could probably be more responsible for the reduced IHg bioaccumulation following Se application. Furthermore, Se dose rather than Se speciation was found to be more important in controlling IHg accumulation in rice. Our findings regarding the importance of IHg-Se interactions in the rhizosphere, together with the systematic investigation of key factors affecting IHg-Se antagonism and IHg bioaccumulation, advance our understanding of Hg dynamics in soil-rice systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. [Lorenz was right, or does aggressive energy accumulate?].

    PubMed

    Kudriavtseva, N N

    2004-06-01

    Evidence supporting the fact that inherited mechanisms of regulation of aggressive behavior as a result of a repeated experience of aggression ending in victories are transformed into pathological mechanisms based on accumulation of neurochemical shifts in the brain, enhancing aggressiveness, and forming aggressive motivation in aggressive winners. This confirms the concept by Lorenz on the existence of a mechanism (but not instinct) of a spontaneous accumulation of aggressive energy that needs a discharge and formation of permanent attraction to manifestation of aggression.

  13. Constant-Differential-Pressure Two-Fluid Accumulator

    NASA Technical Reports Server (NTRS)

    Piecuch, Benjamin; Dalton, Luke T.

    2010-01-01

    A two-fluid accumulator has been designed, built, and demonstrated to provide an acceptably close approximation to constant differential static pressure between two fluids over the full ranges of (1) accumulator stroke, (2) rates of flow of the fluids, and (3) common static pressure applied to the fluids. Prior differential- pressure two-fluid accumulators are generally not capable of maintaining acceptably close approximations to constant differential pressures. The inadequacies of a typical prior differential-pressure two-fluid accumulator can be summarized as follows: The static differential pressure is governed by the intrinsic spring rate (essentially, the stiffness) of an accumulator tank. The spring rate can be tailored through selection of the tank-wall thickness, selection of the number and/or shape of accumulator convolutions, and/or selection of accumulator material(s). Reliance on the intrinsic spring rate of the tank results in three severe limitations: (1) The spring rate and the expulsion efficiency tend to be inversely proportional to each other: that is to say, as the stiffness (and thus the differential pressure) is increased, the range of motion of the accumulator is reduced. (2) As the applied common static pressure increases, the differential pressure tends to decrease. An additional disadvantage, which may or may not be considered limiting, depending on the specific application, is that an increase in stiffness entails an increase in weight. (3) The additional weight required by a low expulsion efficiency accumulator eliminates the advantage given to such gas storage systems. The high expulsion efficiency provided by this two-fluid accumulator allows for a lightweight, tightly packaged system, which can be used in conjunction with a fuel cell-based system.

  14. Deleterious effects of neuronal accumulation of glycogen in flies and mice

    PubMed Central

    Duran, Jordi; Tevy, María Florencia; Garcia-Rocha, Mar; Calbó, Joaquim; Milán, Marco; Guinovart, Joan J

    2012-01-01

    Under physiological conditions, most neurons keep glycogen synthase (GS) in an inactive form and do not show detectable levels of glycogen. Nevertheless, aberrant glycogen accumulation in neurons is a hallmark of patients suffering from Lafora disease or other polyglucosan disorders. Although these diseases are associated with mutations in genes involved in glycogen metabolism, the role of glycogen accumulation remains elusive. Here, we generated mouse and fly models expressing an active form of GS to force neuronal accumulation of glycogen. We present evidence that the progressive accumulation of glycogen in mouse and Drosophila neurons leads to neuronal loss, locomotion defects and reduced lifespan. Our results highlight glycogen accumulation in neurons as a direct cause of neurodegeneration. PMID:22549942

  15. Experimental evidence of dietary ciguatoxin accumulation in an herbivorous coral reef fish.

    PubMed

    Clausing, Rachel J; Losen, Barbara; Oberhaensli, Francois R; Darius, H Taiana; Sibat, Manoella; Hess, Philipp; Swarzenski, Peter W; Chinain, Mireille; Dechraoui Bottein, Marie-Yasmine

    2018-07-01

    Ciguatoxins (CTXs) are potent algal toxins that cause widespread ciguatera poisoning and are found ubiquitously in coral reef food webs. Here we developed an environmentally-relevant, experimental model of CTX trophic transfer involving dietary exposure of herbivorous fish to the CTX-producing microalgae Gambierdiscus polynesiensis. Juvenile Naso brevirostris were fed a gel-food embedded with microalgae for 16 weeks (89 cells g -1 fish daily, 0.4 μg CTX3C equiv kg -1 fish). CTXs in muscle tissue were detectable after 2 weeks at levels above the threshold for human intoxication (1.2 ± 0.2 μg CTX3C equiv kg -1 ). Although tissue CTX concentrations stabilized after 8 weeks (∼3 ± 0.5 μg CTX3C equiv kg -1 ), muscle toxin burden (total μg CTX in muscle tissue) continued to increase linearly through the end of the experiment (16 weeks). Toxin accumulation was therefore continuous, yet masked by somatic growth dilution. The observed CTX concentrations, accumulation rates, and general absence of behavioural signs of intoxication are consistent with field observations and indicate that this method of dietary exposure may be used to develop predictive models of tissue-specific CTX uptake, metabolism and depuration. Results also imply that slow-growing fish may accumulate higher CTX flesh concentrations than fast-growing fish, which has important implications for global seafood safety. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Deleterious effects of neuronal accumulation of glycogen in flies and mice.

    PubMed

    Duran, Jordi; Tevy, María Florencia; Garcia-Rocha, Mar; Calbó, Joaquim; Milán, Marco; Guinovart, Joan J

    2012-08-01

    Under physiological conditions, most neurons keep glycogen synthase (GS) in an inactive form and do not show detectable levels of glycogen. Nevertheless, aberrant glycogen accumulation in neurons is a hallmark of patients suffering from Lafora disease or other polyglucosan disorders. Although these diseases are associated with mutations in genes involved in glycogen metabolism, the role of glycogen accumulation remains elusive. Here, we generated mouse and fly models expressing an active form of GS to force neuronal accumulation of glycogen. We present evidence that the progressive accumulation of glycogen in mouse and Drosophila neurons leads to neuronal loss, locomotion defects and reduced lifespan. Our results highlight glycogen accumulation in neurons as a direct cause of neurodegeneration. Copyright © 2012 EMBO Molecular Medicine.

  17. Accumulation and interaction of hypericin in low-density lipoprotein--a photophysical study.

    PubMed

    Mukherjee, Prasun; Adhikary, Ramkrishna; Halder, Mintu; Petrich, Jacob W; Miskovsky, Pavol

    2008-01-01

    The accumulation and interaction of hypericin with the biologically important macromolecule, low-density lipoprotein (LDL), is investigated using various steady-state and time-resolved fluorescence measurements. It is concluded that multiple hypericins can penetrate considerably deeply into the LDL molecule. Up to approximately 20 nonaggregated hypericin molecules can enter LDL; but upon increasing the hypericin concentration, the fluorescence lifetime of hypericin decreases drastically, suggesting most likely the self-quenching of aggregated hypericin. There is also evidence of energy transfer from tryptophans of the constituent protein, apoB-100, to hypericin in LDL. The results demonstrate the ability of LDL to solubilize hypericin (a known photosensitizer) in nonaggregated form, which has implications for the construction of drug delivery systems.

  18. Direct evidence for microbial-derived soil organic matter formation and its ecophysiological controls

    NASA Astrophysics Data System (ADS)

    Kallenbach, Cynthia M.; Frey, Serita D.; Grandy, A. Stuart

    2016-11-01

    Soil organic matter (SOM) and the carbon and nutrients therein drive fundamental submicron- to global-scale biogeochemical processes and influence carbon-climate feedbacks. Consensus is emerging that microbial materials are an important constituent of stable SOM, and new conceptual and quantitative SOM models are rapidly incorporating this view. However, direct evidence demonstrating that microbial residues account for the chemistry, stability and abundance of SOM is still lacking. Further, emerging models emphasize the stabilization of microbial-derived SOM by abiotic mechanisms, while the effects of microbial physiology on microbial residue production remain unclear. Here we provide the first direct evidence that soil microbes produce chemically diverse, stable SOM. We show that SOM accumulation is driven by distinct microbial communities more so than clay mineralogy, where microbial-derived SOM accumulation is greatest in soils with higher fungal abundances and more efficient microbial biomass production.

  19. Direct evidence for microbial-derived soil organic matter formation and its ecophysiological controls.

    PubMed

    Kallenbach, Cynthia M; Frey, Serita D; Grandy, A Stuart

    2016-11-28

    Soil organic matter (SOM) and the carbon and nutrients therein drive fundamental submicron- to global-scale biogeochemical processes and influence carbon-climate feedbacks. Consensus is emerging that microbial materials are an important constituent of stable SOM, and new conceptual and quantitative SOM models are rapidly incorporating this view. However, direct evidence demonstrating that microbial residues account for the chemistry, stability and abundance of SOM is still lacking. Further, emerging models emphasize the stabilization of microbial-derived SOM by abiotic mechanisms, while the effects of microbial physiology on microbial residue production remain unclear. Here we provide the first direct evidence that soil microbes produce chemically diverse, stable SOM. We show that SOM accumulation is driven by distinct microbial communities more so than clay mineralogy, where microbial-derived SOM accumulation is greatest in soils with higher fungal abundances and more efficient microbial biomass production.

  20. An Update on Accumulating Exercise and Postprandial Lipaemia: Translating Theory Into Practice

    PubMed Central

    Burns, Stephen F; Stensel, David J

    2013-01-01

    Over the last two decades, significant research attention has been given to the acute effect of a single bout of exercise on postprandial lipaemia. A large body of evidence supports the notion that an acute bout of aerobic exercise can reduce postprandial triacylglycerol (TAG) concentrations. However, this effect is short-lived emphasising the important role of regular physical activity for lowering TAG concentrations through an active lifestyle. In 1995, the concept of accumulating physical activity was introduced in expert recommendations with the advice that activity can be performed in several short bouts throughout the day with a minimum duration of 10 minutes per activity bout. Although the concept of accumulation has been widely publicised, there is still limited scientific evidence to support it but several studies have investigated the effects of accumulated activity on health-related outcomes to support the recommendations in physical activity guidelines. One area, which is the focus of this review, is the effect of accumulating exercise on postprandial lipaemia. We propose that accumulating exercise will provide additional physical activity options for lowering postprandial TAG concentrations relevant to individuals with limited time or exercise capacity to engage in more structured forms of exercise, or longer bouts of physical activity. The benefits of accumulated physical activity might translate to a reduced risk of cardiovascular disease in the long-term. PMID:23412842

  1. Accumulation, depuration dynamics and effects of dissolved hexavalent chromium in juvenile Japanese medaka (Oryzias latipes).

    PubMed

    Chen, Hongxing; Guo, Zhongbao; Zhou, Yu; Li, Dan; Mu, Lei; Klerks, Paul L; Luo, Yongju; Xie, Lingtian

    2018-02-01

    We previously demonstrated that chronic exposure to hexavalent chromium (Cr(VI)) causes a variety of adverse effects in the Japanese medaka (Oryzias latipes). The present study investigated the transition of acute to chronic effects by assessing the influences of Cr(VI) exposure concentration and exposure duration on Cr accumulation and their effects on fish growth and antioxidant physiology. Juvenile fish were exposed to 0.05, 0.5, 4 or 8mg/L Cr(VI) for 28 days. Endpoints were evaluated on days 3, 7, 14, 21 and 28. In addition, Cr depuration was examined for fish from two exposure groups (0.5 and 8mg/L). Chromium accumulation was rapid initially, then continued at a slower rate till the end of the exposure period without showing signs of reaching a steady state. Depuration patterns differed between the two exposure groups, but both reached 50% in 14 days. The rapid initial accumulation was accompanied by increased lipid peroxidation and elevated activities of antioxidants (e.g., GST, SOD and CAT). Activities of these enzymes had mostly returned to baseline levels by day 7, but there was no evidence of further cellular damage from ROS. Effects on fish length and weight continued to be evident over the 28-day exposure period. Our study suggest that the initial effects of Cr(VI) exposure may not be a good predictor of more-chronic effects in fish as a consequence of an efficient acclimation response by the antioxidant system that limits ROS-mediated toxicity. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. The accumulation of genetic diversity within a canopy-stored seed bank.

    PubMed

    Ayre, David; O'Brien, Eleanor; Ottewell, Kym; Whelan, Rob

    2010-07-01

    Many plants regenerate after fire from a canopy-stored seed bank, in which seed are housed in fire resistant confructescences (cones) that remain on maternal plants. This strategy would be favoured if plants accumulate a sufficiently large and genetically diverse seed bank during interfire intervals. We use a 16-year demographic study and surveys of microsatellite variation to quantify and explain the rate of accumulation of genetic diversity within the canopy seed bank of the shrub Banksia spinulosa. Flowering and fruit set were highly variable. An initial sample in 1991 of 354 reproductively mature plants generated 426 cones over 16 years, of which only 55 cones from 40 maternal plants persisted until 2005. By genotyping seed from these 55 cones we demonstrated that genetic diversity accumulated rapidly within the seed bank. Resampling revealed that diversity was determined by the number, not the age, of cones. Cones were widely distributed among plants, outcrossing rates were high (mean t(m) = 1.00 +/- 0.04) and biparental inbreeding low. Adults displayed little evidence of isolation by distance and the genotypic diversity of seed cohorts was independent of the density of neighbouring potential sires. We therefore estimate that within at least 13 individual years the number of cones produced per year (14-63) would have contained 100% of the adult genetic diversity. We conclude that a highly outcrossed mating system and relatively widespread pollen dispersal ensure the rapid development of a genetically diverse and spatially and temporally homogeneous seed bank.

  3. How Awareness Changes the Relative Weights of Evidence During Human Decision-Making

    PubMed Central

    Lamme, Victor A. F.; Dehaene, Stanislas

    2011-01-01

    Human decisions are based on accumulating evidence over time for different options. Here we ask a simple question: How is the accumulation of evidence affected by the level of awareness of the information? We examined the influence of awareness on decision-making using combined behavioral methods and magneto-encephalography (MEG). Participants were required to make decisions by accumulating evidence over a series of visually presented arrow stimuli whose visibility was modulated by masking. Behavioral results showed that participants could accumulate evidence under both high and low visibility. However, a top-down strategic modulation of the flow of incoming evidence was only present for stimuli with high visibility: once enough evidence had been accrued, participants strategically reduced the impact of new incoming stimuli. Also, decision-making speed and confidence were strongly modulated by the strength of the evidence for high-visible but not low-visible evidence, even though direct priming effects were identical for both types of stimuli. Neural recordings revealed that, while initial perceptual processing was independent of visibility, there was stronger top-down amplification for stimuli with high visibility than low visibility. Furthermore, neural markers of evidence accumulation over occipito-parietal cortex showed a strategic bias only for highly visible sensory information, speeding up processing and reducing neural computations related to the decision process. Our results indicate that the level of awareness of information changes decision-making: while accumulation of evidence already exists under low visibility conditions, high visibility allows evidence to be accumulated up to a higher level, leading to important strategical top-down changes in decision-making. Our results therefore suggest a potential role of awareness in deploying flexible strategies for biasing information acquisition in line with one's expectations and goals. PMID:22131904

  4. How awareness changes the relative weights of evidence during human decision-making.

    PubMed

    de Lange, Floris P; van Gaal, Simon; Lamme, Victor A F; Dehaene, Stanislas

    2011-11-01

    Human decisions are based on accumulating evidence over time for different options. Here we ask a simple question: How is the accumulation of evidence affected by the level of awareness of the information? We examined the influence of awareness on decision-making using combined behavioral methods and magneto-encephalography (MEG). Participants were required to make decisions by accumulating evidence over a series of visually presented arrow stimuli whose visibility was modulated by masking. Behavioral results showed that participants could accumulate evidence under both high and low visibility. However, a top-down strategic modulation of the flow of incoming evidence was only present for stimuli with high visibility: once enough evidence had been accrued, participants strategically reduced the impact of new incoming stimuli. Also, decision-making speed and confidence were strongly modulated by the strength of the evidence for high-visible but not low-visible evidence, even though direct priming effects were identical for both types of stimuli. Neural recordings revealed that, while initial perceptual processing was independent of visibility, there was stronger top-down amplification for stimuli with high visibility than low visibility. Furthermore, neural markers of evidence accumulation over occipito-parietal cortex showed a strategic bias only for highly visible sensory information, speeding up processing and reducing neural computations related to the decision process. Our results indicate that the level of awareness of information changes decision-making: while accumulation of evidence already exists under low visibility conditions, high visibility allows evidence to be accumulated up to a higher level, leading to important strategical top-down changes in decision-making. Our results therefore suggest a potential role of awareness in deploying flexible strategies for biasing information acquisition in line with one's expectations and goals.

  5. Rapid auxin-induced nitric oxide accumulation and subsequent tyrosine nitration of proteins during adventitious root formation in sunflower hypocotyls

    PubMed Central

    Yadav, Sunita; David, Anisha; Baluška, František; Bhatla, Satish C.

    2013-01-01

    Using NO specific probe (MNIP-Cu), rapid nitric oxide (NO) accumulation as a response to auxin (IAA) treatment has been observed in the protoplasts from the hypocotyls of sunflower seedlings (Helianthus annuus L.). Incubation of protoplasts in presence of NPA (auxin efflux blocker) and PTIO (NO scavenger) leads to significant reduction in NO accumulation, indicating that NO signals represent an early signaling event during auxin-induced response. A surge in NO production has also been demonstrated in whole hypocotyl explants showing adventitious root (AR) development. Evidence of tyrosine nitration of cytosolic proteins as a consequence of NO accumulation has been provided by western blot analysis and immunolocalization in the sections of AR producing hypocotyl segments. Most abundant anti-nitrotyrosine labeling is evident in proteins ranging from 25–80 kDa. Tyrosine nitration of a particular protein (25 kDa) is completely absent in presence of NPA (which suppresses AR formation). Similar lack of tyrosine nitration of this protein is also evident in other conditions which do not allow AR differentiation. Immunofluorescent localization experiments have revealed that non-inductive treatments (such as PTIO) for AR develpoment from hypocotyl segments coincide with symplastic and apoplastic localization of tyrosine nitrated proteins in the xylem elements, in contrast with negligible (and mainly apoplastic) nitration of proteins in the interfascicular cells and phloem elements. Application of NPA does not affect tyrosine nitration of proteins even in the presence of an external source of NO (SNP). Tyrosine nitrated proteins are abundant around the nuclei in the actively dividing cells of the root primordium. Thus, NO-modulated rapid response to IAA treatment through differential distribution of tyrosine nitrated proteins is evident as an inherent aspect of the AR development. PMID:23299324

  6. Direct evidence for microbial-derived soil organic matter formation and its ecophysiological controls

    DOE PAGES

    Kallenbach, Cynthia M.; Frey, Serita D.; Grandy, A. Stuart

    2016-11-28

    Soil organic matter (SOM) and the carbon and nutrients therein drive fundamental submicron- to global-scale biogeochemical processes and influence carbon-climate feedbacks. Consensus is emerging that microbial materials are an important constituent of stable SOM, and new conceptual and quantitative SOM models are rapidly incorporating this view. However, direct evidence demonstrating that microbial residues account for the chemistry, stability and abundance of SOM is still lacking. Further, emerging models emphasize the stabilization of microbial-derived SOM by abiotic mechanisms, while the effects of microbial physiology on microbial residue production remain unclear. Here we provide the first direct evidence that soil microbes producemore » chemically diverse, stable SOM. As a result, we show that SOM accumulation is driven by distinct microbial communities more so than clay mineralogy, where microbial-derived SOM accumulation is greatest in soils with higher fungal abundances and more efficient microbial biomass production.« less

  7. Direct evidence for microbial-derived soil organic matter formation and its ecophysiological controls

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kallenbach, Cynthia M.; Frey, Serita D.; Grandy, A. Stuart

    Soil organic matter (SOM) and the carbon and nutrients therein drive fundamental submicron- to global-scale biogeochemical processes and influence carbon-climate feedbacks. Consensus is emerging that microbial materials are an important constituent of stable SOM, and new conceptual and quantitative SOM models are rapidly incorporating this view. However, direct evidence demonstrating that microbial residues account for the chemistry, stability and abundance of SOM is still lacking. Further, emerging models emphasize the stabilization of microbial-derived SOM by abiotic mechanisms, while the effects of microbial physiology on microbial residue production remain unclear. Here we provide the first direct evidence that soil microbes producemore » chemically diverse, stable SOM. As a result, we show that SOM accumulation is driven by distinct microbial communities more so than clay mineralogy, where microbial-derived SOM accumulation is greatest in soils with higher fungal abundances and more efficient microbial biomass production.« less

  8. Delay of gratification by orangutans (Pongo pygmaeus) in the accumulation task.

    PubMed

    Parrish, Audrey E; Perdue, Bonnie M; Stromberg, Erin E; Bania, Amanda E; Evans, Theodore A; Beran, Michael J

    2014-05-01

    There is considerable evidence indicating that chimpanzees can delay gratification for extended time intervals, particularly in the accumulation task in which food items accumulate within a participant's reach until the participant begins to consume them. However, there is limited evidence that other ape species might also exhibit this capacity, despite there being a number of similar studies indicating that nonape species (e.g., monkeys and birds) can delay gratification, but not for nearly as long as chimpanzees. To help define the taxonomic distribution of delay of gratification behavior in the order Primates, we tested 6 orangutans in the current experiments and compared their performance with comparable data from a previous study with capuchin monkeys. We varied delay length and visibility of the items that were still available for accumulation to determine the impact of these factors on performance. Species differences on the accumulation task emerged when comparing the current data to data from a previous study. Orangutans outperformed capuchin monkeys, suggesting that ape species may generally show better delay of gratification and delay maintenance abilities than monkeys. However, more studies are necessary to rule out alternative hypotheses on the distribution of delay maintenance abilities across primate species. ©2014 APA, all rights reserved.

  9. Intergenotypic replacement of lyssavirus matrix proteins demonstrates the role of lyssavirus M proteins in intracellular virus accumulation.

    PubMed

    Finke, Stefan; Granzow, Harald; Hurst, Jose; Pollin, Reiko; Mettenleiter, Thomas C

    2010-02-01

    Lyssavirus assembly depends on the matrix protein (M). We compared lyssavirus M proteins from different genotypes for their ability to support assembly and egress of genotype 1 rabies virus (RABV). Transcomplementation of M-deficient RABV with M from European bat lyssavirus (EBLV) types 1 and 2 reduced the release of infectious virus. Stable introduction of the heterogenotypic M proteins into RABV led to chimeric viruses with reduced virus release and intracellular accumulation of virus genomes. Although the chimeras indicated genotype-specific evolution of M, rapid selection of a compensatory mutant suggested conserved mechanisms of lyssavirus assembly and the requirement for only few adaptive mutations to fit the heterogenotypic M to a RABV backbone. Whereas the compensatory mutant replicated to similar infectious titers as RABV M-expressing virus, ultrastructural analysis revealed that both nonadapted EBLV M chimeras and the compensatory mutant differed from RABV M expressing viruses in the lack of intracellular viruslike structures that are enveloped and accumulate in cisterna of the degranulated and dilated rough endoplasmic reticulum compartment. Moreover, all viruses were able to bud at the plasma membrane. Since the lack of the intracellular viruslike structures correlated with the type of M protein but not with the efficiency of virus release, we hypothesize that the M proteins of EBLV-1 and RABV differ in their target membranes for virus assembly. Although the biological function of intracellular assembly and accumulation of viruslike structures in the endoplasmic reticulum remain unclear, the observed differences could contribute to diverse host tropism or pathogenicity.

  10. [Nitrate accumulating capability of some market garden vegetables].

    PubMed

    Blanc, D

    1976-01-01

    Nitrate accumulation in plant is essentially function of the amount of nitrate nitrogen present in the substrate. That can be provided by mineral fertilizers or by organic manure. Due to the amount of nitrogen fertilizers needed in order to obtain sufficient yields the presence of nitrate is a general phenomenon in vegetable. Nevertheless the distribution of nitrate ions in the different parts of the plant influences the importance of the accumulation in the different kinds of vegetable. The experiments reported showed that leaves contain more nitrate ions than roots and roots more than fruit. The results obtained in soilless culture on lettuces, tomatoes and egg-plant demonstrated that the amount of accumulated nitrate is also dependent on the equilibrium between the different ions in the nutrient solution. Ammonium, potassium, sulfate and molybdenum have been shown to influence the rate of nitrate accumulation in the different species. It appears that it is not possible to obtain vegetable without nitrate, but it is possible, by an equilibrated fertilization, to reduce the amount accumulated in the tissue.

  11. [Job crisis and transformations in the new model of accumulation].

    PubMed

    Zerda-Sarmiento, Alvaro

    2012-06-01

    The general and structural crisis capitalism is going through is the token of the difficulties accumulation model has been dealing with since 70's in developed countries. This model has been trying to settle down again on the basis of neoliberal principle and a new technical-economical paradigm. The new accumulation pattern has had a effect in employment sphere which have been made evident at all the elements that constitute work relationships. In Colombia, this model implementation has been partial and segmented. However, its consequences (and the long-term current crisis) have been evident in unemployment, precarious work, segmentation, informal work and restricted and private health insurance. Besides, financial accumulation makes labour profits flow at different levels. The economic model current government has aimed to implement leads to strengthening exports, so making population life conditions more difficult. In order to overcome the current state of affairs, the work sphere needs to become more creative. This creative approach should look for new schemes for expression and mobilization of work sphere's claims. This is supposed to be done by establishing a different economic model aimed to build a more inclusive future, with social justice.

  12. Accumulation by fish of contaminants released from dredged sediments

    USGS Publications Warehouse

    Seelye, James G.; Hesselberg, Robert J.; Mac, Michael J.

    1982-01-01

    Inasmuch as the process of dredging and disposing of dredged materials causes a resuspension of these materials and an increase in bioavailability of associated contaminants, we conducted a series of experiments to examine the potential accumulation by fish of contaminants from suspended sediments. In the first experiment we compared accumulation of contaminants by yellow perch of hatchery and lake origin and found that after 10 days of exposure to nonaerated sediments, fish of hatchery origin accumulated PCBs and Fe, while fish of lake origin accumulated As, Cr, Fe, and Na. Two additional exposures were conducted to evaluate the effects of aerating the sediments prior to measuring bioavailability of associated contaminants. Fish of hatchery origin exposed to nonaerated sediments for 10 days accumulated PCBs and Hg, while fish of hatchery origin exposed to aerated sediments for 10 days accumulated PCBs, DDE, Zn, Fe, Cs, and Se. These results demonstrated not only the potential for uptake of contaminants by fish as a result of dredging but also the potential utility of fish bioassays in evaluating proposed dredging operations.

  13. Role of brain iron accumulation in cognitive dysfunction: evidence from animal models and human studies.

    PubMed

    Schröder, Nadja; Figueiredo, Luciana Silva; de Lima, Maria Noêmia Martins

    2013-01-01

    Over the last decades, studies from our laboratory and other groups using animal models have shown that iron overload, resulting in iron accumulation in the brain, produces significant cognitive deficits. Iron accumulation in the hippocampus and the basal ganglia has been related to impairments in spatial memory, aversive memory, and recognition memory in rodents. These results are corroborated by studies showing that the administration of iron chelators attenuates cognitive deficits in a variety of animal models of cognitive dysfunction, including aging and Alzheimer's disease models. Remarkably, recent human studies using magnetic resonance image techniques have also shown a consistent correlation between cognitive dysfunction and iron deposition, mostly in the hippocampus, cortical areas, and basal ganglia. These findings may have relevant implications in the light of the knowledge that iron accumulates in brain regions of patients suffering from neurodegenerative diseases. A better understanding of the functional consequences of iron dysregulation in aging and neurological diseases may help to identify novel targets for treating memory problems that afflict a growing aging population.

  14. Keeping agricultural soil out of rivers: evidence of sediment and nutrient accumulation within field wetlands in the UK.

    PubMed

    Ockenden, Mary C; Deasy, Clare; Quinton, John N; Surridge, Ben; Stoate, Chris

    2014-03-15

    Intensification of agriculture has resulted in increased soil degradation and erosion, with associated pollution of surface waters. Small field wetlands, constructed along runoff pathways, offer one option for slowing down and storing runoff in order to allow more time for sedimentation and for nutrients to be taken up by plants or micro-organisms. This paper describes research to provide quantitative evidence for the effectiveness of small field wetlands in the UK landscape. Ten wetlands were built on four farms in Cumbria and Leicestershire, UK. Annual surveys of sediment and nutrient accumulation in 2010, 2011 and 2012 indicated that most sediment was trapped at a sandy site (70 tonnes over 3 years), compared to a silty site (40 tonnes over 3 years) and a clay site (2 tonnes over 3 years). The timing of rainfall was more important than total annual rainfall for sediment accumulation, with most sediment transported in a few intense rainfall events, especially when these coincided with bare soil or poor crop cover. Nutrient concentration within sediments was inversely related to median particle size, but the total mass of nutrients trapped was dependent on the total mass of sediment trapped. Ratios of nutrient elements in the wetland sediments were consistent between sites, despite different catchment characteristics across the individual wetlands. The nutrient value of sediment collected from the wetlands was similar to that of soil in the surrounding fields; dredged sediment was considered to have value as soil replacement but not as fertiliser. Overall, small field wetlands can make a valuable contribution to keeping soil out of rivers. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Dynamical spin accumulation in large-spin magnetic molecules

    NASA Astrophysics Data System (ADS)

    Płomińska, Anna; Weymann, Ireneusz; Misiorny, Maciej

    2018-01-01

    The frequency-dependent transport through a nanodevice containing a large-spin magnetic molecule is studied theoretically in the Kondo regime. Specifically, the effect of magnetic anisotropy on dynamical spin accumulation is of primary interest. Such accumulation arises due to finite components of frequency-dependent conductance that are off diagonal in spin. Here, employing the Kubo formalism and the numerical renormalization group method, we demonstrate that the dynamical transport properties strongly depend on the relative orientation of spin moments in electrodes of the device, as well as on intrinsic parameters of the molecule. In particular, the effect of dynamical spin accumulation is found to be greatly affected by the type of magnetic anisotropy exhibited by the molecule, and it develops for frequencies corresponding to the Kondo temperature. For the parallel magnetic configuration of the device, the presence of dynamical spin accumulation is conditioned by the interplay of ferromagnetic-lead-induced exchange field and the Kondo correlations.

  16. Regulatory effects of curcumin on lipid accumulation in monocytes/macrophages

    USDA-ARS?s Scientific Manuscript database

    Recent evidence suggests potential benefits from phytochemicals and micronutrients in protecting against oxidative and lipid-mediated damage, but the molecular mechanisms of these actions are still unclear. Here we investigated whether the dietary polyphenol curcumin can modulate the accumulation of...

  17. The Cost of Accumulating Evidence in Perceptual Decision Making

    PubMed Central

    Drugowitsch, Jan; Moreno-Bote, Rubén; Churchland, Anne K.; Shadlen, Michael N.; Pouget, Alexandre

    2012-01-01

    Decision making often involves the accumulation of information over time, but acquiring information typically comes at a cost. Little is known about the cost incurred by animals and humans for acquiring additional information from sensory variables, due, for instance, to attentional efforts. Through a novel integration of diffusion models and dynamic programming, we were able to estimate the cost of making additional observations per unit of time from two monkeys and six humans in a reaction time random dot motion discrimination task. Surprisingly, we find that, the cost is neither zero nor constant over time, but for the animals and humans features a brief period in which it is constant but increases thereafter. In addition, we show that our theory accurately matches the observed reaction time distributions for each stimulus condition, the time-dependent choice accuracy both conditional on stimulus strength and independent of it, and choice accuracy and mean reaction times as a function of stimulus strength. The theory also correctly predicts that urgency signals in the brain should be independent of the difficulty, or stimulus strength, at each trial. PMID:22423085

  18. Ordinary differential equation for local accumulation time.

    PubMed

    Berezhkovskii, Alexander M

    2011-08-21

    Cell differentiation in a developing tissue is controlled by the concentration fields of signaling molecules called morphogens. Formation of these concentration fields can be described by the reaction-diffusion mechanism in which locally produced molecules diffuse through the patterned tissue and are degraded. The formation kinetics at a given point of the patterned tissue can be characterized by the local accumulation time, defined in terms of the local relaxation function. Here, we show that this time satisfies an ordinary differential equation. Using this equation one can straightforwardly determine the local accumulation time, i.e., without preliminary calculation of the relaxation function by solving the partial differential equation, as was done in previous studies. We derive this ordinary differential equation together with the accompanying boundary conditions and demonstrate that the earlier obtained results for the local accumulation time can be recovered by solving this equation. © 2011 American Institute of Physics

  19. Accumulate Repeat Accumulate Coded Modulation

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    In this paper we propose an innovative coded modulation scheme called 'Accumulate Repeat Accumulate Coded Modulation' (ARA coded modulation). This class of codes can be viewed as serial turbo-like codes, or as a subclass of Low Density Parity Check (LDPC) codes that are combined with high level modulation. Thus at the decoder belief propagation can be used for iterative decoding of ARA coded modulation on a graph, provided a demapper transforms the received in-phase and quadrature samples to reliability of the bits.

  20. Accumulation of dechlorination daughter products: A valid metric of chloroethene biodegradation

    USGS Publications Warehouse

    Bradley, Paul M.; Chapelle, Frank H.

    2007-01-01

    In situ reductive dechlorination of perchloroethene (PCE) and trichloroethene (TCE) generates characteristic chlorinated (cis-dichloroethene [cis-DCE] and vinyl chloride [VC]) and nonchlorinated (ethene and ethane) products. The accumulation of these daughter products is commonly used as a metric for ongoing biodegradation at field sites. However, this interpretation assumes that reductive dechlorination is the only chloroethene degradation process of any significance in situ and that the characteristic daughter products of chloroethene reductive dechlorination persist in the environment. Laboratory microcosms, prepared with aquifer and surface-water sediments from hydrologically diverse sites throughout the United States and amended with [1,2-14C] TCE, [1,2-14C] DCE, [1,2-14C] DCA, or [1,2-14C] VC, demonstrated widely variable patterns of intermediate and final product accumulation. In predominantly methanogenic sediment treatments, accumulation of 14C-DCE, 14C-VC, 14C-ethene, and 14C-ethane predominated. Treatments characterized by significant Fe(III) and/or Mn(IV) reduction, on the other hand, demonstrated substantial, and in some cases exclusive, accumulation of 14CO2and 14CH4. These results suggest that relying on the accumulation of cis-DCE, VC, ethene, and ethane may substantially underestimate overall chloroethene biodegradation at many sites.

  1. Triglyceride accumulation protects against fatty acid-induced lipotoxicity

    PubMed Central

    Listenberger, Laura L.; Han, Xianlin; Lewis, Sarah E.; Cases, Sylvaine; Farese, Robert V.; Ory, Daniel S.; Schaffer, Jean E.

    2003-01-01

    Excess lipid accumulation in non-adipose tissues is associated with insulin resistance, pancreatic β-cell apoptosis and heart failure. Here, we demonstrate in cultured cells that the relative toxicity of two common dietary long chain fatty acids is related to channeling of these lipids to distinct cellular metabolic fates. Oleic acid supplementation leads to triglyceride accumulation and is well tolerated, whereas excess palmitic acid is poorly incorporated into triglyceride and causes apoptosis. Unsaturated fatty acids rescue palmitate-induced apoptosis by channeling palmitate into triglyceride pools and away from pathways leading to apoptosis. Moreover, in the setting of impaired triglyceride synthesis, oleate induces lipotoxicity. Our findings support a model of cellular lipid metabolism in which unsaturated fatty acids serve a protective function against lipotoxicity though promotion of triglyceride accumulation. PMID:12629214

  2. First evidence of an extensive Acheulean large cutting tool accumulation in Europe from Porto Maior (Galicia, Spain).

    PubMed

    Méndez-Quintas, E; Santonja, M; Pérez-González, A; Duval, M; Demuro, M; Arnold, L J

    2018-02-15

    We describe a European Acheulean site characterised by an extensive accumulation of large cutting tools (LCT). This type of Lower Paleolithic assemblage, with dense LCT accumulations, has only been found on the African continent and in the Near East until now. The identification of a site with large accumulations of LCTs favours the hypothesis of an African origin for the Acheulean of Southwest Europe. The lithic tool-bearing deposits date back to 293-205 thousand years ago. Our chronological findings confirm temporal overlap between sites with clear "African" Acheulean affinities and Early Middle Paleolithic sites found elsewhere in the region. These complex technological patterns could be consistent with the potential coexistence of different human species in south-western Europe during the Middle Pleistocene.

  3. Flow field induced particle accumulation inside droplets in rectangular channels.

    PubMed

    Hein, Michael; Moskopp, Michael; Seemann, Ralf

    2015-07-07

    Particle concentration is a basic operation needed to perform washing steps or to improve subsequent analysis in many (bio)-chemical assays. In this article we present field free, hydrodynamic accumulation of particles and cells in droplets flowing within rectangular micro-channels. Depending on droplet velocity, particles either accumulate at the rear of the droplet or are dispersed over the entire droplet cross-section. We show that the observed particle accumulation behavior can be understood by a coupling of particle sedimentation to the internal flow field of the droplet. The changing accumulation patterns are explained by a qualitative change of the internal flow field. The topological change of the internal flow field, however, is explained by the evolution of the droplet shape with increasing droplet velocity altering the friction with the channel walls. In addition, we demonstrate that accumulated particles can be concentrated, removing excess dispersed phase by splitting the droplet at a simple channel junction.

  4. Image quality assessment metric for frame accumulated image

    NASA Astrophysics Data System (ADS)

    Yu, Jianping; Li, Gang; Wang, Shaohui; Lin, Ling

    2018-01-01

    The medical image quality determines the accuracy of diagnosis, and the gray-scale resolution is an important parameter to measure image quality. But current objective metrics are not very suitable for assessing medical images obtained by frame accumulation technology. Little attention was paid to the gray-scale resolution, basically based on spatial resolution and limited to the 256 level gray scale of the existing display device. Thus, this paper proposes a metric, "mean signal-to-noise ratio" (MSNR) based on signal-to-noise in order to be more reasonable to evaluate frame accumulated medical image quality. We demonstrate its potential application through a series of images under a constant illumination signal. Here, the mean image of enough images was regarded as the reference image. Several groups of images by different frame accumulation and their MSNR were calculated. The results of the experiment show that, compared with other quality assessment methods, the metric is simpler, more effective, and more suitable for assessing frame accumulated images that surpass the gray scale and precision of the original image.

  5. Five-month-old infants have expectations for the accumulation of nonsolid substances.

    PubMed

    Anderson, Erin M; Hespos, Susan J; Rips, Lance J

    2018-06-01

    Infants fail to represent quantities of non-cohesive substances in paradigms where they succeed with solid objects. Some investigators have interpreted these results as evidence that infants do not yet have representations for substances. More recent research, however, shows that 5-month-old infants expect objects and substances to behave and interact in different ways. In the present experiments, we test whether infants have expectations for substances when the outcomes are not simply the opposite of those for objects. In Experiment 1, we find that 5-month-old infants expect that when a cup of sand pours behind a screen, it will accumulate in just one pile rather than two. Similarly, infants expect that when two cups of sand pour in separate streams, two distinct piles will accumulate rather than one. Infants look significantly longer at outcomes with an inconsistent number of piles, providing evidence that infants have expectations for how sand accumulates. To test whether the number of cups or the number of pours guided expectations about accumulation, Experiment 2 placed these cues in conflict. This resulted in chance performance, suggesting that, for infants to build expectations about these outcomes, they need both cues (cup and pour) to converge. These findings offer insight into the nature of infants' representations for non-cohesive substances like sand. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Evidence to Support Tooth Brushing in Critically Ill Patients

    PubMed Central

    Ames, Nancy J.

    2012-01-01

    Tooth brushing in critically ill patients has been advocated by many as a standard of care despite the limited evidence to support this practice. Attention has been focused on oral care as the evidence accumulates to support an association between the bacteria in the oral microbiome and those respiratory pathogens that cause pneumonia. It is plausible to assume that respiratory pathogens originating in the oral cavity are aspirated into the lungs, causing infection. A recent study of the effects of a powered toothbrush on the incidence of ventilator-associated pneumonia was stopped early because of a lack of effect in the treatment group. This review summarizes the evidence that supports the effectiveness of tooth brushing in critically ill adults and children receiving mechanical ventilation. Possible reasons for the lack of benefit of tooth brushing demonstrated in clinical trials are discussed. Recommendations for future trials in critically ill patients are suggested. With increased emphasis being placed on oral care, the evidence that supports this intervention must be evaluated carefully. PMID:21532045

  7. Evidence to support tooth brushing in critically ill patients.

    PubMed

    Ames, Nancy J

    2011-05-01

    Tooth brushing in critically ill patients has been advocated by many as a standard of care despite the limited evidence to support this practice. Attention has been focused on oral care as the evidence accumulates to support an association between the bacteria in the oral microbiome and those respiratory pathogens that cause pneumonia. It is plausible to assume that respiratory pathogens originating in the oral cavity are aspirated into the lungs, causing infection. A recent study of the effects of a powered toothbrush on the incidence of ventilator-associated pneumonia was stopped early because of a lack of effect in the treatment group. This review summarizes the evidence that supports the effectiveness of tooth brushing in critically ill adults and children receiving mechanical ventilation. Possible reasons for the lack of benefit of tooth brushing demonstrated in clinical trials are discussed. Recommendations for future trials in critically ill patients are suggested. With increased emphasis being placed on oral care, the evidence that supports this intervention must be evaluated carefully.

  8. Accumulation of /sup 60/Co by freshwater plants under natural conditions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Trapeznikov, A.V.; Trapeznikova, V.N.

    1979-03-01

    The study of /sup 60/Co accumulation by aquatic plants is of interest in finding effective bioindicators for radioactive pollution of nuclear power station cooling ponds. In this respect, /sup 60/Co accumulation was studied in four species of higher aquatic plants most commonly found in the Urals: water thyme (Elodea canadensis), hornwort (Ceratophyllum demersum), lesser duckweed (Lemna minor), and fennel pondweed (Potamogeton pectinatus). The /sup 60/Co accumulation coefficients in the plants studied reached considerable values. The data obtained demonstrate that plants such as hornwort and water thyme with /sup 60/Co accumulation coefficients of 33,500 and 21,500, respectively, may be recommended asmore » bioindicators for these radionuclides in the water bodies polluted with radioactive cobalt.« less

  9. Anthocyanins facilitate tungsten accumulation in Brassica

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hale, K.L.

    2002-11-01

    Accumulation of molybdenum in Brassica was recently found to be correlated with anthocyanin content, involving the formation of a blue complex. Here the role of anthocyanins in tungsten sequestration was investigated using three species of Brassica: B. rapa (cv. Fast plants), B. juncea (Indian mustard) and B. oleracea (red cabbage). Seedlings of B. rapa and B. juncea turned blue when supplied with colourless tungstate. The blue compound co-localized with anthocyanins in the peripheral cell layers, and the degree of blueness was correlated with anthocyanin content. The direct involvement of anthocyanins in the blue coloration was evident when purified anthocyanins showedmore » a colour change from pink to blue in vitro upon addition of tungstate, over a wide pH range. Anthocyanin production was upregulated 3-fold by W in B. juncea, possibly reflecting a function for anthocyanins in W tolerance or sequestration. The presence of anthocyanins facilitated W accumulation in B. rapa: anthocyanin-containing seedlings accumulated 3-fold more W than an anthocyaninless mutant. There was no correlation between anthocyanin content and W tolerance under these conditions. The nature of the interaction between anthocyanins and tungstate was investigated. X-ray absorption spectroscopy showed no change in the local chemical environment of Wupon uptake of tungstate by the plant; HPLC analysis of purified anthocyanin with or without tungstate showed no peak shift after metal treatment.« less

  10. Annual Greenland Accumulation Rates (2009-2012) from Airborne Snow Radar

    NASA Technical Reports Server (NTRS)

    Koenig, Lora S.; Ivanoff, Alvaro; Alexander, Patrick M.; MacGregor, Joseph A.; Fettweis, Xavier; Panzer, Ben; Paden, John D.; Forster, Richard R.; Das, Indrani; McConnell, Joseph R.; hide

    2016-01-01

    Contemporary climate warming over the Arctic is accelerating mass loss from the Greenland Ice Sheet through increasing surface melt, emphasizing the need to closely monitor its surface mass balance in order to improve sea-level rise predictions. Snow accumulation is the largest component of the ice sheet's surface mass balance, but in situ observations thereof are inherently sparse and models are difficult to evaluate at large scales. Here, we quantify recent Greenland accumulation rates using ultra-wideband (2-6.5 gigahertz) airborne snow radar data collected as part of NASA's Operation IceBridge between 2009 and 2012. We use a semi-automated method to trace the observed radiostratigraphy and then derive annual net accumulation rates for 2009-2012. The uncertainty in these radar-derived accumulation rates is on average 14 percent. A comparison of the radarderived accumulation rates and contemporaneous ice cores shows that snow radar captures both the annual and longterm mean accumulation rate accurately. A comparison with outputs from a regional climate model (MAR - Modele Atmospherique Regional for Greenland and vicinity) shows that this model matches radar-derived accumulation rates in the ice sheet interior but produces higher values over southeastern Greenland. Our results demonstrate that snow radar can efficiently and accurately map patterns of snow accumulation across an ice sheet and that it is valuable for evaluating the accuracy of surface mass balance models.

  11. Demonstration of anaerobic stabilization of black water in accumulation systems under tropical conditions.

    PubMed

    Chaggu, Esnati J; Sanders, Wendy; Lettinga, Gatze

    2007-11-01

    The anaerobic digestion of "human waste" was studied at Mlalakuwa residential settlement in Dar-es-Salaam, Tanzania at ambient tropical temperatures (24-31 degrees C). This settlement experiences a high water table with flooding during the rainy season, resulting in a very costly emptying of the latrines once per month. To improve the situation, two plastic tanks (while one is in use, the other one is on stand-by) of 3000 l capacity each, named as Improved Pit-Latrines Without Urine Separation (IMPLWUS), were used as latrine pits. They received faeces+urine+wash water; basically, an accumulation system. Septic tank seed sludge was used. The dissolved chemical oxygen demand (COD(dis)) remaining when the reactor was closed after 380 days was about 8 g COD/l, volatile fatty acids were 100 mg COD/l and total ammonium nitrogen was about 2.8 g N/l, implying the possibility of methanogenesis inhibition. Stability results indicated a need for more degradation time after reactor closure. Estimated biogas production from wastewater generated by 10 people was 544 g COD-CH(4)/day, not enough for cooking purposes.

  12. Developmental accumulation of inorganic polyphosphate affects germination and energetic metabolism in Dictyostelium discoideum

    PubMed Central

    Livermore, Thomas Miles; Chubb, Jonathan Robert; Saiardi, Adolfo

    2016-01-01

    Inorganic polyphosphate (polyP) is composed of linear chains of phosphate groups linked by high-energy phosphoanhydride bonds. However, this simple, ubiquitous molecule remains poorly understood. The use of nonstandardized analytical methods has contributed to this lack of clarity. By using improved polyacrylamide gel electrophoresis we were able to visualize polyP extracted from Dictyostelium discoideum. We established that polyP is undetectable in cells lacking the polyphosphate kinase (DdPpk1). Generation of this ppk1 null strain revealed that polyP is important for the general fitness of the amoebae with the mutant strain displaying a substantial growth defect. We discovered an unprecedented accumulation of polyP during the developmental program, with polyP increasing more than 100-fold. The failure of ppk1 spores to accumulate polyP results in a germination defect. These phenotypes are underpinned by the ability of polyP to regulate basic energetic metabolism, demonstrated by a 2.5-fold decrease in the level of ATP in vegetative ppk1. Finally, the lack of polyP during the development of ppk1 mutant cells is partially offset by an increase of both ATP and inositol pyrophosphates, evidence for a model in which there is a functional interplay between inositol pyrophosphates, ATP, and polyP. PMID:26755590

  13. 34 CFR 366.63 - What evidence must a center present to demonstrate that it is in minimum compliance with the...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION CENTERS FOR INDEPENDENT LIVING Evaluation Standards and... 34 Education 2 2011-07-01 2010-07-01 true What evidence must a center present to demonstrate that it is in minimum compliance with the evaluation standards? 366.63 Section 366.63 Education...

  14. Evidence of common and separate eye and hand accumulators underlying flexible eye-hand coordination

    PubMed Central

    Jana, Sumitash; Gopal, Atul

    2016-01-01

    Eye and hand movements are initiated by anatomically separate regions in the brain, and yet these movements can be flexibly coupled and decoupled, depending on the need. The computational architecture that enables this flexible coupling of independent effectors is not understood. Here, we studied the computational architecture that enables flexible eye-hand coordination using a drift diffusion framework, which predicts that the variability of the reaction time (RT) distribution scales with its mean. We show that a common stochastic accumulator to threshold, followed by a noisy effector-dependent delay, explains eye-hand RT distributions and their correlation in a visual search task that required decision-making, while an interactive eye and hand accumulator model did not. In contrast, in an eye-hand dual task, an interactive model better predicted the observed correlations and RT distributions than a common accumulator model. Notably, these two models could only be distinguished on the basis of the variability and not the means of the predicted RT distributions. Additionally, signatures of separate initiation signals were also observed in a small fraction of trials in the visual search task, implying that these distinct computational architectures were not a manifestation of the task design per se. Taken together, our results suggest two unique computational architectures for eye-hand coordination, with task context biasing the brain toward instantiating one of the two architectures. NEW & NOTEWORTHY Previous studies on eye-hand coordination have considered mainly the means of eye and hand reaction time (RT) distributions. Here, we leverage the approximately linear relationship between the mean and standard deviation of RT distributions, as predicted by the drift-diffusion model, to propose the existence of two distinct computational architectures underlying coordinated eye-hand movements. These architectures, for the first time, provide a computational basis for

  15. Conifer ovulate cones accumulate pollen principally by simple impaction.

    PubMed

    Cresswell, James E; Henning, Kevin; Pennel, Christophe; Lahoubi, Mohamed; Patrick, Michael A; Young, Phillipe G; Tabor, Gavin R

    2007-11-13

    In many pine species (Family Pinaceae), ovulate cones structurally resemble a turbine, which has been widely interpreted as an adaptation for improving pollination by producing complex aerodynamic effects. We tested the turbine interpretation by quantifying patterns of pollen accumulation on ovulate cones in a wind tunnel and by using simulation models based on computational fluid dynamics. We used computer-aided design and computed tomography to create computational fluid dynamics model cones. We studied three species: Pinus radiata, Pinus sylvestris, and Cedrus libani. Irrespective of the approach or species studied, we found no evidence that turbine-like aerodynamics made a significant contribution to pollen accumulation, which instead occurred primarily by simple impaction. Consequently, we suggest alternative adaptive interpretations for the structure of ovulate cones.

  16. Conifer ovulate cones accumulate pollen principally by simple impaction

    PubMed Central

    Cresswell, James E.; Henning, Kevin; Pennel, Christophe; Lahoubi, Mohamed; Patrick, Michael A.; Young, Phillipe G.; Tabor, Gavin R.

    2007-01-01

    In many pine species (Family Pinaceae), ovulate cones structurally resemble a turbine, which has been widely interpreted as an adaptation for improving pollination by producing complex aerodynamic effects. We tested the turbine interpretation by quantifying patterns of pollen accumulation on ovulate cones in a wind tunnel and by using simulation models based on computational fluid dynamics. We used computer-aided design and computed tomography to create computational fluid dynamics model cones. We studied three species: Pinus radiata, Pinus sylvestris, and Cedrus libani. Irrespective of the approach or species studied, we found no evidence that turbine-like aerodynamics made a significant contribution to pollen accumulation, which instead occurred primarily by simple impaction. Consequently, we suggest alternative adaptive interpretations for the structure of ovulate cones. PMID:17986613

  17. [Genetic Mutation Accumulation and Clinical Outcome of Immune Checkpoint Blockade Therapy].

    PubMed

    Takahashi, Masanobu

    2016-06-01

    Immune checkpoint blockade therapy has recently attracted great attention in the area of oncology. In Japan, since 2014, an anti-PD-1 antibody nivolumab and anti-CTLA-4 antibody ipilimumab have been available for the treatment of patients with malignant melanoma, and nivolumab has been available for patients with non-small cell lung cancer. Clinical trials using these drugs and other immune checkpoint inhibitors are currently in progress worldwide. The immune checkpoint blockade therapy is a promising new cancer therapy; however, not all patients with cancer can benefit from this therapy. Recent evidence shows that markers reflecting the extent of genetic mutation accumulation, including mutation burden, non-synonymous mutation that produces neoantigen, and microsatellite instability, possibly serve as promising marker to predict who can benefit from the immune checkpoint blockade therapy. Here, I introduce the recent evidence and discuss the correlation between genetic mutation accumulation and clinical outcome of immune checkpoint blockade therapy.

  18. The Physics of Decision Making:. Stochastic Differential Equations as Models for Neural Dynamics and Evidence Accumulation in Cortical Circuits

    NASA Astrophysics Data System (ADS)

    Holmes, Philip; Eckhoff, Philip; Wong-Lin, K. F.; Bogacz, Rafal; Zacksenhouse, Miriam; Cohen, Jonathan D.

    2010-03-01

    We describe how drift-diffusion (DD) processes - systems familiar in physics - can be used to model evidence accumulation and decision-making in two-alternative, forced choice tasks. We sketch the derivation of these stochastic differential equations from biophysically-detailed models of spiking neurons. DD processes are also continuum limits of the sequential probability ratio test and are therefore optimal in the sense that they deliver decisions of specified accuracy in the shortest possible time. This leaves open the critical balance of accuracy and speed. Using the DD model, we derive a speed-accuracy tradeoff that optimizes reward rate for a simple perceptual decision task, compare human performance with this benchmark, and discuss possible reasons for prevalent sub-optimality, focussing on the question of uncertain estimates of key parameters. We present an alternative theory of robust decisions that allows for uncertainty, and show that its predictions provide better fits to experimental data than a more prevalent account that emphasises a commitment to accuracy. The article illustrates how mathematical models can illuminate the neural basis of cognitive processes.

  19. Evidence-based evaluation of the cumulative effects of ecosystem restoration

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Diefenderfer, Heida L.; Johnson, Gary E.; Thom, Ronald M.

    Evaluating the cumulative effects of large-scale ecological restoration programs is necessary to inform adaptive ecosystem management and provide society with resilient and sustainable services. However, complex linkages between restorative actions and ecosystem responses make evaluations problematic. Despite long-term federal investments in restoring aquatic ecosystems, no standard evaluation method has been adopted and most programs focus on monitoring and analysis, not synthesis and evaluation. In this paper, we demonstrate a new transdisciplinary approach integrating techniques from evidence-based medicine, critical thinking, and cumulative effects assessment. Tiered hypotheses are identified using an ecosystem conceptual model. The systematic literature review at the core ofmore » evidence-based assessment becomes one of many lines of evidence assessed collectively, using critical thinking strategies and causal criteria from a cumulative effects perspective. As a demonstration, we analyzed data from 166 locations on the Columbia River and estuary representing 12 indicators of habitat and fish response to floodplain restoration actions intended to benefit threatened and endangered salmon. Synthesis of seven lines of evidence showed that hydrologic reconnection promoted macrodetritis export, prey availability, and fish access and feeding. The evidence was sufficient to infer cross-boundary, indirect, compounding and delayed cumulative effects, and suggestive of nonlinear, landscape-scale, and spatial density effects. On the basis of causal inferences regarding food web functions, we concluded that the restoration program has a cumulative beneficial effect on juvenile salmon. As a result, this evidence-based approach will enable the evaluation of restoration in complex coastal and riverine ecosystems where data have accumulated without sufficient synthesis.« less

  20. Evidence-based evaluation of the cumulative effects of ecosystem restoration

    DOE PAGES

    Diefenderfer, Heida L.; Johnson, Gary E.; Thom, Ronald M.; ...

    2016-03-18

    Evaluating the cumulative effects of large-scale ecological restoration programs is necessary to inform adaptive ecosystem management and provide society with resilient and sustainable services. However, complex linkages between restorative actions and ecosystem responses make evaluations problematic. Despite long-term federal investments in restoring aquatic ecosystems, no standard evaluation method has been adopted and most programs focus on monitoring and analysis, not synthesis and evaluation. In this paper, we demonstrate a new transdisciplinary approach integrating techniques from evidence-based medicine, critical thinking, and cumulative effects assessment. Tiered hypotheses are identified using an ecosystem conceptual model. The systematic literature review at the core ofmore » evidence-based assessment becomes one of many lines of evidence assessed collectively, using critical thinking strategies and causal criteria from a cumulative effects perspective. As a demonstration, we analyzed data from 166 locations on the Columbia River and estuary representing 12 indicators of habitat and fish response to floodplain restoration actions intended to benefit threatened and endangered salmon. Synthesis of seven lines of evidence showed that hydrologic reconnection promoted macrodetritis export, prey availability, and fish access and feeding. The evidence was sufficient to infer cross-boundary, indirect, compounding and delayed cumulative effects, and suggestive of nonlinear, landscape-scale, and spatial density effects. On the basis of causal inferences regarding food web functions, we concluded that the restoration program has a cumulative beneficial effect on juvenile salmon. As a result, this evidence-based approach will enable the evaluation of restoration in complex coastal and riverine ecosystems where data have accumulated without sufficient synthesis.« less

  1. Effects of different mechanized soil fertilization methods on corn nutrient accumulation and yield

    NASA Astrophysics Data System (ADS)

    Shi, Qingwen; Bai, Chunming; Wang, Huixin; Wu, Di; Song, Qiaobo; Dong, Zengqi; Gao, Depeng; Dong, Qiping; Cheng, Xin; Zhang, Yahao; Mu, Jiahui; Chen, Qinghong; Liao, Wenqing; Qu, Tianru; Zhang, Chunling; Zhang, Xinyu; Liu, Yifei; Han, Xiaori

    2017-05-01

    Aim: Experiments for mechanized corn soil fertilization were conducted in Faku demonstration zone. On this basis, we studied effects on corn nutrient accumulation and yield traits at brown soil regions due to different mechanized soil fertilization measures. We also evaluated and optimized the regulation effects of mechanized soil fertilization for the purpose of crop yield increase and production efficiency improvement. Method: Based on the survey of soil background value in the demonstration zone, we collected plant samples during different corn growth periods to determine and make statistical analysis. Conclusions: Decomposed cow dung, when under mechanical broadcasting, was able to remarkably increase nitrogen and potassium accumulation content of corns at their ripe stage. Crushed stalk returning combined with deep tillage would remarkably increase phosphorus accumulation content of corn plants. When compared with top application, crushed stalk returning combined with deep tillage would remarkably increase corn thousand kernel weight (TKW). Mechanized broadcasting of granular organic fertilizer and crushed stalk returning combined with deep tillage, when compared with surface application, were able to boost corn yield in the in the demonstration zone.

  2. 40 CFR 86.1825-08 - Durability demonstration procedures for refueling emissions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...), or (e) of this section. (c) Whole vehicle refueling durability demonstration. The following procedures must be used when conducting a whole vehicle durability demonstration: (1) Mileage accumulation... available fuels, including the Tier 2 requirement to include alcohol fuel; (3) Vibration of components; (4...

  3. 40 CFR 86.1825-08 - Durability demonstration procedures for refueling emissions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...), or (e) of this section. (c) Whole vehicle refueling durability demonstration. The following procedures must be used when conducting a whole vehicle durability demonstration: (1) Mileage accumulation... available fuels, including the Tier 2 requirement to include alcohol fuel; (3) Vibration of components; (4...

  4. 40 CFR 86.1825-08 - Durability demonstration procedures for refueling emissions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .... (c) Whole vehicle refueling durability demonstration. The following procedures must be used when conducting a whole vehicle durability demonstration: (1) Mileage accumulation must be conducted using the SRC... Tier 2 requirement to include alcohol fuel; (3) Vibration of components; (4) Deterioration of hoses...

  5. MYB89 Transcription Factor Represses Seed Oil Accumulation1[OPEN

    PubMed Central

    Li, Dong; Jin, Changyu; Duan, Shaowei; Zhu, Yana; Qi, Shuanghui; Liu, Kaige; Gao, Chenhao; Ma, Haoli; Liao, Yuncheng

    2017-01-01

    In many higher plants, seed oil accumulation is precisely controlled by intricate multilevel regulatory networks, among which transcriptional regulation mainly influences oil biosynthesis. In Arabidopsis (Arabidopsis thaliana), the master positive transcription factors, WRINKLED1 (WRI1) and LEAFY COTYLEDON1-LIKE (L1L), are important for seed oil accumulation. We found that an R2R3-MYB transcription factor, MYB89, was expressed predominantly in developing seeds during maturation. Oil and major fatty acid biosynthesis in seeds was significantly promoted by myb89-1 mutation and MYB89 knockdown; thus, MYB89 was an important repressor during seed oil accumulation. RNA sequencing revealed remarkable up-regulation of numerous genes involved in seed oil accumulation in myb89 seeds at 12 d after pollination. Posttranslational activation of a MYB89-glucocorticoid receptor fusion protein and chromatin immunoprecipitation assays demonstrated that MYB89 inhibited seed oil accumulation by directly repressing WRI1 and five key genes and by indirectly suppressing L1L and 11 key genes involved in oil biosynthesis during seed maturation. These results help us to understand the novel function of MYB89 and provide new insights into the regulatory network of transcriptional factors controlling seed oil accumulation in Arabidopsis. PMID:27932421

  6. Multisite Studies Demonstrate Positive Relationship Between Practice Environments and Smoking Cessation Counseling Evidence-Based Practices.

    PubMed

    Newhouse, Robin; Byon, Ha Do; Storkman Wolf, Emily; Johantgen, Meg

    2018-06-01

    High-quality smoking cessation counseling guidelines for people who use tobacco are not fully integrated in acute-care services presenting missed opportunities to improve health outcomes. The role of the practice environment on enhancing or inhibiting guideline use is unknown. To examine the relationship between the nurse practice environment and nurses' use of smoking cessation counseling practices, and to evaluate the effect of the individual nurse and organization characteristics on nurse smoking cessation counseling practices. Cross-sectional secondary analysis of survey data from two multisite studies. The sample included responses from registered nurses (N = 844) in 45 hospitals (22 rural hospitals from the Eastern United States and 23 Magnet hospitals across the United States). Linear mixed model was used to adjust intradependency among the responses of individual nurses nested within hospitals. Data were abstracted from survey responses including nurse characteristics, the Smoking Cessation Counseling Scale (SCCS), and the Practice Environment Scale-Nursing Work Index (PES). Increasing positive relationships exist between PES and SCCS total and subscales scores. Also, SCCS total scores were significantly related with favorable PES total scores (SCCS score difference of 0.26 between favorable and unfavorable PES scores, SE = .08, p = .002) controlling for other covariates. Non-White respondents (vs. White) demonstrated a positive association with SCCS total scores (difference of .18, SE = .07, p = .010), but not in advanced counseling. Nurse practice environments are positively associated with the use of evidence-based smoking cessation practices by nurses. As practice environments become more favorable, higher level counseling practices occur more often. Healthcare leaders should focus on enhancing the practice environment using a quality improvement approach and framework for evidence translation. Quality improvement initiatives should be prioritized in

  7. Maximum likelihood decoding analysis of Accumulate-Repeat-Accumulate Codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, Aliazam; Divsalar, Dariush; Yao, Kung

    2004-01-01

    Repeat-Accumulate (RA) codes are the simplest turbo-like codes that achieve good performance. However, they cannot compete with Turbo codes or low-density parity check codes (LDPC) as far as performance is concerned. The Accumulate Repeat Accumulate (ARA) codes, as a subclass of LDPC codes, are obtained by adding a pre-coder in front of RA codes with puncturing where an accumulator is chosen as a precoder. These codes not only are very simple, but also achieve excellent performance with iterative decoding. In this paper, the performance of these codes with (ML) decoding are analyzed and compared to random codes by very tight bounds. The weight distribution of some simple ARA codes is obtained, and through existing tightest bounds we have shown the ML SNR threshold of ARA codes approaches very closely to the performance of random codes. We have shown that the use of precoder improves the SNR threshold but interleaving gain remains unchanged with respect to RA code with puncturing.

  8. Characterizing Adversity of Lysosomal Accumulation in Nonclinical Toxicity Studies: Results from the 5th ESTP International Expert Workshop.

    PubMed

    Lenz, B; Braendli-Baiocco, A; Engelhardt, J; Fant, P; Fischer, H; Francke, S; Fukuda, R; Gröters, S; Harada, T; Harleman, H; Kaufmann, W; Kustermann, S; Nolte, T; Palazzi, X; Pohlmeyer-Esch, G; Popp, A; Romeike, A; Schulte, A; Lima, B Silva; Tomlinson, L; Willard, J; Wood, C E; Yoshida, M

    2018-02-01

    Lysosomes have a central role in cellular catabolism, trafficking, and processing of foreign particles. Accumulation of endogenous and exogenous materials in lysosomes represents a common finding in nonclinical toxicity studies. Histologically, these accumulations often lack distinctive features indicative of lysosomal or cellular dysfunction, making it difficult to consistently interpret and assign adverse dose levels. To help address this issue, the European Society of Toxicologic Pathology organized a workshop where representative types of lysosomal accumulation induced by pharmaceuticals and environmental chemicals were presented and discussed. The expert working group agreed that the diversity of lysosomal accumulations requires a case-by-case weight-of-evidence approach and outlined several factors to consider in the adversity assessment, including location and type of cell affected, lysosomal contents, severity of the accumulation, and related pathological effects as evidence of cellular or organ dysfunction. Lysosomal accumulations associated with cytotoxicity, inflammation, or fibrosis were generally considered to be adverse, while those found in isolation (without morphologic or functional consequences) were not. Workshop examples highlighted the importance of thoroughly characterizing the biological context of lysosomal effects, including mechanistic data and functional in vitro readouts if available. The information provided here should facilitate greater consistency and transparency in the interpretation of lysosomal effects.

  9. Glutamate Dysregulation and Glutamatergic Therapeutics for PTSD: Evidence from Human Studies

    PubMed Central

    Averill, Lynnette A.; Purohit, Prerana; Averill, Christopher L.; Boesl, Markus A.; Krystal, John H.; Abdallah, Chadi G.

    2017-01-01

    Posttraumatic stress disorder (PTSD) is a chronic and debilitating psychiatric disorder afflicting millions of individuals across the world. While the availability of robust pharmacologic interventions is quite lacking, our understanding of the putative neurobiological underpinnings of PTSD has significantly increased over the past two decades. Accumulating evidence demonstrates aberrant glutamatergic function in mood, anxiety, and trauma-related disorders and dysfunction in glutamate neurotransmission is increasingly considered a cardinal feature of stress-related psychiatric disorders including PTSD. As part of a PTSD Special Issue, this mini-review provides a concise discussion of (1) evidence of glutamatergic abnormalities in PTSD, with emphasis on human subjects data; (2) glutamate-modulating agents as potential alternative pharmacologic treatments for PTSD; and (3) selected gaps in the literature and related future directions. PMID:27916636

  10. Transcriptional program for nitrogen starvation-induced lipid accumulation in Chlamydomonas reinhardtii

    DOE PAGES

    Garcia de Lomana, Adrian Lopez; Schäuble, Sascha; Valenzuela, Jacob; ...

    2015-12-02

    Algae accumulate lipids to endure different kinds of environmental stresses including macronutrient starvation. Although this response has been extensively studied, an in depth understanding of the transcriptional regulatory network (TRN) that controls the transition into lipid accumulation remains elusive. In this study, we used a systems biology approach to elucidate the transcriptional program that coordinates the nitrogen starvation-induced metabolic readjustments that drive lipid accumulation in Chlamydomonas reinhardtii. We demonstrate that nitrogen starvation triggered differential regulation of 2147 transcripts, which were co-regulated in 215 distinct modules and temporally ordered as 31 transcriptional waves. An early-stage response was triggered within 12 minmore » that initiated growth arrest through activation of key signaling pathways, while simultaneously preparing the intracellular environment for later stages by modulating transport processes and ubiquitin-mediated protein degradation. Subsequently, central metabolism and carbon fixation were remodeled to trigger the accumulation of triacylglycerols. Further analysis revealed that these waves of genome-wide transcriptional events were coordinated by a regulatory program orchestrated by at least 17 transcriptional regulators, many of which had not been previously implicated in this process. We demonstrate that the TRN coordinates transcriptional downregulation of 57 metabolic enzymes across a period of nearly 4 h to drive an increase in lipid content per unit biomass. Notably, this TRN appears to also drive lipid accumulation during sulfur starvation, while phosphorus starvation induces a different regulatory program. The TRN model described here is available as a community-wide web-resource at http://networks.systemsbiology.net/chlamy-portal. In conclusion, in this work, we have uncovered a comprehensive mechanistic model of the TRN controlling the transition from N starvation to lipid

  11. Transcriptional program for nitrogen starvation-induced lipid accumulation in Chlamydomonas reinhardtii

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Garcia de Lomana, Adrian Lopez; Schäuble, Sascha; Valenzuela, Jacob

    Algae accumulate lipids to endure different kinds of environmental stresses including macronutrient starvation. Although this response has been extensively studied, an in depth understanding of the transcriptional regulatory network (TRN) that controls the transition into lipid accumulation remains elusive. In this study, we used a systems biology approach to elucidate the transcriptional program that coordinates the nitrogen starvation-induced metabolic readjustments that drive lipid accumulation in Chlamydomonas reinhardtii. We demonstrate that nitrogen starvation triggered differential regulation of 2147 transcripts, which were co-regulated in 215 distinct modules and temporally ordered as 31 transcriptional waves. An early-stage response was triggered within 12 minmore » that initiated growth arrest through activation of key signaling pathways, while simultaneously preparing the intracellular environment for later stages by modulating transport processes and ubiquitin-mediated protein degradation. Subsequently, central metabolism and carbon fixation were remodeled to trigger the accumulation of triacylglycerols. Further analysis revealed that these waves of genome-wide transcriptional events were coordinated by a regulatory program orchestrated by at least 17 transcriptional regulators, many of which had not been previously implicated in this process. We demonstrate that the TRN coordinates transcriptional downregulation of 57 metabolic enzymes across a period of nearly 4 h to drive an increase in lipid content per unit biomass. Notably, this TRN appears to also drive lipid accumulation during sulfur starvation, while phosphorus starvation induces a different regulatory program. The TRN model described here is available as a community-wide web-resource at http://networks.systemsbiology.net/chlamy-portal. In conclusion, in this work, we have uncovered a comprehensive mechanistic model of the TRN controlling the transition from N starvation to lipid

  12. Local accumulation times for spatial difference in morphogen concentration

    NASA Astrophysics Data System (ADS)

    Wen, Xiaoqing; Yin, Hongwei

    During development of multicellular organisms, spatial patterns of cells and tissue organizations rely on the action of morphogens, which are signaling molecules and act as dose-dependent regulators of gene expression and cellular differentiation. Since some experimental evidences have indicated that the spatial difference in morphogen concentration regulates cellular proliferation rather than this concentration profile in developing tissues, we propose spatially discrete models to describe this difference for a synthesis-diffusion-degradation process of morphogen in infinite and finite development fields, respectively. For both of models, we respectively derive analytical expressions of local accumulation times, which are required to form the steady state of the spatial difference in morphogen concentration. Our results show that the local accumulation times for the spatial difference in morphogen concentrations are different from the ones for morphogen concentration profiles.

  13. The BH3 Mimetic Obatoclax Accumulates in Lysosomes and Causes Their Alkalinization.

    PubMed

    Stamelos, Vasileios A; Fisher, Natalie; Bamrah, Harnoor; Voisey, Carolyn; Price, Joshua C; Farrell, William E; Redman, Charles W; Richardson, Alan

    2016-01-01

    Obatoclax belongs to a class of compounds known as BH3 mimetics which function as antagonists of Bcl-2 family apoptosis regulators. It has undergone extensive preclinical and clinical evaluation as a cancer therapeutic. Despite this, it is clear that obatoclax has additional pharmacological effects that contribute to its cytotoxic activity. It has been claimed that obatoclax, either alone or in combination with other molecularly targeted therapeutics, induces an autophagic form of cell death. In addition, obatoclax has been shown to inhibit lysosomal function, but the mechanism of this has not been elucidated. We have evaluated the mechanism of action of obatoclax in eight ovarian cancer cell lines. Consistent with its function as a BH3 mimetic, obatoclax induced apoptosis in three cell lines. However, in the remaining cell lines another form of cell death was evident because caspase activation and PARP cleavage were not observed. Obatoclax also failed to show synergy with carboplatin and paclitaxel, chemotherapeutic agents which we have previously shown to be synergistic with authentic Bcl-2 family antagonists. Obatoclax induced a profound accumulation of LC-3 but knockdown of Atg-5 or beclin had only minor effects on the activity of obatoclax in cell growth assays suggesting that the inhibition of lysosomal function rather than stimulation of autophagy may play a more prominent role in these cells. To evaluate how obatoclax inhibits lysosomal function, confocal microscopy studies were conducted which demonstrated that obatoclax, which contains two basic pyrrole groups, accumulates in lysosomes. Studies using pH sensitive dyes demonstrated that obatoclax induced lysosomal alkalinization. Furthermore, obatoclax was synergistic in cell growth/survival assays with bafilomycin and chloroquine, two other drugs which cause lysosomal alkalinization. These studies explain, for the first time, how obatoclax inhibits lysosomal function and suggest that lysosomal

  14. Refeeding-Induced Brown Adipose Tissue Glycogen Hyper-Accumulation in Mice Is Mediated by Insulin and Catecholamines

    PubMed Central

    Carmean, Christopher M.; Bobe, Alexandria M.; Yu, Justin C.; Volden, Paul A.; Brady, Matthew J.

    2013-01-01

    Brown adipose tissue (BAT) generates heat during adaptive thermogenesis through a combination of oxidative metabolism and uncoupling protein 1-mediated electron transport chain uncoupling, using both free-fatty acids and glucose as substrate. Previous rat-based work in 1942 showed that prolonged partial fasting followed by refeeding led to a dramatic, transient increase in glycogen stores in multiple fat depots. In the present study, the protocol was replicated in male CD1 mice, resulting in a 2000-fold increase in interscapular BAT (IBAT) glycogen levels within 4–12 hours (hr) of refeeding, with IBAT glycogen stores reaching levels comparable to fed liver glycogen. Lesser effects occurred in white adipose tissues (WAT). Over the next 36 hr, glycogen levels dissipated and histological analysis revealed an over-accumulation of lipid droplets, suggesting a potential metabolic connection between glycogenolysis and lipid synthesis. 24 hr of total starvation followed by refeeding induced a robust and consistent glycogen over-accumulation similar in magnitude and time course to the prolonged partial fast. Experimentation demonstrated that hyperglycemia was not sufficient to drive glycogen accumulation in IBAT, but that elevated circulating insulin was sufficient. Additionally, pharmacological inhibition of catecholamine production reduced refeeding-induced IBAT glycogen storage, providing evidence of a contribution from the central nervous system. These findings highlight IBAT as a tissue that integrates both canonically-anabolic and catabolic stimulation for the promotion of glycogen storage during recovery from caloric deficit. The preservation of this robust response through many generations of animals not subjected to food deprivation suggests that the over-accumulation phenomenon plays a critical role in IBAT physiology. PMID:23861810

  15. Shape memory alloy actuated accumulator for ultra-deepwater oil and gas exploration

    NASA Astrophysics Data System (ADS)

    Patil, Devendra; Song, Gangbing

    2016-04-01

    As offshore oil and gas exploration moves further offshore and into deeper waters to reach hydrocarbon reserves, it is becoming essential for the industry to develop more reliable and efficient hydraulic accumulators to supply pressured hydraulic fluid for various control and actuation operations, such as closing rams of blowout preventers and controlling subsea valves on the seafloor. By utilizing the shape memory effect property of nitinol, which is a type of shape memory alloy (SMA), an innovative SMA actuated hydraulic accumulator prototype has been developed and successfully tested at Smart Materials and Structure Laboratory at the University of Houston. Absence of gas in the developed SMA accumulator prototype makes it immune to hydrostatic head loss caused by water depth and thus reduces the number of accumulators required in deep water operations. Experiments with a feedback control have demonstrated that the proposed SMA actuated accumulator can provide precisely regulated pressurized fluids. Furthermore the potential use of ultracapacitors along with an embedded system to control the electric power supplied to SMA allows this accumulator to be an autonomous device for deployment. The developed SMA accumulator will make deepwater oil extraction systems more compact and cost effective.

  16. Coaching and Demonstration of Evidence-Based Book-Reading Practices: Effects on Head Start Teachers' Literacy-Related Behaviors and Classroom Environment

    ERIC Educational Resources Information Center

    Gettinger, Maribeth; Stoiber, Karen C.

    2016-01-01

    This study examined the effects of coaching with versus without demonstrations of evidence-based book-reading practices on teachers' use of strategies during independent book-reading periods. A total of 22 Head Start teachers were randomly assigned to one of two cohorts. One cohort (n = 12) participated in biweekly coaching sessions that included…

  17. Accumulated financial strain and women's health over three decades.

    PubMed

    Shippee, Tetyana Pylypiv; Wilkinson, Lindsay R; Ferraro, Kenneth F

    2012-09-01

    Drawing from cumulative inequality theory, this research examines how accumulated financial strain affects women's self-rated health in middle and later life. Using data from the National Longitudinal Survey of Mature Women (1967-2003), we employ random-coefficient growth curve models to examine whether recurring financial strain influences women's health, above and beyond several measures of objective social status. Predicted probabilities of poor health were estimated by the frequency of financial strain. Financial strain is associated with rapid declines in women's health during middle and later life, especially for those women who reported recurrent strain. Changes in household income and household wealth were also associated with women's health but did not eliminate the effects due to accumulated financial strain. Accumulated financial strain has long-term effects on women's health during middle and later life. The findings demonstrate the importance of measuring life course exposure to stressors in studies of health trajectories.

  18. A Model for Evidence Accumulation in the Lexical Decision Task

    ERIC Educational Resources Information Center

    Wagenmakers, Eric-Jan; Steyvers, Mark; Raaijmakers, Jeroen G. W.; Shiffrin, Richard M.; van Rijn, Hedderik; Zeelenberg, Rene

    2004-01-01

    We present a new model for lexical decision, REM-LD, that is based on REM theory (e.g., Shiffrin & Steyvers, 1997). REM-LD uses a principled (i.e., Bayes' rule) decision process that simultaneously considers the diagnosticity of the evidence for the 'WORD' response and the 'NONWORD' response. The model calculates the odds ratio that the presented…

  19. Reducing arsenic accumulation in rice grain through iron oxide amendment

    USDA-ARS?s Scientific Manuscript database

    In this research, we investigated the accumulation of arsenic (As), selenium (Se), molybdenum (Mo), and cadmium (Cd) in rice grain under different soil conditions in standard straighthead-resistant and straighthead-susceptible cultivars, Zhe 733 and Cocodrie, respectively. Results demonstrated that,...

  20. Streptococcus mutans Adherence: Presumptive Evidence for Protein-Mediated Attachment Followed by Glucan-Dependent Cellular Accumulation

    PubMed Central

    Staat, Robert H.; Langley, Sharon D.; Doyle, R. J.

    1980-01-01

    Adherence of Streptococcus mutans to smooth surfaces has been attributed to the production of sucrose-derived d-glucans. However, several studies indicate that the bacterium will adhere in the absence of sucrose. The present data confirmed that S. mutans adherence to saliva-coated hydroxyapatite beads in the absence of sucrose is described by the Langmuir equation. The nature of the sucrose-independent adherence was studied with the Persea americana agglutinin as a selective adherence inhibitor. Pretreatment of the bacterium with P. americana agglutinin caused a 10-fold reduction in adherence, and the inhibition was not reversed with the addition of sucrose. Pretreatment of S. mutans with proteases also reduced adherence, regardless of the sucrose content, whereas periodate oxidation and glucanohydrolase treatment of the bacteria reduced sucrose-mediated adherence to the levels found for sucrose-independent adherence. The P. americana agglutinin, glucanohydrolase, and pepsin pretreatment of the cells did not eliminate sucrose-induced agglutination. Scanning electron microscopy showed that short streptococcal chains were bound to saliva-coated hydroxyapatite crystals in the sucrose-independent system, whereas the presence of sucrose caused larger bacterial clumps to be found. A two-reaction model of S. mutans adherence was developed from these data. It is proposed that one reaction is attachment to the tooth pellicle which is mediated by cell-surface proteins rather than glucans or teichoic acids. The other reaction is cellular accumulation mediated by sucrose-derived d-glucans and cell surface lectins. A series of sequential adherence experiments with P. americana agglutinin as a selective inhibitor provided presumptive evidence for the validity of our model of S. mutans adherence. Images Fig. 1 PMID:7380545

  1. Analytical evidence of heterogeneous lead accumulation in the hypothalamic defence area and nucleus tractus solitarius.

    PubMed

    Guimarães, D; Santos, J P; Carvalho, M L; Diniz, M S; House, B; Miller, V M

    2014-09-01

    Lead is a potent toxicant associated with adverse cardiovascular effects and hypertension in children. Yet, few studies have determined if autonomic dysfunction associated with lead exposure involves brain regions which regulate autonomic responses. Central autonomic nuclei such as the nucleus tractus solitarius (NTS) and hypothalamic defence area (HDA) may be particularly sensitive to lead infiltration because they are adjacent to ventricles and areas with semi-permeable blood-brain-barriers. To understand if autonomic nuclei are sensitive to lead accumulation Wistar rats were exposed to lead from the gestational period and lead levels were quantified in brain regions that regulate arterial pressure: the NTS and the HDA. Energy dispersive X-ray fluorescence (EDXRF) was used to quantify total brain lead levels and revealed no differences between exposed and control tissues; measured values were close to the detection limit (2μg/g). Electrothermal atomic absorption spectrometry (ETAAS) was also used, which has a greater sensitivity, to quantify lead. There was ∼2.1μg/g lead in the NTS and ∼3.1μg/g lead in the HDA of exposed rats, and no lead in the control rats. There were greater lead levels in the HDA (∼50%) as compared with the NTS. Pathology studies revealed more prominent lead granules in the HDA as compared with the NTS. Increased microglia and astrocyte activation was also noted in the NTS of lead exposed rats as compared with the HDA. Regional differences in neuro-inflammatory responses likely contribute to heterogeneous lead accumulation, with enhanced clearance of lead in the NTS. Future studies will resolve the mechanisms underpinning tissue-specific lead accumulation. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Regional Greenland accumulation variability from Operation IceBridge airborne accumulation radar

    NASA Astrophysics Data System (ADS)

    Lewis, Gabriel; Osterberg, Erich; Hawley, Robert; Whitmore, Brian; Marshall, Hans Peter; Box, Jason

    2017-03-01

    The mass balance of the Greenland Ice Sheet (GrIS) in a warming climate is of critical interest to scientists and the general public in the context of future sea-level rise. An improved understanding of temporal and spatial variability of snow accumulation will reduce uncertainties in GrIS mass balance models and improve projections of Greenland's contribution to sea-level rise, currently estimated at 0.089 ± 0.03 m by 2100. Here we analyze 25 NASA Operation IceBridge accumulation radar flights totaling > 17 700 km from 2013 to 2014 to determine snow accumulation in the GrIS dry snow and percolation zones over the past 100-300 years. IceBridge accumulation rates are calculated and used to validate accumulation rates from three regional climate models. Averaged over all 25 flights, the RMS difference between the models and IceBridge accumulation is between 0.023 ± 0.019 and 0.043 ± 0.029 m w.e. a-1, although each model shows significantly larger differences from IceBridge accumulation on a regional basis. In the southeast region, for example, the Modèle Atmosphérique Régional (MARv3.5.2) overestimates by an average of 20.89 ± 6.75 % across the drainage basin. Our results indicate that these regional differences between model and IceBridge accumulation are large enough to significantly alter GrIS surface mass balance estimates. Empirical orthogonal function analysis suggests that the first two principal components account for 33 and 19 % of the variance, and correlate with the Atlantic Multidecadal Oscillation (AMO) and wintertime North Atlantic Oscillation (NAO), respectively. Regions that disagree strongest with climate models are those in which we have the fewest IceBridge data points, requiring additional in situ measurements to verify model uncertainties.

  3. Accumulation of polyubiquitylated proteins in response to Ala-Ala-Phe-chloromethylketone is independent of the inhibition of Tripeptidyl peptidase II.

    PubMed

    Villasevil, Eugenia M; Guil, Sara; López-Ferreras, Lorena; Sánchez, Carlos; Del Val, Margarita; Antón, Luis C

    2010-09-01

    In the present study we have addressed the issue of proteasome independent cytosolic protein degradation. Tripeptidyl peptidase II (TPPII) has been suggested to compensate for a reduced proteasome activity, partly based on evidence using the inhibitor Ala-Ala-Phe-chloromethylketone (AAF-cmk). Here we show that AAF-cmk induces the formation of polyubiquitin-containing accumulations in osteosarcoma and Burkitt's lymphoma cell lines. These accumulations meet many of the landmarks of the aggresomes that form after proteasome inhibition. Using a combination of experiments with chemical inhibitors and interference of gene expression, we show that TPPII inhibition is not responsible for these accumulations. Our evidence suggests that the relevant target(s) is/are in the ubiquitin-proteasome pathway, most likely upstream the proteasome. We obtained evidence supporting this model by inhibition of Hsp90, which also acts upstream the proteasome. Although our data suggest that Hsp90 is not a target of AAF-cmk, its inhibition resulted in accumulations similar to those obtained with AAF-cmk. Therefore, our results question the proposed role for TPPII as a prominent alternative to the proteasome in cellular proteolysis. Copyright 2010 Elsevier B.V. All rights reserved.

  4. Episodic strain accumulation in southern california.

    PubMed

    Thatcher, W

    1976-11-12

    Reexamination of horizontal geodetic data in the region of recently discovered aseismic uplift has demonstrated that equally unusual horizontal crustal deformation accompanied the development of the uplift. During this time interval compressive strains were oriented roughly normal to the San Andreas fault, suggesting that the uplift produced little shear strain accumulation across this fault. On the other hand, the orientation of the anomalous shear straining is consistent with strain accumulation across northdipping range-front thrusts like the San Fernando fault. Accordingly, the horizontal and vertical crustal deformation disclosed by geodetic observation is interpreted as a short epoch of rapid strain accumulation on these frontal faults. If this interpretation is correct, thrust-type earthquakes will eventually release the accumulated strains, but the geodetic data examined here cannot be used to estimate when these events might occur. However, observation of an unusual sequence of tilts prior to 1971 on a level line lying to the north of the magnitude 6.4 San Fernando earthquake offers some promise for precursor monitoring. The data are adequately explained by a simple model of up-dip aseismic slip propagation toward the 1971 epicentral region. These observations and the simple model that accounts for them suggest a conceptually straightforward monitoring scheme to search for similar uplift and tilt precursors within the uplifted region. Such premonitory effects could be detected by a combination of frequenlty repeated short (30 to 70 km in length) level line measurements, precise gravity traverses, and continuously recording gravimeters sited to the north of the active frontal thrust faults. Once identified, such precursors could be closely followed in space and time, and might then provide effective warnings of impending potentially destructive earth-quakes.

  5. Response of salt-marsh carbon accumulation to climate change.

    PubMed

    Kirwan, Matthew L; Mudd, Simon M

    2012-09-27

    About half of annual marine carbon burial takes place in shallow water ecosystems where geomorphic and ecological stability is driven by interactions between the flow of water, vegetation growth and sediment transport. Although the sensitivity of terrestrial and deep marine carbon pools to climate change has been studied for decades, there is little understanding of how coastal carbon accumulation rates will change and potentially feed back on climate. Here we develop a numerical model of salt marsh evolution, informed by recent measurements of productivity and decomposition, and demonstrate that competition between mineral sediment deposition and organic-matter accumulation determines the net impact of climate change on carbon accumulation in intertidal wetlands. We find that the direct impact of warming on soil carbon accumulation rates is more subtle than the impact of warming-driven sea level rise, although the impact of warming increases with increasing rates of sea level rise. Our simulations suggest that the net impact of climate change will be to increase carbon burial rates in the first half of the twenty-first century, but that carbon-climate feedbacks are likely to diminish over time.

  6. Preferential Osmolyte Accumulation: a Mechanism of Osmotic Stress Adaptation in Diazotrophic Bacteria

    PubMed Central

    Madkour, Magdy A.; Smith, Linda Tombras; Smith, Gary M.

    1990-01-01

    A common cellular mechanism of osmotic-stress adaptation is the intracellular accumulation of organic solutes (osmolytes). We investigated the mechanism of osmotic adaptation in the diazotrophic bacteria Azotobacter chroococcum, Azospirillum brasilense, and Klebsiella pneumoniae, which are adversely affected by high osmotic strength (i.e., soil salinity and/or drought). We used natural-abundance 13C nuclear magnetic resonance spectroscopy to identify all the osmolytes accumulating in these strains during osmotic stress generated by 0.5 M NaCl. Evidence is presented for the accumulation of trehalose and glutamate in Azotobacter chroococcum ZSM4, proline and glutamate in Azospirillum brasilense SHS6, and trehalose and proline in K. pneumoniae. Glycine betaine was accumulated in all strains grown in culture media containing yeast extract as the sole nitrogen source. Alternative nitrogen sources (e.g., NH4Cl or casamino acids) in the culture medium did not result in measurable glycine betaine accumulation. We suggest that the mechanism of osmotic adaptation in these organisms entails the accumulation of osmolytes in hyperosmotically stressed cells resulting from either enhanced uptake from the medium (of glycine betaine, proline, and glutamate) or increased net biosynthesis (of trehalose, proline, and glutamate) or both. The preferred osmolyte in Azotobacter chroococcum ZSM4 shifted from glutamate to trehalose as a consequence of a prolonged osmotic stress. Also, the dominant osmolyte in Azospirillum brasilense SHS6 shifted from glutamate to proline accumulation as the osmotic strength of the medium increased. PMID:16348295

  7. Step changes in leaf oil accumulation via iterative metabolic engineering.

    PubMed

    Vanhercke, Thomas; Divi, Uday K; El Tahchy, Anna; Liu, Qing; Mitchell, Madeline; Taylor, Matthew C; Eastmond, Peter J; Bryant, Fiona; Mechanicos, Anna; Blundell, Cheryl; Zhi, Yao; Belide, Srinivas; Shrestha, Pushkar; Zhou, Xue-Rong; Ral, Jean-Philippe; White, Rosemary G; Green, Allan; Singh, Surinder P; Petrie, James R

    2017-01-01

    Synthesis and accumulation of plant oils in the entire vegetative biomass offers the potential to deliver yields surpassing those of oilseed crops. However, current levels still fall well short of those typically found in oilseeds. Here we show how transcriptome and biochemical analyses pointed to a futile cycle in a previously established Nicotiana tabacum line, accumulating up to 15% (dry weight) of the storage lipid triacylglycerol in leaf tissue. To overcome this metabolic bottleneck, we either silenced the SDP1 lipase or overexpressed the Arabidopsis thaliana LEC2 transcription factor in this transgenic background. Both strategies independently resulted in the accumulation of 30-33% triacylglycerol in leaf tissues. Our results demonstrate that the combined optimization of de novo fatty acid biosynthesis, storage lipid assembly and lipid turnover in leaf tissue results in a major overhaul of the plant central carbon allocation and lipid metabolism. The resulting further step changes in oil accumulation in the entire plant biomass offers the possibility of delivering yields that outperform current oilseed crops. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  8. Head shape disparity impacts pollutant accumulation in European eel.

    PubMed

    De Meyer, Jens; Belpaire, Claude; Boeckx, Pascal; Bervoets, Lieven; Covaci, Adrian; Malarvannan, Govindan; De Kegel, Barbara; Adriaens, Dominique

    2018-05-08

    Several aspects of the life cycle of the critically endangered European eel (Anguilla anguilla) remain poorly understood. One such aspect is the broad-versus narrow-head dimorphism, and how this impacts their overall performance at different stages of their life cycle. At the yellow eel stage, the phenotypes show a trophic divergence. We investigated whether pollutant accumulation is affected by this disparity. We show that broad-headed eels contained higher concentrations of mercury and several lipophilic organic pollutants, compared to narrow-headed ones, irrespective of their fat content. The hereby confirmed link between the phenotypic disparity, its associated feeding ecology and its impact on pollutant accumulation thus raises further concerns about their migratory and reproductive success. Considering that pollution is an important contributor to the European eel's decline, our results demonstrate that broad-headed eels are more vulnerable to detrimental pollutant accumulation. This compromises their successful contribution to their population's reproduction and its restoration. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Re-accumulation of Asteroids to Equilibrium Figures

    NASA Astrophysics Data System (ADS)

    Hestroffer, D.; Tanga, P.; Richardson, D. C.; Berthier, J.; Cellino, A.; Durech, J.; Michel, P.

    2008-09-01

    Since their formation, asteroids since their formation have experienced little physical, geological or thermal evolution. Like comets they are thought to be among the most pristine remnants of the early solar system. One physical process, however, has played a major role since the ancient times: collisions. Dynamical families were produced by catastrophic collisions involving large enough energy to break the parent body. Other lines of evidence suggest that catastrophic collisions can also produce rubble-piles, i.e., loosely bound of post-collisional aggregates that re-accumulate to form a single body, and are kept together by gravity. The main objective of this work is to understand if—and under what conditions—Jacobi ellipsoids or other equilibrium figures can be obtained naturally by this way. This is done by performing numerical experiments simulating the re-accumulation process, and by performing high-angular resolution observations in order to better constrain the shape and density of the targets. It is shown that the outcomes of reaccumulation events tend to produce a rather narrow variety of possible shapes, and in some cases also binary systems.

  10. Hematological, biochemical, and histopathological impacts of barium chloride and barium carbonate accumulation in soft tissues of male Sprague-Dawley rats.

    PubMed

    Mohammed, Amany Tharwat; Ismail, Hager Tarek H

    2017-12-01

    The present study was designed to investigate the hematotoxicity, sero-biochemical and histological changes due to the accumulation of BaCl 2 and BaCO 3 , the most important barium salts in our daily lives, in different soft tissues including the liver, kidney, heart, and spleen of adult rats after an oral exposure for 30 consecutive days, and to explain the different mechanisms by which this metal can exert these impacts. For this purpose, adult male rats were divided into three main groups of 15 animals each: group I, serving as controls, group II, receiving BaCl 2 orally in a dose of 179 mg barium/kg b.wt, and group III, receiving BaCO 3 orally in a dose of 418 mg barium/kg b.wt. for 30 consecutive days. Obviously, normocytic normochromic anemia was evident in both barium groups. Serum biochemical analysis revealed significant declines in glutathione peroxidase, catalase, superoxide dismutase, and urea with significant elevations in malondialdehyde, lactate dehydrogenase, and creatine kinase levels. Hyperphosphatemia, hypokalemia, hypocalcemia, and hypochloremia were also evident in both barium groups. Besides, residual analysis of both barium salts in different body organs revealed significantly abundant barium residues in the liver, spleen, heart, and kidney, respectively in both barium salts groups. Moreover, splenic tissue showed hemosiderosis, peritubular congestion, and necrotic glomeruli with intratubular hemorrhage. Sever subepicardial congestion with intramuscular edema was evident in the heart. In conclusion, BaCl 2 and BaCO 3 were able to deliver mortalities, antioxidant enzymes exhaustion, and a sort of normocytic normochromic anemia, as well as marked disturbances in cardiac, hepatic, and renal functions due to the accumulation of these two salts in the soft tissues. Therefore, these results demonstrate the unrecognized toxicity of those two barium salts due to their accumulation in various soft tissues of the body and so, this needs to reconsider

  11. Accumulation of pyrethroid compounds in primary cultures of rat cortical neurons

    EPA Science Inventory

    Recent studies have demonstrated that lipophilic compounds (e.g. methylmercury, polychlorinated biphenyls (PCBs) and polybrominated diphenylethers (PBDEs)) rapidly accumulate in cells in culture to concentrations much higher than in the surrounding media. Primary cultures of neur...

  12. ACCUMULATION OF RADIOCESIUM BY MUSHROOMS IN THE ENVIRONMENT: A LITERATURE REVIEW

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Duff, M

    2007-05-28

    During the last 50 years, a large amount of information on radionuclide accumulators or ''sentinel-type'' organisms in the environment has been published. Much of this work focused on the risks of food-chain transfer of radionuclides to higher organisms such as reindeer and man. However, until the 1980's and 1990's, there has been little published data on the radiocesium ({sup 134}Cs and {sup 137}Cs) accumulation by mushrooms. This presentation will consist of a review of the published data for {sup 134,137}Cs accumulation by mushrooms in nature. This review will discuss the aspects that promote {sup 134,137}Cs uptake by mushrooms and focusmore » on mushrooms that demonstrate a large propensity for use in the environmental biomonitoring of radiocesium contamination. It will also provide descriptions of habitats for many of these mushrooms and discuss on how growth media and other conditions relate to Cs accumulation.« less

  13. Positron accumulation effect in particles embedded in a low-density matrix

    NASA Astrophysics Data System (ADS)

    Dryzek, Jerzy; Siemek, Krzysztof

    2015-02-01

    Systematic studies of the so-called positron accumulation effect for samples with particles embedded in a matrix are reported. This effect is related to energetic positrons which penetrate inhomogeneous medium. Due to differences in the linear absorption coefficient, different amounts of positrons are accumulated and annihilate in the identical volume of both materials. Positron lifetime spectroscopy and Doppler broadening of the annihilation line using Na-22 positrons were applied to the studies of the epoxy resin samples with embedded micro-sized particles of transition metals, i.e., Ni, Sn, Mo, W, and nonmetal particles, i.e., Si and NaF. The significant difference between the determined fraction of positrons annihilating in the particles and the particle volume fraction indicates the positron accumulation effect. The simple phenomenological model and Monte Carlo simulations are able to describe the main features of the obtained dependencies. The aluminum alloy with embedded Sn nanoparticles is also considered for demonstration differences between the accumulation and another related effect, i.e., the positron affinity.

  14. Subcellular metal imaging identifies dynamic sites of Cu accumulation in Chlamydomonas

    DOE PAGES

    Hong-Hermesdorf, Anne; Miethke, Marcus; Gallaher, Sean D.; ...

    2014-10-26

    Here we identified a Cu-accumulating structure with a dynamic role in intracellular Cu homeostasis. During Zn limitation, Chlamydomonas reinhardtii hyperaccumulates Cu, a process dependent on the nutritional Cu sensor CRR1, but it is functionally Cu deficient. Visualization of intracellular Cu revealed major Cu accumulation sites coincident with electron-dense structures that stained positive for low pH and polyphosphate, suggesting that they are lysosome-related organelles. Nano-secondary ion MS showed colocalization of Ca and Cu, and X-ray absorption spectroscopy was consistent with Cu + accumulation in an ordered structure. Zn resupply restored Cu homeostasis concomitant with reduced abundance of these structures. Cu isotopemore » labeling demonstrated that sequestered Cu + became bioavailable for the synthesis of plastocyanin, and transcriptome profiling indicated that mobilized Cu became visible to CRR1. Cu trafficking to intracellular accumulation sites may be a strategy for preventing protein mismetallation during Zn deficiency and enabling efficient cuproprotein metallation or remetallation upon Zn resupply.« less

  15. Mitochondrial accumulation of APP and Aβ: significance for Alzheimer disease pathogenesis

    PubMed Central

    Pavlov, Pavel F; Petersen, Camilla Hansson; Glaser, Elzbieta; Ankarcrona, Maria

    2009-01-01

    Accumulating evidence suggest that alterations in energy metabolism are among the earliest events that occur in the Alzheimer disease (AD) affected brain. Energy consumption is drastically decreased in the AD-affected regions of cerebral cortex and hippocampus pointing towards compromised mitochondrial function of neurons within specific brain regions. This is accompanied by an elevated production of reactive oxygen species contributing to increased rates of neuronal loss in the AD-affected brain regions. In this review, we will discuss the role of mitochondrial function and dysfunction in AD. We will focus on the consequences of amyloid precursor protein and amyloid-β peptide accumulation in mitochondria and their involvement in AD pathogenesis. PMID:19725915

  16. 5-Aminolevulinic Acid Accumulation in a Cerebral Infarction Mimicking High-Grade Glioma.

    PubMed

    Behling, Felix; Hennersdorf, Florian; Bornemann, Antje; Tatagiba, Marcos; Skardelly, Marco

    2016-08-01

    5-Aminolevulinic acid (5-ALA) has become an integral part in the neurosurgical treatment of malignant glioma. Over time, several other tumor entities have been identified to metabolize 5-ALA and show a similar fluorescence pattern during surgical resection. This case report is the first description of 5-ALA accumulation in postischemic cerebral tissue. This evidence questions the assumption that 5-ALA accumulation in glioma is exclusively attributed to tumor infiltration. Instead, 5-ALA accumulation can also occur beyond the tumor borders and may be partially ascribed to inflammatory changes in the surrounding brain tissue. A 64-year old woman presented with episodes of apraxia and a ring-enhancing lesion in postcontrast T1-weighted magnetic resonance sequences suggestive of high grade glioma. Strong fluorescence was observed during 5-ALA-guided resection. However, although the frozen section was inconclusive, the final histopathologic examination revealed a stage II cerebral infarction. 5-ALA accumulation in postischemic cerebral tissue should be considered for intended supramarginal resections near eloquent brain regions. Therefore, sufficient preoperative imaging should regularly include magnetic resonance imaging spectroscopy and perfusion sequences to ascertain the proper diagnosis. Moreover, further research is warranted to determine the role of 5-ALA accumulation in postischemic and inflammatory brain tissue. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. HdhQ111 Mice Exhibit Tissue Specific Metabolite Profiles that Include Striatal Lipid Accumulation

    PubMed Central

    Carroll, Jeffrey B.; Deik, Amy; Fossale, Elisa; Weston, Rory M.; Guide, Jolene R.; Arjomand, Jamshid; Kwak, Seung; Clish, Clary B.; MacDonald, Marcy E.

    2015-01-01

    The HTT CAG expansion mutation causes Huntington’s Disease and is associated with a wide range of cellular consequences, including altered metabolism. The mutant allele is expressed widely, in all tissues, but the striatum and cortex are especially vulnerable to its effects. To more fully understand this tissue-specificity, early in the disease process, we asked whether the metabolic impact of the mutant CAG expanded allele in heterozygous B6.HdhQ111/+ mice would be common across tissues, or whether tissues would have tissue-specific responses and whether such changes may be affected by diet. Specifically, we cross-sectionally examined steady state metabolite concentrations from a range of tissues (plasma, brown adipose tissue, cerebellum, striatum, liver, white adipose tissue), using an established liquid chromatography-mass spectrometry pipeline, from cohorts of 8 month old mutant and wild-type littermate mice that were fed one of two different high-fat diets. The differential response to diet highlighted a proportion of metabolites in all tissues, ranging from 3% (7/219) in the striatum to 12% (25/212) in white adipose tissue. By contrast, the mutant CAG-expanded allele primarily affected brain metabolites, with 14% (30/219) of metabolites significantly altered, compared to wild-type, in striatum and 11% (25/224) in the cerebellum. In general, diet and the CAG-expanded allele both elicited metabolite changes that were predominantly tissue-specific and non-overlapping, with evidence for mutation-by-diet interaction in peripheral tissues most affected by diet. Machine-learning approaches highlighted the accumulation of diverse lipid species as the most genotype-predictive metabolite changes in the striatum. Validation experiments in cell culture demonstrated that lipid accumulation was also a defining feature of mutant HdhQ111 striatal progenitor cells. Thus, metabolite-level responses to the CAG expansion mutation in vivo were tissue specific and most evident

  18. Electric Ground Support Equipment Advanced Battery Technology Demonstration Project at the Ontario Airport

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tyler Gray; Jeremy Diez; Jeffrey Wishart

    2013-07-01

    The intent of the electric Ground Support Equipment (eGSE) demonstration is to evaluate the day-to-day vehicle performance of electric baggage tractors using two advanced battery technologies to demonstrate possible replacements for the flooded lead-acid (FLA) batteries utilized throughout the industry. These advanced battery technologies have the potential to resolve barriers to the widespread adoption of eGSE deployment. Validation testing had not previously been performed within fleet operations to determine if the performance of current advanced batteries is sufficient to withstand the duty cycle of electric baggage tractors. This report summarizes the work performed and data accumulated during this demonstration inmore » an effort to validate the capabilities of advanced battery technologies. This report summarizes the work performed and data accumulated during this demonstration in an effort to validate the capabilities of advanced battery technologies. The demonstration project also grew the relationship with Southwest Airlines (SWA), our demonstration partner at Ontario International Airport (ONT), located in Ontario, California. The results of this study have encouraged a proposal for a future demonstration project with SWA.« less

  19. Accumulated α-synuclein affects the progression of GM2 gangliosidoses.

    PubMed

    Suzuki, Kyoko; Yamaguchi, Akira; Yamanaka, Shoji; Kanzaki, Seiichi; Kawashima, Masato; Togo, Takashi; Katsuse, Omi; Koumitsu, Noriko; Aoki, Naoya; Iseki, Eizo; Kosaka, Kenji; Yamaguchi, Kayoko; Hashimoto, Makoto; Aoki, Ichiro; Hirayasu, Yoshio

    2016-10-01

    The accumulation of α-synuclein (ASyn) has been observed in several lysosomal storage diseases (LSDs) but it remains unclear if ASyn accumulation contributes to LSD pathology. ASyn also accumulates in the neurons of Sandhoff disease (SD) patients and SD model mice (Hexb-/- ASyn+/+ mice). SD is a lysosomal storage disorder caused by the absence of a functional β-subunit on the β-hexosaminidase A and B enzymes, which leads to the accumulation of ganglioside in the central nervous system. Here, we explored the role of accumulated ASyn in the progression of Hexb-/- mice by creating a Hexb-/- ASyn-/- double-knockout mice. Our results show that Hexb-/- ASyn-/- mice demonstrated active microglia levels and less dopaminergic neuron loss, without altering the neuronal storage of ganglioside. The autophagy and ubiquitin proteasome pathways are defective in the neurons of Hexb-/- ASyn+/+ mice. In ultrastructural physiological studies, the mitochondria structures look degenerated and dysfunctional. As a result, expression of manganese superoxide dismutase 2 are reduced, and reactive oxygen species-mediated oxidative damage in the neurons of Hexb-/- ASyn+/+ mice. Interestingly, these dysfunctions improved in Hexb-/- ASyn-/- mice. But any clinical improvement were hardly observed in Hexb-/- ASyn-/- mice. Taken together, these findings suggest that ASyn accumulation plays an important role in the pathogenesis of neuropathy in SD and other LSDs, and is therefore a target for novel therapies. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. MARRIAGE AND MEN’S WEALTH ACCUMULATION IN THE UNITED STATES, 1860-1870

    PubMed Central

    HONG, SOK CHUL

    2013-01-01

    This paper explores how changes in marital status affected men’s wealth accumulation in mid-nineteenth-century America, using a longitudinal sample of Union Army veterans linked to the 1860 and 1870 census manuscript schedules. Controlling for the endogeneity of wealth and marital selection, this paper provides strong evidence that marriage had positive effects on men’s wealth accumulation, whereas ending a marriage had negative effects. The estimated wealth premium on married men is about 60 percent per marital year. This substantial wealth premium is closely related to wives’ specializing in household production, and farmers and craftsmen economically benefited from the unpaid labor of their wives. PMID:24058226

  1. Demise of reef-flat carbonate accumulation with late Holocene sea-level fall: Evidence from Molokai, Hawaii

    USGS Publications Warehouse

    Engels, M.S.; Fletcher, C.H.; Field, M.; Conger, C.L.; Bochicchio, C.

    2008-01-01

    Twelve cores from the protected reef-flat of Molokai revealed that carbonate sediment accumulation, ranging from 3 mm year-1 to less than 1 mm year-1, ended on average 2,500 years ago. Modern sediment is present as a mobile surface veneer but is not trapped within the reef framework. This finding is consistent with the arrest of deposition at the end of the mid-Holocene highstand, known locally as the "Kapapa Stand of the Sea," ???2 m above the present datum ca. 3,500 years ago in the main Hawaiian Islands. Subsequent erosion, non-deposition, and/or a lack of rigid binding were probable factors leading to the lack of reef-flat accumulation during the late Holocene sea-level fall. Given anticipated climate changes, increased sedimentation of reef-flat environments is to be expected as a consequence of higher sea level. ?? 2008 Springer-Verlag.

  2. Rescue of cardiac leptin receptors in db/db mice prevents myocardial triglyceride accumulation.

    PubMed

    Hall, Michael E; Maready, Matthew W; Hall, John E; Stec, David E

    2014-08-01

    Increased leptin levels have been suggested to contribute to cardiac hypertrophy and attenuate cardiac lipid accumulation in obesity, although it has been difficult to separate leptin's direct effects from those caused by changes in body weight and adiposity. To determine whether leptin attenuates cardiac lipid accumulation in obesity or directly causes left ventricular hypertrophy (LVH), we generated a novel mouse model in which the long form of the leptin receptor (LepR) was "rescued" only in cardiomyocytes of obese db/db mice. Reexpression of cardiomyocyte leptin receptors in db/db mice did not cause LVH but reduced cardiac triglycerides and improved cardiac function. Compared with lean wild-type (WT) or db/db-cardiac LepR rescue mice, db/db mice exhibited significantly lower E/A ratio, a measurement of early to late diastolic filling, which averaged 1.5 ± 0.07 in db/db vs. 1.9 ± 0.08 and 1.8 ± 0.11 in WT and db/db-cardiac LepR rescue mice, respectively. No differences in systolic function were observed. Although db/db and db/db-cardiac LepR rescue mice exhibited similar increases in plasma triglycerides, insulin, glucose, and body weight, cardiac triglycerides were significantly higher in db/db compared with WT and db/db cardiac LepR rescue mice, averaging 13.4 ± 4.2 vs. 3.8 ± 1.6 vs. 3.8 ± 0.7 mg/g, respectively. These results demonstrate that despite significant obesity and increases in plasma glucose and triglycerides, db/db cardiac LepR rescue mice are protected against myocardial lipid accumulation. However, we found no evidence that leptin directly causes LVH. Copyright © 2014 the American Physiological Society.

  3. Identification and Metabolite Profiling of Chemical Activators of Lipid Accumulation in Green Algae.

    PubMed

    Wase, Nishikant; Tu, Boqiang; Allen, James W; Black, Paul N; DiRusso, Concetta C

    2017-08-01

    Microalgae are proposed as feedstock organisms useful for producing biofuels and coproducts. However, several limitations must be overcome before algae-based production is economically feasible. Among these is the ability to induce lipid accumulation and storage without affecting biomass yield. To overcome this barrier, a chemical genetics approach was employed in which 43,783 compounds were screened against Chlamydomonas reinhardtii , and 243 compounds were identified that increase triacylglyceride (TAG) accumulation without terminating growth. Identified compounds were classified by structural similarity, and 15 were selected for secondary analyses addressing impacts on growth fitness, photosynthetic pigments, and total cellular protein and starch concentrations. TAG accumulation was verified using gas chromatography-mass spectrometry quantification of total fatty acids, and targeted TAG and galactolipid measurements were performed using liquid chromatography-multiple reaction monitoring/mass spectrometry. These results demonstrated that TAG accumulation does not necessarily proceed at the expense of galactolipid. Untargeted metabolite profiling provided important insights into pathway shifts due to five different compound treatments and verified the anabolic state of the cells with regard to the oxidative pentose phosphate pathway, Calvin cycle, tricarboxylic acid cycle, and amino acid biosynthetic pathways. Metabolite patterns were distinct from nitrogen starvation and other abiotic stresses commonly used to induce oil accumulation in algae. The efficacy of these compounds also was demonstrated in three other algal species. These lipid-inducing compounds offer a valuable set of tools for delving into the biochemical mechanisms of lipid accumulation in algae and a direct means to improve algal oil content independent of the severe growth limitations associated with nutrient deprivation. © 2017 American Society of Plant Biologists. All Rights Reserved.

  4. Lifespan mercury accumulation pattern in Liza aurata : Evidence from two southern European estuaries

    NASA Astrophysics Data System (ADS)

    Tavares, S.; Oliveira, H.; Coelho, J. P.; Pereira, M. E.; Duarte, A. C.; Pardal, M. A.

    2011-10-01

    Mercury accumulation throughout the lifespan of Liza aurata (Risso, 1810) was analysed in four tissues (muscle, gills, liver and brain) in two southern European coastal ecosystems with distinct mercury contamination. Specimens from four to five age classes were captured in two sampling sites in the Ria de Aveiro (Laranjo bay and Mira), a system historically contaminated by industrial mercury, and in one site in the Mondego estuary, assumed as a mercury-free ecosystem. Mercury concentration in all tissues was found to be significantly higher in the Ria de Aveiro (Laranjo bay) compared to the Mondego, in accordance with the environmental contamination (water, sediments and suspended particulate matter). Significant differences inside the Ria de Aveiro (between the Mira and Laranjo bay) were only detected in the liver. This tissue registered the highest levels of mercury (ranging from 0.11 to 4.2 μg g -1 ) in all sampling sites, followed by muscle, brain, and gills. In all sampling sites and tissues was denoted a mercury dilution pattern along the lifecycle (except in liver at the Mondego, the reference area where the concentrations are always very low). An exponential trend was found in the metal age variation patterns in Laranjo (the most contaminated area) and a linear trend in the Mira and the Mondego (the least contaminated areas). Organic mercury concentration in muscle generally accounted for over 95% of total mercury concentration, and followed the same accumulation pattern of total mercury. This fish species is of lesser importance in mercury transfer to adjacent coastal areas and although the consumption of fish from Laranjo may present some risk for the humans, this risk decreases with fish age/size.

  5. Stinging Nettle (Urtica dioica L.) Attenuates FFA Induced Ceramide Accumulation in 3T3-L1 Adipocytes in an Adiponectin Dependent Manner.

    PubMed

    Obanda, Diana N; Zhao, Peng; Richard, Allison J; Ribnicky, David; Cefalu, William T; Stephens, Jacqueline M

    2016-01-01

    Excess dietary lipids result in the accumulation of lipid metabolites including ceramides that can attenuate insulin signaling. There is evidence that a botanical extract of Urtica dioica L. (stinging nettle) improves insulin action, yet the precise mechanism(s) are not known. Hence, we examined the effects of Urtica dioica L. (UT) on adipocytes. We investigated the effects of an ethanolic extract of UT on free fatty acid (palmitic acid) induced inhibition of insulin-stimulated Akt serine phosphorylation and modulation of ceramidase expression in 3T3-L1 adipocytes. Adipocytes were exposed to excess FFAs in the presence or absence of UT. Effects on adiponectin expression, ceramidase expression, ceramidase activity, ceramide accumulation and insulin signaling were determined. As expected, FFAs reduced adiponectin expression and increased the expression of ceramidase enzymes but not their activity. FFA also induced the accumulation of ceramides and reduced insulin-stimulated phosphorylation of Akt in adipocytes. The effects of FFA were partially reversed by UT. UT enhanced adiponectin expression and ceramidase activity in the presence of excess FFAs. UT abated ceramide accumulation and increased insulin sensitivity via enhanced Akt phosphorylation. A siRNA knockdown of adiponectin expression prevented UT from exerting positive effects on ceramidase activity but not Akt phosphorylation. In adipocytes, the ability of UT to antagonize the negative effects of FFA by modulating ceramidase activity and ceramide accumulation is dependent on the presence of adiponectin. However, the ability of UT to enhance Akt phosphorylation is independent of adiponectin expression. These studies demonstrate direct effects of UT on adipocytes and suggest this botanical extract is metabolically beneficial.

  6. Character, paleoenvironment, rate of accumulation, and evidence for seismic triggering of Holocene turbidites, Canada Abyssal Plain, Arctic Ocean

    USGS Publications Warehouse

    Grantz, A.; Phillips, R.L.; Mullen, M.W.; Starratt, S.W.; Jones, Glenn A.; Naidu, A.S.; Finney, B.P.

    1996-01-01

    Four box cores and one piston core show that Holocene sedimentation on the southern Canada Abyssal Plain for the last 8010??120 yr has consisted of a continuing rain of pelagic organic and ice-rafted elastic sediment with a net accumulation rate during the late Holocene of ???10 mm/1000 yr, and episodically emplaced turbidites 1-5 m thick deposited at intervals of 830 to 3450 yr (average 2000 yr). The average net accumulation rate of the mixed sequence of turbidites and thin pelagite interbeds in the cores is about 1.2 m/1000 yr. Physiography suggests that the turbidites originated on the Mackenzie Delta or its clinoform, and ??13C values of -27 to - 25??? in the turbidites are compatible with a provenance on a delta. Extant displaced neritic and lower slope to basin plain calcareous benthic foraminifers coexist in the turbidite units. Their joint occurence indicates that the turbidites originated on the modern continental shelf and entrained sediment from the slope and rise enroute to their final resting place on the Canada Abyssal Plain. The presence of Middle Pleistocene diatoms in the turbidites suggests, in addition, that the turbidites may have originated in shallow submarine slides beneath the upper slope or outer shelf. Small but consistent differences in organic carbon content and ??13C values between the turbidite units suggest that they did not share an identical provenance, which is at least compatible with an origin in slope failures. The primary provenance of the ice-rafted component of the pelagic beds was the glaciated terrane of northwestern Canada; and the provenance of the turbidite units was Pleistocene and Holocene sedimentary deposits on the outer continental shelf and upper slope of the Mackenzie Delta. Largely local derivation of the sediment of the Canada Abyssal Plain indicates that sediment accumulation rates in the Arctic Ocean are valid only for regions with similar depositional sources and processes, and that these rates cannot be

  7. Masked nonword repetition effects in yes/no and go/no-go lexical decision: a test of the evidence accumulation and deadline accounts.

    PubMed

    Perea, Manuel; Gómez, Pablo; Fraga, Isabel

    2010-06-01

    The pattern of masked repetition priming effects for word and nonword targets differs across tasks: Masked-priming effects in lexical decision occur for positive responses (i.e., words), but not for negative responses (nonwords), whereas masked-priming effects in the cross-case same-different task occur for positive responses (same), but not for negative responses (different)--regardless of lexical status. Here, we examined whether masked nonword priming effects are greater when the task involves an active go response to nonwords than when it involves the standard yes/no procedure in lexical decision. The obtained masked repetition priming effect for nonwords was of similar size in yes/no and go/no-go tasks. This finding is compatible with accounts of nonword priming that posit that nonword responses are produced by actively accumulating evidence for the nonword alternative in yes/no and go/no-go procedures, whereas it is inconsistent with the assumption of a deadline for no responses in the yes/no task.

  8. An ice core record of net snow accumulation and seasonal snow chemistry at Mt. Waddington, southwest British Columbia, Canada

    NASA Astrophysics Data System (ADS)

    Neff, P. D.; Steig, E. J.; Clark, D. H.; McConnell, J. R.; Pettit, E. C.; Menounos, B.

    2011-12-01

    We recovered a 141 m ice core from Combatant Col (51.39°N, 125.22°W, 3000 m asl) on the flank of Mt. Waddington, southern Coast Mountains, British Columbia, Canada. Aerosols and other impurities in the ice show unambiguous seasonal variations, allowing for annual dating of the core. Clustered melt layers, originating from summer surface heating, also aid in the dating of the core. Seasonality in water stable isotopes is preserved throughout the record, showing little evidence of diffusion at depth, and serves as an independent verification of the timescale. The annual signal of deuterium excess is especially well preserved. The record of lead deposition in the core agrees with those of ice cores from Mt. Logan and from Greenland, with a sharp drop-off in concentration in the 1970s and early 1980s, further validating the timescales. Despite significant summertime melt at this mid-latitude site, these data collectively reveal a continuous and annually resolved 36-year record of snow accumulation. We derived an accumulation time series from the Mt. Waddington ice core, after correcting for ice flow. Years of anomalously high or low snow accumulation in the core correspond with extremes in precipitation data and geopotential height anomalies from reanalysis data that make physical sense. Specifically, anomalously high accumulation years at Mt. Waddington correlate with years where "Pineapple Express" atmospheric river events bring large amounts of moisture from the tropical Pacific to western North America. The Mt. Waddington accumulation record thus reflects regional-scale climate. These results demonstrate the potential of ice core records from temperate glaciers to provide meaningful paleoclimate information. A longer core to bedrock (250-300 m) at the Mt. Waddington site could yield ice with an age of several hundred to 1000 years.

  9. Induction of Nickel Accumulation in Response to Zinc Deficiency in Arabidopsis thaliana

    PubMed Central

    Nishida, Sho; Kato, Aki; Tsuzuki, Chisato; Yoshida, Junko; Mizuno, Takafumi

    2015-01-01

    Excessive accumulation of nickel (Ni) can be toxic to plants. In Arabidopsis thaliana, the Fe2+ transporter, iron (Fe)-regulated transporter1 (IRT1), mediates Fe uptake and also implicates in Ni2+ uptake at roots; however, the underlying mechanism of Ni2+ uptake and accumulation remains unelucidated. In the present study, we found that zinc (Zn) deficient conditions resulted in increased accumulation of Ni in plants, particularly in roots, in A. thaliana. In order to elucidate the underlying mechanisms of Ni uptake correlating zinc condition, we traced 63Ni isotope in response to Zn and found that (i) Zn deficiency induces short-term Ni2+ absorption and (ii) Zn2+ inhibits Ni2+ uptake, suggesting competitive uptake between Ni and Zn. Furthermore, the Zrt/Irt-like protein 3 (ZIP3)-defective mutant with an elevated Zn-deficient response exhibited higher Ni accumulation than the wild type, further supporting that the response to Zn deficiency induces Ni accumulation. Previously, expression profile study demonstrated that IRT1 expression is not inducible by Zn deficiency. In the present study, we found increased Ni accumulation in IRT1-null mutant under Zn deficiency in agar culture. These suggest that Zn deficiency induces Ni accumulation in an IRT1-independen manner. The present study revealed that Ni accumulation is inducible in response to Zn deficiency, which may be attributable to a Zn uptake transporter induced by Zn deficiency. PMID:25923075

  10. Delay in micro-discharges appearance during PEO of Al: Evidence of a mechanism of charge accumulation at the electrolyte/oxide interface

    NASA Astrophysics Data System (ADS)

    Martin, J.; Nominé, A.; Brochard, F.; Briançon, J.-L.; Noël, C.; Belmonte, T.; Czerwiec, T.; Henrion, G.

    2017-07-01

    PEO was conducted on Al by applying a pulsed bipolar current. The role of the cathodic polarization on the appearance of micro-discharges (MDs) and on the subsequent formation of the PEO oxide layers is investigated. Various ratios of the charge quantity RCQ = Qp/Qn (defined as the anodic Qp to cathodic Qn charge quantity ratio over one current pulse period) in the range [0.5; 6.0] were selected by changing the waveform parameters of the cathodic current while keeping the waveform of the anodic current unchanged. Results show that the appearance of MDs is delayed with respect to the rising edge of the anodic current; this delay strongly depends on both the processing time and the applied cathodic charge quantity. It is also evidenced that shorter delays promoted by high RCQ values (RCQ > 1) are associated with stronger MDs (large size and long life) that have detrimental effects on the formed PEO oxide layers. Thicker and the more compact oxide layer morphology is achieved with the intermediate RCQ value (RCQ = 0.9) for which the delay of the MDs appearance is high and the MDs softer. Low RCQ (RCQ < 0.9) results in an earlier extinction of the MDs as the process goes on, which leads to poorly oxidized metal. A mechanism of charge accumulation taking place at the oxide/electrolyte interface and arising before the occurrence of dielectric breakdown is proposed to explain the ignition of MDs during pulsed bipolar PEO of aluminium. A close examination of the voltage-time response which can be adequately simulated with an equivalent RC circuit evidences the capacitive behaviour of the oxide layer and therefore confirms this proposed mechanism of charge accumulation.

  11. Adaptive antioxidant methionine accumulation in respiratory chain complexes explains the use of a deviant genetic code in mitochondria.

    PubMed

    Bender, Aline; Hajieva, Parvana; Moosmann, Bernd

    2008-10-28

    Humans and most other animals use 2 different genetic codes to translate their hereditary information: the standard code for nuclear-encoded proteins and a modern variant of this code in mitochondria. Despite the pivotal role of the genetic code for cell biology, the functional significance of the deviant mitochondrial code has remained enigmatic since its first description in 1979. Here, we show that profound and functionally beneficial alterations on the encoded protein level were causative for the AUA codon reassignment from isoleucine to methionine observed in most mitochondrial lineages. We demonstrate that this codon reassignment leads to a massive accumulation of the easily oxidized amino acid methionine in the highly oxidative inner mitochondrial membrane. This apparently paradoxical outcome can yet be smoothly settled if the antioxidant surface chemistry of methionine is taken into account, and we present direct experimental evidence that intramembrane accumulation of methionine exhibits antioxidant and cytoprotective properties in living cells. Our results unveil that methionine is an evolutionarily selected antioxidant building block of respiratory chain complexes. Collective protein alterations can thus constitute the selective advantage behind codon reassignments, which authenticates the "ambiguous decoding" hypothesis of genetic code evolution. Oxidative stress has shaped the mitochondrial genetic code.

  12. Mineral transformation and biomass accumulation associated with uranium bioremediation at Rifle, Colorado

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li, L.; Steefel, C.I.; Williams, K.H.

    2009-04-20

    Injection of organic carbon into the subsurface as an electron donor for bioremediation of redox-sensitive contaminants like uranium often leads to mineral transformation and biomass accumulation, both of which can alter the flow field and potentially bioremediation efficacy. This work combines reactive transport modeling with a column experiment and field measurements to understand the biogeochemical processes and to quantify the biomass and mineral transformation/accumulation during a bioremediation experiment at a uranium contaminated site near Rifle, Colorado. We use the reactive transport model CrunchFlow to explicitly simulate microbial community dynamics of iron and sulfate reducers, and their impacts on reaction rates.more » The column experiment shows clear evidence of mineral precipitation, primarily in the form of calcite and iron monosulfide. At the field scale, reactive transport simulations suggest that the biogeochemical reactions occur mostly close to the injection wells where acetate concentrations are highest, with mineral precipitate and biomass accumulation reaching as high as 1.5% of the pore space. This work shows that reactive transport modeling coupled with field data can be an effective tool for quantitative estimation of mineral transformation and biomass accumulation, thus improving the design of bioremediation strategies.« less

  13. Mechanisms of formation and accumulation of mitochondrial DNA deletions in aging neurons.

    PubMed

    Fukui, Hirokazu; Moraes, Carlos T

    2009-03-15

    Age-dependent accumulation of partially deleted mitochondrial DNA (DeltamtDNA) has been suggested to contribute to aging and the development of age-associated diseases including Parkinson's disease. However, the molecular mechanisms underlying the generation and accumulation of DeltamtDNA have not been addressed in vivo. In this study, we have developed a mouse model expressing an inducible mitochondria-targeted restriction endonuclease (PstI). Using this system, we could trigger mtDNA double-strand breaks (DSBs) in adult neurons. We found that this transient event leads to the generation of a family of DeltamtDNA with features that closely resemble naturally-occurring mtDNA deletions. The formation of these deleted species is likely to be mediated by yet uncharacterized DNA repairing machineries that participate in homologous recombination and non-homologous end-joining. Furthermore, we obtained in vivo evidence that DeltamtDNAs with larger deletions accumulate faster than those with smaller deletions, implying a replicative advantage of smaller mtDNAs. These findings identify DSB, DNA repair systems and replicative advantage as likely mechanisms underlying the generation and age-associated accumulation of DeltamtDNA in mammalian neurons.

  14. Mineral transformation and biomass accumulation associated with uranium bioremediation at Rifle, Colorado.

    PubMed

    Li, Li; Steefel, Carl I; Williams, Kenneth H; Wilkins, Michael J; Hubbard, Susan S

    2009-07-15

    Injection of organic carbon into the subsurface as an electron donor for bioremediation of redox-sensitive contaminants like uranium often leads to mineral transformation and biomass accumulation, both of which can alter the flow field and potentially bioremediation efficacy. This work combines reactive transport modeling with a column experiment and field measurements to understand the biogeochemical processes and to quantify the biomass and mineral transformation/accumulation during a bioremediation experiment at a uranium contaminated site near Rifle, Colorado. We use the reactive transport model CrunchFlow to explicitly simulate microbial community dynamics of iron and sulfate reducers, and their impacts on reaction rates. The column experiment shows clear evidence of mineral precipitation, primarily in the form of calcite and iron monosulfide. At the field scale, reactive transport simulations suggest that the biogeochemical reactions occur mostly close to the injection wells where acetate concentrations are highest, with mineral precipitate and biomass accumulation reaching as high as 1.5% of the pore space. This work shows that reactive transport modeling coupled with field data can bean effective tool for quantitative estimation of mineral transformation and biomass accumulation, thus improving the design of bioremediation strategies.

  15. Carbon isotope evidence for recent climate-related enhancement of CO 2 assimilation and peat accumulation rates in Antarctica.

    PubMed

    Royles, Jessica; Ogée, Jérôme; Wingate, Lisa; Hodgson, Dominic A; Convey, Peter; Griffiths, Howard

    2012-10-01

    Signy Island, maritime Antarctic, lies within the region of the Southern Hemisphere that is currently experiencing the most rapid rates of environmental change. In this study, peat cores up to 2 m in depth from four moss banks on Signy Island were used to reconstruct changes in moss growth and climatic characteristics over the late Holocene. Measurements included radiocarbon dating (to determine peat accumulation rates) and stable carbon isotope composition of moss cellulose (to estimate photosynthetic limitation by CO 2 supply and model CO 2 assimilation rate). For at least one intensively 14 C-dated Chorisodontium aciphyllum moss peat bank, the vertical accumulation rate of peat was 3.9 mm yr -1 over the last 30 years. Before the industrial revolution, rates of peat accumulation in all cores were much lower, at around 0.6-1 mm yr -1 . Carbon-13 discrimination (Δ), corrected for background and anthropogenic source inputs, was used to develop a predictive model for CO 2 assimilation. Between 1680 and 1900, there had been a gradual increase in Δ, and hence assimilation rate. Since 1800, assimilation has also been stimulated by the changes in atmospheric CO 2 concentration, but a recent decline in Δ (over the past 50-100 years) can perhaps be attributed to documented changes in temperature and/or precipitation. The overall increase in CO 2 assimilation rate ( 13 C proxy) and enhanced C accumulation ( 14 C proxy) are consistent with warmer and wetter conditions currently generating higher growth rates than at any time in the past three millennia, with the decline in Δ perhaps compensated by a longer growing season. © 2012 Blackwell Publishing Ltd.

  16. Four-hour quantitative real-time polymerase chain reaction-based comprehensive chromosome screening and accumulating evidence of accuracy, safety, predictive value, and clinical efficacy.

    PubMed

    Treff, Nathan R; Scott, Richard T

    2013-03-15

    Embryonic comprehensive chromosomal euploidy may represent a powerful biomarker to improve the success of IVF. However, there are a number of aneuploidy screening strategies to consider, including different technologic platforms with which to interrogate the embryonic DNA, and different embryonic developmental stages from which DNA can be analyzed. Although there are advantages and disadvantages associated with each strategy, a series of experiments producing evidence of accuracy, safety, clinical predictive value, and clinical efficacy indicate that trophectoderm biopsy and quantitative real-time polymerase chain reaction (qPCR)-based comprehensive chromosome screening (CCS) may represent a useful strategy to improve the success of IVF. This Biomarkers in Reproductive Medicine special issue review summarizes the accumulated experience with the development and clinical application of a 4-hour blastocyst qPCR-based CCS technology. Copyright © 2013 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  17. Accumulation of Cytoplasmic Dynein and Dynactin at Microtubule Plus Ends in Aspergillus nidulans Is Kinesin DependentV⃞

    PubMed Central

    Zhang, Jun; Li, Shihe; Fischer, Reinhard; Xiang, Xin

    2003-01-01

    The mechanism(s) by which microtubule plus-end tracking proteins are targeted is unknown. In the filamentous fungus Aspergillus nidulans, both cytoplasmic dynein and NUDF, the homolog of the LIS1 protein, localize to microtubule plus ends as comet-like structures. Herein, we show that NUDM, the p150 subunit of dynactin, also forms dynamic comet-like structures at microtubule plus ends. By examining proteins tagged with green fluorescent protein in different loss-of-function mutants, we demonstrate that dynactin and cytoplasmic dynein require each other for microtubule plus-end accumulation, and the presence of cytoplasmic dynein is also important for NUDF's plus-end accumulation. Interestingly, deletion of NUDF increases the overall accumulation of dynein and dynactin at plus ends, suggesting that NUDF may facilitate minus-end–directed dynein movement. Finally, we demonstrate that a conventional kinesin, KINA, is required for the microtubule plus-end accumulation of cytoplasmic dynein and dynactin, but not of NUDF. PMID:12686603

  18. Extending the Reach of Evidence-Based Medicine: A Proposed Categorization of Lower-Level Evidence.

    PubMed

    Detterbeck, Frank C; Gould, Michael K; Lewis, Sandra Zelman; Patel, Sheena

    2018-02-01

    Clinical practice involves making many treatment decisions for which only limited formal evidence exists. While the methodology of evidence-based medicine (EBM) has evolved tremendously, there is a need to better characterize lower-level evidence. This should enhance the ability to appropriately weigh the evidence against other considerations, and counter the temptation to think it is more robust than it actually is. A framework to categorize lower-level evidence is proposed, consisting of nonrandomized comparisons, extrapolation using indirect evidence, rationale, and clinical experience (ie, an accumulated general impression). Subtypes are recognized within these categories, based on the degree of confounding in nonrandomized comparisons, the uncertainty involved in extrapolation from indirect evidence, and the plausibility of a rationale. Categorizing the available evidence in this way can promote a better understanding of the strengths and limitations of using such evidence as the basis for treatment decisions in clinically relevant areas that are devoid of higher-level evidence. Copyright © 2017 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

  19. Accumulation of atmospheric sulfur in some Costa Rican soils

    USGS Publications Warehouse

    Bern, Carleton R.; Townsend, Alan R.

    2013-01-01

    Sulfur is one of the macronutrient elements whose sources to terrestrial ecosystems should shift from dominance by rock-weathering to atmospheric deposition as soils and underlying substrate undergo progressive weathering and leaching. However, the nature and timing of this transition is not well known. We investigated sources of sulfur to tropical rain forests growing on basalt-derived soils in the Osa Peninsula region of Costa Rica. Sulfur sources were examined using stable isotope ratios (δ34S) and compared to chemical indices of soil development. The most weathered soils, and the forests they supported, are dominated by atmospheric sulfur, while a less weathered soil type contains both rock-derived and atmospheric sulfur. Patterns of increasing δ34S with increasing soil sulfur concentration across the landscape suggest atmospheric sulfur is accumulating, and little rock-derived sulfur has been retained. Soil sulfur, minus adsorbed sulfate, is correlated with carbon and nitrogen, implying that sulfur accumulation occurs as plants and microbes incorporate sulfur into organic matter. Only the lower depth increments of the more weathered soils contained significant adsorbed sulfate. The evidence suggests a pattern of soil development in which sulfur-bearing minerals in rock, such as sulfides, weather early relative to other minerals, and the released sulfate is leached away. Sulfur added via atmospheric deposition is retained as organic matter accumulates in the soil profile. Adsorbed sulfate accumulates later, driven by changes in soil chemistry and mineralogy. These aspects of sulfur behavior during pedogenesis in this environment may hasten the transition to dominance by atmospheric sources.

  20. Biochar amendment reduced methylmercury accumulation in rice plants.

    PubMed

    Shu, Rui; Wang, Yongjie; Zhong, Huan

    2016-08-05

    There is growing concern about methylmercury (MeHg) accumulation in rice grains and thus enhanced dietary exposure to MeHg in Asian countries. Here, we explored the possibility of reducing grain MeHg levels by biochar amendment, and the underlying mechanisms. Pot (i.e., rice cultivation in biochar amended soils) and batch experiments (i.e., incubation of amended soils under laboratory conditions) were carried out, to investigate MeHg dynamics (i.e., MeHg production, partitioning and phytoavailability in paddy soils, and MeHg uptake by rice) under biochar amendment (1-4% of soil mass). We demonstrate for the first time that biochar amendment could evidently reduce grain MeHg levels (49-92%). The declines could be attributed to the combined effects of: (1) increased soil MeHg concentrations, probably explained by the release of sulfate from biochar and thus enhanced microbial production of MeHg (e.g., by sulfate-reducing bacteria), (2) MeHg immobilization in soils, facilitated by the large surface areas and high organosulfur content of biochar, and (3) biodilution of MeHg in rice grains, due to the increased grain biomass under biochar amendment (35-79%). These observations together with mechanistic explanations improve understanding of MeHg dynamics in soil-rice systems, and support the possibility of reducing MeHg phytoaccumulation under biochar amendment. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Iron accumulates in the lavage and explanted lungs of cystic fibrosis patients.

    EPA Science Inventory

    Abstract Oxidative stress participates in the pathophysiology of cystic fibrosis (CF). An underlying disruption in iron homeostasis can frequently be demonstrated in injuries and diseases associated with an oxidative stress. We tested the hypothesis that iron accumulation and ...

  2. [Evidence-based management of medical disposable materials].

    PubMed

    Yang, Hai

    2009-03-01

    Evidence-based management of medical disposable materials pays attention to collect evidence comprehensively and systematically, accumulate and create evidence through its own work and also evaluate evidence strictly. This can be used as a function to guide out job. Medical disposable materials evidence system contains product register qualification, product quality certification, supplier's behavior, internal and external communication evidence. Managers can find different ways in creating and using evidence referring to specific inside and outside condition. Evidence-based management can help accelerating the development of management of medical disposable materials from traditional experience pattern to a systematic and scientific pattern. It also has the very important meaning to improve medical quality, control the unreasonable growth of medical expense and make purchase and supply chain be more efficient.

  3. Accumulation of Succinate in Cardiac Ischemia Primarily Occurs via Canonical Krebs Cycle Activity.

    PubMed

    Zhang, Jimmy; Wang, Yves T; Miller, James H; Day, Mary M; Munger, Joshua C; Brookes, Paul S

    2018-05-29

    Succinate accumulates during ischemia, and its oxidation at reperfusion drives injury. The mechanism of ischemic succinate accumulation is controversial and is proposed to involve reversal of mitochondrial complex II. Herein, using stable-isotope-resolved metabolomics, we demonstrate that complex II reversal is possible in hypoxic mitochondria but is not the primary succinate source in hypoxic cardiomyocytes or ischemic hearts. Rather, in these intact systems succinate primarily originates from canonical Krebs cycle activity, partly supported by aminotransferase anaplerosis and glycolysis from glycogen. Augmentation of canonical Krebs cycle activity with dimethyl-α-ketoglutarate both increases ischemic succinate accumulation and drives substrate-level phosphorylation by succinyl-CoA synthetase, improving ischemic energetics. Although two-thirds of ischemic succinate accumulation is extracellular, the remaining one-third is metabolized during early reperfusion, wherein acute complex II inhibition is protective. These results highlight a bifunctional role for succinate: its complex-II-independent accumulation being beneficial in ischemia and its complex-II-dependent oxidation being detrimental at reperfusion. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  4. miR-34a-5p Inhibition Alleviates Intestinal Ischemia/Reperfusion-Induced Reactive Oxygen Species Accumulation and Apoptosis via Activation of SIRT1 Signaling.

    PubMed

    Wang, Guangzhi; Yao, Jihong; Li, Zhenlu; Zu, Guo; Feng, Dongcheng; Shan, Wen; Li, Yang; Hu, Yan; Zhao, Yongfu; Tian, Xiaofeng

    2016-06-10

    Reactive oxygen species (ROS) generation and massive epithelial apoptosis are critical in the pathogenesis of intestinal ischemia/reperfusion (I/R) injury. We previously found that the Sirtuin 1 (SIRT1)-mediated antioxidant pathway was impaired in the intestine after I/R. Here, we investigate the potential role of SIRT1-targeting microRNAs (miRNAs) in regulating ROS accumulation and apoptosis in intestinal I/R, and the important role SIRT1 involved in. C57BL/6 mice were subjected to intestinal I/R induced by occlusion of the superior mesenteric artery followed by reperfusion. Caco-2 cells were incubated under hypoxia/reoxygenation condition to mimic I/R in vivo. We find that SIRT1 is gradually repressed during the early reperfusion, and that this repression results in intestinal ROS accumulation and apoptosis. Using bioinformatics analysis and real-time PCR, we demonstrate that miR-34a-5p and miR-495-3p are significantly increased among the 41 putative miRNAs that can target SIRT1. Inhibition of miR-34a-5p, but not miR-495-3p, attenuates intestinal I/R injury, as demonstrated by repressing p66shc upregulation, manganese superoxide dismutase repression, and the caspase-3 activation in vitro and in vivo; it further alleviates systemic injury, as demonstrated by reducing inflammatory cytokine release, attenuating lung and liver lesions, and improving survival. Interestingly, SIRT1 plays an indispensable role in the protection afforded by miR-34a-5p inhibition. This study provides the first evidence of miRNAs in regulating oxidative stress and apoptosis in intestinal I/R. miR-34a-5p knockdown attenuates intestinal I/R injury through promoting SIRT1-mediated suppression of epithelial ROS accumulation and apoptosis. This may represent a novel prophylactic approach to intestinal I/R injury. Antioxid. Redox Signal. 24, 961-973.

  5. Fibrocytes Regulate Wilms’ Tumor 1-Positive Cell Accumulation in Severe Fibrotic Lung Disease

    PubMed Central

    Sontake, Vishwaraj; Shanmukhappa, Shiva K.; DiPasquale, Betsy A.; Reddy, Geereddy B.; Medvedovic, Mario; Hardie, William D.; White, Eric S.; Madala, Satish K.

    2015-01-01

    Collagen-producing myofibroblast transdifferentiation is considered a crucial determinant in the formation of scar tissue in the lungs of patients with idiopathic pulmonary fibrosis (IPF). Multiple resident pulmonary cell types and bone marrow-derived fibrocytes have been implicated as contributors to fibrotic lesions due to the transdifferentiation potential of these cells into myofibroblasts. In this study, we assessed the expression of Wilms’ tumor 1 (WT1), a known marker of mesothelial cells, in various cell types in normal and fibrotic lungs. We demonstrate that WT1 is expressed by both mesothelial and mesenchymal cells in IPF lungs, but has limited or no expression in normal human lungs. We also demonstrate that WT1-positive cells accumulate in fibrotic lung lesions, using two different mouse models of pulmonary fibrosis and WT1 promoter-driven fluorescent reporter mice. Reconstitution of bone-marrow cells into a transforming growth factor-α transgenic-mouse model demonstrated that fibrocytes do not transform into WT1-positive mesenchymal cells, but do augment accumulation of WT1-positive cells in severe fibrotic lung disease. Importantly, the number of WT1-positive cells in fibrotic lesions were correlated with severity of lung disease as assessed by changes in lung function, histology, and hydroxyproline levels in mice. Finally, inhibition of WT1 expression was sufficient to attenuate collagen and other extracellular-matrix gene production by mesenchymal cells from both murine and human fibrotic lungs. Thus, the results of this study demonstrate a novel association between fibrocyte-driven WT1-positive cell accumulation and severe fibrotic lung disease. PMID:26371248

  6. Stinging Nettle (Urtica dioica L.) Attenuates FFA Induced Ceramide Accumulation in 3T3-L1 Adipocytes in an Adiponectin Dependent Manner

    PubMed Central

    Obanda, Diana N.; Zhao, Peng; Richard, Allison J.; Ribnicky, David; Cefalu, William T.; Stephens, Jacqueline M.

    2016-01-01

    Objective Excess dietary lipids result in the accumulation of lipid metabolites including ceramides that can attenuate insulin signaling. There is evidence that a botanical extract of Urtica dioica L. (stinging nettle) improves insulin action, yet the precise mechanism(s) are not known. Hence, we examined the effects of Urtica dioica L. (UT) on adipocytes. Research Design We investigated the effects of an ethanolic extract of UT on free fatty acid (palmitic acid) induced inhibition of insulin-stimulated Akt serine phosphorylation and modulation of ceramidase expression in 3T3-L1 adipocytes. Adipocytes were exposed to excess FFAs in the presence or absence of UT. Effects on adiponectin expression, ceramidase expression, ceramidase activity, ceramide accumulation and insulin signaling were determined. Results As expected, FFAs reduced adiponectin expression and increased the expression of ceramidase enzymes but not their activity. FFA also induced the accumulation of ceramides and reduced insulin-stimulated phosphorylation of Akt in adipocytes. The effects of FFA were partially reversed by UT. UT enhanced adiponectin expression and ceramidase activity in the presence of excess FFAs. UT abated ceramide accumulation and increased insulin sensitivity via enhanced Akt phosphorylation. A siRNA knockdown of adiponectin expression prevented UT from exerting positive effects on ceramidase activity but not Akt phosphorylation. Conclusions In adipocytes, the ability of UT to antagonize the negative effects of FFA by modulating ceramidase activity and ceramide accumulation is dependent on the presence of adiponectin. However, the ability of UT to enhance Akt phosphorylation is independent of adiponectin expression. These studies demonstrate direct effects of UT on adipocytes and suggest this botanical extract is metabolically beneficial. PMID:26939068

  7. Identification and Metabolite Profiling of Chemical Activators of Lipid Accumulation in Green Algae1[OPEN

    PubMed Central

    2017-01-01

    Microalgae are proposed as feedstock organisms useful for producing biofuels and coproducts. However, several limitations must be overcome before algae-based production is economically feasible. Among these is the ability to induce lipid accumulation and storage without affecting biomass yield. To overcome this barrier, a chemical genetics approach was employed in which 43,783 compounds were screened against Chlamydomonas reinhardtii, and 243 compounds were identified that increase triacylglyceride (TAG) accumulation without terminating growth. Identified compounds were classified by structural similarity, and 15 were selected for secondary analyses addressing impacts on growth fitness, photosynthetic pigments, and total cellular protein and starch concentrations. TAG accumulation was verified using gas chromatography-mass spectrometry quantification of total fatty acids, and targeted TAG and galactolipid measurements were performed using liquid chromatography-multiple reaction monitoring/mass spectrometry. These results demonstrated that TAG accumulation does not necessarily proceed at the expense of galactolipid. Untargeted metabolite profiling provided important insights into pathway shifts due to five different compound treatments and verified the anabolic state of the cells with regard to the oxidative pentose phosphate pathway, Calvin cycle, tricarboxylic acid cycle, and amino acid biosynthetic pathways. Metabolite patterns were distinct from nitrogen starvation and other abiotic stresses commonly used to induce oil accumulation in algae. The efficacy of these compounds also was demonstrated in three other algal species. These lipid-inducing compounds offer a valuable set of tools for delving into the biochemical mechanisms of lipid accumulation in algae and a direct means to improve algal oil content independent of the severe growth limitations associated with nutrient deprivation. PMID:28652262

  8. Experimental evidence of zone-center optical phonon softening by accumulating holes in thin Ge

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kabuyanagi, Shoichi; Nishimura, Tomonori; Yajima, Takeaki

    2016-01-15

    We discuss the impact of free carriers on the zone-center optical phonon frequency in germanium (Ge). By taking advantage of the Ge-on-insulator structure, we measured the Raman spectroscopy by applying back-gate bias. Phonon softening by accumulating holes in Ge film was clearly observed. This fact strongly suggests that the phonon softening in heavily-doped Ge is mainly attributed to the free carrier effect rather than the dopant atom counterpart. Furthermore, we propose that the free carrier effect on phonon softening is simply understandable from the viewpoint of covalent bonding modification by free carriers.

  9. Lactofen induces isoflavone accumulation and glyceollin elicitation competency in soybean.

    PubMed

    Landini, Serena; Graham, Madge Y; Graham, Terrence L

    2003-03-01

    Lactofen, the active ingredient of the soybean disease resistance-inducing herbicide, Cobra, induces large accumulations of isoflavone conjugates and aglycones in soybean tissues. The predominant isoflavones induced in cotyledon tissues are daidzein (and its conjugates) and formononetin and glycitein aglycones. The latter two isoflavones are usually present only at very low levels in soybean seedling tissues. In leaves, the predominant lactofen-induced isoflavones are daidzein and formononetin aglycones and the malonyl-glucosyl conjugate of genistein. Isoflavone induction also occurs in cells distal to the point of treatment, but is only weakly systemic. Lactofen also induces elicitation competency, the capacity of soybean cells to accumulate the pterocarpan phytoalexin glyceollin in response to glucan elicitors from the cell wall of the pathogen Phytophthora sojae. Comparison of the activity of a series of diphenyl ether herbicides demonstrated that while all diphenyl ethers tested induced some degree of elicitation competency, only certain ones induced isoflavone accumulation in the absence of glucan elicitor. As a group the diphenyl ethers are thought to inhibit protoporhyrinogen oxidase, eventually leading to singlet oxygen generation. Another singlet oxygen generator, rose bengal, also induced elicitation competency, but little isoflavone accumulation. It is hypothesized that diphenyl ether-induced activated oxygen species mimic some aspects of hypersensitive cell death, which leads to elicitation competency in infected tissues.

  10. Uptake, accumulation and metabolization of the antidepressant fluoxetine by Mytilus galloprovincialis.

    PubMed

    Silva, Liliana J G; Martins, Margarida C; Pereira, André M P T; Meisel, Leonor M; Gonzalez-Rey, Maria; Bebianno, Maria João; Lino, Celeste M; Pena, Angelina

    2016-06-01

    Fluoxetine, a selective serotonin re-uptake inhibitor (SSRI) antidepressant, is among the most prescribed pharmaceutical active substances worldwide. This study aimed to assess its accumulation and metabolization in the mussel Mytillus galloprovincialis, considered an excellent sentinel species for traditional and emerging pollutants. Mussels were collected from Ria Formosa Lagoon, Portugal, and exposed to a nominal concentration of fluoxetine (75 ng L(-1)) for 15 days. Approximately 1 g of whole mussel soft tissues was extracted with acetonitrile:formic acid, loaded into an Oasis MCX cartridge, and fluoxetine analysed by liquid chromatography with tandem mass spectrometry (LC-MSn). After 3 days of exposure, fluoxetine was accumulated in 70% of the samples, with a mean of 2.53 ng g(-1) dry weight (d.w.) and norfluoxetine was only detected in one sample (10%), at 3.06 ng g(-1) d.w. After 7 days of exposure, the accumulation of fluoxetine and norfluoxetine increased up to 80 and 50% respectively, and their mean accumulated levels in mussel tissues were up to 4.43 and 2.85 ng g(-1) d.w., respectively. By the end of the exposure period (15 days), both compounds were detected in 100% of the samples (mean of 9.31 and 11.65 ng g(-1) d.w., respectively). Statistical analysis revealed significant accumulation differences between the 3rd and 15th day of exposure for fluoxetine, and between the 3rd and 7th against the 15th day of exposure for norfluoxetine. These results suggest that the fluoxetine accumulated in mussel tissues is likely to be metabolised into norfluoxetine with the increase of the time of exposure, giving evidence that at these realistic environmental concentrations, toxic effects of fluoxetine in mussel tissues may occur. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Effect of Hypergravity and Phytohormones on Isoflavonoid Accumulation in Soybean ( Glycine max. L.) Callus

    NASA Astrophysics Data System (ADS)

    Downey, Peter J.; Levine, Lanfang H.; Musgrave, Mary E.; McKeon-Bennett, Michelle; Moane, Siobhán

    2013-02-01

    The objective of this study was to explore the potential interaction between gravity and growth hormones on isoflavonoid accumulation. Soybean callus ( Glycine max (L.) Merr. cv. `Acme') was grown in the dark for 16 days at 22 °C in a growth medium supplemented with four different combinations of phytohormones and subjected to 4- g and 8- g forces simulated in a centrifuge and 1- g in an adjacent stationary control. Isoflavonoid aglycones and their glycoside concentrations (daidzein, genistein, daidzin, 6″-O-malonyl-7-O-glucosyl daidzein, genistin, 6″-O-malonyl-7-O-glucosyl genistein) were determined in the resulting tissues. Although gravity had no significant impact on callus growth, increasing gravity reduced isoflavonoid accumulation in three out of the four phytohormone-supplemented culture media. The ratio of the auxin naphthalene acetic acid (NAA) to the cytokinin benzylaminopurine (BAP) was found to have profound effect on both callus growth and isoflavonoid accumulation. The cytokinin BAP promoted callus tissue growth, but reduced callus isoflavonoid suggesting the isoflavonoid accumulation was not keeping pace with the cell growth in the elevated concentration of BAP. On the other hand, NAA had little or no effect on callus growth, but greatly enhanced isoflavonoid accumulation. Interactive effects of gravity and hormone on isoflavonoid accumulation were evident and its implication to the mechanism by which gravity exerts the effect on plant secondary metabolites is discussed.

  12. Transgenic salt-tolerant tomato plants accumulate salt in foliage but not in fruit.

    PubMed

    Zhang, H X; Blumwald, E

    2001-08-01

    Transgenic tomato plants overexpressing a vacuolar Na+/H+ antiport were able to grow, flower, and produce fruit in the presence of 200 mM sodium chloride. Although the leaves accumulated high sodium concentrations, the tomato fruit displayed very low sodium content. Contrary to the notion that multiple traits introduced by breeding into crop plants are needed to obtain salt-tolerant plants, the modification of a single trait significantly improved the salinity tolerance of this crop plant. These results demonstrate that with a combination of breeding and transgenic plants it could be possible to produce salt-tolerant crops with far fewer target traits than had been anticipated. The accumulation of sodium in the leaves and not in the fruit demonstrates the utility of such a modification in preserving the quality of the fruit.

  13. Continuous and Episodic Modern Sediment Accumulation on Monterey Fan: Evidence from Ddt, 137Cs and Excess 210Pb

    NASA Astrophysics Data System (ADS)

    Gwiazda, R.; Paull, C. K.; Alexander, C. R.; Ussler, W.

    2012-12-01

    The mode and magnitude of fine-grained sediment accumulation on the Monterey Fan off the California central coast was investigated using pesticide concentrations and radioactive tracer profiles in sediment cores. DDT is a man-made pesticide that was used extensively in central California between 1945 and 1970. As such, its presence in marine sediments is a telltale sign of a modern sedimentation age. DDT and its metabolites, DDE and DDD, (collectively referred to as DDTr) were measured in fifty-five ~20cm-long sediment cores collected from the surface of the Monterey Fan up to 250 km to the south and 210 km to the west of the Monterey Canyon head, and in four transects across the Monterey Canyon channel at maximum water depths of 3160, 3380, 3580, and 3880 meters. Profiles of excess 210Pb (210Pbxs) and 137Cs were measured in 5 cores from the Fan to estimate recent sedimentation rates. Detectable levels of DDTr were observed in all but one of these cores, with DDTr concentrations characteristically highest at the surface and decreasing with depth. The area-normalized and depth-integrated DDTr content measured in all the cores in the Fan and in the deepest two channel transects was geographically fairly homogenous, with no statistical relationship between DDTr inventory and distance from the main channel crossing the Fan. The total sediment mass deposited on the Fan over the last 60 years, inferred from the total inventory of DDTr present in the area surveyed, is consistent with the amount of sediment delivered by the Salinas River over the same time period. 210Pbxs activities are fairly homogeneous within an uppermost layer of variable thickness (4.6-8cm) and decrease exponentially below it, but these exponential decreases are often interrupted by horizons with constant or increased 210Pbxs activity. Moreover, the coexistence of variable DDTr concentrations with homogeneous 210Pbxs activities in the top sediment indicates that the uniformity of 210Pbxs is not due

  14. A lee-side eddy and its influence on snow accumulation

    NASA Astrophysics Data System (ADS)

    Gerber, Franziska; Mott, Rebecca; Hoch, Sebastian W.; Lehning, Michael

    2016-04-01

    Knowledge of changes in seasonal mountain snow water resources is essential for e.g. hydropower companies. To successfully predict these changes a fundamental understanding of precipitation patterns and their changes in mountainous terrain is needed. Both, snow accumulation and ablation need to be investigated to make precise predictions of the amount of water stored in seasonal snow cover. Only if the processes governing snow accumulation and ablation are understood with sufficient quantitative accuracy, the evolution of snow water resources under a changing climate can be addressed. Additionally, knowledge of detailed snow accumulation patterns is essential to assess avalanche danger. In alpine terrain, snow accumulation is strongly dependent on the local wind field. Based on the concept of preferential deposition, reduced snow accumulation is expected on the upper windward slope of a mountain due to updrafts, while enhanced snow accumulation should occur through blocking at the windward foot or due to flow separation on the leeward side. However, the understanding of these processes is mainly based on numerical simulations, as they are hard to measure. A LiDAR (Light Detection And Ranging) campaign was conducted in October 2015 in the Dischma valley (Davos, CH) to investigate the local flow field in the lee of the Sattelhorn during a one-day snowfall event. The flow field was monitored using a plane position indicator (PPI) scan at 25/28° and a range height indicator (RHI) scan across the Sattelhorn. Additionally, snow height change measurements on the leeward side of the Sattelhorn were performed by terrestrial laser scanning (TLS). Analyses of the flow field in the framework of preferential deposition are in agreement with the concept of flow separation and preferred snow deposition on leeward slopes. A very persistent eddy that formed over the leeward slope of the Sattelhorn detached from the main flow became evident from the retrievals of the RHI scans. An

  15. 150,000 years of loess accumulation in central Alaska

    NASA Astrophysics Data System (ADS)

    Jensen, Britta J. L.; Evans, Michael E.; Froese, Duane G.; Kravchinsky, Vadim A.

    2016-03-01

    The Halfway House site in interior Alaska is arguably the most studied loess deposit in northwestern North America. The site contains a complex paleomagnetic and paleoenvironmental record, but has lacked the robust chronologic control that would allow its full potential to be exploited. Detailed reexamination of stratigraphy, paleomagnetics and tephrostratigraphy reveals a relatively complete marine isotope stage (MIS) 6 to Holocene record constrained by the Old Crow (124 ± 10 ka), VT (106 ± 10 ka), Sheep Creek-Klondike (ca. 80 ka), Dominion Creek (77 ± 8 ka) and Dawson (ca. 30.2 cal ka BP) tephras. We show two well-developed paleosols formed during Marine Isotope Stages (MIS) 5e and 5a, while MIS 5c and 5b are either poorly represented or absent. The new tephrostratigraphy presented here is the most complete one to date for the late Pleistocene and indicates MIS 5 sediments are more common than previously recognized. A magnetic excursion within the sediments is identified as the post-Blake excursion (94.1 ± 7.8 ka), providing independent age control and adding to the increasing body of evidence that Alaskan loess is a detailed recorder of variations of the Earth's magnetic field over time. A high-resolution magnetic susceptibility profile placed into this new chronostratigraphic framework supports the hypothesis that wind-intensity is the main variable controlling fluctuations in susceptibility. Correlation of the susceptibility record to global marine δ18O records is complicated by highly variable accumulation rates. We find the lowest rates of accumulation during peak warm and cold stages, while abrupt increases are associated with periods of transition between marine isotope (sub)stages. Building on previous accumulation models for Alaska, surface roughness is likely a leading variable controlling loess accumulation rates during transitions and peak cold periods, but the negligible accumulation during MIS 5e and 5a suggests that loess production was

  16. Ultrasound ablation enhances drug accumulation and survival in mammary carcinoma models.

    PubMed

    Wong, Andrew W; Fite, Brett Z; Liu, Yu; Kheirolomoom, Azadeh; Seo, Jai W; Watson, Katherine D; Mahakian, Lisa M; Tam, Sarah M; Zhang, Hua; Foiret, Josquin; Borowsky, Alexander D; Ferrara, Katherine W

    2016-01-01

    Magnetic resonance-guided focused ultrasound (MRgFUS) facilitates noninvasive image-guided conformal thermal therapy of cancer. Yet in many scenarios, the sensitive tissues surrounding the tumor constrain the margins of ablation; therefore, augmentation of MRgFUS with chemotherapy may be required to destroy remaining tumor. Here, we used 64Cu-PET-CT, MRI, autoradiography, and fluorescence imaging to track the kinetics of long-circulating liposomes in immunocompetent mammary carcinoma-bearing FVB/n and BALB/c mice. We observed a 5-fold and 50-fold enhancement of liposome and drug concentration, respectively, within MRgFUS thermal ablation-treated tumors along with dense accumulation within the surrounding tissue rim. Ultrasound-enhanced drug accumulation was rapid and durable and greatly increased total tumor drug exposure over time. In addition, we found that the small molecule gadoteridol accumulates around and within ablated tissue. We further demonstrated that dilated vasculature, loss of vascular integrity resulting in extravasation of blood cells, stromal inflammation, and loss of cell-cell adhesion and tissue architecture all contribute to the enhanced accumulation of the liposomes and small molecule probe. The locally enhanced liposome accumulation was preserved even after a multiweek protocol of doxorubicin-loaded liposomes and partial ablation. Finally, by supplementing ablation with concurrent liposomal drug therapy, a complete and durable response was obtained using protocols for which a sub-mm rim of tumor remained after ablation.

  17. Ultrasound ablation enhances drug accumulation and survival in mammary carcinoma models

    PubMed Central

    Wong, Andrew W.; Fite, Brett Z.; Liu, Yu; Kheirolomoom, Azadeh; Seo, Jai W.; Watson, Katherine D.; Mahakian, Lisa M.; Tam, Sarah M.; Zhang, Hua; Foiret, Josquin; Borowsky, Alexander D.; Ferrara, Katherine W.

    2015-01-01

    Magnetic resonance–guided focused ultrasound (MRgFUS) facilitates noninvasive image-guided conformal thermal therapy of cancer. Yet in many scenarios, the sensitive tissues surrounding the tumor constrain the margins of ablation; therefore, augmentation of MRgFUS with chemotherapy may be required to destroy remaining tumor. Here, we used 64Cu-PET-CT, MRI, autoradiography, and fluorescence imaging to track the kinetics of long-circulating liposomes in immunocompetent mammary carcinoma–bearing FVB/n and BALB/c mice. We observed a 5-fold and 50-fold enhancement of liposome and drug concentration, respectively, within MRgFUS thermal ablation–treated tumors along with dense accumulation within the surrounding tissue rim. Ultrasound-enhanced drug accumulation was rapid and durable and greatly increased total tumor drug exposure over time. In addition, we found that the small molecule gadoteridol accumulates around and within ablated tissue. We further demonstrated that dilated vasculature, loss of vascular integrity resulting in extravasation of blood cells, stromal inflammation, and loss of cell-cell adhesion and tissue architecture all contribute to the enhanced accumulation of the liposomes and small molecule probe. The locally enhanced liposome accumulation was preserved even after a multiweek protocol of doxorubicin-loaded liposomes and partial ablation. Finally, by supplementing ablation with concurrent liposomal drug therapy, a complete and durable response was obtained using protocols for which a sub-mm rim of tumor remained after ablation. PMID:26595815

  18. Sugar versus fat: elimination of glycogen storage improves lipid accumulation in Yarrowia lipolytica.

    PubMed

    Bhutada, Govindprasad; Kavšcek, Martin; Ledesma-Amaro, Rodrigo; Thomas, Stéphane; Rechberger, Gerald N; Nicaud, Jean-Marc; Natter, Klaus

    2017-05-01

    Triacylglycerol (TAG) and glycogen are the two major metabolites for carbon storage in most eukaryotic organisms. We investigated the glycogen metabolism of the oleaginous Yarrowia lipolytica and found that this yeast accumulates up to 16% glycogen in its biomass. Assuming that elimination of glycogen synthesis would result in an improvement of lipid accumulation, we characterized and deleted the single gene coding for glycogen synthase, YlGSY1. The mutant was grown under lipogenic conditions with glucose and glycerol as substrates and we obtained up to 60% improvement in TAG accumulation compared to the wild-type strain. Additionally, YlGSY1 was deleted in a background that was already engineered for high lipid accumulation. In this obese background, TAG accumulation was also further increased. The highest lipid content of 52% was found after 3 days of cultivation in nitrogen-limited glycerol medium. Furthermore, we constructed mutants of Y. lipolytica and Saccharomyces cerevisiae that are deleted for both glycogen and TAG synthesis, demonstrating that the ability to store carbon is not essential. Overall, this work showed that glycogen synthesis is a competing pathway for TAG accumulation in oleaginous yeasts and that deletion of the glycogen synthase has beneficial effects on neutral lipid storage. © FEMS 2017.

  19. Streptomyces sp. ASBV-1 reduces aflatoxin accumulation by Aspergillus parasiticus in peanut grains.

    PubMed

    Zucchi, T D; de Moraes, L A B; de Melo, I S

    2008-12-01

    To evaluate the ability of Streptomyces sp. (strain ASBV-1) to restrict aflatoxin accumulation in peanut grains. In the control of many phytopathogenic fungi the Streptomyces sp. ASBV-1 strain showed promise. An inhibitory test using this strain and A. parasiticus was conducted in peanut grains to evaluate the effects of this interaction on spore viability and aflatoxin accumulation. In some treatments the Streptomyces sp ASBV-1 strain reduced the viability of A. parasiticus spores by c. 85%, and inhibited aflatoxin accumulation in peanut grains. The values of these reductions ranged from 63 to 98% and from 67% to 96% for aflatoxins B(1) and G(1), respectively. It was demonstrated that Streptomyces sp. ASBV-1 is able to colonize peanut grains and thus inhibit the spore viability of A. parasiticus, as well as reducing aflatoxin production. The positive finding for aflatoxin accumulation reduction in peanut grains seems promising and suggests a wider use of this actinobacteria in biological control programmes.

  20. Two Outer Membrane Proteins Contribute to Caulobacter crescentus Cellular Fitness by Preventing Intracellular S-Layer Protein Accumulation

    DOE PAGES

    Overton, K. Wesley; Park, Dan M.; Yung, Mimi C.; ...

    2016-09-23

    phenomenon can conceivably also occur in natural systems. As one example of a system evolved to prevent intracellular protein accumulation, our study demonstrates thatCaulobacter crescentushas two homologous outer membrane transporter proteins that are involved in S-layer export. This is an interesting case study that demonstrates how bacteria can evolve redundancy to ensure adequate protein export functionality and maintain high cellular fitness. Moreover, we provide evidence that these two outer membrane proteins, although being the closestC. crescentushomologs to TolC inE. coli, do not process TolC functionality inC. crescentus.« less

  1. Two Outer Membrane Proteins Contribute to Caulobacter crescentus Cellular Fitness by Preventing Intracellular S-Layer Protein Accumulation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Overton, K. Wesley; Park, Dan M.; Yung, Mimi C.

    . This phenomenon can conceivably also occur in natural systems. As one example of a system evolved to prevent intracellular protein accumulation, our study demonstrates thatCaulobacter crescentushas two homologous outer membrane transporter proteins that are involved in S-layer export. This is an interesting case study that demonstrates how bacteria can evolve redundancy to ensure adequate protein export functionality and maintain high cellular fitness. Moreover, we provide evidence that these two outer membrane proteins, although being the closestC. crescentushomologs to TolC inE. coli, do not process TolC functionality inC. crescentus.« less

  2. Two Outer Membrane Proteins Contribute to Caulobacter crescentus Cellular Fitness by Preventing Intracellular S-Layer Protein Accumulation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Overton, K. Wesley; Park, Dan M.; Yung, Mimi C.

    phenomenon can conceivably also occur in natural systems. As one example of a system evolved to prevent intracellular protein accumulation, our study demonstrates thatCaulobacter crescentushas two homologous outer membrane transporter proteins that are involved in S-layer export. This is an interesting case study that demonstrates how bacteria can evolve redundancy to ensure adequate protein export functionality and maintain high cellular fitness. Moreover, we provide evidence that these two outer membrane proteins, although being the closestC. crescentushomologs to TolC inE. coli, do not process TolC functionality inC. crescentus.« less

  3. Stillage reflux in food waste ethanol fermentation and its by-product accumulation.

    PubMed

    Ma, Hongzhi; Yang, Jian; Jia, Yan; Wang, Qunhui; Tashiro, Yukihiro; Sonomoto, Kenji

    2016-06-01

    Raw materials and pollution control are key issues for the ethanol fermentation industry. To address these concerns, food waste was selected as fermentation substrate, and stillage reflux was carried out in this study. Reflux was used seven times during fermentation. Corresponding ethanol and reducing sugar were detected. Accumulation of by-products, such as organic acid, sodium chloride, and glycerol, was investigated. Lactic acid was observed to accumulate up to 120g/L, and sodium chloride reached 0.14mol/L. Other by-products did not accumulate. The first five cycles of reflux increased ethanol concentration, which prolonged fermentation time. Further increases in reflux time negatively influenced ethanol fermentation. Single-factor analysis with lactic acid and sodium chloride demonstrated that both factors affected ethanol fermentation, but lactic acid induced more effects. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Abnormal accumulation and recycling of glycoproteins visualized in Niemann–Pick type C cells using the chemical reporter strategy

    PubMed Central

    Mbua, Ngalle Eric; Flanagan-Steet, Heather; Johnson, Steven; Wolfert, Margreet A.; Boons, Geert-Jan; Steet, Richard

    2013-01-01

    Niemann–Pick type C (NPC) disease is characterized by impaired cholesterol efflux from late endosomes and lysosomes and secondary accumulation of lipids. Although impaired trafficking of individual glycoproteins and glycolipids has been noted in NPC cells and other storage disorders, there is currently no effective way to monitor their localization and movement en masse. Using a chemical reporter strategy in combination with pharmacologic treatments, we demonstrate a disease-specific and previously unrecognized accumulation of a diverse set of glycoconjugates in NPC1-null and NPC2-deficient fibroblasts within endocytic compartments. These labeled vesicles do not colocalize with the cholesterol-laden compartments of NPC cells. Experiments using the endocytic uptake marker dextran show that the endosomal accumulation of sialylated molecules can be largely attributed to impaired recycling as opposed to altered fusion of vesicles. Treatment of either NPC1-null or NPC2-deficient cells with cyclodextrin was effective in reducing cholesterol storage as well as the endocytic accumulation of sialoglycoproteins, demonstrating a direct link between cholesterol storage and abnormal recycling. Our data further demonstrate that this accumulation is largely glycoproteins, given that inhibitors of O-glycan initiation or N-glycan processing led to a significant reduction in staining intensity. Taken together, our results provide a unique perspective on the trafficking defects in NPC cells, and highlight the utility of this methodology in analyzing cells with altered recycling and turnover of glycoproteins. PMID:23733943

  5. Proline accumulation in baker's yeast enhances high-sucrose stress tolerance and fermentation ability in sweet dough.

    PubMed

    Sasano, Yu; Haitani, Yutaka; Ohtsu, Iwao; Shima, Jun; Takagi, Hiroshi

    2012-01-03

    During bread-making processes, yeast cells are exposed to various baking-associated stresses. High-sucrose concentrations exert severe osmotic stress that seriously damages cellular components by generation of reactive oxygen species (ROS). Previously, we found that the accumulation of proline conferred freeze-thaw stress tolerance and the baker's yeast strain that accumulated proline retained higher-level fermentation abilities in frozen doughs than the wild-type strain. In this study, we constructed self-cloning diploid baker's yeast strains that accumulate proline. These resultant strains showed higher cell viability and lower intracellular oxidation levels than that observed in the wild-type strain under high-sucrose stress condition. Proline accumulation also enhanced the fermentation ability in high-sucrose-containing dough. These results demonstrate the usefulness of proline-accumulating baker's yeast for sweet dough baking. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Observational evidence and strength of evidence domains: case examples

    PubMed Central

    2014-01-01

    Background Systematic reviews of healthcare interventions most often focus on randomized controlled trials (RCTs). However, certain circumstances warrant consideration of observational evidence, and such studies are increasingly being included as evidence in systematic reviews. Methods To illustrate the use of observational evidence, we present case examples of systematic reviews in which observational evidence was considered as well as case examples of individual observational studies, and how they demonstrate various strength of evidence domains in accordance with current Agency for Healthcare Research and Quality (AHRQ) Evidence-based Practice Center (EPC) methods guidance. Results In the presented examples, observational evidence is used when RCTs are infeasible or raise ethical concerns, lack generalizability, or provide insufficient data. Individual study case examples highlight how observational evidence may fulfill required strength of evidence domains, such as study limitations (reduced risk of selection, detection, performance, and attrition); directness; consistency; precision; and reporting bias (publication, selective outcome reporting, and selective analysis reporting), as well as additional domains of dose-response association, plausible confounding that would decrease the observed effect, and strength of association (magnitude of effect). Conclusions The cases highlighted in this paper demonstrate how observational studies may provide moderate to (rarely) high strength evidence in systematic reviews. PMID:24758494

  7. A patient with type I CD36 deficiency whose myocardium accumulated 123I-BMIPP after 4 years.

    PubMed

    Ito, K; Sugihara, H; Tanabe, T; Zen, K; Hikosaka, T; Adachi, Y; Katoh, S; Azuma, A; Nakagawa, M

    2001-06-01

    A 73-year-old man with aortic regurgitation was examined by 123I-alpha-methyl-p-iodophenylpentadecanoic acid (BMIPP) myocardial single photon emission computed tomography (SPECT) in 1995. Myocardial accumulation was not evident on either the early or the delayed image obtained 15 minutes and 3 hours, respectively, after injecting 123I-BMIPP. Flow cytometric analysis of CD36 expression in monocytes and platelets identified a type I CD36 deficiency. The patient was hospitalized for severe heart failure in 1999. Upon admission, the cardiothoracic ratio on chest X-rays was 73%, and the left ventricular end-diastolic diameter on echocardiograms was enlarged to 77 mm. On the second day, we performed 123I-BMIPP myocardial SPECT. Myocardial accumulation was evident in the delayed, but not in the early image. We repeated 123I-BMIPP myocardial SPECT on the 10th day after admission. Myocardial accumulation was evident on both early and delayed images. 99mTc-tetrofosmin myocardial SPECT was immediately performed after 123I-BMIPP myocardial SPECT to distinguish myocardial from pooling images in the left ventricle, but, because the images from both 99Tc-tetrofosmin and 123I-BMIPP myocardial SPECT were idential, we considered that the 123I-BMIPP myocardial SPECT images reflected the actual myocardial condition. The CD36 molecule transports long-chain fatty acid (LCFA) on the myocardial membrane, but 123I-BMIPP scintigraphy does not show any myocardial accumulation in patients with type I CD36 deficiency, indicating that myocardial LCFA uptake occurs through CD36 on the human myocardial membrane. Even though our patient had type I CD36 deficiency, BMIPP was uptaken by the myocardium during heart failure, suggesting a variant pathway on the human myocardial membrane for LCFA uptake.

  8. High-Affinity Accumulation of Chloroquine by Mouse Erythrocytes Infected with Plasmodium berghei

    PubMed Central

    Fitch, Coy D.; Yunis, Norman G.; Chevli, Rekha; Gonzalez, Yolanda

    1974-01-01

    Washed erythrocytes infected with chloroquine-susceptible (CS) or with chloroquine-resistant (CR) P. berghei were used in model systems in vitro to study the accumulation of chloroquine with high affinity. The CS model could achieve distribution ratios (chloroquine in cells: chloroquine in medium) of 100 in the absence of substrate. 200—300 in the presence of 10 mM pyruvate or lactate, and over 600 in the presence of 1 mM glucose or glycerol. In comparable studies of the CR model, the distribution ratios were 100 in the absence of substrate and 300 or less in the presence of glucose or glycerol. The presence of lactate stimulated chloroquine accumulation in the CR model, whereas the presence of pyruvate did not. Lactate production from glucose and glycerol was undiminished in the CR model, and ATP concentrations were higher than in the CS model. Cold, iodoacetate, 2,4-dinitrophenol, or decreasing pH inhibited chloroquine accumulation in both models. These findings demonstrate substrate involvement in the accumulation of chloroquine with high affinity. In studies of the CS model, certain compounds competitively inhibited chloroquine accumulation, while others did not. This finding is attributable to a specific receptor that imposes structural constraints on the process of accumulation. For chloroquine analogues, the position and length of the side chain, the terminal nitrogen atom of the side chain, and the nitrogen atom in the quinoline ring are important determinants of binding to this receptor. PMID:4600044

  9. Death rates reflect accumulating brain damage in arthropods.

    PubMed

    Fonseca, Duane B; Brancato, Carolina L; Prior, Andrew E; Shelton, Peter M J; Sheehy, Matt R J

    2005-09-22

    We present the results of the first quantitative, whole-lifespan study of the relationship between age-specific neurolipofuscin concentration and natural mortality rate in any organism. In a convenient laboratory animal, the African migratory locust, Locusta migratoria, we find an unusual delayed-onset neurolipofuscin accumulation pattern that is highly correlated with exponentially accelerating age-specific Gompertz-Makeham death rates in both males (r=0.93, p=0.0064) and females (r=0.97, p=0.0052). We then test the conservation of this association by aggregating the locust results with available population-specific data for a range of other terrestrial, freshwater, marine, tropical and temperate arthropods whose longevities span three orders of magnitude. This synthesis shows that the strong association between neurolipofuscin deposition and natural mortality is a phylogenetically and environmentally widespread phenomenon (r=0.96, p < 0.0001). These results highlight neurolipofuscin as a unique and outstanding integral biomarker of ageing. They also offer compelling evidence for the proposal that, in vital organs like the brain, either the accumulation of toxic garbage in the form of lipofuscin itself, or the particular molecular reactions underlying lipofuscinogenesis, including free-radical damage, are the primary events in senescence.

  10. Evolution in response to climate change: in pursuit of the missing evidence.

    PubMed

    Merilä, Juha

    2012-09-01

    Climate change is imposing intensified and novel selection pressures on organisms by altering abiotic and biotic environmental conditions on Earth, but studies demonstrating genetic adaptation to climate change mediated selection are still scarce. Evidence is accumulating to indicate that both genetic and ecological constrains may often limit populations' abilities to adapt to large scale effects of climate warming. These constraints may predispose many organisms to respond to climate change with range shifts and phenotypic plasticity, rather than through evolutionary adaptation. In general, broad conclusions about the role of evolutionary adaptation in mitigating climate change induced fitness loss in the wild are as yet difficult to make. Copyright © 2012 WILEY Periodicals, Inc.

  11. Controlled Speed Accessory Drive demonstration program

    NASA Technical Reports Server (NTRS)

    Hoehn, F. W.

    1981-01-01

    A Controlled Speed Accessory Drive System was examined in an effort to improve the fuel economy of passenger cars. Concept feasibility and the performance of a typical system during actual road driving conditions were demonstrated. The CSAD system is described as a mechanical device which limits engine accessory speeds, thereby reducing parasitic horsepower losses and improving overall vehicle fuel economy. Fuel consumption data were compiled for fleets of GSA vehicles. Various motor pool locations were selected, each representing different climatic conditions. On the basis of a total accumulated fleet usage of nearly three million miles, an overall fuel economy improvement of 6 percent to 7 percent was demonstrated. Coincident chassis dynamometer tests were accomplished on selected vehicles to establish the effect of different accessory drive systems on exhaust emissions, and to evaluate the magnitude of the mileage benefits which could be derived.

  12. Adipocyte differentiation-related protein promotes lipid accumulation in goat mammary epithelial cells.

    PubMed

    Shi, H B; Yu, K; Luo, J; Li, J; Tian, H B; Zhu, J J; Sun, Y T; Yao, D W; Xu, H F; Shi, H P; Loor, J J

    2015-10-01

    Milk fat originates from the secretion of cytosolic lipid droplets (CLD) synthesized within mammary epithelial cells. Adipocyte differentiation-related protein (ADRP; gene symbol PLIN2) is a CLD-binding protein that is crucial for synthesis of mature CLD. Our hypothesis was that ADRP regulates CLD production and metabolism in goat mammary epithelial cells (GMEC) and thus plays a role in determining milk fat content. To understand the role of ADRP in ruminant milk fat metabolism, ADRP (PLIN2) was overexpressed or knocked down in GMEC using an adenovirus system. Immunocytochemical staining revealed that ADRP localized to the surface of CLD. Supplementation with oleic acid (OA) enhanced its colocalization with CLD surface and enhanced lipid accumulation. Overexpression of ADRP increased lipid accumulation and the concentration of triacylglycerol in GMEC. In contrast, morphological examination revealed that knockdown of ADRP decreased lipid accumulation even when OA was supplemented. This response was confirmed by the reduction in mass of cellular TG when ADRP was knocked down. The fact that knockdown of ADRP did not completely eliminate lipid accumulation at a morphological level in GMEC without OA suggests that some other compensatory factors may also aid in the process of CLD formation. The ADRP reversed the decrease of CLD accumulation induced by adipose triglyceride lipase. This is highly suggestive of ADRP promoting triacylglycerol stability within CLD by preventing access to adipose triglyceride lipase. Collectively, these data provide direct in vitro evidence that ADRP plays a key role in CLD formation and stability in GMEC. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  13. Carotenoid accumulation in orange-pigmented Capsicum annuum fruit, regulated at multiple levels.

    PubMed

    Rodriguez-Uribe, Laura; Guzman, Ivette; Rajapakse, Wathsala; Richins, Richard D; O'Connell, Mary A

    2012-01-01

    The pericarp of Capsicum fruit is a rich dietary source of carotenoids. Accumulation of these compounds may be controlled, in part, by gene transcription of biosynthetic enzymes. The carotenoid composition in a number of orange-coloured C. annuum cultivars was determined using HPLC and compared with transcript abundances for four carotenogenic enzymes, Psy, LcyB, CrtZ-2, and Ccs determined by qRT-PCR. There were unique carotenoid profiles as well as distinct patterns of transcription of carotenogenic enzymes within the seven orange-coloured cultivars. In one cultivar, 'Fogo', carrying the mutant ccs-3 allele, transcripts were detected for this gene, but no CCS protein accumulated. The premature stop termination in ccs-3 prevented expression of the biosynthetic activity to synthesize the capsanthin and capsorubin forms of carotenoids. In two other orange-coloured cultivars, 'Orange Grande' and 'Oriole', both with wild-type versions of all four carotenogenic enzymes, no transcripts for Ccs were detected and no red pigments accumulated. Finally, in a third case, the orange-coloured cultivar, Canary, transcripts for all four of the wild-type carotenogenic enzymes were readily detected yet no CCS protein appeared to accumulate and no red carotenoids were synthesized. In the past, mutations in Psy and Ccs have been identified as the loci controlling colour in the fruit. Now there is evidence that a non-structural gene may control colour development in Capsicum.

  14. Neurodegeneration with Brain Iron Accumulation

    MedlinePlus

    ... are here Home » Disorders » All Disorders Neurodegeneration with Brain Iron Accumulation Information Page Neurodegeneration with Brain Iron Accumulation Information Page What research is being ...

  15. Influence of Transcutol CG on the skin accumulation and transdermal permeation of ultraviolet absorbers.

    PubMed

    Godwin, Donald A; Kim, Nae-Hwa; Felton, Linda A

    2002-01-01

    The objective of this study was to determine the influence of Transcutol CG concentration on the transdermal permeation and skin accumulation of two ultraviolet (UV) absorbers, 2-hydroxy-4-methoxybenzophenone (oxybenzone) and 2-octyl-4-methoxycinnamate (cinnamate). The concentration of the UV absorber was held constant at 6% (w/w) for all vehicle systems while the concentration of Transcutol CG was varied from 0 to 50% (w/w). Data showed that both UV absorbers exhibited increases in skin accumulation with increasing concentrations of Transcutol CG. Skin accumulation of oxybenzone was significantly (P<0.05) greater than that of cinnamate for all formulations investigated. Oxybenzone skin accumulation ranged from 22.9+/-2.8 microg/mg (0% Transcutol CG) to 80.8+/-27.2 microg/mg (50% Transcutol CG). Cinnamate skin accumulation ranged from 9.0+/-0.9 microg/mg to 39.8+/-12.2 microg/mg at 0 and 50% Transcutol CG, respectively. No significant differences were found in the transdermal permeation of oxybenzone or cinnamate for any of the formulations tested. The results of this study demonstrate that the inclusion of Transcutol CG in sunscreen formulations increases the skin accumulation of the UV absorbers oxybenzone and cinnamate without a concomitant increase in transdermal permeation.

  16. Free cholesterol accumulation impairs antioxidant activities and aggravates apoptotic cell death in menadione-induced oxidative injury.

    PubMed

    Lee, Waisin; Xu, Mingjing; Li, Yue; Gu, Yong; Chen, Jianping; Wong, Derek; Fung, Peter C W; Shen, Jiangang

    2011-10-01

    Although the relationship between hypercholesterolemia and oxidative stress has been extensively investigated, direct evidence regarding to the roles of cholesterol accumulation in the generations of reactive oxygen species (ROS) and apoptotic cell death under oxidative stress is lack. In this study, we investigated productions of superoxide anions (O(2)(-)) and nitric oxide (NO), and apoptotic cell death in wild type Chinese hamster ovary (CHO) cells and cholesterol accumulated CHO cells genetically and chemically. Oxidative stress was induced by menadione challenge. The results revealed that abundance of free cholesterol (FC) promoted menadione-induced O(2)(-) and NO productions. FC accumulation down-regulated eNOS expression but up-regulated NADPH oxidases, and inhibited the activities of superoxide dismutase (SOD) and catalase. Treatment of menadione increased the expressions of iNOS and qp91 phox, enhanced the activities of SOD and catalase in the wild-type CHO cells but inhibited the activity of glutathione peroxidase in the cholesterol accumulated CHO cells. Moreover, FC abundance promoted apoptotic cell death in these cells. Taken together, those results suggest that free cholesterol accumulation aggravates menadione-induced oxidative stress and exacerbates apoptotic cell death. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. Heat accumulation during sequential cortical bone drilling.

    PubMed

    Palmisano, Andrew C; Tai, Bruce L; Belmont, Barry; Irwin, Todd A; Shih, Albert; Holmes, James R

    2016-03-01

    Significant research exists regarding heat production during single-hole bone drilling. No published data exist regarding repetitive sequential drilling. This study elucidates the phenomenon of heat accumulation for sequential drilling with both Kirschner wires (K wires) and standard two-flute twist drills. It was hypothesized that cumulative heat would result in a higher temperature with each subsequent drill pass. Nine holes in a 3 × 3 array were drilled sequentially on moistened cadaveric tibia bone kept at body temperature (about 37 °C). Four thermocouples were placed at the center of four adjacent holes and 2 mm below the surface. A battery-driven hand drill guided by a servo-controlled motion system was used. Six samples were drilled with each tool (2.0 mm K wire and 2.0 and 2.5 mm standard drills). K wire drilling increased temperature from 5 °C at the first hole to 20 °C at holes 6 through 9. A similar trend was found in standard drills with less significant increments. The maximum temperatures of both tools increased from <0.5 °C to nearly 13 °C. The difference between drill sizes was found to be insignificant (P > 0.05). In conclusion, heat accumulated during sequential drilling, with size difference being insignificant. K wire produced more heat than its twist-drill counterparts. This study has demonstrated the heat accumulation phenomenon and its significant effect on temperature. Maximizing the drilling field and reducing the number of drill passes may decrease bone injury. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  18. Ischaemic accumulation of succinate controls reperfusion injury through mitochondrial ROS

    PubMed Central

    Gaude, Edoardo; Aksentijević, Dunja; Sundier, Stephanie Y.; Robb, Ellen L.; Logan, Angela; Nadtochiy, Sergiy M.; Ord, Emily N. J.; Smith, Anthony C.; Eyassu, Filmon; Shirley, Rachel; Hu, Chou-Hui; Dare, Anna J.; James, Andrew M.; Rogatti, Sebastian; Hartley, Richard C.; Eaton, Simon; Costa, Ana S.H.; Brookes, Paul S.; Davidson, Sean M.; Duchen, Michael R.; Saeb-Parsy, Kourosh; Shattock, Michael J.; Robinson, Alan J.; Work, Lorraine M.; Frezza, Christian; Krieg, Thomas; Murphy, Michael P.

    2014-01-01

    Ischaemia-reperfusion (IR) injury occurs when blood supply to an organ is disrupted and then restored, and underlies many disorders, notably heart attack and stroke. While reperfusion of ischaemic tissue is essential for survival, it also initiates oxidative damage, cell death, and aberrant immune responses through generation of mitochondrial reactive oxygen species (ROS)1-5. Although mitochondrial ROS production in IR is established, it has generally been considered a non-specific response to reperfusion1,3. Here, we developed a comparative in vivo metabolomic analysis and unexpectedly identified widely conserved metabolic pathways responsible for mitochondrial ROS production during IR. We showed that selective accumulation of the citric acid cycle (CAC) intermediate succinate is a universal metabolic signature of ischaemia in a range of tissues and is responsible for mitochondrial ROS production during reperfusion. Ischaemic succinate accumulation arises from reversal of succinate dehydrogenase (SDH), which in turn is driven by fumarate overflow from purine nucleotide breakdown and partial reversal of the malate/aspartate shuttle. Upon reperfusion, the accumulated succinate is rapidly re-oxidised by SDH, driving extensive ROS generation by reverse electron transport (RET) at mitochondrial complex I. Decreasing ischaemic succinate accumulation by pharmacological inhibition is sufficient to ameliorate in vivo IR injury in murine models of heart attack and stroke. Thus, we have identified a conserved metabolic response of tissues to ischaemia and reperfusion that unifies many hitherto unconnected aspects of IR injury. Furthermore, these findings reveal a novel pathway for metabolic control of ROS production in vivo, while demonstrating that inhibition of ischaemic succinate accumulation and its oxidation upon subsequent reperfusion is a potential therapeutic target to decrease IR injury in a range of pathologies. PMID:25383517

  19. Mapping the accumulation of co-infiltrating CNS dendritic cells and encephalitogenic T cells during EAE

    PubMed Central

    Clarkson, Benjamin D; Walker, Alec; Harris, Melissa; Rayasam, Aditya; Sandor, Matyas; Fabry, Zsuzsanna

    2014-01-01

    Evidence from experimental autoimmune encephalomyelitis (EAE) suggests that CNS-infiltrating dendritic cells (DCs) are crucial for restimulation of coinfiltrating T cells. Here we systematically quantified and visualized the distribution and interaction of CNS DCs and T cells during EAE. We report marked periventricular accumulation of DCs and myelin-specific T cells during EAE disease onset prior to accumulation in the spinal cord, indicating that the choroid plexus-CSF axis is a CNS entry portal. Moreover, despite emphasis on spinal cord inflammation in EAE and in correspondence with MS pathology, inflammatory lesions containing interacting DCs and T cells are present in specific brain regions. PMID:25288303

  20. The HSP terminator of Arabidopsis thaliana induces a high level of miraculin accumulation in transgenic tomatoes.

    PubMed

    Hirai, Tadayoshi; Kurokawa, Natsuko; Duhita, Narendra; Hiwasa-Tanase, Kyoko; Kato, Kazuhisa; Kato, Ko; Ezura, Hiroshi

    2011-09-28

    High-level accumulation of the target recombinant protein is a significant issue in heterologous protein expression using transgenic plants. Miraculin, a taste-modifying protein, was accumulated in transgenic tomatoes using an expression cassette in which the miraculin gene was expressed by the cauliflower mosaic virus (CaMV) 35S promoter and the heat shock protein (HSP) terminator (MIR-HSP). The HSP terminator was derived from heat shock protein 18.2 in Arabidopsis thaliana . Using this HSP-containing cassette, the miraculin concentration in T0 transgenic tomato lines was 1.4-13.9% of the total soluble protein (TSP), and that in the T1 transgenic tomato line homozygous for the miraculin gene reached 17.1% of the TSP. The accumulation level of the target protein was comparable to levels observed with chloroplast transformation. The high-level accumulation of miraculin in T0 transgenic tomato lines achieved by the HSP terminator was maintained in the successive T1 generation, demonstrating the genetic stability of this accumulation system.

  1. Multiple microscopic approaches demonstrate linkage between chromoplast architecture and carotenoid composition in diverse Capsicum annuum fruit.

    PubMed

    Kilcrease, James; Collins, Aaron M; Richins, Richard D; Timlin, Jerilyn A; O'Connell, Mary A

    2013-12-01

    Increased accumulation of specific carotenoids in plastids through plant breeding or genetic engineering requires an understanding of the limitations that storage sites for these compounds may impose on that accumulation. Here, using Capsicum annuum L. fruit, we demonstrate directly the unique sub-organellar accumulation sites of specific carotenoids using live cell hyperspectral confocal Raman microscopy. Further, we show that chromoplasts from specific cultivars vary in shape and size, and these structural variations are associated with carotenoid compositional differences. Live-cell imaging utilizing laser scanning confocal (LSCM) and confocal Raman microscopy, as well as fixed tissue imaging by scanning and transmission electron microscopy (SEM and TEM), all demonstrated morphological differences with high concordance for the measurements across the multiple imaging modalities. These results reveal additional opportunities for genetic controls on fruit color and carotenoid-based phenotypes. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

  2. NOX1-induced accumulation of reactive oxygen species in abdominal fat-derived mesenchymal stromal cells impinges on long-term proliferation

    PubMed Central

    Sela, M; Tirza, G; Ravid, O; Volovitz, I; Solodeev, I; Friedman, O; Zipori, D; Gur, E; Krelin, Y; Shani, N

    2015-01-01

    Mesenchymal stromal cells (MSCs) are multipotent and can be derived from different adult tissues including fat. Our repeated attempts to produce long-term proliferative cultures of rat abdominal adipose stem cells (aASCs) under normal oxygen concentration (21%) were unsuccessful. We set to examine the events controlling this cytostasis of aASCs and found that it resulted from overproduction of reactive oxygen species (ROS) that led to apoptosis. ROS overproduction in aASCs was accompanied by increased expression of NOX1 but not of NOX2 or NOX4. NOX family members are an important source of intracellular ROS pointing to NOX1 involvement in ROS accumulation. This was verified when aASCs that were grown under 3% oxygen conditions expanded long term, displaying reduced NOX1 expression and decreased ROS accumulation. NOX1 involvement in aASC cytostasis was reaffirmed when cells that were expanded under normoxic conditions in the presence of a specific NOX1 inhibitor, ML171, demonstrated reduced ROS accumulation, reduced apoptosis and long-term expansion. aASC expansion arrest was accompanied also by a weak fat differentiation and migratory potential, which was enhanced by NOX1 inhibition. This suggests an inhibitory role for NOX1-induced ROS overproduction on aASCs, their fat differentiation and migratory potential. In contrast to aASCs, similar cells produced from subcutaneous fat were easily expanded in normoxic cultures, exhibiting low ROS concentrations, a low number of apoptotic cells and improved fat differentiation and migration. Taken together, our results show, for the first time, that NOX1-induced ROS accumulation halts ASC expansion and reduces their differentiation and migratory potential under normoxic conditions. Importantly, this phenotype comprises a tissue-specific signature as it was evident in aASCs but not in subcutaneous ASCs. NOX-induced ROS accumulation and cytokine production by fat are part of the metabolic syndrome. The similarity of this

  3. The accumulation, transformation, and effects of quinestrol in duckweed (Spirodela polyrhiza L.).

    PubMed

    Geng, Qianqian; Li, Tian; Li, Pingliang; Wang, Xin; Chu, Weijing; Ma, Yanan; Ma, Hui; Ni, Hanwen

    2018-09-01

    Potential risk of endocrine disrupting compounds on non-target organisms has received extensive attentions in recent years. The present work aimed to investigate the behavior and effect of a synthetic steroid estrogen quinestrol in duckweed Spirodela polyrhiza L. Experimental results showed that quinestrol could be uptaken, accumulated, and biotransformed into 17 α-ethynylestradiol in S. polyrhiza L. The accumulation of quinestrol had a positive relation to the exposure concentration. The bioaccumulation rate was higher when the duckweed was exposed to quinestrol solutions at low concentrations than at high concentration. While the transformation of quinestrol showed no concentration-dependent manner. Quinestrol reduced the biomass and pigment content and increased superoxide dismutase and catalase activities and malondialdehyde contents in the duckweed. The results demonstrated that quinestrol could be accumulated and biotransformed in aquatic plant S. polyrhiza L. This work would provide supplemental data on the behavior of this steroid estrogen compound in aquatic system. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Radio Frequency Sensing of Particulate Matter Accumulation on a Gasoline Particulate Filter

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Parks, James; Prikhodko, Vitaly Y.; Sappok, Alex

    Filter Sensing Technology’s radio frequency (RF) sensor for particulate filter on-board diagnostics (OBD) was studied on a lean gasoline engine at the National Transportation Research Center (NTRC) at Oak Ridge National Laboratory (ORNL). The response of the RF sensor to particulate matter (PM) or “soot” accumulation on the gasoline particulate filter (GPF) installed in the engine exhaust was evaluated. In addition, end plugs of the GPF were purposely removed, and subsequent changes to the RF sensor measured soot loading on the GPF were characterized. Results from the study showed that the RF sensor can accurately measure soot accumulation on amore » GPF; furthermore, the predicted decreased soot accumulation due to plug removal was detected by the RF sensor. Overall, the studies were short and preliminary in nature; however, clearly, the RF sensor demonstrated the capability of measuring GPF soot loading at a level suitable for use in lean gasoline engine emission control OBD and control.« less

  5. Civil Conflict and Human Capital Accumulation: The Long-Term Effects of Political Violence in Peru

    ERIC Educational Resources Information Center

    Leon, Gianmarco

    2012-01-01

    This paper provides empirical evidence of the persistent effect of exposure to political violence on human capital accumulation. I exploit the variation in conflict location and birth cohorts to identify the long- and short-term effects of the civil war on educational attainment. Conditional on being exposed to violence, the average person…

  6. Chemicals to enhance microalgal growth and accumulation of high-value bioproducts

    PubMed Central

    Yu, Xinheng; Chen, Lei; Zhang, Weiwen

    2015-01-01

    Photosynthetic microalgae have attracted significant attention as they can serve as important sources for cosmetic, food and pharmaceutical products, industrial materials and even biofuel biodiesels. However, current productivity of microalga-based processes is still very low, which has restricted their scale-up application. In addition to various efforts in strain improvement and cultivation optimization, it was proposed that the productivity of microalga-based processes can also be increased using various chemicals to trigger or enhance cell growth and accumulation of bioproducts. Herein, we summarized recent progresses in applying chemical triggers or enhancers to improve cell growth and accumulation of bioproducts in algal cultures. Based on their enhancing mechanisms, these chemicals can be classified into four categories:chemicals regulating biosynthetic pathways, chemicals inducing oxidative stress responses, phytohormones and analogs regulating multiple aspects of microalgal metabolism, and chemicals directly as metabolic precursors. Taken together, the early researches demonstrated that the use of chemical stimulants could be a very effective and economical way to improve cell growth and accumulation of high-value bioproducts in large-scale cultivation of microalgae. PMID:25741321

  7. Breast cancer risk accumulation starts early: prevention must also.

    PubMed

    Colditz, Graham A; Bohlke, Kari; Berkey, Catherine S

    2014-06-01

    Nearly one in four breast cancers is diagnosed before the age of 50, and many early-stage premalignant lesions are present but not yet diagnosed. Therefore, we review evidence to support the strategy that breast cancer prevention efforts must begin early in life. This study follows the literature review methods and format. Exposures during childhood and adolescence affect a woman's long-term risk of breast cancer, but have received far less research attention than exposures that occur later in life. Breast tissue undergoes rapid cellular proliferation between menarche and first full-term pregnancy, and risk accumulates rapidly until the terminal differentiation that accompanies first pregnancy. Evidence on childhood diet and growth in height, and adolescent alcohol intake, among other adolescent factors is related to breast cancer risk and risk of premalignant proliferative benign lesions. Breast cancer prevention efforts will have the greatest effect when initiated at an early age and continued over a lifetime. Gaps in knowledge are identified and deserve increase attention to inform prevention.

  8. Social skills interventions for individuals with autism: evaluation for evidence-based practices within a best evidence synthesis framework.

    PubMed

    Reichow, Brian; Volkmar, Fred R

    2010-02-01

    This paper presents a best evidence synthesis of interventions to increase social behavior for individuals with autism. Sixty-six studies published in peer-reviewed journals between 2001 and July 2008 with 513 participants were included. The results are presented by the age of the individual receiving intervention and by delivery agent of intervention. The findings suggest there is much empirical evidence supporting many different treatments for the social deficits of individuals with autism. Using the criteria of evidence-based practice proposed by Reichow et al. (Journal of Autism and Developmental Disorders, 38:1311-1318, 2008), social skills groups and video modeling have accumulated the evidence necessary for the classifications of established EBP and promising EBP, respectively. Recommendations for practice and areas of future research are provided.

  9. Biota-Sediment Accumulation Factor Data

    EPA Pesticide Factsheets

    The Biota-Sediment Accumulation Factor contains approximately 20,000 biota-sediment accumulation factors (BSAFs) from 20 locations (mostly Superfund sites) for nonionic organic chemicals and pesticides. Fresh, tidal, and marine ecosystems are included in the data.

  10. Small target detection based on difference accumulation and Gaussian curvature under complex conditions

    NASA Astrophysics Data System (ADS)

    Zhang, He; Niu, Yanxiong; Zhang, Hao

    2017-12-01

    Small target detection is a significant subject in infrared search and track and other photoelectric imaging systems. The small target is imaged under complex conditions, which contains clouds, horizon and bright part. In this paper, a novel small target detection method is proposed based on difference accumulation, clustering and Gaussian curvature. Difference accumulation varies from regions. Therefore, after obtaining difference accumulations, clustering is applied to determine whether the pixel belongs to the heterogeneous region, and eliminate heterogeneous region. Then Gaussian curvature is used to separate target from the homogeneous region. Experiments are conducted for verification, along with comparisons to several other methods. The experimental results demonstrate that our method has an advantage of 1-2 orders of magnitude on SCRG and BSF than others. Given that the false alarm rate is 1, the detection probability can be approximately 0.9 by using proposed method.

  11. Carotenoid accumulation in orange-pigmented Capsicum annuum fruit, regulated at multiple levels

    PubMed Central

    Rodriguez-Uribe, Laura; Guzman, Ivette; Rajapakse, Wathsala; Richins, Richard D.; O’Connell, Mary A.

    2012-01-01

    The pericarp of Capsicum fruit is a rich dietary source of carotenoids. Accumulation of these compounds may be controlled, in part, by gene transcription of biosynthetic enzymes. The carotenoid composition in a number of orange-coloured C. annuum cultivars was determined using HPLC and compared with transcript abundances for four carotenogenic enzymes, Psy, LcyB, CrtZ-2, and Ccs determined by qRT-PCR. There were unique carotenoid profiles as well as distinct patterns of transcription of carotenogenic enzymes within the seven orange-coloured cultivars. In one cultivar, ‘Fogo’, carrying the mutant ccs-3 allele, transcripts were detected for this gene, but no CCS protein accumulated. The premature stop termination in ccs-3 prevented expression of the biosynthetic activity to synthesize the capsanthin and capsorubin forms of carotenoids. In two other orange-coloured cultivars, ‘Orange Grande’ and ‘Oriole’, both with wild-type versions of all four carotenogenic enzymes, no transcripts for Ccs were detected and no red pigments accumulated. Finally, in a third case, the orange-coloured cultivar, Canary, transcripts for all four of the wild-type carotenogenic enzymes were readily detected yet no CCS protein appeared to accumulate and no red carotenoids were synthesized. In the past, mutations in Psy and Ccs have been identified as the loci controlling colour in the fruit. Now there is evidence that a non-structural gene may control colour development in Capsicum. PMID:21948863

  12. Long-term accumulation and microdistribution of uranium in the bone and marrow of beagle dog.

    PubMed

    Arruda-Neto, J D T; Manso Guevara, M V; Nogueira, G P; Taricano, I D; Saiki, M; Zamboni, C B; Bonamin, L V; Camargo, S P; Cestari, A C; Deppman, A; Garcia, F; Gouveia, A N; Guzman, F; Helene, O A M; Jorge, S A C; Likhachev, V P; Martins, M N; Mesa, J; Rodriguez, O; Vanin, V R

    2004-08-01

    The accumulation and microdistribution of uranium in the bone and marrow of Beagle dogs were determined by both neutron activation and neutron-fission analysis. The experiment started immediately after the weaning period, lasting till maturity. Two animal groups were fed daily with uranyl nitrate at concentrations of 20 and 100 microg g(-1) food. Of the two measuring techniques, uranium accumulated along the marrow as much as in the bone, contrary to the results obtained with single, acute doses. The role played by this finding for the evaluation of radiobiological long-term risks is discussed. It was demonstrated, by means of a biokinetical approach, that the long-term accumulation of uranium in bone and marrow could be described by a piling up of single dose daily incorporation.

  13. Massive accumulation of luminal protease-deficient axonal lysosomes at Alzheimer's disease amyloid plaques.

    PubMed

    Gowrishankar, Swetha; Yuan, Peng; Wu, Yumei; Schrag, Matthew; Paradise, Summer; Grutzendler, Jaime; De Camilli, Pietro; Ferguson, Shawn M

    2015-07-14

    Through a comprehensive analysis of organellar markers in mouse models of Alzheimer's disease, we document a massive accumulation of lysosome-like organelles at amyloid plaques and establish that the majority of these organelles reside within swollen axons that contact the amyloid deposits. This close spatial relationship between axonal lysosome accumulation and extracellular amyloid aggregates was observed from the earliest stages of β-amyloid deposition. Notably, we discovered that lysosomes that accumulate in such axons are lacking in multiple soluble luminal proteases and thus are predicted to be unable to efficiently degrade proteinaceous cargos. Of relevance to Alzheimer's disease, β-secretase (BACE1), the protein that initiates amyloidogenic processing of the amyloid precursor protein and which is a substrate for these proteases, builds up at these sites. Furthermore, through a comparison between the axonal lysosome accumulations at amyloid plaques and neuronal lysosomes of the wild-type brain, we identified a similar, naturally occurring population of lysosome-like organelles in neuronal processes that is also defined by its low luminal protease content. In conjunction with emerging evidence that the lysosomal maturation of endosomes and autophagosomes is coupled to their retrograde transport, our results suggest that extracellular β-amyloid deposits cause a local impairment in the retrograde axonal transport of lysosome precursors, leading to their accumulation and a blockade in their further maturation. This study both advances understanding of Alzheimer's disease brain pathology and provides new insights into the subcellular organization of neuronal lysosomes that may have broader relevance to other neurodegenerative diseases with a lysosomal component to their pathology.

  14. Modelling past, present and future peatland carbon accumulation across the pan-Arctic region

    NASA Astrophysics Data System (ADS)

    Chaudhary, Nitin; Miller, Paul A.; Smith, Benjamin

    2017-09-01

    Most northern peatlands developed during the Holocene, sequestering large amounts of carbon in terrestrial ecosystems. However, recent syntheses have highlighted the gaps in our understanding of peatland carbon accumulation. Assessments of the long-term carbon accumulation rate and possible warming-driven changes in these accumulation rates can therefore benefit from process-based modelling studies. We employed an individual-based dynamic global ecosystem model with dynamic peatland and permafrost functionalities and patch-based vegetation dynamics to quantify long-term carbon accumulation rates and to assess the effects of historical and projected climate change on peatland carbon balances across the pan-Arctic region. Our results are broadly consistent with published regional and global carbon accumulation estimates. A majority of modelled peatland sites in Scandinavia, Europe, Russia and central and eastern Canada change from carbon sinks through the Holocene to potential carbon sources in the coming century. In contrast, the carbon sink capacity of modelled sites in Siberia, far eastern Russia, Alaska and western and northern Canada was predicted to increase in the coming century. The greatest changes were evident in eastern Siberia, north-western Canada and in Alaska, where peat production hampered by permafrost and low productivity due the cold climate in these regions in the past was simulated to increase greatly due to warming, a wetter climate and higher CO2 levels by the year 2100. In contrast, our model predicts that sites that are expected to experience reduced precipitation rates and are currently permafrost free will lose more carbon in the future.

  15. Tissue accumulation of microplastics in mice and biomarker responses suggest widespread health risks of exposure

    NASA Astrophysics Data System (ADS)

    Deng, Yongfeng; Zhang, Yan; Lemos, Bernardo; Ren, Hongqiang

    2017-04-01

    Microplastics (MPs) are a significant environmental health issue and increasingly greater source of concern. MPs have been detected in oceans, rivers, sediments, sewages, soil and even table salts. MPs exposure on marine organisms and humans has been documented, but information about the toxicity of MPs in mammal is limited. Here we used fluorescent and pristine polystyrene microplastics (PS-MPs) particles with two diameters (5 μm and 20 μm) to investigate the tissue distribution, accumulation, and tissue-specific health risk of MPs in mice. Results indicated that MPs accumulated in liver, kidney and gut, with a tissue-accumulation kinetics and distribution pattern that was strongly depended on the MPs particle size. In addition, analyses of multiple biochemical biomarkers and metabolomic profiles suggested that MPs exposure induced disturbance of energy and lipid metabolism as well as oxidative stress. Interestingly, blood biomarkers of neurotoxicity were also altered. Our results uncovered the distribution and accumulation of MPs across mice tissues and revealed significant alteration in several biomarkers that indicate potential toxicity from MPs exposure. Collectively, our data provided new evidence for the adverse consequences of MPs.

  16. Tissue accumulation of microplastics in mice and biomarker responses suggest widespread health risks of exposure

    PubMed Central

    Deng, Yongfeng; Zhang, Yan; Lemos, Bernardo; Ren, Hongqiang

    2017-01-01

    Microplastics (MPs) are a significant environmental health issue and increasingly greater source of concern. MPs have been detected in oceans, rivers, sediments, sewages, soil and even table salts. MPs exposure on marine organisms and humans has been documented, but information about the toxicity of MPs in mammal is limited. Here we used fluorescent and pristine polystyrene microplastics (PS-MPs) particles with two diameters (5 μm and 20 μm) to investigate the tissue distribution, accumulation, and tissue-specific health risk of MPs in mice. Results indicated that MPs accumulated in liver, kidney and gut, with a tissue-accumulation kinetics and distribution pattern that was strongly depended on the MPs particle size. In addition, analyses of multiple biochemical biomarkers and metabolomic profiles suggested that MPs exposure induced disturbance of energy and lipid metabolism as well as oxidative stress. Interestingly, blood biomarkers of neurotoxicity were also altered. Our results uncovered the distribution and accumulation of MPs across mice tissues and revealed significant alteration in several biomarkers that indicate potential toxicity from MPs exposure. Collectively, our data provided new evidence for the adverse consequences of MPs. PMID:28436478

  17. Choice Rules and Accumulator Networks

    PubMed Central

    2015-01-01

    This article presents a preference accumulation model that can be used to implement a number of different multi-attribute heuristic choice rules, including the lexicographic rule, the majority of confirming dimensions (tallying) rule and the equal weights rule. The proposed model differs from existing accumulators in terms of attribute representation: Leakage and competition, typically applied only to preference accumulation, are also assumed to be involved in processing attribute values. This allows the model to perform a range of sophisticated attribute-wise comparisons, including comparisons that compute relative rank. The ability of a preference accumulation model composed of leaky competitive networks to mimic symbolic models of heuristic choice suggests that these 2 approaches are not incompatible, and that a unitary cognitive model of preferential choice, based on insights from both these approaches, may be feasible. PMID:28670592

  18. Modeling snow accumulation and ablation processes in forested environments

    NASA Astrophysics Data System (ADS)

    Andreadis, Konstantinos M.; Storck, Pascal; Lettenmaier, Dennis P.

    2009-05-01

    The effects of forest canopies on snow accumulation and ablation processes can be very important for the hydrology of midlatitude and high-latitude areas. A mass and energy balance model for snow accumulation and ablation processes in forested environments was developed utilizing extensive measurements of snow interception and release in a maritime mountainous site in Oregon. The model was evaluated using 2 years of weighing lysimeter data and was able to reproduce the snow water equivalent (SWE) evolution throughout winters both beneath the canopy and in the nearby clearing, with correlations to observations ranging from 0.81 to 0.99. Additionally, the model was evaluated using measurements from a Boreal Ecosystem-Atmosphere Study (BOREAS) field site in Canada to test the robustness of the canopy snow interception algorithm in a much different climate. Simulated SWE was relatively close to the observations for the forested sites, with discrepancies evident in some cases. Although the model formulation appeared robust for both types of climates, sensitivity to parameters such as snow roughness length and maximum interception capacity suggested the magnitude of improvements of SWE simulations that might be achieved by calibration.

  19. Therapeutic Targeting of Eosinophil Adhesion and Accumulation in Allergic Conjunctivitis

    PubMed Central

    Baiula, Monica; Bedini, Andrea; Carbonari, Gioia; Dattoli, Samantha Deianira; Spampinato, Santi

    2012-01-01

    Considerable evidence indicates that eosinophils are important effectors of ocular allergy. Increased worldwide prevalence of allergic eye pathologies has stimulated the identification of novel drug targets, including eosinophils and adhesion molecules. Accumulation of eosinophils in the eye is a key event in the onset and maintenance of allergic inflammation and is mediated by different adhesion molecules. Antihistamines with multiple mechanisms of action can be effective during the early and late phases of allergic conjunctivitis by blocking the interaction between β1 integrins and vascular cell adhesion molecule (VCAM)-1. Small molecule antagonists that target key elements in the process of eosinophil recruitment have been identified and reinforce the validity of α4β1 integrin as a therapeutic target. Glucocorticoids are among the most effective drugs for ocular allergy, but their use is limited by adverse effects. Novel dissociated glucocorticoids can prevent eosinophil accumulation and induce apoptosis of eosinophils, making them promising candidates for ophthalmic drugs. This article reviews recent understanding of the role of adhesion molecules in eosinophil recruitment in the inflamed conjunctiva along with effective treatments for allergic conjunctivitis. PMID:23271999

  20. Microscopic Measurements of Axial Accumulation of Red Blood Cells in Capillary Flows Effects of Deformability

    NASA Astrophysics Data System (ADS)

    Sasaki, Takahiro; Seki, Junji; Itano, Tomoaki; Sugihara-Seki, Masako

    2017-11-01

    In the microcirculation, red blood cells (RBCs) are known to accumulate in the region near the central axis of microvessels, which is called the ``axial accumulation''. Although this behavior of RBCs is considered to originate from high deformability of RBCs, there have been few experimental studies on the mechanism. In order to elucidate the effect of RBC deformability on the axial accumulation, we measured the cross-sectional distributions of RBCs flowing through capillary tubes with a high spatial resolution by a newly devised observation system for intact and softened RBCs as well as hardened RBCs to various degrees. It was found that the intact and softened RBCs are concentrated in the small area centered on the tube axis, whereas the hardened RBCs are dispersed widely over the tube cross section dependent on the degree of hardness. These results demonstrate clearly the essential role of the deformability of RBCs in the ``axial accumulation'' of RBCs. JSPS KAKENHI Grant Number 17H03176, Kansai University ORDIST group funds.

  1. How to Say "No" to a Nonword: A Leaky Competing Accumulator Model of Lexical Decision

    ERIC Educational Resources Information Center

    Dufau, Stephane; Grainger, Jonathan; Ziegler, Johannes C.

    2012-01-01

    We describe a leaky competing accumulator (LCA) model of the lexical decision task that can be used as a response/decision module for any computational model of word recognition. The LCA model uses evidence for a word, operationalized as some measure of lexical activity, as input to the "YES" decision node. Input to the "NO" decision node is…

  2. Sediment focusing creates 100-ka cycles in interplanetary dust accumulation on the Ontong Java Plateau

    NASA Astrophysics Data System (ADS)

    Higgins, Sean M.; Anderson, Robert F.; Marcantonio, Franco; Schlosser, Peter; Stute, Martin

    2002-10-01

    The accumulation of extraterrestrial 3He, a tracer for interplanetary dust particles (IDPs), in sediments from the Ontong Java Plateau (OJP; western equatorial Pacific Ocean) has been shown previously to exhibit a regular cyclicity during the late Pleistocene, with a period of ∼100 ka. Those results have been interpreted to reflect periodic variability in the global accretion of IDPs that, in turn, has been linked to changes in the inclination of Earth's orbit with respect to the invariable plane of the solar system. Here we show that the accumulation in OJP sediments of authigenic 230Th, produced by radioactive decay of 234U in seawater, exhibits a 100-ka cyclicity similar in phase and amplitude to that evident in the 3He record. We interpret the similar patterns of 230Th and 3He accumulation to reflect a common origin within the ocean-climate system. Comparing spatial and temporal patterns of sediment accumulation against regional patterns of biological productivity and against the well-established pattern of CaCO3 dissolution in the deep Pacific Ocean leads to the further conclusion that a common 100-ka cycle in accumulation of biogenic, authigenic and extraterrestrial constituents in OJP sediments reflects the influence of climate-related changes in sediment focusing, rather than changes in the rate of production or supply of sedimentary constituents.

  3. Temperature-fluctuation-sensitive accumulative effect of the phase measurement errors in low-coherence interferometry in characterizing arrayed waveguide gratings.

    PubMed

    Zhao, Changyun; Wei, Bing; Yang, Longzhi; Wang, Gencheng; Wang, Yuehai; Jiang, Xiaoqing; Li, Yubo; Yang, Jianyi

    2015-09-20

    We investigate the accumulative effect of the phase measurement errors in characterizing optical multipath components by low-coherence interferometry. The accumulative effect is caused by the fluctuation of the environment temperature, which leads to the variation of the refractive index of the device under test. The resulting phase measurement errors accumulate with the increasing of the phase difference between the two interferometer arms. Our experiments were carried out to demonstrate that the accumulative effect is still obvious even though the thermo-optical coefficient of the device under test is quite small. Shortening the measurement time to reduce the fluctuation of the environment temperature can effectively restrain the accumulative effect. The experiments show that when the scanning speed increases to 4.8 mm/s, the slope of the phase measurement errors decreases to 5.52×10(-8), which means the accumulative effect can be ignored.

  4. East-West Cultural Differences in Context-Sensitivity are Evident in Early Childhood

    ERIC Educational Resources Information Center

    Imada, Toshie; Carlson, Stephanie M.; Itakura, Shoji

    2013-01-01

    Accumulating evidence suggests that North Americans tend to focus on central objects whereas East Asians tend to pay more attention to contextual information in a visual scene. Although it is generally believed that such culturally divergent attention tendencies develop through socialization, existing evidence largely depends on adult samples.…

  5. Ethanol induced astaxanthin accumulation and transcriptional expression of carotenogenic genes in Haematococcus pluvialis.

    PubMed

    Wen, Zewen; Liu, Zhiyong; Hou, Yuyong; Liu, Chenfeng; Gao, Feng; Zheng, Yubin; Chen, Fangjian

    2015-10-01

    Haematococcus pluvialis is one of the most promising natural sources of astaxanthin. However, inducing the accumulation process has become one of the primary obstacles in astaxanthin production. In this study, the effect of ethanol on astaxanthin accumulation was investigated. The results demonstrated that astaxanthin accumulation occurred with ethanol addition even under low-light conditions. The astaxanthin productivity could reach 11.26 mg L(-1) d(-1) at 3% (v/v) ethanol, which was 2.03 times of that of the control. The transcriptional expression patterns of eight carotenogenic genes were evaluated using real-time PCR. The results showed that ethanol greatly enhanced transcription of the isopentenyl diphosphate (IPP) isomerase genes (ipi-1 and ipi-2), which were responsible for isomerization reaction of IPP and dimethylallyl diphosphate (DMAPP). This finding suggests that ethanol induced astaxanthin biosynthesis was up-regulated mainly by ipi-1 and ipi-2 at transcriptional level, promoting isoprenoid synthesis and substrate supply to carotenoid formation. Thus ethanol has the potential to be used as an effective reagent to induce astaxanthin accumulation in H. pluvialis. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Secondary Metabolite Accumulation Associates with Ecological Succession of Endophytic Fungi in Cynomorium songaricum Rupr.

    PubMed

    Cui, Jin-Long; Zhang, Yan-Yan; Vijayakumar, Vinod; Zhang, Gang; Wang, Meng-Liang; Wang, Jun-Hong

    2018-06-06

    Cynomorium songaricum Rupr. is a rare root-parasitic plant distributed in the desert ecosystem. Little is known about the role of endophytes in accumulation of metabolites in C. songaricum. Here, the correlations between the seven active components (total sugars, flavonoids, protocatechuic acid, catechins, tannins, gallic acid, and ursolic acid) and the endophytic fungi of C. songaricum were investigated, and their causal relationships are discussed further. The results showed that the accumulation of these components and the assembly of endophytic fungi changed with different plant developmental stages. Diverse relationships including positive and negative correlation were found among chemicals and endophytic fungal operational taxonomic units based on correlation coefficient matrices, which demonstrated that the accumulation of secondary metabolites in C. songaricum is closely related to the endophytic fungal community composition. These results present new opportunities to deeply understand plant-fungal symbioses and secondary metabolite productions.

  7. Long-term myocardial preservation: effects of hyperkalemia, sodium channel, and Na/K/2Cl cotransport inhibition on extracellular potassium accumulation during hypothermic storage.

    PubMed

    Snabaitis, A K; Shattock, M J; Chambers, D J

    1999-07-01

    We previously demonstrated improved myocardial preservation with polarized (tetrodotoxin-induced), compared with depolarized (hyperkalemia-induced), arrest and hypothermic storage. This study was undertaken to determine whether polarized arrest reduced ionic imbalance during ischemic storage and whether this was influenced by Na+/K +/2Cl- cotransport inhibition. We used the isolated crystalloid perfused working rat heart preparation (1) to measure extracellular K+ accumulation (using a K+-sensitive intramyocardial electrode) during ischemic (control), depolarized (K+ 16 mmol/L), and polarized (tetrodotoxin, 22 micromol/L) arrest and hypothermic (7.5 degrees C) storage (5 hours), (2) to determine dose-dependent (0.1, 1.0, 10 and 100 micromol/L) effects of the Na +/K+/2Cl- cotransport inhibitor, furosemide, on extracellular K+ accumulation during polarized arrest and 7.5 degrees C storage, and (3) to correlate extracellular K+ accumulation to postischemic recovery of cardiac function. Characteristic triphasic profiles of extracellular K+ accumulation were observed in control and depolarized arrested hearts; a significantly attenuated profile with polarized arrested hearts demonstrated reduced extracellular K+ accumulation, correlating with higher postischemic function (recovery of aortic flow was 54% +/-4% [P =.01] compared with 39% +/-3% and 32% +/-3% in depolarized and control hearts, respectively). Furosemide (0.1, 1.0, 10, and 100 micromol/L) modified extracellular K+ accumulation by -18%, -38%, -0.2%, and +9%, respectively, after 30 minutes and by -4%, -27%, +31%, and +42%, respectively, after 5 hours of polarized storage. Recovery of aortic flow was 53% +/-4% (polarized arrest alone), 56% +/-8%, 70% +/-2% (P =.04 vs control), 69% +/-4% (P =.04 vs control), and 65% +/-3% ( P =. 04 vs control), respectively. Polarized arrest was associated with a reduced ionic imbalance (demonstrated by reduced extracellular K+ accumulation) and improved recovery of cardiac

  8. cGMP accumulation causes photoreceptor degeneration in CNG channel deficiency: evidence of cGMP cytotoxicity independently of enhanced CNG channel function.

    PubMed

    Xu, Jianhua; Morris, Lynsie; Thapa, Arjun; Ma, Hongwei; Michalakis, Stylianos; Biel, Martin; Baehr, Wolfgang; Peshenko, Igor V; Dizhoor, Alexander M; Ding, Xi-Qin

    2013-09-11

    Photoreceptor cyclic nucleotide-gated (CNG) channels regulate Ca(2+) influx in rod and cone photoreceptors. cGMP, the native ligand of the photoreceptor CNG channels, has been associated with cytotoxicity when its levels rise above normal due to defects in photoreceptor phosphodiesterase (PDE6) or regulation of retinal guanylyl cyclase (retGC). We found a massive accumulation of cGMP in CNGA3-deficient retina and investigated whether cGMP accumulation plays a role in cone degeneration in CNG channel deficiency. The time course study showed that the retinal cGMP level in Cnga3(-/-);Nrl(-/-) mice with CNGA3 deficiency on a cone-dominant background was sharply increased at postnatal day 8 (P8), peaked around P10-P15, remained high through P30-P60, and returned to near control level at P90. This elevation pattern correlated with photoreceptor apoptotic death, which peaked around P15-P20. In Cnga3(-/-);Gucy2e(-/-) mice lacking retGC1, cone density and expression levels of cone-specific proteins were significantly increased compared with Cnga3(-/-), consistent with a role of cGMP accumulation as the major contributor to cone death caused by CNG channel deficiency. The activity and expression levels of cGMP-dependent protein kinase G (PKG) were significantly increased in Cnga3(-/-);Nrl(-/-) retina compared with Nrl(-/-), suggesting an involvement of PKG regulation in cell death. Our results indicate that cGMP accumulation in photoreceptors can itself exert cytotoxic effect in cones, independently of CNG channel activity and Ca(2+) influx.

  9. Difference in initial dental biofilm accumulation between night and day.

    PubMed

    Dige, Irene; Schlafer, Sebastian; Nyvad, Bente

    2012-12-01

    The study of initial microbial colonization on dental surfaces is a field of intensive research because of the aetiological role of biofilms in oral diseases. Most previous studies of de novo accumulation and composition of dental biofilms in vivo do not differentiate between biofilms formed during day and night. This study hypothesized that there is a diurnal variation in the rate of accumulation of bacteria on solid surfaces in the oral cavity. In situ biofilm from healthy individuals was collected for 12 h during day and night, respectively, subjected to fluorescent in situ hybridization and visualized using confocal laser scanning microscopy. Analysis of the biofilms using stereological methods and digital image analysis revealed a consistent statistically significant difference between both the total number of bacteria and the biovolume in the two 12-h groups (p = 0.012), with the highest accumulation of bacteria during daytime (a factor of 8.8 and 6.1 higher, respectively). Hybridization with probes specific for streptococci and Actinomyces naeslundii indicated a higher proportion of streptococci in biofilms grown during daytime as compared to night-time. No differences could be observed for A. naeslundii. The degree of microbial coverage and the bacterial composition varied considerably between different individuals. The data provide firm evidence that initial biofilm formation decreases during the night, which may reflect differences in the availability of salivary nutrients. This finding is of significant importance when studying population dynamics during experimental dental biofilm formation.

  10. Detection of the Cyanotoxins L-BMAA Uptake and Accumulation in Primary Neurons and Astrocytes.

    PubMed

    Tan, Vanessa X; Mazzocco, Claire; Varney, Bianca; Bodet, Dominique; Guillemin, Tristan A; Bessede, Alban; Guillemin, Gilles J

    2018-01-01

    We show for the first time that a newly developed polyclonal antibody (pAb) can specifically target the cyanotoxin β-methylamino-L-alanine (BMAA) and can be used to enable direct visualization of BMAA entry and accumulation in primary brain cells. We used this pAb to investigate the effect of acute and chronic accumulation, and toxicity of both BMAA and its natural isomer 2,4-diaminobutyric acid (DAB), separately or in combination, on primary cultures of rat neurons. We further present evidence that co-treatment with BMAA and DAB increased neuronal death, as measured by MAP2 fluorescence level, and appeared to reduce BMAA accumulation. DAB is likely to be acting synergistically with BMAA resulting in higher level of cellular toxicity. We also found that glial cells such as microglia and astrocytes are also able to directly uptake BMAA indicating that additional brain cell types are affected by BMAA-induced toxicity. Therefore, BMAA clearly acts at multiple cellular levels to possibly increase the risk of developing neurodegenerative diseases, including neuro- and gliotoxicity and synergetic exacerbation with other cyanotoxins.

  11. Assessment of neutron skyshine near unmodified Accumulator Debuncher storage rings under Mu2e operational conditions

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cossairt, J.Donald; /Fermilab

    2010-12-01

    Preliminary plans for providing the proton beam needed by the proposed Mu2e experiment at Fermilab will require the transport of 8 GeV protons to the Accumulator/Debuncher where they be processed into an intensity and time structure useful for the experiment. The intensities involved are far greater that those encountered with antiprotons of the same kinetic energy in the same beam enclosures under Tevatron Collider operational conditions, the operating parameters for which the physical facilities of the Antiproton Source were designed. This note explores some important ramifications of the proposed operation for radiation safety and demonstrates the need for extensive modificationsmore » of significant portions of the shielding of the Accumulator Debuncher storage rings; notably that underneath the AP Service Buildings AP10, AP30, and AP50. While existing shielding is adequate for the current operating mode of the Accumulator/Debuncher as part of the Antiproton Source used in the Tevatron Collider program, without significant modifications of the shielding configuration in the Accumulator/Debuncher region and/or beam loss control systems far more effective than seen in most applications at Fermilab, the proposed operational mode for Mu2e is not viable for the following reasons: 1. Due to skyshine alone, under normal operational conditions large areas of the Fermilab site would be exposed to unacceptable levels of radiation where most of the Laboratory workforce and some members of the general public who regularly visit Fermilab would receive measurable doses annually, contrary to workforce, public, and DOE expectations concerning the As Low as Reasonably Achievable (ALARA) principle. 2. Under normal operational conditions, a sizeable region of the Fermilab site would also require fencing due to skyshine. The size of the areas involved would likely invite public inquiry about the significant and visible enlargement of Fermilab's posted radiological areas. 3

  12. Radiation-induced effects on the mechanical properties of natural ZrSiO4: double cascade-overlap damage accumulation

    NASA Astrophysics Data System (ADS)

    Beirau, Tobias; Nix, William D.; Pöllmann, Herbert; Ewing, Rodney C.

    2018-05-01

    Several different models are known to describe the structure-dependent radiation-induced damage accumulation process in materials (e.g. Gibbons Proc IEEE 60:1062-1096, 1972; Weber Nuc Instr Met Phys Res B 166-167:98-106, 2000). In the literature, two different models of damage accumulation due to α-decay events in natural ZrSiO4 (zircon) have been described. The direct impact damage accumulation model is based on amorphization occurring directly within the collision cascade. However, the double cascade-overlap damage accumulation model predicts that amorphization will only occur due to the overlap of disordered domains within the cascade. By analyzing the dose-dependent evolution of mechanical properties (i.e., Poisson's ratios, compliance constants, elastic modulus, and hardness) as a measure of the increasing amorphization, we provide support for the double cascade-overlap damage accumulation model. We found no evidence to support the direct impact damage accumulation model. Additionally, the amount of radiation damage could be related to an anisotropic-to-isotropic transition of the Poisson's ratio for stress along and perpendicular to the four-fold c-axis and of the related compliance constants of natural U- and Th-bearing zircon. The isotropification occurs in the dose range between 3.1 × and 6.3 × 1018 α-decays/g.

  13. Radiation-induced effects on the mechanical properties of natural ZrSiO4: double cascade-overlap damage accumulation

    NASA Astrophysics Data System (ADS)

    Beirau, Tobias; Nix, William D.; Pöllmann, Herbert; Ewing, Rodney C.

    2017-11-01

    Several different models are known to describe the structure-dependent radiation-induced damage accumulation process in materials (e.g. Gibbons Proc IEEE 60:1062-1096, 1972; Weber Nuc Instr Met Phys Res B 166-167:98-106, 2000). In the literature, two different models of damage accumulation due to α-decay events in natural ZrSiO4 (zircon) have been described. The direct impact damage accumulation model is based on amorphization occurring directly within the collision cascade. However, the double cascade-overlap damage accumulation model predicts that amorphization will only occur due to the overlap of disordered domains within the cascade. By analyzing the dose-dependent evolution of mechanical properties (i.e., Poisson's ratios, compliance constants, elastic modulus, and hardness) as a measure of the increasing amorphization, we provide support for the double cascade-overlap damage accumulation model. We found no evidence to support the direct impact damage accumulation model. Additionally, the amount of radiation damage could be related to an anisotropic-to-isotropic transition of the Poisson's ratio for stress along and perpendicular to the four-fold c-axis and of the related compliance constants of natural U- and Th-bearing zircon. The isotropification occurs in the dose range between 3.1 × and 6.3 × 1018 α-decays/g.

  14. Quantification of Hepcidin-related Iron Accumulation in the Rat Liver.

    PubMed

    Böser, Preethne; Mordashova, Yulia; Maasland, Mark; Trommer, Isabel; Lorenz, Helga; Hafner, Mathias; Seemann, Dietmar; Mueller, Bernhard K; Popp, Andreas

    2016-02-01

    Hepcidin was originally detected as a liver peptide with antimicrobial activity and it functions as a central regulator in the systemic iron metabolism. Consequently suppression of hepcidin leads to iron accumulation in the liver. AbbVie developed a monoclonal antibody ([mAb]; repulsive guidance molecule [RGMa/c] mAb) that downregulates hepcidin expression by influencing the RGMc/bone morphogenetic protein (BMP)/neogenin receptor complex and causes iron deposition in the liver. In a dose range finding study with RGMa/c mAb, rats were treated with different dose levels for a total of 4 weekly doses. The results of this morphometric analysis in the liver showed that iron accumulation is not homogenous between liver lobes and the left lateral lobe was the most responsive lobe in the rat. Quantitative hepcidin messenger RNA analysis showed that the left lateral lobe was the most responsive lobe showing hepcidin downregulation with increasing antibody dose. In addition, the morphometric analysis had higher sensitivity than the chemical iron extraction and quantification using a colorimetric assay. In conclusion, the Prussian blue stain in combination with semi-quantitative and quantitative morphometric analysis is the most reliable method to demonstrate iron accumulation in the liver compared to direct measurement of iron in unfixed tissue using a colorimetric assay. © The Author(s) 2016.

  15. Sodium accumulation in Atriplex. Final report

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Norton, J.A.; Caldwell, M.M.; Richardson, S.G.

    1984-09-01

    This study was undertaken to determine the ecological significance and the significance to arid land reclamation of sodium accumulation and nonaccumulation in Atriplex. There was a continuum in the genetic tendency of Atriplex canescens to accumulate sodium, from populations which accumulated almost no sodium to populations which accumulated up to 7% in the leaves. There were also substantial differences in sodium uptake between populations of A. tridentata, A. falcata and A. gardneri, with some populations having less than 0.1% leaf sodium and other populations having up to 5 or 6%. In three experiments (a field study, a greenhouse pot studymore » and a hydroponics study) there were no significant differences in salinity tolerance between sodium accumulating and nonaccumulating A. canescens: both genotypes were highly salt tolerant. There was a significant buildup of sodium in the soil beneath sodium accumulating Atriplex plants, both in natural populations and on revegetated oil shale study plots. The sodium buildup was not sufficient to be detrimental to the growth or establishment of most herbaceous species, but with older Atriplex plants or with more saline soil, the buildup could potentially be detrimental. 14 references, 42 figures, 3 tables.« less

  16. Accumulation and effects of metal mixtures in two seaweed species.

    PubMed

    Jarvis, Tayler A; Bielmyer-Fraser, Gretchen K

    2015-05-01

    Metal pollution, due to various anthropogenic sources, may pose a threat to marine ecosystems. Metals can be introduced into food chains via bioaccumulation in primary producers, and may potentially lead to toxic effects. Macroalgae are used as food by a wide variety of organisms, and are therefore extremely important in aquatic systems. This study investigated the accumulation and effects of metals in two macroalgae species. The green seaweed, Ulva lactuca and the red seaweed, Agardhiella subulata were each concurrently exposed to five metals (Cu, Ni, Pb, Cd, and Zn) and U. lactuca was also exposed to each metal individually for 48 h. Metal accumulation in the seaweed was measured, and various photosynthetic parameters were assessed, using imaging pulse amplitude modulated (PAM) fluorometry. Increased metal accumulation occurred in both seaweed species after 48 h exposure to metal mixtures and each metal individually. The distribution of metals in both seaweed species changed with increasing metal exposure concentrations, resulting in higher proportions of Cu and Zn in the metal-exposed groups, as compared to respective controls. Further, U. lactuca accumulated higher concentrations of metals when exposed to each metal individually rather than in metal mixtures, suggesting interactions among metals for uptake and/or bioaccumulation. Significant impairment of photosynthetic parameters in U. lactuca was observed after exposure to 100 and 1000 μg/L metal mixtures, as well as 100 μg/L of either Cd or Cu. These results demonstrate metal bioaccumulation and toxic effects in important primary producers, and may have implications for higher trophic levels. Published by Elsevier Inc.

  17. PML clastosomes prevent nuclear accumulation of mutant ataxin-7 and other polyglutamine proteins

    PubMed Central

    Janer, Alexandre; Martin, Elodie; Muriel, Marie-Paule; Latouche, Morwena; Fujigasaki, Hiroto; Ruberg, Merle; Brice, Alexis; Trottier, Yvon; Sittler, Annie

    2006-01-01

    The pathogenesis of spinocerebellar ataxia type 7 and other neurodegenerative polyglutamine (polyQ) disorders correlates with the aberrant accumulation of toxic polyQ-expanded proteins in the nucleus. Promyelocytic leukemia protein (PML) nuclear bodies are often present in polyQ aggregates, but their relation to pathogenesis is unclear. We show that expression of PML isoform IV leads to the formation of distinct nuclear bodies enriched in components of the ubiquitin-proteasome system. These bodies recruit soluble mutant ataxin-7 and promote its degradation by proteasome-dependent proteolysis, thus preventing the aggregate formation. Inversely, disruption of the endogenous nuclear bodies with cadmium increases the nuclear accumulation and aggregation of mutant ataxin-7, demonstrating their role in ataxin-7 turnover. Interestingly, β-interferon treatment, which induces the expression of endogenous PML IV, prevents the accumulation of transiently expressed mutant ataxin-7 without affecting the level of the endogenous wild-type protein. Therefore, clastosomes represent a potential therapeutic target for preventing polyQ disorders. PMID:16818720

  18. Maximum likelihood decoding analysis of accumulate-repeat-accumulate codes

    NASA Technical Reports Server (NTRS)

    Abbasfar, A.; Divsalar, D.; Yao, K.

    2004-01-01

    In this paper, the performance of the repeat-accumulate codes with (ML) decoding are analyzed and compared to random codes by very tight bounds. Some simple codes are shown that perform very close to Shannon limit with maximum likelihood decoding.

  19. Polyhydroxyalkanoate (PHA) accumulation potential and PHA-accumulating microbial communities in various activated sludge processes of municipal wastewater treatment plants.

    PubMed

    Sakai, K; Miyake, S; Iwama, K; Inoue, D; Soda, S; Ike, M

    2015-01-01

    To clarify the polyhydroxyalkanoate (PHA) accumulation potential and the PHA-accumulating microbial community structure in activated sludge in municipal wastewater treatment plants (WWTPs) and to identify their influential factors. Nine activated sludge samples were collected from municipal WWTPs employing various biological treatment processes. In acetate-fed 24-h batch experiments under aerobic and nitrogen- and phosphorus-limited conditions, polyhydroxybutyrate (PHB) content of activated sludge increased from 0-1·3 wt% to 7·9-24 wt%, with PHB yields of 0·22-0·50 C-mol 3-hydroxybutyrate (C-mol acetate)(-1). Microbial community analyses found that activated sludge samples that accumulated >20 wt% of PHB after 24-h PHA accumulation experiments had >5·0 × 10(8) copies g(-1)-mixed liquor-suspended solid of phaC genes. Results indicated that (i) activated sludge in municipal WWTPs can accumulate up to approx. 20 wt% of PHA without enrichment processes, (ii) PHA accumulation potential of activated sludge varied depending on the operational conditions (treatment processes) of WWTPs, and (iii) phaC gene number can provide a simple indication of PHA accumulation potential. This is the first study to compare the PHA accumulation potential and PHA-accumulating microbial communities in activated sludge of various treatment processes. Our findings may be useful for enhancing the resource recovery potential of wastewater treatment systems. © 2014 The Society for Applied Microbiology.

  20. Methylmercury production and accumulation in urban stormwater ponds and habitat wetlands.

    PubMed

    Strickman, R J; Mitchell, C P J

    2017-02-01

    Stormwater management ponds and created habitat wetlands effectively manage erosion, flooding, and pollutant loadings while providing biodiversity and aesthetic benefits, but these structures are also potential sources of methylmercury (MeHg), a bioaccumulative neurotoxin. While MeHg accumulation has been confirmed in habitat wetlands, the extent of MeHg production and accumulation in stormwater ponds is unknown. Additionally, the fine-scale spatial variation in MeHg in these wetlands has never been explored despite the possibility that cycles of wetting and drying, and the presence of aquatic plants may stimulate methylation at their margins. To address these knowledge gaps, we compared MeHg and inorganic mercury concentrations, the percent of total mercury present as MeHg (%MeHg), and potential mercury methylation rate constants (K meth ) in the sediments of terrestrial-aquatic transects through several stormwater and habitat wetlands. We present novel evidence confirming the in situ production of MeHg in both stormwater ponds and habitat wetlands, but observe no systematic differences across the terrestrial-aquatic gradient, suggesting that routine variations in water level do not alter MeHg production and accumulation. Stormwater ponds effectively trap mercury while converting relatively little to MeHg, as evidenced by lower MeHg concentrations, %-MeHg, and K meth values than habitat wetlands, but often greater inorganic Hg concentrations. The relationship of aquatic vegetation to MeHg accumulation is weak and ambiguous, suggesting plants are not strong drivers of MeHg biogeochemistry in these systems. Although the MeHg hazard associated with individual artificial wetlands is low, they may be important sources of MeHg at the landscape level. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Applications of species accumulation curves in large-scale biological data analysis.

    PubMed

    Deng, Chao; Daley, Timothy; Smith, Andrew D

    2015-09-01

    The species accumulation curve, or collector's curve, of a population gives the expected number of observed species or distinct classes as a function of sampling effort. Species accumulation curves allow researchers to assess and compare diversity across populations or to evaluate the benefits of additional sampling. Traditional applications have focused on ecological populations but emerging large-scale applications, for example in DNA sequencing, are orders of magnitude larger and present new challenges. We developed a method to estimate accumulation curves for predicting the complexity of DNA sequencing libraries. This method uses rational function approximations to a classical non-parametric empirical Bayes estimator due to Good and Toulmin [Biometrika, 1956, 43, 45-63]. Here we demonstrate how the same approach can be highly effective in other large-scale applications involving biological data sets. These include estimating microbial species richness, immune repertoire size, and k -mer diversity for genome assembly applications. We show how the method can be modified to address populations containing an effectively infinite number of species where saturation cannot practically be attained. We also introduce a flexible suite of tools implemented as an R package that make these methods broadly accessible.

  2. Applications of species accumulation curves in large-scale biological data analysis

    PubMed Central

    Deng, Chao; Daley, Timothy; Smith, Andrew D

    2016-01-01

    The species accumulation curve, or collector’s curve, of a population gives the expected number of observed species or distinct classes as a function of sampling effort. Species accumulation curves allow researchers to assess and compare diversity across populations or to evaluate the benefits of additional sampling. Traditional applications have focused on ecological populations but emerging large-scale applications, for example in DNA sequencing, are orders of magnitude larger and present new challenges. We developed a method to estimate accumulation curves for predicting the complexity of DNA sequencing libraries. This method uses rational function approximations to a classical non-parametric empirical Bayes estimator due to Good and Toulmin [Biometrika, 1956, 43, 45–63]. Here we demonstrate how the same approach can be highly effective in other large-scale applications involving biological data sets. These include estimating microbial species richness, immune repertoire size, and k-mer diversity for genome assembly applications. We show how the method can be modified to address populations containing an effectively infinite number of species where saturation cannot practically be attained. We also introduce a flexible suite of tools implemented as an R package that make these methods broadly accessible. PMID:27252899

  3. Organochlorine pesticides accumulation and breast cancer: A hospital-based case-control study.

    PubMed

    He, Ting-Ting; Zuo, An-Jun; Wang, Ji-Gang; Zhao, Peng

    2017-05-01

    The aim of this study is to detect the accumulation status of organochlorine pesticides in breast cancer patients and to explore the relationship between organochlorine pesticides contamination and breast cancer development. We conducted a hospital-based case-control study in 56 patients with breast cancer and 46 patients with benign breast disease. We detected the accumulation level of several organochlorine pesticides products (β-hexachlorocyclohexane, γ-hexachlorocyclohexane, polychlorinated biphenyls-28, polychlorinated biphenyls-52, pentachlorothioanisole, and pp'-dichlorodiphenyldichloroethane) in breast adipose tissues of all 102 patients using gas chromatography. Thereafter, we examined the expression status of estrogen receptor, progesterone receptor, human epidermal growth factor receptor-2 (HER2), and Ki-67 in 56 breast cancer cases by immunohistochemistry. In addition, we analyzed the risk of breast cancer in those patients with organochlorine pesticides contamination using a logistic regression model. Our data showed that breast cancer patients suffered high accumulation levels of pp'-dichlorodiphenyldichloroethane and polychlorinated biphenyls-52. However, the concentrations of pp'-dichlorodiphenyldichloroethane and polychlorinated biphenyls-52 were not related to clinicopathologic parameters of breast cancer. Further logistic regression analysis showed polychlorinated biphenyls-52 and pp'-dichlorodiphenyldichloroethane were risk factors for breast cancer. Our results provide new evidence on etiology of breast cancer.

  4. Sediment accumulation on the Southern California Bight continental margin during the twentieth century

    USGS Publications Warehouse

    Alexander, C.R.; Lee, H.J.

    2009-01-01

    Sediment discharged into the portion of the Southern California Bight extending from Santa Barbara to Dana Point enters a complex system of semi-isolated coastal cells, narrow continental shelves, submarine canyons, and offshore basins. On both the Santa Monica and San Pedro margins, 210Pb accumulation rates decrease in an offshore direction (from ??0.5 g cm-2yr-1 to 0.02 g cm-2yr -1), in concert with a fining in sediment grain size (from 4.5?? to 8.5??), suggesting that offshore transport of wave-resuspended material occurs as relatively dilute nepheloid layers and that hemiplegic sedimentation dominates the supply of sediment to the outer shelf, slope, and basins. Together, these areas are effectively sequestering up to 100% of the annual fluvial input. In contrast to the Santa Monica margin, which does not display evidence of mass wasting as an important process of sediment delivery and redistribution, the San Pedro margin does provide numerous examples of failures and mass wasting, suggesting that intraslope sediment redistribution may play a more important role there. Basin deposits in both areas exhibit evidence of turbidites tentatively associated with both major floods and earthquakes, sourced from either the Redondo Canyon (San Pedro Basin) or Dume Canyon (Santa Monica Basin). On the Palos Verdes shelf, sediment-accumulation rates decrease along and across the shelf away from the White's Point outfall, which has been a major source of contaminants to the shelf deposits. Accumulation rates prior to the construction of the outfall were ??0.2 g cm-2yr-1 and increased 1.5-3.7 times during peak discharges from the outfall in 1971. The distal rate of accumulation has decreased by ??50%, from 0.63 g cm -2yr-1 during the period 1971-1992 to 0.29 g cm -2yr-1 during the period 1992-2003. The proximal rate of accumulation, however, has only decreased ??10%, from 0.83 g cm -2yr-1 during the period 1971-1992 to 0.73 g cm -2yr-1 during the period 1992-2003. Effluent

  5. Test Plan - Solids Accumulation Scouting Studies

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Duignan, M. R.; Steeper, T. J.; Steimke, J. L.

    This plan documents the highlights of the Solids Accumulations Scouting Studies test; a project, from Washington River Protection Solutions (WRPS), that began on February 1, 2012. During the last 12 weeks considerable progress has been made to design and plan methods that will be used to estimate the concentration and distribution of heavy fissile solids in accumulated solids in the Hanford double-shell tank (DST) 241-AW-105 (AW-105), which is the primary goal of this task. This DST will be one of the several waste feed delivery staging tanks designated to feed the Pretreatment Facility (PTF) of the Waste Treatment and Immobilizationmore » Plant (WTP). Note that over the length of the waste feed delivery mission AW-105 is currently identified as having the most fill empty cycles of any DST feed tanks, which is the reason for modeling this particular tank. At SRNL an existing test facility, the Mixing Demonstration Tank, which will be modified for the present work, will use stainless steel particles in a simulant that represents Hanford waste to perform mock staging tanks transfers that will allow solids to accumulate in the tank heel. The concentration and location of the mock fissile particles will be measured in these scoping studies to produce information that will be used to better plan larger scaled tests. Included in these studies is a secondary goal of developing measurement methods to accomplish the primary goal. These methods will be evaluated for use in the larger scale experiments. Included in this plan are the several pretest activities that will validate the measurement techniques that are currently in various phases of construction. Aspects of each technique, e.g., particle separations, volume determinations, topographical mapping, and core sampling, have been tested in bench-top trials, as discussed herein, but the actual equipment to be employed during the full test will need evaluation after fabrication and integration into the test facility.« less

  6. Prodigious degassing of a billion years of accumulated radiogenic helium at Yellowstone

    USGS Publications Warehouse

    Lowenstern, Jacob B.; Evans, William C.; Bergfeld, D.; Hunt, Andrew G.

    2014-01-01

    Helium is used as a critical tracer throughout the Earth sciences, where its relatively simple isotopic systematics is used to trace degassing from the mantle, to date groundwater and to time the rise of continents1. The hydrothermal system at Yellowstone National Park is famous for its high helium-3/helium-4 isotope ratio, commonly cited as evidence for a deep mantle source for the Yellowstone hotspot2. However, much of the helium emitted from this region is actually radiogenic helium-4 produced within the crust by α-decay of uranium and thorium. Here we show, by combining gas emission rates with chemistry and isotopic analyses, that crustal helium-4 emission rates from Yellowstone exceed (by orders of magnitude) any conceivable rate of generation within the crust. It seems that helium has accumulated for (at least) many hundreds of millions of years in Archaean (more than 2.5 billion years old) cratonic rocks beneath Yellowstone, only to be liberated over the past two million years by intense crustal metamorphism induced by the Yellowstone hotspot. Our results demonstrate the extremes in variability of crustal helium efflux on geologic timescales and imply crustal-scale open-system behaviour of helium in tectonically and magmatically active regions.

  7. Gypsum accumulation on carbonate stone

    USGS Publications Warehouse

    McGee, E.S.; Mossotti, V.G.

    1992-01-01

    The accumulation of gypsum on carbonate stone has been investigated through exposure of fresh samples of limestone and marble at monitored sites, through examination of alteration crusts from old buildings and through laboratory experiments. Several factors contribute to gypsum accumulation on carbonate stone. Marble or limestone that is sheltered from direct washing by rain in an urban environment with elevated pollution levels is likely to accumulate a gypsum crust. Crust development may be enhanced if the stone is porous or has an irregular surface area. Gypsum crusts are a surficial alteration feature; gypsum crystals form at the pore opening-air interface, where evaporation is greatest.

  8. Mammography image quality and evidence based practice: Analysis of the demonstration of the inframammary angle in the digital setting.

    PubMed

    Spuur, Kelly; Webb, Jodi; Poulos, Ann; Nielsen, Sharon; Robinson, Wayne

    2018-03-01

    The aim of this study is to determine the clinical rates of the demonstration of the inframammary angle (IMA) on the mediolateral oblique (MLO) view of the breast on digital mammograms and to compare the outcomes with current accreditation standards for compliance. Relationships between the IMA, age, the posterior nipple line (PNL) and compressed breast thickness will be identified and the study outcomes validated using appropriate analyses of inter-reader and inter-rater reliability and variability. Differences in left versus right data were also investigated. A quantitative retrospective study of 2270 randomly selected paired digital mammograms performed by BreastScreen NSW was undertaken. Data was collected by direct measurement and visual analysis. Intra-class correlation analyses were used to evaluate inter- and intra-rater reliability. The IMA was demonstrated on 52.4% of individual and 42.6% of paired mammograms. A linear relationship was found between the posterior nipple line (PNL) and age (p-value <0.001). The PNL was predicted to increase by 0.48 mm for every one year increment in age. The odds of demonstrating the IMA reduced by 2% for every one year increase in age (p-value = 0.001); are 0.4% higher for every 1 mm increase in PNL (p-value = 0.001) and 1.6% lower for every 1 mm increase in compressed breast thickness, (p-value<0.001). There was high inter- and intra-rater reliability for the PNL while there was 100% agreement for the demonstration of the IMA. Analysis of the demonstration of the IMA indicates clinically achievable rates (42.6%) well below that required for compliance (50%-75%) to known worldwide accreditation standards for screening mammography. These standards should be aligned to the reported evidence base. Visualisation of the IMA is impacted negatively by increasing age and compressed breast thickness but positively by breast size (PNL). Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Breast cancer risk accumulation starts early – Prevention must also

    PubMed Central

    Colditz, Graham A; Bohlke, Kari; Berkey, Catherine S.

    2014-01-01

    Purpose Nearly 1 in 4 breast cancers is diagnosed before the age of 50, and many early-stage premalignant lesions are present but not yet diagnosed. Therefore, we review evidence to support the strategy that breast cancer prevention efforts must begin early in life. Methods Literature review Results Exposures during childhood and adolescence affect a woman’s long-term risk of breast cancer, but have received far less research attention than exposures that occur later in life. Breast tissue undergoes rapid cellular proliferation between menarche and first full-term pregnancy, and risk accumulates rapidly until the terminal differentiation that accompanies first pregnancy. Evidence on childhood diet and growth in height, and adolescent alcohol intake, among other adolescent factors are related to breast cancer risk and risk of premalignant proliferative benign lesions. Conclusion Breast cancer prevention efforts will have the greatest effect when initiated at an early age and continued over a lifetime. Gaps in knowledge are identified and deserve increase attention to inform prevention. PMID:24820413

  10. Massive accumulation of luminal protease-deficient axonal lysosomes at Alzheimer’s disease amyloid plaques

    PubMed Central

    Gowrishankar, Swetha; Yuan, Peng; Wu, Yumei; Schrag, Matthew; Paradise, Summer; Grutzendler, Jaime; De Camilli, Pietro; Ferguson, Shawn M.

    2015-01-01

    Through a comprehensive analysis of organellar markers in mouse models of Alzheimer’s disease, we document a massive accumulation of lysosome-like organelles at amyloid plaques and establish that the majority of these organelles reside within swollen axons that contact the amyloid deposits. This close spatial relationship between axonal lysosome accumulation and extracellular amyloid aggregates was observed from the earliest stages of β-amyloid deposition. Notably, we discovered that lysosomes that accumulate in such axons are lacking in multiple soluble luminal proteases and thus are predicted to be unable to efficiently degrade proteinaceous cargos. Of relevance to Alzheimer’s disease, β-secretase (BACE1), the protein that initiates amyloidogenic processing of the amyloid precursor protein and which is a substrate for these proteases, builds up at these sites. Furthermore, through a comparison between the axonal lysosome accumulations at amyloid plaques and neuronal lysosomes of the wild-type brain, we identified a similar, naturally occurring population of lysosome-like organelles in neuronal processes that is also defined by its low luminal protease content. In conjunction with emerging evidence that the lysosomal maturation of endosomes and autophagosomes is coupled to their retrograde transport, our results suggest that extracellular β-amyloid deposits cause a local impairment in the retrograde axonal transport of lysosome precursors, leading to their accumulation and a blockade in their further maturation. This study both advances understanding of Alzheimer’s disease brain pathology and provides new insights into the subcellular organization of neuronal lysosomes that may have broader relevance to other neurodegenerative diseases with a lysosomal component to their pathology. PMID:26124111

  11. Jasmonate response decay and defense metabolite accumulation contributes to age-regulated dynamics of plant insect resistance

    PubMed Central

    Mao, Ying-Bo; Liu, Yao-Qian; Chen, Dian-Yang; Chen, Fang-Yan; Fang, Xin; Hong, Gao-Jie; Wang, Ling-Jian; Wang, Jia-Wei; Chen, Xiao-Ya

    2017-01-01

    Immunity deteriorates with age in animals but comparatively little is known about the temporal regulation of plant resistance to herbivores. The phytohormone jasmonate (JA) is a key regulator of plant insect defense. Here, we show that the JA response decays progressively in Arabidopsis. We show that this decay is regulated by the miR156-targeted SQUAMOSA PROMOTER BINDING PROTEIN-LIKE9 (SPL9) group of proteins, which can interact with JA ZIM-domain (JAZ) proteins, including JAZ3. As SPL9 levels gradually increase, JAZ3 accumulates and the JA response is attenuated. We provide evidence that this pathway contributes to insect resistance in young plants. Interestingly however, despite the decay in JA response, older plants are still comparatively more resistant to both the lepidopteran generalist Helicoverpa armigera and the specialist Plutella xylostella, along with increased accumulation of glucosinolates. We propose a model whereby constitutive accumulation of defense compounds plays a role in compensating for age-related JA-response attenuation during plant maturation. PMID:28067238

  12. Accumulation of Radioactive Cesium Released from Fukushima Daiichi Nuclear Power Plant in Terrestrial Cyanobacteria Nostoc commune

    PubMed Central

    Sasaki, Hideaki; Shirato, Susumu; Tahara, Tomoya; Sato, Kenji; Takenaka, Hiroyuki

    2013-01-01

    The Fukushima Daiichi Nuclear Power Plant accident released large amounts of radioactive substances into the environment and contaminated the soil of Tohoku and Kanto districts in Japan. Removal of radioactive material from the environment is an urgent problem, and soil purification using plants is being considered. In this study, we investigated the ability of 12 seed plant species and a cyanobacterium to accumulate radioactive material. The plants did not accumulate radioactive material at high levels, but high accumulation was observed in the terrestrial cyanobacterium Nostoc commune. In Nihonmatsu City, Fukushima Prefecture, N. commune accumulated 415,000 Bq/kg dry weight 134Cs and 607,000 Bq kg−1 dry weight 137Cs. The concentration of cesium in N. commune tended to be high in areas where soil radioactivity was high. A cultivation experiment confirmed that N. commune absorbed radioactive cesium from polluted soil. These data demonstrated that radiological absorption using N. commune might be suitable for decontaminating polluted soil. PMID:24256969

  13. Phase accumulation tracking algorithm for effective index retrieval of fishnet metamaterials and other resonant guided wave networks

    NASA Astrophysics Data System (ADS)

    Feigenbaum, Eyal; Hiszpanski, Anna M.

    2017-07-01

    A phase accumulation tracking (PAT) algorithm is proposed and demonstrated for the retrieval of the effective index of fishnet metamaterials (FMMs) in order to avoid the multi-branch uncertainty problem. This algorithm tracks the phase and amplitude of the dominant propagation mode across the FMM slab. The suggested PAT algorithm applies to resonant guided wave networks having only one mode that carries the light between the two slab ends, where the FMM is one example of this metamaterials sub-class. The effective index is a net effect of positive and negative accumulated phase in the alternating FMM metal and dielectric layers, with a negative effective index occurring when negative phase accumulation dominates.

  14. Ontogenetic dynamics of mercury accumulation in Northwest Atlantic sea lamprey (Petromyzon marinus)

    USGS Publications Warehouse

    Drevnick, P.E.; Horgan, M.J.; Oris, J.T.; Kynard, B.E.

    2006-01-01

    We examined the ontogenetic dynamics of mercury accumulation in sea lamprey (Petromyzon marinus) from the Connecticut River, USA. Mercury concentrations in eggs (mean 84 ng??g-1 wet weight) were lowest of all life stages and correlated to concentrations in females. There was a higher rate of maternal transfer of mercury to eggs compared with teleosts. Ammocoetes had high mercury concentrations for their trophic level (e.g., mean of age-4 ammocoetes 492 ng??g-1 wet weight). A further investigation of four streams showed that ammocoetes reflected the level of contamination in their nursery streams. Concentrations of mercury decreased during metamorphosis from ammocoete to adult. Mercury concentrations in adults ranged from 83 to 942 ng??g-1 wet weight and, unlike teleosts, showed no relation to sex, length, or weight. We provide evidence from stable isotope analyses that this high variability is due to feeding ecology. There are fundamental differences in mercury accumulation between sea lamprey and teleosts. ?? 2006 NRC Canada.

  15. Lack of Glycogenin Causes Glycogen Accumulation and Muscle Function Impairment.

    PubMed

    Testoni, Giorgia; Duran, Jordi; García-Rocha, Mar; Vilaplana, Francisco; Serrano, Antonio L; Sebastián, David; López-Soldado, Iliana; Sullivan, Mitchell A; Slebe, Felipe; Vilaseca, Marta; Muñoz-Cánoves, Pura; Guinovart, Joan J

    2017-07-05

    Glycogenin is considered essential for glycogen synthesis, as it acts as a primer for the initiation of the polysaccharide chain. Against expectations, glycogenin-deficient mice (Gyg KO) accumulate high amounts of glycogen in striated muscle. Furthermore, this glycogen contains no covalently bound protein, thereby demonstrating that a protein primer is not strictly necessary for the synthesis of the polysaccharide in vivo. Strikingly, in spite of the higher glycogen content, Gyg KO mice showed lower resting energy expenditure and less resistance than control animals when subjected to endurance exercise. These observations can be attributed to a switch of oxidative myofibers toward glycolytic metabolism. Mice overexpressing glycogen synthase in the muscle showed similar alterations, thus indicating that this switch is caused by the excess of glycogen. These results may explain the muscular defects of GSD XV patients, who lack glycogenin-1 and show high glycogen accumulation in muscle. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Recrystallization texture in nickel heavily deformed by accumulative roll bonding

    NASA Astrophysics Data System (ADS)

    Mishin, O. V.; Zhang, Y. B.; Godfrey, A.

    2017-07-01

    The recrystallization behavior of Ni processed by accumulative roll bonding to a total accumulated von Mises strain of 4.8 has been examined, and analyzed with respect to heterogeneity in the deformation microstructure. The regions near the bonding interface are found to be more refined and contain particle deformation zones around fragments of the steel wire brush used to prepare the surface for bonding. Sample-scale gradients are also observed, manifested as differences between the subsurface, intermediate and central layers, where the distributions of texture components are different. These heterogeneities affect the progress of recrystallization. While the subsurface and near-interface regions typically contain lower frequencies of cube-oriented grains than anywhere else in the sample, a strong cube texture forms in the sample during recrystallization, attributed to both a high nucleation rate and fast growth rate of cube-oriented grains. The observations highlight the sensitivity of recrystallization to heterogeneity in the deformation microstructure and demonstrate the importance of characterizing this heterogeneity over several length scales.

  17. Accumulation of contaminants of emerging concern in food crops-part 2: Plant distribution.

    PubMed

    Hyland, Katherine C; Blaine, Andrea C; Higgins, Christopher P

    2015-10-01

    Arid agricultural regions often turn to using treated wastewater (reclaimed water) to irrigate food crops. Concerns arise, however, when considering the potential for persistent contaminants of emerging concern to accumulate into plants intended for human consumption. The present study examined the accumulation of a suite of 9 contaminants of emerging concern into 2 representative food crops, lettuce and strawberry, following uptake via the roots and subsequent distribution to other plant tissues. Calculating accumulation metrics (concentration factors) allowed for comparison of the compartmental affinity of each chemical for each plant tissue compartment. The root concentration factor was found to exhibit a positive linear correlation with the pH-adjusted octanol-water partition coefficient (DOW ) for the target contaminants of emerging concern. Coupled with the concentration-dependent accumulation observed in the roots, this result implies that accumulation of these contaminants of emerging concern into plant roots is driven by passive partitioning. Of the contaminants of emerging concern examined, nonionizable contaminants, such as triclocarban, carbamazepine, and organophosphate flame retardants displayed the greatest potential for translocation from the roots to above-ground plant compartments. In particular, the organophosphate flame retardants displayed increasing affinity for shoots and fruits with decreasing size/octanol-water partition coefficient (KOW ). Cationic diphenhydramine and anionic sulfamethoxazole, once transported to the shoots of the strawberry plant, demonstrated the greatest potential of the contaminants examined to be then carried to the edible fruit portion. © 2015 SETAC.

  18. Identifying change in spatial accumulation of soil salinity in an inland river watershed, China.

    PubMed

    Wang, Yugang; Deng, Caiyun; Liu, Yan; Niu, Ziru; Li, Yan

    2018-04-15

    Soil salinity accumulation is strong in arid areas and it has become a serious environmental problem. Knowledge of the process and spatial changes of accumulated salinity in soil can provide an insight into the spatial patterns of soil salinity accumulation. This is especially useful for estimating the spatial transport of soil salinity at the watershed scale. This study aimed to identify spatial patterns of salt accumulation in the top 20cm soils in a typical inland watershed, the Sangong River watershed in arid northwest China, using geostatistics, spatial analysis technology and the Lorenz curve. The results showed that: (1) soil salt content had great spatial variability (coefficient variation >1.0) in both in 1982 and 2015, and about 56% of the studied area experienced transition the degree of soil salt content from one class to another during 1982-2015. (2) Lorenz curves describing the proportions of soil salinity accumulation (SSA) identified that the boundary between soil salinity migration and accumulation regions was 24.3m lower in 2015 than in 1982, suggesting a spatio-temporal inequality in loading of the soil salinity transport region, indicating significant migration of soil salinity from the upstream to the downstream watershed. (3) Regardless of migration or accumulation region, the mean value of SSA per unit area was 0.17kg/m 2 higher in 2015 than 1982 (p<0.01) and the increasing SSA per unit area in irrigated land significantly increased by 0.19kg/m 2 compared with the migration region. Dramatic accumulation of soil salinity in all land use types was clearly increased by 0.29kg/m 2 in this agricultural watershed during the studied period in the arid northwest of China. This study demonstrates the spatial patterns of soil salinity accumulation, which is particularly useful for estimating the spatial transport of soil salinity at the watershed scale. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Oxidative stress accumulates in adipose tissue during aging and inhibits adipogenesis.

    PubMed

    Findeisen, Hannes M; Pearson, Kevin J; Gizard, Florence; Zhao, Yue; Qing, Hua; Jones, Karrie L; Cohn, Dianne; Heywood, Elizabeth B; de Cabo, Rafael; Bruemmer, Dennis

    2011-04-14

    Aging constitutes a major independent risk factor for the development of type 2 diabetes and is accompanied by insulin resistance and adipose tissue dysfunction. One of the most important factors implicitly linked to aging and age-related chronic diseases is the accumulation of oxidative stress. However, the effect of increased oxidative stress on adipose tissue biology remains elusive. In this study, we demonstrate that aging in mice results in a loss of fat mass and the accumulation of oxidative stress in adipose tissue. In vitro, increased oxidative stress through glutathione depletion inhibits preadipocyte differentiation. This inhibition of adipogenesis is at least in part the result of reduced cell proliferation and an inhibition of G(1)→S-phase transition during the initial mitotic clonal expansion of the adipocyte differentiation process. While phosphorylation of the retinoblastoma protein (Rb) by cyclin/cdk complexes remains unaffected, oxidative stress decreases the expression of S-phase genes downstream of Rb. This silencing of S phase gene expression by increased oxidative stress is mediated through a transcriptional mechanism involving the inhibition of E2F recruitment and transactivation of its target promoters. Collectively, these data demonstrate a previously unrecognized role of oxidative stress in the regulation of adipogenesis which may contribute to age-associated adipose tissue dysfunction.

  20. Oxidative Stress Accumulates in Adipose Tissue during Aging and Inhibits Adipogenesis

    PubMed Central

    Findeisen, Hannes M.; Pearson, Kevin J.; Gizard, Florence; Zhao, Yue; Qing, Hua; Jones, Karrie L.; Cohn, Dianne; Heywood, Elizabeth B.; de Cabo, Rafael; Bruemmer, Dennis

    2011-01-01

    Aging constitutes a major independent risk factor for the development of type 2 diabetes and is accompanied by insulin resistance and adipose tissue dysfunction. One of the most important factors implicitly linked to aging and age-related chronic diseases is the accumulation of oxidative stress. However, the effect of increased oxidative stress on adipose tissue biology remains elusive. In this study, we demonstrate that aging in mice results in a loss of fat mass and the accumulation of oxidative stress in adipose tissue. In vitro, increased oxidative stress through glutathione depletion inhibits preadipocyte differentiation. This inhibition of adipogenesis is at least in part the result of reduced cell proliferation and an inhibition of G1→S-phase transition during the initial mitotic clonal expansion of the adipocyte differentiation process. While phosphorylation of the retinoblastoma protein (Rb) by cyclin/cdk complexes remains unaffected, oxidative stress decreases the expression of S-phase genes downstream of Rb. This silencing of S phase gene expression by increased oxidative stress is mediated through a transcriptional mechanism involving the inhibition of E2F recruitment and transactivation of its target promoters. Collectively, these data demonstrate a previously unrecognized role of oxidative stress in the regulation of adipogenesis which may contribute to age-associated adipose tissue dysfunction. PMID:21533223

  1. Dietary accumulation efficiencies and biotransformation of polybrominated diphenyl ethers in farmed Atlantic salmon (Salmo salar).

    PubMed

    Isosaari, P; Lundebye, A-K; Ritchie, G; Lie, O; Kiviranta, H; Vartiainen, T

    2005-09-01

    The consumer safety of farm-raised salmon could be improved by determining the transfer efficiency of hazardous pollutants from fish feed to the salmon. A controlled feeding trial for 30 weeks was carried out to investigate the transfer of polybrominated diphenyl ethers (PBDEs) in Atlantic salmon (Salmo salar). Using three feed concentrations, an average of 95% of the total PBDE content of feed accumulated in whole salmon. Skinned fillet accumulated 42-59% of the PBDE intake. Equal partitioning according to the lipid content of the tissue was demonstrated. The formation of less brominated PBDEs via preferential debromination from the meta-position was thought to explain the exceptional accumulation efficiencies of BDE 47, BDE 66, BDE 75, BDE 119 and BDE 183 that were either >100% or else increasing with the exposure dose. Monitoring of a larger number of PBDE congeners is recommended to verify the biotransformation routes. The PBDE concentration in salmon of different ages, fed on a known concentration of PBDEs in fish feed, could be predicted by using the accumulation efficiencies determined in this study.

  2. Differential accumulation and pigmenting ability of dietary carotenoids in colorful finches.

    PubMed

    McGraw, Kevin J; Hill, Geoffrey E; Navara, Kristen J; Parker, Robert S

    2004-01-01

    Many animals develop bright red, orange, or yellow carotenoid pigmentation that they use to attract mates. Colorful carotenoid pigments are acquired from the diet and are either directly incorporated as integumentary colorants or metabolized into other forms before deposition. Because animals often obtain several different carotenoids from plant and animal food sources, it is possible that these pigments are accumulated at different levels in the body and may play unique roles in shaping the ultimate color expression of individuals. We studied patterns of carotenoid accumulation and integumentary pigmentation in two colorful finch species--the American goldfinch (Carduelis tristis) and the zebra finch (Taeniopygia guttata). Both species acquire two main hydroxycarotenoids, lutein and zeaxanthin, from their seed diet but transform these into a series of metabolites that are used as colorful pigments in the plumage (goldfinches only) and beak (both species). We conducted a series of carotenoid-supplementation experiments to investigate the relative extent to which lutein and zeaxanthin are accumulated in blood and increase carotenoid coloration in feathers and bare parts. First, we supplemented the diets of both species with either lutein or zeaxanthin and measured plasma pigment status, feather carotenoid concentration (goldfinches only), and integumentary color. Zeaxanthin-supplemented males grew more colorful feathers and beaks than lutein-supplemented males, and in goldfinches incorporated a different ratio of carotenoids in feathers (favoring the accumulation of canary xanthophyll B). We also fed goldfinches different concentrations of a standard lutein-zeaxanthin mix and found that at physiologically normal and high concentrations, birds circulated proportionally more zeaxanthin over lutein than occurred in the diet. Collectively, these results demonstrate that zeaxanthin is preferentially accumulated in the body and serves as a more potent substrate for

  3. Correlation of neural activity with behavioral kinematics reveals distinct sensory encoding and evidence accumulation processes during active tactile sensing.

    PubMed

    Delis, Ioannis; Dmochowski, Jacek P; Sajda, Paul; Wang, Qi

    2018-07-15

    Many real-world decisions rely on active sensing, a dynamic process for directing our sensors (e.g. eyes or fingers) across a stimulus to maximize information gain. Though ecologically pervasive, limited work has focused on identifying neural correlates of the active sensing process. In tactile perception, we often make decisions about an object/surface by actively exploring its shape/texture. Here we investigate the neural correlates of active tactile decision-making by simultaneously measuring electroencephalography (EEG) and finger kinematics while subjects interrogated a haptic surface to make perceptual judgments. Since sensorimotor behavior underlies decision formation in active sensing tasks, we hypothesized that the neural correlates of decision-related processes would be detectable by relating active sensing to neural activity. Novel brain-behavior correlation analysis revealed that three distinct EEG components, localizing to right-lateralized occipital cortex (LOC), middle frontal gyrus (MFG), and supplementary motor area (SMA), respectively, were coupled with active sensing as their activity significantly correlated with finger kinematics. To probe the functional role of these components, we fit their single-trial-couplings to decision-making performance using a hierarchical-drift-diffusion-model (HDDM), revealing that the LOC modulated the encoding of the tactile stimulus whereas the MFG predicted the rate of information integration towards a choice. Interestingly, the MFG disappeared from components uncovered from control subjects performing active sensing but not required to make perceptual decisions. By uncovering the neural correlates of distinct stimulus encoding and evidence accumulation processes, this study delineated, for the first time, the functional role of cortical areas in active tactile decision-making. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. Correlation of Versican Expression, Accumulation, and Degradation during Embryonic Development by Quantitative Immunohistochemistry

    PubMed Central

    Snyder, Jessica M.; Washington, Ida M.; Birkland, Timothy; Chang, Mary Y.; Frevert, Charles W.

    2015-01-01

    Versican, a chondroitin sulfate proteoglycan, is important in embryonic development, and disruption of the versican gene is embryonically lethal in the mouse. Although several studies show that versican is increased in various organs during development, a focused quantitative study on versican expression and distribution during lung and central nervous system development in the mouse has not previously been performed. We tracked changes in versican (Vcan) gene expression and in the accumulation and degradation of versican. Vcan expression and quantitative immunohistochemistry performed from embryonic day (E) 11.5 to E15.5 showed peak Vcan expression at E13.5 in the lungs and brain. Quantitative mRNA analysis and versican immunohistochemistry showed differences in the expression of the versican isoforms in the embryonic lung and head. The expression of Vcan mRNA and accumulation of versican in tissues was complementary. Immunohistochemistry demonstrated co-localization of versican accumulation and degradation, suggesting distinct roles of versican deposition and degradation in embryogenesis. Very little versican mRNA or protein was found in the lungs of 12- to 16-week-old mice but versican accumulation was significantly increased in mice with Pseudomonas aeruginosa lung infection. These data suggest that versican plays an important role in fundamental, overlapping cellular processes in lung development and infection. PMID:26385570

  5. EFFECT OF ACTIVE ACCUMULATION OF CALCIUM AND PHOSPHATE IONS ON THE STRUCTURE OF RAT LIVER MITOCHONDRIA

    PubMed Central

    Greenawalt, John W.; Rossi, Carlo S.; Lehninger, Albert L.

    1964-01-01

    Rat liver mitochondria allowed to accumulate maximal amounts of Ca++ and HPO4 = ions from the suspending medium in vitro during respiration have a considerably higher specific gravity than normal mitochondria and may be easily separated from the latter by isopycnic centrifugation in density gradients of sucrose or cesium chloride. When the mitochondria are allowed to accumulate less than maximal amounts of Ca++ and HPO4 = from the medium, they have intermediate specific gravities which are roughly proportional to their content of calcium phosphate. Maximally "loaded" mitochondria are relatively homogeneous with respect to specific gravity. Correlated biochemical and electron microscopic studies show that Ca++-loaded mitochondria contain numerous dense granules, of which some 85 per cent are over 500 A in diameter. These granules are electron-opaque not only following fixation and staining with heavy metal reagents, but also following fixation with formaldehyde, demonstrating that the characteristic granules in Ca++-loaded mitochondria have intrinsic electron-opacity. The dense granules are almost always located within the inner compartment of the mitochondria and not in the space between the inner and outer membranes. They are frequently located at or near the cristae and they often show electron-transparent "cores." Such granules appear to be made up of clusters of smaller dense particles, but preliminary x-ray diffraction analysis and electron diffraction studies have revealed no evidence of crystallinity in the deposits. The electron-opaque granules decrease in number when the Ca++-loaded mitochondria are incubated with 2,4-dinitrophenol; simultaneously there is discharge of Ca++ and phosphate from the mitochondria into the medium. PMID:14228516

  6. Increased Interleukin-23 in Hashimoto's Thyroiditis Disease Induces Autophagy Suppression and Reactive Oxygen Species Accumulation.

    PubMed

    Zheng, Tingting; Xu, Chengcheng; Mao, Chaoming; Mou, Xiao; Wu, Fei; Wang, Xuefeng; Bu, Ling; Zhou, Yuepeng; Luo, Xuan; Lu, Qingyan; Liu, Hongli; Yuan, Guoyue; Wang, Shengjun; Chen, Deyu; Xiao, Yichuan

    2018-01-01

    Hashimoto's thyroiditis (HT) represents the most common organ-specific autoimmune disease. Inflammatory factors and reactive oxygen species (ROS) play detrimental roles during the pathogenesis of HT. In this study, we found that thyroid follicular cells (TFCs) from HT patients expressed an elevated level of interleukin-23 (IL-23), which contributed to autophagy suppression and ROS accumulation. Additionally, IL-23-induced autophagy suppression and ROS accumulation in human TFCs was attributed to AKT/mTOR/NF-κB signaling pathway activation. Inhibition of either IL-23 by a specific neutralization antibody, or mTOR by rapamycin, or NF-κB by IKK-16, significantly reversed the autophagy suppression and ROS accumulation. These results demonstrate a key role for IL-23 in HT pathogenesis and provide a potential therapeutic strategy against IL-23 or its signaling pathway in HT.

  7. Large spin accumulation and crystallographic dependence of spin transport in single crystal gallium nitride nanowires

    PubMed Central

    Park, Tae-Eon; Park, Youn Ho; Lee, Jong-Min; Kim, Sung Wook; Park, Hee Gyum; Min, Byoung-Chul; Kim, Hyung-jun; Koo, Hyun Cheol; Choi, Heon-Jin; Han, Suk Hee; Johnson, Mark; Chang, Joonyeon

    2017-01-01

    Semiconductor spintronics is an alternative to conventional electronics that offers devices with high performance, low power and multiple functionality. Although a large number of devices with mesoscopic dimensions have been successfully demonstrated at low temperatures for decades, room-temperature operation still needs to go further. Here we study spin injection in single-crystal gallium nitride nanowires and report robust spin accumulation at room temperature with enhanced spin injection polarization of 9%. A large Overhauser coupling between the electron spin accumulation and the lattice nuclei is observed. Finally, our single-crystal gallium nitride samples have a trigonal cross-section defined by the (001), () and () planes. Using the Hanle effect, we show that the spin accumulation is significantly different for injection across the (001) and () (or ()) planes. This provides a technique for increasing room temperature spin injection in mesoscopic systems. PMID:28569767

  8. A novel role for methyl cysteinate, a cysteine derivative, in cesium accumulation in Arabidopsis thaliana

    PubMed Central

    Adams, Eri; Miyazaki, Takae; Hayaishi-Satoh, Aya; Han, Minwoo; Kusano, Miyako; Khandelia, Himanshu; Saito, Kazuki; Shin, Ryoung

    2017-01-01

    Phytoaccumulation is a technique to extract metals from soil utilising ability of plants. Cesium is a valuable metal while radioactive isotopes of cesium can be hazardous. In order to establish a more efficient phytoaccumulation system, small molecules which promote plants to accumulate cesium were investigated. Through chemical library screening, 14 chemicals were isolated as ‘cesium accumulators’ in Arabidopsis thaliana. Of those, methyl cysteinate, a derivative of cysteine, was found to function within the plant to accumulate externally supplemented cesium. Moreover, metabolite profiling demonstrated that cesium treatment increased cysteine levels in Arabidopsis. The cesium accumulation effect was not observed for other cysteine derivatives or amino acids on the cysteine metabolic pathway tested. Our results suggest that methyl cysteinate, potentially metabolised from cysteine, binds with cesium on the surface of the roots or inside plant cells and improve phytoaccumulation. PMID:28230101

  9. Inorganic phosphate accumulation and cadmium detoxification in Klebsiella aerogenes NCTC 418 growing in continuous culture

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Aiking, H.; Stijnman, A.; van Garderen, C.

    1984-02-01

    Klebsiella aerogenes NCTC-418, growing in the presence of cadmium under glucose-, sulfate-, or phosphate-limited conditions in continuous culture, exhibits two different cadmium detoxifying mechanisms. In addition to sulfide formation, increased accumulation of P/sub i/ is demonstrated as a novel mechanism. Intracellular cadmium is always quantitatively counterbalanced by a concerted increase in both inorganic sulfide and P/sub i/ contents of the cells. This led to the conclusion that production of sulfide and accumulation of P/sub i/ are detoxification mechanisms present in K. aerogenes but that their relative importance is crucially dependent on the strain and the growth conditions employed.

  10. Predictive Coding or Evidence Accumulation? False Inference and Neuronal Fluctuations

    PubMed Central

    Friston, Karl J.; Kleinschmidt, Andreas

    2010-01-01

    Perceptual decisions can be made when sensory input affords an inference about what generated that input. Here, we report findings from two independent perceptual experiments conducted during functional magnetic resonance imaging (fMRI) with a sparse event-related design. The first experiment, in the visual modality, involved forced-choice discrimination of coherence in random dot kinematograms that contained either subliminal or periliminal motion coherence. The second experiment, in the auditory domain, involved free response detection of (non-semantic) near-threshold acoustic stimuli. We analysed fluctuations in ongoing neural activity, as indexed by fMRI, and found that neuronal activity in sensory areas (extrastriate visual and early auditory cortex) biases perceptual decisions towards correct inference and not towards a specific percept. Hits (detection of near-threshold stimuli) were preceded by significantly higher activity than both misses of identical stimuli or false alarms, in which percepts arise in the absence of appropriate sensory input. In accord with predictive coding models and the free-energy principle, this observation suggests that cortical activity in sensory brain areas reflects the precision of prediction errors and not just the sensory evidence or prediction errors per se. PMID:20369004

  11. Intestinal HIF2α promotes tissue-iron accumulation in disorders of iron overload with anemia

    PubMed Central

    Anderson, Erik R.; Taylor, Matthew; Xue, Xiang; Ramakrishnan, Sadeesh K.; Martin, Angelical; Xie, Liwei; Bredell, Bryce X.; Gardenghi, Sara; Rivella, Stefano; Shah, Yatrik M.

    2013-01-01

    Several distinct congenital disorders can lead to tissue-iron overload with anemia. Repeated blood transfusions are one of the major causes of iron overload in several of these disorders, including β-thalassemia major, which is characterized by a defective β-globin gene. In this state, hyperabsorption of iron is also observed and can significantly contribute to iron overload. In β-thalassemia intermedia, which does not require blood transfusion for survival, hyperabsorption of iron is the leading cause of iron overload. The mechanism of increased iron absorption in β-thalassemia is unclear. We definitively demonstrate, using genetic mouse models, that intestinal hypoxia-inducible factor-2α (HIF2α) and divalent metal transporter-1 (DMT1) are activated early in the pathogenesis of β-thalassemia and are essential for excess iron accumulation in mouse models of β-thalassemia. Moreover, thalassemic mice with established iron overload had significant improvement in tissue-iron levels and anemia following disruption of intestinal HIF2α. In addition to repeated blood transfusions and increased iron absorption, chronic hemolysis is the major cause of tissue-iron accumulation in anemic iron-overload disorders caused by hemolytic anemia. Mechanistic studies in a hemolytic anemia mouse model demonstrated that loss of intestinal HIF2α/DMT1 signaling led to decreased tissue-iron accumulation in the liver without worsening the anemia. These data demonstrate that dysregulation of intestinal hypoxia and HIF2α signaling is critical for progressive iron overload in β-thalassemia and may be a novel therapeutic target in several anemic iron-overload disorders. PMID:24282296

  12. Noise Reduction by Signal Accumulation

    ERIC Educational Resources Information Center

    Kraftmakher, Yaakov

    2006-01-01

    The aim of this paper is to show how the noise reduction by signal accumulation can be accomplished with a data acquisition system. This topic can be used for student projects. In many cases, the noise reduction is an unavoidable part of experimentation. Several techniques are known for this purpose, and among them the signal accumulation is the…

  13. Burridge-Knopoff Model as an Educational and Demonstrational Tool in Seismicity Prediction

    NASA Astrophysics Data System (ADS)

    Kato, M.

    2007-12-01

    While our effort is ongoing, the fact that predicting destructive earthquakes is not a straightforward business is hard to sell to the general public. Japan is prone to two types of destructive earthquakes; interplate events along Japan Trench and Nankai Trough, and intraplate events that often occur beneath megacities. Periodicity of interplate earthquakes is usually explained by the elastic rebound theory, but we are aware that the historical seismicity along Nankai Trough is not simply periodic. Inland intraplate events have geologically postulated recurrence intervals that are far longer than human lifetime, and we do not have ample knowledge to model their behavior that includes interaction among intraplate and interplate events. To demonstrate that accumulation and release of elastic energy is complex even in a simple system, we propose to utilize the Burridge-Knopoff (BK) model as a demonstrational tool. This original one-dimensional model is easy to construct and handle so that this is also an effective educational tool for classroom use. Our simulator is a simple realization of the original one dimensional BK, which consists of small blocks, springs and a motor. Accumulation and release of strain is visibly observable, and by guessing when the next large events occur we are able to intuitively learn that observation of strain accumulation is only one element in predicting large events. Quantitative analysis of the system is also possible by measuring the movement of blocks. While the long term average of strain energy is controlled by the loading rate, observed seismicity is neither time-predictable nor slip-predictable. Time between successive events is never a constant. Distribution of released energy obeys the power law, similar to Ishimoto- Iida and Gutenberg-Richter Law. This tool is also useful in demonstration of nonlinear behavior of complex system.

  14. Influence of Vegetation on Sediment Accumulation in Restored Tidal Saltmarshes: Field Evidence from the Blackwater Estuary, Essex, UK

    NASA Astrophysics Data System (ADS)

    Price, D.; French, J.; Burningham, H.

    2013-12-01

    Tidal saltmarshes in the UK, and especially in the estuaries of southeast England, have been subject to degradation and erosion over the last few decades, primarily caused by sea-level rise and coastal squeeze due to fixed coastal defences. This is of great concern to a range of coastal stakeholders due to the corresponding loss of functions and services associated with these systems. The coastal defence role that saltmarshes play is well established, and the importance of saltmarsh ecosystems as habitats for birds, fish, and other species is evidenced in the fact that a large proportion of saltmarsh in the southeast England is designated for its scientific and conservation significance. Sediment accumulation is critical for the maintenance of marsh elevation within the tidal frame and for delivery of the aforementioned functions and services. Although many studies have examined accumulation processes, key questions have yet to be fully tested through intensive field observations. One such question relates to the role of vegetation in mediating the retention of newly introduced sediment, as recent research has called into doubt the traditional view of halophytes significantly enhancing rates of sedimentation through wave dissipation. This study presents early results from a project designed to advance our understanding of the processes controlling sediment accumulation. The research focuses on the UK's first large-scale experimental managed flood defence realignment at Tollesbury, Blackwater estuary, Essex. The seawall protecting 21ha of reclaimed agricultural land was artificially breached in 1995 and saltmarsh has progressively developed as tidal exchange has introduced fine sediment into the site. Results from a 12 month monitoring campaign involving hierarchical two-week sediment trap deployments indicates that the role of vegetation in marsh development is less clear cut that previously thought. Gross sedimentation rates were generally higher in non

  15. Light-induced morphological alteration in anthocyanin-accumulating vacuoles of maize cells

    PubMed Central

    Irani, Niloufer G; Grotewold, Erich

    2005-01-01

    Background Plant pigmentation is affected by a variety of factors. Light, an important plant developmental signal, influences the accumulation of anthocyanins primarily through the activation of the transcription factors that regulate the flavonoid biosynthetic pathway. In this study, we utilized maize Black Mexican Sweet (BMS) cells expressing the R and C1 regulators of anthocyanin biosynthesis from a light-insensitive promoter as a means to investigate the existence of additional levels of control of pigmentation by light. Results BMS cells expressing the R and C1 regulators from the CaMV 35S constitutive promoter accumulate anthocyanins when grown in complete darkness, suggesting that the transcription factors R and C1 are sufficient for the transcription of the genes corresponding to the structural enzymes of the pathway, with no requirement for additional light-induced regulators. Interestingly, light induces a "darkening" in the color of the purple anthocyanin pigmentation of transgenic BMS cells expressing R and C1. This change in the pigment hue is not associated with a variation in the levels or types of anthocyanins present, or with an alteration of the transcript levels of several flavonoid biosynthetic genes. However, cytological observations show that light drives unexpected changes in the morphology and distribution of the anthocyanins-containing vacuolar compartments. Conclusion By uncoupling the effect of light on anthocyanin accumulation, we have found light to induce the fusion of anthocyanin-containing vacuoles, the coalescence of anthocyanic vacuolar inclusion (AVI)-like structures contained, and the spread of anthocyanins from the inclusions into the vacuolar sap. Similar light-induced alterations in vacuolar morphology are also evident in the epidermal cells of maize floral whorls accumulating anthocyanins. Our findings suggest a novel mechanism for the action of light on the vacuolar storage of anthocyanin. PMID:15907203

  16. 31 CFR 501.732 - Evidence.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the Enemy Act (TWEA) Penalties § 501.732 Evidence. The applicable evidentiary standard for proceedings... Administrative Law Judge shall admit any relevant and material oral, documentary, or demonstrative evidence. The... by oral or documentary evidence, to submit rebuttal evidence, and to conduct such cross-examination...

  17. Slip distribution, strain accumulation and aseismic slip on the Chaman Fault system

    NASA Astrophysics Data System (ADS)

    Amelug, F.

    2015-12-01

    The Chaman fault system is a transcurrent fault system developed due to the oblique convergence of the India and Eurasia plates in the western boundary of the India plate. To evaluate the contemporary rates of strain accumulation along and across the Chaman Fault system, we use 2003-2011 Envisat SAR imagery and InSAR time-series methods to obtain a ground velocity field in radar line-of-sight (LOS) direction. We correct the InSAR data for different sources of systematic biases including the phase unwrapping errors, local oscillator drift, topographic residuals and stratified tropospheric delay and evaluate the uncertainty due to the residual delay using time-series of MODIS observations of precipitable water vapor. The InSAR velocity field and modeling demonstrates the distribution of deformation across the Chaman fault system. In the central Chaman fault system, the InSAR velocity shows clear strain localization on the Chaman and Ghazaband faults and modeling suggests a total slip rate of ~24 mm/yr distributed on the two faults with rates of 8 and 16 mm/yr, respectively corresponding to the 80% of the total ~3 cm/yr plate motion between India and Eurasia at these latitudes and consistent with the kinematic models which have predicted a slip rate of ~17-24 mm/yr for the Chaman Fault. In the northern Chaman fault system (north of 30.5N), ~6 mm/yr of the relative plate motion is accommodated across Chaman fault. North of 30.5 N where the topographic expression of the Ghazaband fault vanishes, its slip does not transfer to the Chaman fault but rather distributes among different faults in the Kirthar range and Sulaiman lobe. Observed surface creep on the southern Chaman fault between Nushki and north of City of Chaman, indicates that the fault is partially locked, consistent with the recorded M<7 earthquakes in last century on this segment. The Chaman fault between north of the City of Chaman to North of Kabul, does not show an increase in the rate of strain

  18. Quantitation of nanoparticle accumulation in flow using optimized microfluidic chambers

    PubMed Central

    Kusunose, J.; Gagnon, M. K. J.; Seo, J. W.; Ferrara, K. W.

    2014-01-01

    Background The vascular cell adhesion molecule-1 (VCAM-1) targeting peptide sequence, VHPKQHR, is a promising moiety for targeting atherosclerosis through incorporation into nanoparticles such as dendrimers and liposomes. Purpose We aim to develop VCAM-1-targeted nanoparticles that effectively accumulate on the endothelium under shear conditions and to develop robust microfluidic chambers able to house sufficient cells for flow cytometric measurements. Methods Carboxyfluorescein-labeled monomeric VHP-peptide, tetrameric VHP-dendrimers (bisbidentate or radial architecture, with or without N-terminal acetylation) and VHP-peptide liposomes were prepared. Human umbilical vein endothelial cells were treated with nano-particles under 0 or 2.9 dyne/cm2 shear, and particle binding was quantified. Flow chambers cured at various temperatures, with or without glass backings were fabricated, characterized for deformation and applied in experiments. Results Although liposomes accumulated with highest efficiency, dendrimers also demonstrated specific binding. N-terminal acetylation significantly reduced dendrimer binding, and despite shorter movement range, bisbidentate dendrimers outperformed radial dendrimers, suggesting multiple epitope presence within its estimated arm-span of 57 Å. Under shear, while liposome binding increased 300%, dendrimer binding to cells decreased 65%. Through higher temperature curing and glass backing insertion, polydimethylsiloxane flow chambers maintaining rectangular cross-section with aspect-ratio as low as 1:111 were achieved. Conclusion Optimized dendrimers and liposomal nanocarriers specifically accumulated onto cells within microfluidic chambers. PMID:24079404

  19. Toxicity and accumulation of mercury in three species of crabs with different osmoregulatory capacities

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bianchini, A.; Gilles, R.

    1996-07-01

    Synergism between mercury and salinity has been shown in invertebrates. Two authors have tied to correlate salinity effects with a higher or lower accumulation of mercury. Zauke, demonstrated lower mercury levels in several benthic invertebrates from limnic regions of the Elbe estuary when compared to those from Marine regions. On the other hand, Kendall did not report any significant difference in mercury concentrations in benthic macroinvertebrates throughout a salinity gradient in two estuaries from Georgia. In species hyperosmoregulating in diluted media, it could, however, be considered that the high water turnover would favor mercury accumulation. In this context, one couldmore » also expect a relationship between environmental salinity and mercury toxicity in different euryhaline species depending on their osmoregulatory capacities. We have tested this hypothesis analyzing the toxic effects and accumulation of mercury in three euryhaline crabs presenting different osmoregulatory capacities: Eriocheir sinensis (strong hyperosmoregulator), Carcinus maenas (weak hyperosmoregulator) and Cancer pagurus (osmoconformer). 16 refs., 4 figs., 1 tab.« less

  20. Reduced circulating levels of sTWEAK are associated with NAFLD and may affect hepatocyte triglyceride accumulation.

    PubMed

    Lozano-Bartolomé, J; Llauradó, G; Rodriguez, M M; Fernandez-Real, J M; Garcia-Fontgivell, J F; Puig, J; Maymó-Masip, E; Vendrell, J; Chacón, M R

    2016-09-01

    Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome and is strongly associated with obesity, dyslipidaemia and altered glucose regulation. Previous data demonstrated that low circulating levels of tumour necrosis factor weak inducer of apoptosis (sTWEAK) were associated with obesity, diabetes and insulin resistance, all traits associated with an increased risk of NALFD. Circulating sTWEAK levels are expected to be reduced in the presence of NAFLD. We aimed to explore the relationship between NAFLD and circulating sTWEAK levels in obese patients, and to evaluate the effect of sTWEAK on hepatocyte triglyceride accumulation.Design setting and patients:This is an observational case-control study performed in n=112 severely obese patients evaluated for NAFLD by abdominal ultrasound and n=32 non-obese patients without steatosis. Serum sTWEAK concentrations were measured by ELISA. Multivariable analyses were performed to determine the independent predictors of NAFLD. We analysed TWEAK and Fn14 protein expression in liver biopsies by western blotting and immunohistochemistry. An immortalized primary human hepatocyte cell line (HHL) was used to evaluate the effect of sTWEAK on triglyceride accumulation. We observed a reduction in serum circulating sTWEAK concentrations with the presence of liver steatosis. On multivariable analysis, lower sTWEAK concentrations were independently associated with the presence of NAFLD (odds ratio (OR)=0.023; 95% confidence interval: 0.001-0.579; P<0.022). In human hepatocytes, sTWEAK administration reduced fat accumulation as demonstrated by the reduction in palmitic acid-induced accumulation of triglyceride and the decreased expression of cluster of differentiation 36 (CD36) and perilipin 1 and 2 (PLIN1 and PLIN2) genes. Decreased sTWEAK concentrations are independently associated with the presence of NAFLD. This is concordant with the observation that TWEAK reduces lipid accumulation in human

  1. Enhanced lipid accumulation of green microalga Scenedesmus sp. by metal ions and EDTA addition.

    PubMed

    Ren, Hong-Yu; Liu, Bing-Feng; Kong, Fanying; Zhao, Lei; Xie, Guo-Jun; Ren, Nan-Qi

    2014-10-01

    Effects of Fe(3+) (0-0.12 g/L), Mg(2+) (0-0.73 g/L) and Ca(2+) (0-0.98 g/L) on the biomass and lipid accumulation of heterotrophic microalgae were investigated in dark environment. The biomass and lipid production exhibited an increasing trend with increasing the concentrations of metal ions. In cultures with 1.2 × 10(-3) g/L Fe(3+), 7.3 × 10(-3) g/L Mg(2+) and 9.8 × 10(-4) g/L Ca(2+), the maximum biomass, total lipid content and lipid productivity reached 3.49 g/L, 47.4% and 275.7 mg/L/d, respectively. More importantly, EDTA addition (1.0 × 10(-3) g/L) could enhance the solubility of metal ions (iron and calcium) and increase their availability by microalgae, which evidently promote the lipid accumulation. Compared with the control, the total lipid content and lipid productivity increased 28.2% and 29.7%, respectively. These show that appropriate concentrations of metal ions and EDTA in the culture medium were beneficial to lipid accumulation of heterotrophic Scenedesmus sp. cells. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Reduction of B-integral accumulation in lasers

    DOEpatents

    Meyerhofer, David D.; Konoplev, Oleg A.

    2000-01-01

    A pulsed laser is provided wherein the B-integral accumulated in the laser pulse is reduced using a semiconductor wafer. A laser pulse is generated by a laser pulse source. The laser pulse passes through a semiconductor wafer that has a negative nonlinear index of refraction. Thus, the laser pulse accumulates a negative B-integral. The laser pulse is then fed into a laser amplification medium, which has a positive nonlinear index of refraction. The laser pulse may make a plurality of passes through the laser amplification medium and accumulate a positive B-integral during a positive non-linear phase change. The semiconductor and laser pulse wavelength are chosen such that the negative B-integral accumulated in the semiconductor wafer substantially cancels the positive B-integral accumulated in the laser amplification medium. There may be additional accumulation of positive B-integral if the laser pulse passes through additional optical mediums such as a lens or glass plates. Thus, the effects of self-phase modulation in the laser pulse are substantially reduced.

  3. The Quality Improvement Demonstration Study: An example of evidence-based policy-making in practice

    PubMed Central

    Shimkhada, Riti; Peabody, John W; Quimbo, Stella A; Solon, Orville

    2008-01-01

    unanticipated findings; introducing sustainable policy interventions based on the reform agenda; and providing results in real-time to policy makers through a combination of venues. Conclusion QIDS demonstrates that a large, prospective, randomized controlled policy experiment can be successfully implemented at a national level as part of sectoral reform. While we believe policy experiments should be used to generate evidence-based health policy, to do this requires opportunity and trust, strong collaborative relationships, and timing. This study nurtures the growing attitude that translation of scientific findings from the bedside to the community can be done successfully and that we should raise the bar on project evaluation and the policy-making process. PMID:18364050

  4. Accumulation of potassium in scala vestibuli perilymph of the mammalian cochlea.

    PubMed

    Salt, A N; Ohyama, K

    1993-01-01

    Movements of potassium (K+) were monitored during perfusion of either the scala tympani (ST) or the scala vestibuli (SV) of the guinea pig cochlea with a solution containing 15 mmol/LK+. A highly asymmetric clearance of K+ was observed, with K+ rapidly being taken up from the ST and allowed to accumulate in the SV. Under some conditions the SV K+ concentration could exceed that in the perfused ST. These observations are believed to result from the distortion of passive K+ diffusion by the high circulating current of K+ that is part of the transduction process. Calculations are presented to demonstrate that circulating fluxes are of sufficient magnitude to generate the results observed. The high rate of circulating K+ current is probably also responsible for the difference in physiologic K+ concentration between the ST and SV, in which the ST perilymph K+ concentration is typically found to be half that of the SV. A clearance of K+ from the ST and its eventual accumulation in the SV could play a role in how the ear responds to abnormal ion concentrations, such as may occur in Meniere's disease. It is proposed that an accumulation of K+ in the SV would result in vestibular dysfunction that might contribute to the vestibular symptoms of the disease.

  5. Effects of lead exposure before pregnancy and dietary calcium during pregnancy on fetal development and lead accumulation.

    PubMed Central

    Han, S; Pfizenmaier, D H; Garcia, E; Eguez, M L; Ling, M; Kemp, F W; Bogden, J D

    2000-01-01

    Millions of women of child-bearing age have substantial bone lead stores due to lead exposure as children. Dietary calcium ingested simultaneously with lead exposure can reduce lead absorption and accumulation. However, the effects of dietary calcium on previously accumulated maternal lead stores and transfer to the fetus have not been investigated. We studied the effects of lead exposure of female rats at an early age on fetal development during a subsequent pregnancy. We gave 5-week-old female Sprague-Dawley rats lead as the acetate in their drinking water for 5 weeks; controls received equimolar sodium acetate. This was followed by a 1-month period without lead exposure before mating. We randomly assigned pregnant rats (n = 39) to diets with a deficient (0.1%) or normal (0.5%) calcium content during pregnancy. A total of 345 pups were delivered alive. Lead-exposed dams and their pups had significantly higher blood lead concentrations than controls, but the concentrations were in the range of those found in many pregnant women. Pups born to dams fed the calcium-deficient diet during pregnancy had higher blood and organ lead concentrations than pups born to dams fed the 0. 5% calcium diet. Pups born to lead-exposed dams had significantly (p<0.0001) lower mean birth weights and birth lengths than controls. There were significant inverse univariate associations between dam or pup organ lead concentrations and birth weight or length. The 0.5% calcium diet did not increase in utero growth. Stepwise regression analysis demonstrated that greater litter size and female sex were significantly associated with reduced pup birth weight and length. However, lead exposure that ended well before pregnancy was significantly (p<0.0001) associated with reduced birth weight and length, even after litter size, pup sex, and dam weight gain during pregnancy were included in the regression analysis. The data demonstrate that an increase in dietary calcium during pregnancy can reduce

  6. Effect of collagen turnover on the accumulation of advanced glycation end products.

    PubMed

    Verzijl, N; DeGroot, J; Thorpe, S R; Bank, R A; Shaw, J N; Lyons, T J; Bijlsma, J W; Lafeber, F P; Baynes, J W; TeKoppele, J M

    2000-12-15

    Collagen molecules in articular cartilage have an exceptionally long lifetime, which makes them susceptible to the accumulation of advanced glycation end products (AGEs). In fact, in comparison to other collagen-rich tissues, articular cartilage contains relatively high amounts of the AGE pentosidine. To test the hypothesis that this higher AGE accumulation is primarily the result of the slow turnover of cartilage collagen, AGE levels in cartilage and skin collagen were compared with the degree of racemization of aspartic acid (% d-Asp, a measure of the residence time of a protein). AGE (N(epsilon)-(carboxymethyl)lysine, N(epsilon)-(carboxyethyl)lysine, and pentosidine) and % d-Asp concentrations increased linearly with age in both cartilage and skin collagen (p < 0.0001). The rate of increase in AGEs was greater in cartilage collagen than in skin collagen (p < 0.0001). % d-Asp was also higher in cartilage collagen than in skin collagen (p < 0.0001), indicating that cartilage collagen has a longer residence time in the tissue, and thus a slower turnover, than skin collagen. In both types of collagen, AGE concentrations increased linearly with % d-Asp (p < 0.0005). Interestingly, the slopes of the curves of AGEs versus % d-Asp, i.e. the rates of accumulation of AGEs corrected for turnover, were identical for cartilage and skin collagen. The present study thus provides the first experimental evidence that protein turnover is a major determinant in AGE accumulation in different collagen types. From the age-related increases in % d-Asp the half-life of cartilage collagen was calculated to be 117 years and that of skin collagen 15 years, thereby providing the first reasonable estimates of the half-lives of these collagens.

  7. Giant edge spin accumulation in a symmetric quantum well with two subbands

    NASA Astrophysics Data System (ADS)

    Khaetskii, Alexander; Egues, J. Carlos

    We have studied the edge spin accumulation due to an electric current in a high mobility two-dimensional electron gas formed in a symmetric well with two subbands. This study is strongly motivated by recent experiments which demonstrated the spin accumulation near the edges of a symmetric bilayer GaAs structure in contrast to no effect in a single-layer configuration. The intrinsic mechanism of the spin-orbit interaction we consider arises from the coupling between two subband states of opposite parities. Following the method developed in, we show that the presence of a gap in the system (i.e., the energy separation between the two subband bottoms) changes drastically the picture of the edge spin accumulation. We obtain a parametrically large magnitude of the edge spin density for a two-subband well as compared to the usual single-subband structure, and show that by changing the gap from zero up to 1 ÷2 K, the magnitude of the effect changes by three orders of magnitude. It opens up the possibility for the design of new interesting spintronic devices. We acknowledge financial support from FAPESP.

  8. Low Medium pH Value Enhances Anthocyanin Accumulation in Malus Crabapple Leaves

    PubMed Central

    Tian, Ji; Jin, Kaina; Yao, Yuncong

    2014-01-01

    Anthocyanin is a critical factor involved in coloration of plant tissues, but the mechanism how medium pH values affect anthocyanin accumulation in woody plants is unknown. We analyzed anthocyanin composition and the expression of elements encoding anthocyanin and flavonols biosynthesis underlying different medium pH values by using three different leave color type cultivars. HPLC analysis demonstrated that high medium pH values treatment induced a dramatic decrease in the concentration of cyaniding in crabapple leaves. Conversely, the high medium pH values induced up-regulation of the content of flavones and flavonols, suggesting that low pH treatment-induced anthocyanin accumulation. Quantitative real time PCR experiment showed the expression level of anthocyanidin synthase (McANS) and uridine diphosphate glucose flavonoid 3-O-glucosyltransferase (McUFGT) was up-regulated by low pH values treatment, and high medium pH value treatment up-regulate the transcription level of flavonol synthase (McFLS). Meanwhile, several MYB TFs have been suggested in the regulation of pH responses. These results strongly indicate that the low pH treatment-induced anthocyanin accumulation is mediated by the variation of mRNA transcription of the anthocyanin biosynthetic genes. PMID:24914811

  9. Programmed Death 1 Regulates Memory Phenotype CD4 T Cell Accumulation, Inhibits Expansion of the Effector Memory Phenotype Subset and Modulates Production of Effector Cytokines

    PubMed Central

    Charlton, Joanna J.; Tsoukatou, Debbie; Mamalaki, Clio; Chatzidakis, Ioannis

    2015-01-01

    Memory phenotype CD4 T cells are found in normal mice and arise through response to environmental antigens or homeostatic mechanisms. The factors that regulate the homeostasis of memory phenotype CD4 cells are not clear. In the present study we demonstrate that there is a marked accumulation of memory phenotype CD4 cells, specifically of the effector memory (TEM) phenotype, in lymphoid organs and tissues of mice deficient for the negative co-stimulatory receptor programmed death 1 (PD-1). This can be correlated with decreased apoptosis but not with enhanced homeostatic turnover potential of these cells. PD-1 ablation increased the frequency of memory phenotype CD4 IFN-γ producers but decreased the respective frequency of IL-17A-producing cells. In particular, IFN-γ producers were more abundant but IL-17A producing cells were more scarce among PD-1 KO TEM-phenotype cells relative to WT. Transfer of peripheral naïve CD4 T cells suggested that accumulated PD-1 KO TEM-phenotype cells are of peripheral and not of thymic origin. This accumulation effect was mediated by CD4 cell-intrinsic mechanisms as shown by mixed bone marrow chimera experiments. Naïve PD-1 KO CD4 T cells gave rise to higher numbers of TEM-phenotype lymphopenia-induced proliferation memory cells. In conclusion, we provide evidence that PD-1 has an important role in determining the composition and functional aspects of memory phenotype CD4 T cell pool. PMID:25803808

  10. S1PR1 is crucial for accumulation of regulatory T cells in tumors via STAT3

    PubMed Central

    Priceman, Saul J.; Shen, Shudan; Wang, Lin; Deng, Jiehui; Yue, Chanyu; Kujawski, Maciej; Yu, Hua

    2014-01-01

    Summary S1PR1 signaling has been shown to restrain the number and function of Tregs in the periphery under physiological conditions and in colitis models, but its role in regulating tumor-associated T cells is unknown. Here, we show that S1PR1 signaling in T cells drives Treg accumulation in tumors, limits CD8+ T cell recruitment and activation, and promotes tumor growth. S1PR1 intrinsic in T cells affects Tregs, but not CD8+ T cells, as demonstrated by adoptive transfer models and transient pharmacological S1PR1 modulation. We further investigated the molecular mechanism(s) underlying S1PR1-mediated Treg accumulation in tumors, showing that increasing S1PR1 in CD4+ T cells promotes STAT3 activation and JAK/STAT3-dependent Treg tumor migration. Furthermore functionally ablating STAT3 in T cells diminishes tumor-associated Treg accumulation and tumor growth. Our study demonstrates a stark contrast of the consequences by the same signaling receptor, namely S1PR1, in regulating Tregs in the periphery and in tumors. PMID:24630990

  11. Hydrogeological influences on petroleum accumulations in the Arabian Gulf

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Vizgirda, J.; Burke, L.

    1995-08-01

    The stratigraphic and topographic conditions in the Arabian Gulf are appropriate for the instigation and maintenance of an active hydrodynamic regime. The setting is that of a gentle basin surrounded by topographic highs. The central Arabian highlands to the west-southwest, the Tarus-Zagros mountains to the north, and the Oman mountains to the east rim the structural low occupied by the Gulf. Elevations in these areas reach maximum values of approximately 1000 meters. Paleozoic through Cenozoic strata stretch continuously across the basin, are relatively unfaulted, and outcrop in the topographic highs. Such a setting is propitious for a regional hydrodynamic systemmore » with meteoric recharge in the topographic highs and discharge in the middle of the Gulf. The prolific oil and gas accumulations of this region would be subject to influence by these hydrodynamic processes. The existence of such a hydrodynamic regime is documented by a variety of evidence, including potentiometric data, water salinity measurements, and observed tilts in oil-water contacts. Potentiometric data for several Tertiary and Cretaceous units on the Arabian platform, in the Gulf, and in Iraq show a pattern of consistently decreasing potential from topographic highs to lows. Water salinities show a consistent, but inverse, variation with the potentiometric data. Tilted oil-water contacts in Cretaceous and Jurassic reservoirs are observed in several fields of the Gulf region. The direction and magnitude of the observed tilts are consistent with the water potential and salinity data, and suggest that petroleum accumulations are being influenced by a regional hydrodynamic drive. Basin modelling is used to simulate petroleum generation and migration scenarios, and to integrate these histories with the structural evolution of the Gulf. The integrated modelling study illustrates the influence of hydrodynamic processes on the distribution of petroleum accumulations.« less

  12. Demonstration of the spin solar cell and spin photodiode effect

    PubMed Central

    Endres, B.; Ciorga, M.; Schmid, M.; Utz, M.; Bougeard, D.; Weiss, D.; Bayreuther, G.; Back, C.H.

    2013-01-01

    Spin injection and extraction are at the core of semiconductor spintronics. Electrical injection is one method of choice for the creation of a sizeable spin polarization in a semiconductor, requiring especially tailored tunnel or Schottky barriers. Alternatively, optical orientation can be used to generate spins in semiconductors with significant spin-orbit interaction, if optical selection rules are obeyed, typically by using circularly polarized light at a well-defined wavelength. Here we introduce a novel concept for spin injection/extraction that combines the principle of a solar cell with the creation of spin accumulation. We demonstrate that efficient optical spin injection can be achieved with unpolarized light by illuminating a p-n junction where the p-type region consists of a ferromagnet. The discovered mechanism opens the window for the optical generation of a sizeable spin accumulation also in semiconductors without direct band gap such as Si or Ge. PMID:23820766

  13. Inference and interrogation of a coregulatory network in the context of lipid accumulation in Yarrowia lipolytica.

    PubMed

    Trébulle, Pauline; Nicaud, Jean-Marc; Leplat, Christophe; Elati, Mohamed

    2017-01-01

    Complex phenotypes, such as lipid accumulation, result from cooperativity between regulators and the integration of multiscale information. However, the elucidation of such regulatory programs by experimental approaches may be challenging, particularly in context-specific conditions. In particular, we know very little about the regulators of lipid accumulation in the oleaginous yeast of industrial interest Yarrowia lipolytica . This lack of knowledge limits the development of this yeast as an industrial platform, due to the time-consuming and costly laboratory efforts required to design strains with the desired phenotypes. In this study, we aimed to identify context-specific regulators and mechanisms, to guide explorations of the regulation of lipid accumulation in Y. lipolytica . Using gene regulatory network inference, and considering the expression of 6539 genes over 26 time points from GSE35447 for biolipid production and a list of 151 transcription factors, we reconstructed a gene regulatory network comprising 111 transcription factors, 4451 target genes and 17048 regulatory interactions (YL-GRN-1) supported by evidence of protein-protein interactions. This study, based on network interrogation and wet laboratory validation (a) highlights the relevance of our proposed measure, the transcription factors influence, for identifying phases corresponding to changes in physiological state without prior knowledge (b) suggests new potential regulators and drivers of lipid accumulation and (c) experimentally validates the impact of six of the nine regulators identified on lipid accumulation, with variations in lipid content from +43.2% to -31.2% on glucose or glycerol.

  14. Photodynamic Therapy Can Induce a Protective Innate Immune Response against Murine Bacterial Arthritis via Neutrophil Accumulation

    PubMed Central

    Tanaka, Masamitsu; Mroz, Pawel; Dai, Tianhong; Huang, Liyi; Morimoto, Yuji; Kinoshita, Manabu; Yoshihara, Yasuo; Nemoto, Koichi; Shinomiya, Nariyoshi; Seki, Suhji; Hamblin, Michael R.

    2012-01-01

    Background Local microbial infections induced by multiple-drug-resistant bacteria in the orthopedic field can be intractable, therefore development of new therapeutic modalities is needed. Photodynamic therapy (PDT) is a promising alternative modality to antibiotics for intractable microbial infections, and we recently reported that PDT has the potential to accumulate neutrophils into the infected site which leads to resolution of the infection. PDT for cancer has long been known to be able to stimulate the innate and adaptive arms of the immune system. Methodology/Principal Findings In the present study, a murine methicillin-resistant Staphylococcus aureus (MRSA) arthritis model using bioluminescent MRSA and polystyrene microparticles was established, and both the therapeutic (Th-PDT) and preventive (Pre-PDT) effects of PDT using methylene blue as photosensitizer were examined. Although Th-PDT could not demonstrate direct bacterial killing, neutrophils were accumulated into the infectious joint space after PDT and MRSA arthritis was reduced. With the preconditioning Pre-PDT regimen, neutrophils were quickly accumulated into the joint immediately after bacterial inoculation and bacterial growth was suppressed and the establishment of infection was inhibited. Conclusions/Significance This is the first demonstration of a protective innate immune response against a bacterial pathogen produced by PDT. PMID:22761911

  15. Uptake and intra-inclusion accumulation of exogenous immunoglobulin by Chlamydia-infected cells

    PubMed Central

    Pollack, David V; Croteau, Nancy L; Stuart, Elizabeth S

    2008-01-01

    Background Obligate intracellular pathogens belonging to the Chlamydiaceae family possess a number of mechanisms by which to manipulate the host cell and surrounding environment. Such capabilities include the inhibition of apoptosis, down-regulation of major histocompatability complex (MHC) and CD1/d gene expression, and the acquisition of host-synthesized nutrients. It is also documented that a limited number of host-derived macromolecules such as β-catenin and sphingomyelin accumulate within the inclusion. Results This report provides evidence that immunoglobulin, inherently present in the extracellular environment in vivo and in vitro, enters infected cells and accumulates within the chlamydial inclusion. Using epi-fluorescent and confocal microscopy, this selective uptake of Ig is shown to occur among human leukocytes in vivo as well as cells cultured in vitro. These findings were confirmed by detection of IgG in the lysate of infected cells by western blot hybridization. Sequestered antibodies appear to be present during the entire course of the chlamydial developmental cycle and are distributed throughout this compartment. IgG pre-labeled with fluorescein, when added to the supernatant of infected cell cultures, was also imported and readily visualized. Accumulation of these molecules within the inclusion and the failure of bovine serum albumin or F(ab')2 fragments to accumulate in a similar manner suggests the process of entry is specific for intact IgG molecules and not a result of pinocytosis, diffusion, or any other mass endocytic event. Conclusion Sequestration of a host cell-derived protein within the chlamydial inclusion, although unexpected, is not an unprecedented occurrence. However, selective accumulation of an exogenous host protein, such as extracellular IgG, has not been previously reported in connection with chlamydial infections. The selectivity of this process may indicate that this uptake plays an important role in pathogen physiology or

  16. Low Temperature Induces the Accumulation of Phenylalanine Ammonia-Lyase and Chalcone Synthase mRNAs of Arabidopsis thaliana in a Light-Dependent Manner.

    PubMed Central

    Leyva, A.; Jarillo, J. A.; Salinas, J.; Martinez-Zapater, J. M.

    1995-01-01

    Anthocyanins, which accumulate in leaves and stems in response to low temperature and changes in light intensity, are synthesized through the phenylpropanoid pathway that is controlled by key enzymes that include phenylalanine ammonia-lyase (PAL) and chalcone synthase (CHS). In this work we demonstrate that PAL and CHS mRNAs accumulate in leaves of Arabidopsis thaliana (L.) Heynh. upon exposure to low temperature in a light-dependent manner. The regulation of the PAL1 gene expression by low temperature and light was examined by analyzing the expression of the [beta]-glucuronidase (uidA) reporter gene in transgenic Arabidopsis plants containing the uidA gene of Escherichia coli under the control of the PAL1 promoter. The results indicate that the accumulation of PAL1 mRNA is transcriptionally regulated. Histochemical staining for [beta]-glucuronidase activity showed that the PAL1 promoter is preferentially activated in photosynthetically active cells, paralleling anthocyanin accumulation. Moreover, we show that light may also be implicated in the regulation of the CHS gene in response to bacterial infiltration. Finally, using two transparent testa Arabidopsis mutants that are unable to accumulate anthocyanins, we demonstrate that these pigments are not required for successful development of freezing tolerance in this species. PMID:12228452

  17. Phytochelatins play a key role in arsenic accumulation and tolerance in the aquatic macrophyte Wolffia globosa.

    PubMed

    Zhang, Xin; Uroic, M Kalle; Xie, Wan-Ying; Zhu, Yong-Guan; Chen, Bao-Dong; McGrath, Steve P; Feldmann, Jörg; Zhao, Fang-Jie

    2012-06-01

    The rootless duckweed Wolffia globosa can accumulate and tolerate relatively large amounts of arsenic (As); however, the underlying mechanisms were unknown. W. globosa was exposed to different concentrations of arsenate with or without l-buthionine sulphoximine (BSO), a specific inhibitor of γ-glutamylcysteine synthetase. Free thiol compounds and As(III)-thiol complexes were identified and quantified using HPLC - high resolution ICP-MS - accurate mass ESI-MS. Without BSO, 74% of the As accumulated in the duckweed was complexed with phytochelatins (PCs), with As(III)-PC(4) and As(III)-PC(3) being the main species. BSO was taken up by the duckweed and partly deaminated. The BSO treatment completely suppressed the synthesis of PCs and the formation of As(III)-PC complexes, and also inhibited the reduction of arsenate to arsenite. BSO markedly decreased both As accumulation and As tolerance in W. globosa. The results demonstrate an important role of PCs in detoxifying As and enabling As accumulation in W. globosa. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Accumulation effects in modulation spectroscopy with high-repetition-rate pulses: Recursive solution of optical Bloch equations

    NASA Astrophysics Data System (ADS)

    Osipov, Vladimir Al.; Pullerits, Tõnu

    2017-10-01

    Application of the phase-modulated pulsed light for advance spectroscopic measurements is the area of growing interest. The phase modulation of the light causes modulation of the signal. Separation of the spectral components of the modulations allows to distinguish the contributions of various interaction pathways. The lasers with high repetition rate used in such experiments can lead to appearance of the accumulation effects, which become especially pronounced in systems with long-living excited states. Recently it was shown that such accumulation effects can be used to evaluate parameters of the dynamical processes in the material. In this work we demonstrate that the accumulation effects are also important in the quantum characteristics measurements provided by modulation spectroscopy. In particular, we consider a model of quantum two-level system driven by a train of phase-modulated light pulses, organized in analogy with the two-dimensional spectroscopy experiments. We evaluate the harmonics' amplitudes in the fluorescent signal and calculate corrections appearing from the accumulation effects. We show that the corrections can be significant and have to be taken into account at analysis of experimental data.

  19. Using multiple-accumulator CMACs to improve efficiency of the X part of an input-buffered FX correlator

    NASA Astrophysics Data System (ADS)

    Lapshev, Stepan; Hasan, S. M. Rezaul

    2017-04-01

    This paper presents the approach of using complex multiplier-accumulators (CMACs) with multiple accumulators to reduce the total number of memory operations in an input-buffered architecture for the X part of an FX correlator. A processing unit of this architecture uses an array of CMACs that are reused for different groups of baselines. The disadvantage of processing correlations in this way is that each input data sample has to be read multiple times from the memory because each input signal is used in many of these baseline groups. While a one-accumulator CMAC cannot switch to a different baseline until it is finished integrating the current one, a multiple-accumulator CMAC can. Thus, the array of multiple-accumulator CMACs can switch between processing different baselines that share some input signals at any moment to reuse the current data in the processing buffers. In this way significant reductions in the number of memory read operations are achieved with only a few accumulators per CMAC. For example, for a large number of input signals three-accumulator CMACs reduce the total number of memory operations by more than a third. Simulated energy measurements of four VLSI designs in a high-performance 28 nm CMOS technology are presented in this paper to demonstrate that using multiple accumulators can also lead to reduced power dissipation of the processing array. Using three accumulators as opposed to one has been found to reduce the overall energy of 8-bit CMACs by 1.4% through the reduction of the switching activity within their circuits, which is in addition to a more than 30% reduction in the memory.

  20. Leucine Biosynthesis Is Involved in Regulating High Lipid Accumulation in Yarrowia lipolytica

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kerkhoven, Eduard J.; Kim, Young-Mo; Wei, Siwei

    ABSTRACT The yeastYarrowia lipolyticais a potent accumulator of lipids, and lipogenesis in this organism can be influenced by a variety of factors, such as genetics and environmental conditions. Using a multifactorial study, we elucidated the effects of both genetic and environmental factors on regulation of lipogenesis inY. lipolyticaand identified how two opposite regulatory states both result in lipid accumulation. This study involved comparison of a strain overexpressing diacylglycerol acyltransferase (DGA1) with a control strain grown under either nitrogen or carbon limitation conditions. A strong correlation was observed between the responses on the transcript and protein levels. Combination ofDGA1overexpression with nitrogen limitationmore » resulted in a high level of lipid accumulation accompanied by downregulation of several amino acid biosynthetic pathways, including that of leucine in particular, and these changes were further correlated with a decrease in metabolic fluxes. This downregulation was supported by the measured decrease in the level of 2-isopropylmalate, an intermediate of leucine biosynthesis. Combining the multi-omics data with putative transcription factor binding motifs uncovered a contradictory role for TORC1 in controlling lipid accumulation, likely mediated through 2-isopropylmalate and a Leu3-like transcription factor. IMPORTANCEThe ubiquitous metabolism of lipids involves refined regulation, and an enriched understanding of this regulation would have wide implications. Various factors can influence lipid metabolism, including the environment and genetics. We demonstrated, using a multi-omics and multifactorial experimental setup, that multiple factors affect lipid accumulation in the yeastYarrowia lipolytica. Using integrative analysis, we identified novel interactions between nutrient restriction and genetic factors involving regulators that are highly conserved among eukaryotes. Given that lipid metabolism is involved in many

  1. Increased Interleukin-23 in Hashimoto’s Thyroiditis Disease Induces Autophagy Suppression and Reactive Oxygen Species Accumulation

    PubMed Central

    Zheng, Tingting; Xu, Chengcheng; Mao, Chaoming; Mou, Xiao; Wu, Fei; Wang, Xuefeng; Bu, Ling; Zhou, Yuepeng; Luo, Xuan; Lu, Qingyan; Liu, Hongli; Yuan, Guoyue; Wang, Shengjun; Chen, Deyu; Xiao, Yichuan

    2018-01-01

    Hashimoto’s thyroiditis (HT) represents the most common organ-specific autoimmune disease. Inflammatory factors and reactive oxygen species (ROS) play detrimental roles during the pathogenesis of HT. In this study, we found that thyroid follicular cells (TFCs) from HT patients expressed an elevated level of interleukin-23 (IL-23), which contributed to autophagy suppression and ROS accumulation. Additionally, IL-23-induced autophagy suppression and ROS accumulation in human TFCs was attributed to AKT/mTOR/NF-κB signaling pathway activation. Inhibition of either IL-23 by a specific neutralization antibody, or mTOR by rapamycin, or NF-κB by IKK-16, significantly reversed the autophagy suppression and ROS accumulation. These results demonstrate a key role for IL-23 in HT pathogenesis and provide a potential therapeutic strategy against IL-23 or its signaling pathway in HT. PMID:29434604

  2. Surface charge accumulation of solid insulator under nanosecond pulse in vacuum: 3D distribution features and mechanism

    NASA Astrophysics Data System (ADS)

    Qi, Bo; Gao, Chunjia; Sun, Zelai; Li, Chengrong

    2017-11-01

    Surface charge accumulation can incur changes in electric field distribution, involved in the electron propagation process, and result in a significant decrease in the surface flashover voltage. The existing 2D surface charge measurement fails to meet the actual needs in real engineering applications that usually adopt the 45° conical frustum insulators. The present research developed a novel 3D measurement platform to capture surface charge distribution on solid insulation under nanosecond pulse in a vacuum. The results indicate that all surface charges are positive under a positive pulse and negative under a negative pulse. Surface charges tend to accumulate more near the upper electrode. Surface charge density increases significantly with the increase in pulse counts and amplitudes. Accumulation of surface charge results in a certain decrease of flashover voltage. Taking consideration of the secondary electron emission for the surface charge accumulation, four materials were obtained to demonstrate the effects on surface charge. Combining the effect incurred by secondary electron emission and the weighty action taken by surface charge accumulation on the flashover phenomena, the discharge mechanism along the insulator surface under nanosecond pulse voltage was proposed.

  3. Transcription Factor AREB2 Is Involved in Soluble Sugar Accumulation by Activating Sugar Transporter and Amylase Genes.

    PubMed

    Ma, Qi-Jun; Sun, Mei-Hong; Lu, Jing; Liu, Ya-Jing; Hu, Da-Gang; Hao, Yu-Jin

    2017-08-01

    Sugars play important roles in plant growth and development, crop yield and quality, as well as responses to abiotic stresses. Abscisic acid (ABA) is a multifunctional hormone. However, the exact mechanism by which ABA regulates sugar accumulation is largely unknown in plants. Here, we tested the expression profile of several sugar transporter and amylase genes in response to ABA treatment. MdSUT2 and MdAREB2 were isolated and genetically transformed into apple ( Malus domestica ) to investigate their roles in ABA-induced sugar accumulation. The MdAREB2 transcription factor was found to bind to the promoters of the sugar transporter and amylase genes and activate their expression. Both MdAREB2 and MdSUT2 transgenic plants produced more soluble sugars than controls. Furthermore, MdAREB2 promoted the accumulation of sucrose and soluble sugars in an MdSUT2 -dependent manner. Our results demonstrate that the ABA-responsive transcription factor MdAREB2 directly activates the expression of amylase and sugar transporter genes to promote soluble sugar accumulation, suggesting a mechanism by which ABA regulates sugar accumulation in plants. © 2017 American Society of Plant Biologists. All Rights Reserved.

  4. Evidence integration in model-based tree search

    PubMed Central

    Solway, Alec; Botvinick, Matthew M.

    2015-01-01

    Research on the dynamics of reward-based, goal-directed decision making has largely focused on simple choice, where participants decide among a set of unitary, mutually exclusive options. Recent work suggests that the deliberation process underlying simple choice can be understood in terms of evidence integration: Noisy evidence in favor of each option accrues over time, until the evidence in favor of one option is significantly greater than the rest. However, real-life decisions often involve not one, but several steps of action, requiring a consideration of cumulative rewards and a sensitivity to recursive decision structure. We present results from two experiments that leveraged techniques previously applied to simple choice to shed light on the deliberation process underlying multistep choice. We interpret the results from these experiments in terms of a new computational model, which extends the evidence accumulation perspective to multiple steps of action. PMID:26324932

  5. Evidence Value of Textile Fiber - Transfer and Persistence of Fibers.

    PubMed

    Siegel, J A

    1997-12-01

    Fibers comprise probably the most common form of trace evidence in forensic science today. They occur in perhaps one-quarter of all cases that involve trace evidence and a large majority of crime laboratories routinely characterize textile fibers. Although a great deal of research has been done on how to best characterize and compare fibers, relatively little time has been spent on determining the significance of fiber evidence. This article presents a summary of the studies of fiber transfer and persistence and determination of the significance of fiber evidence. This accumulated research and analysis will enable fiber examiners to better interpret evidence in cases where foreign fibers have been transferred during contact between victims and perpetrators of crimes. Copyright © 1997 Central Police University.

  6. Gamma-ray irradiation enhanced boron-10 compound accumulation in murine tumors.

    PubMed

    Liu, Yong; Nagata, Kenji; Masunaga, Shin-ichiro; Suzuki, Minoru; Kashino, Genro; Kinashi, Yuko; Tanaka, Hiroki; Sakurai, Yoshinori; Maruhashi, Akira; Ono, Koji

    2009-11-01

    Previous studies have demonstrated that X-ray irradiation affects angiogenesis in tumors. Here, we studied the effects of gamma-ray irradiation on boron-10 compound accumulation in a murine tumor model. The mouse squamous cell carcinoma was irradiated with gamma-ray before BSH ((10)B-enriched borocaptate sodium) administration. Then, the boron-10 concentrations in tumor and normal muscle tissues were measured by prompt gamma-ray spectrometry (PGA). A tumor blood flow assay was performed, and cell killing effects of neutron irradiation with various combinations of BSH and gamma-rays were also examined. BSH concentrations of tumor tissues were 16.1 +/- 0.6 microg/g, 16.7 +/- 0.5 microg/g and 17.8 +/- 0.5 microg/g at 72 hours after gamma-ray irradiation at doses of 5, 10, and 20 Gy, compared with 13.1 +/- 0.5 microg/g in unirradiated tumor tissues. The enhancing inhibition of colony formation by neutron irradiation with BSH was also found after gamma-ray irradiation. In addition, increasing Hoechst 33342 perfusion was also observed. In this study, we demonstrated that gamma-ray irradiation enhances BSH accumulation in tumors. The present results suggest that the enhancement of (10)B concentration that occurs after gamma-ray irradiation may be due to the changes in the extracellular microenvironment, including in tumor vessels, induced by gamma-ray irradiation.

  7. 'We hold these truths to be self-evident': deconstructing 'evidence-based' medical practice.

    PubMed

    Devisch, Ignaas; Murray, Stuart J

    2009-12-01

    Rationale, aims and objectives Evidence-based medicine (EBM) claims to be based on 'evidence', rather than 'intuition'. However, EBM's fundamental distinction between quantitative 'evidence' and qualitative 'intuition' is not self-evident. The meaning of 'evidence' is unclear and no studies of quality exist to demonstrate the superiority of EBM in health care settings. This paper argues that, despite itself, EBM holds out only the illusion of conclusive scientific rigour for clinical decision making, and that EBM ultimately is unable to fulfil its own structural criteria for 'evidence'. Methods Our deconstructive analysis of EBM draws on the work of the French philosopher, Jacques Derrida. Deconstruction works in the name of justice to lay bare, to expose what has been hidden from view. In plain language, we deconstruct EBM's paradigm of 'evidence', the randomized controlled trial (RCT), to demonstrate that there cannot be incontrovertible evidence for EBM as such. We argue that EBM therefore 'auto-deconstructs' its own paradigm, and that medical practitioners, policymakers and patients alike ought to be aware of this failure within EBM itself. Results EBM's strict distinction between admissible evidence (based on RCTs) and other supposedly inadmissible evidence is not itself based on evidence, but rather, on intuition. In other words, according to EBM's own logic, there can be no 'evidentiary' basis for its distinction between admissible and inadmissible evidence. Ultimately, to uphold this fundamental distinction, EBM must seek recourse in (bio)political ideology and an epistemology akin to faith.

  8. Proteomic analysis of Chlorella vulgaris: Potential targets for enhanced lipid accumulation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Guarnieri, Michael T.; Nag, Ambarish; Yang, Shihui

    2013-11-01

    Oleaginous microalgae are capable of producing large quantities of fatty acids and triacylglycerides. As such, they are promising feedstocks for the production of biofuels and bioproducts. Genetic strain-engineering strategies offer a means to accelerate the commercialization of algal biofuels by improving the rate and total accumulation of microalgal lipids. However, the industrial potential of these organisms remains to be met, largely due to the incomplete knowledgebase surrounding the mechanisms governing the induction of algal lipid biosynthesis. Such strategies require further elucidation of genes and gene products controlling algal lipid accumulation. In this study, we have set out to examine thesemore » mechanisms and identify novel strain-engineering targets in the oleaginous microalga, Chlorella vulgaris. Comparative shotgun proteomic analyses have identified a number of novel targets, including previously unidentified transcription factors and proteins involved in cell signaling and cell cycle regulation. These results lay the foundation for strain-improvement strategies and demonstrate the power of translational proteomic analysis.« less

  9. Hippocampal activation is associated with longitudinal amyloid accumulation and cognitive decline

    DOE PAGES

    Leal, Stephanie L.; Landau, Susan M.; Bell, Rachel K.; ...

    2017-02-08

    The amyloid hypothesis suggests that beta-amyloid (Aβ) deposition leads to alterations in neural function and ultimately to cognitive decline in Alzheimer’s disease. However, factors that underlie Aβ deposition are incompletely understood. One proposed model suggests that synaptic activity leads to increased Aβ deposition. More specifically, hyperactivity in the hippocampus may be detrimental and could be one factor that drives Aβ deposition. To test this model, we examined the relationship between hippocampal activity during a memory task using fMRI and subsequent longitudinal change in Aβ using PIB-PET imaging in cognitively normal older adults. We found that greater hippocampal activation at baselinemore » was associated with increased Aβ accumulation. Furthermore, increasing Aβ accumulation mediated the influence of hippocampal activation on declining memory performance, demonstrating a crucial role of Aβ in linking hippocampal activation and memory. These findings support a model linking increased hippocampal activation to subsequent Aβ deposition and cognitive decline.« less

  10. Hippocampal activation is associated with longitudinal amyloid accumulation and cognitive decline

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Leal, Stephanie L.; Landau, Susan M.; Bell, Rachel K.

    The amyloid hypothesis suggests that beta-amyloid (Aβ) deposition leads to alterations in neural function and ultimately to cognitive decline in Alzheimer’s disease. However, factors that underlie Aβ deposition are incompletely understood. One proposed model suggests that synaptic activity leads to increased Aβ deposition. More specifically, hyperactivity in the hippocampus may be detrimental and could be one factor that drives Aβ deposition. To test this model, we examined the relationship between hippocampal activity during a memory task using fMRI and subsequent longitudinal change in Aβ using PIB-PET imaging in cognitively normal older adults. We found that greater hippocampal activation at baselinemore » was associated with increased Aβ accumulation. Furthermore, increasing Aβ accumulation mediated the influence of hippocampal activation on declining memory performance, demonstrating a crucial role of Aβ in linking hippocampal activation and memory. These findings support a model linking increased hippocampal activation to subsequent Aβ deposition and cognitive decline.« less

  11. The Accumulating Data to Optimally Predict Obesity Treatment (ADOPT) Core Measures Project: Rationale and Approach.

    PubMed

    MacLean, Paul S; Rothman, Alexander J; Nicastro, Holly L; Czajkowski, Susan M; Agurs-Collins, Tanya; Rice, Elise L; Courcoulas, Anita P; Ryan, Donna H; Bessesen, Daniel H; Loria, Catherine M

    2018-04-01

    Individual variability in response to multiple modalities of obesity treatment is well documented, yet our understanding of why some individuals respond while others do not is limited. The etiology of this variability is multifactorial; however, at present, we lack a comprehensive evidence base to identify which factors or combination of factors influence treatment response. This paper provides an overview and rationale of the Accumulating Data to Optimally Predict obesity Treatment (ADOPT) Core Measures Project, which aims to advance the understanding of individual variability in response to adult obesity treatment. This project provides an integrated model for how factors in the behavioral, biological, environmental, and psychosocial domains may influence obesity treatment responses and identify a core set of measures to be used consistently across adult weight-loss trials. This paper provides the foundation for four companion papers that describe the core measures in detail. The accumulation of data on factors across the four ADOPT domains can inform the design and delivery of effective, tailored obesity treatments. ADOPT provides a framework for how obesity researchers can collectively generate this evidence base and is a first step in an ongoing process that can be refined as the science advances. © 2018 The Obesity Society.

  12. Intravenous insertion site protection: moisture accumulation in intravenous site protectors.

    PubMed

    Lee, W E; Vallino, L M

    1996-01-01

    Stabilizing the intravenous catheter after insertion is a significant part of intravenous therapy. Dislodgments of the cannula from its optimal position in the vein can lead to complications such as phlebitis, thrombophlebitis, infiltration, and infection. Intravenous site protector shields are designed to protect the catheter from impact and tissue trauma at the insertion site. Nurses have requested ventilation in these shields to avoid moisture build up that may increase the risk of infections. To address this issue, experimental laboratory testing was performed to determine if moisture accumulation as evidenced by increased weight of the shield and visible evidence of condensation occurred. No moisture condensation problems with the ventilated intravenous site protectors were found.

  13. Sugar Potentiation of Fatty Acid and Triacylglycerol Accumulation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhai, Zhiyang; Liu, Hui; Xu, Changcheng

    Photosynthetically derived sugar provides carbon skeletons for lipid biosynthesis. We used mutants of Arabidopsis (Arabidopsis thaliana) and the expression of oleogenic factors to investigate relationships among sugar availability, lipid synthesis, and the accumulation of triacylglycerol (TAG) in leaf tissue. The adg1 mutation disables the small subunit of ADP-glucose pyrophosphorylase, the first step in starch synthesis, and the suc2 mutation disables a sucrose/proton symporter that facilitates sucrose loading from leaves into phloem. The adg1suc2 double mutant increases glucose plus sucrose content in leaves 80-fold relative to the wild type, total fatty acid (FA) content 1.8-fold to 8.3% dry weight, and TAGmore » more than 10-fold to 1.2% dry weight. The WRINKLED1 transcription factor also accumulates to higher levels in these leaves, and the rate of FA synthesis increases by 58%. Adding tt4, which disables chalcone synthase, had little effect, but adding the tgd1 mutation, which disables an importer of lipids into plastids to create adg1suc2tt4tgd1, increased total leaf FA to 13.5% dry weight and TAG to 3.8% dry weight, demonstrating a synergistic effect upon combining these mutations. Combining adg1suc2 with the sdp1 mutation, deficient in the predominant TAG lipase, had little effect on total FA content but increased the TAG accumulation by 66% to 2% dry weight. Expression of the WRINKLED1 transcription factor, along with DIACYLGLYCEROL ACYLTRANSFERASE1 and the OLEOSIN1 oil body-associated protein, in the adg1suc2 mutant doubled leaf FA content and increased TAG content to 2.3% dry weight, a level 4.6-fold higher than that resulting from expression of the same factors in the wild type.« less

  14. Sugar Potentiation of Fatty Acid and Triacylglycerol Accumulation

    DOE PAGES

    Zhai, Zhiyang; Liu, Hui; Xu, Changcheng; ...

    2017-10-01

    Photosynthetically derived sugar provides carbon skeletons for lipid biosynthesis. We used mutants of Arabidopsis (Arabidopsis thaliana) and the expression of oleogenic factors to investigate relationships among sugar availability, lipid synthesis, and the accumulation of triacylglycerol (TAG) in leaf tissue. The adg1 mutation disables the small subunit of ADP-glucose pyrophosphorylase, the first step in starch synthesis, and the suc2 mutation disables a sucrose/proton symporter that facilitates sucrose loading from leaves into phloem. The adg1suc2 double mutant increases glucose plus sucrose content in leaves 80-fold relative to the wild type, total fatty acid (FA) content 1.8-fold to 8.3% dry weight, and TAGmore » more than 10-fold to 1.2% dry weight. The WRINKLED1 transcription factor also accumulates to higher levels in these leaves, and the rate of FA synthesis increases by 58%. Adding tt4, which disables chalcone synthase, had little effect, but adding the tgd1 mutation, which disables an importer of lipids into plastids to create adg1suc2tt4tgd1, increased total leaf FA to 13.5% dry weight and TAG to 3.8% dry weight, demonstrating a synergistic effect upon combining these mutations. Combining adg1suc2 with the sdp1 mutation, deficient in the predominant TAG lipase, had little effect on total FA content but increased the TAG accumulation by 66% to 2% dry weight. Expression of the WRINKLED1 transcription factor, along with DIACYLGLYCEROL ACYLTRANSFERASE1 and the OLEOSIN1 oil body-associated protein, in the adg1suc2 mutant doubled leaf FA content and increased TAG content to 2.3% dry weight, a level 4.6-fold higher than that resulting from expression of the same factors in the wild type.« less

  15. Whole Genome Re-Sequencing Identifies a Quantitative Trait Locus Repressing Carbon Reserve Accumulation during Optimal Growth in Chlamydomonas reinhardtii

    PubMed Central

    Goold, Hugh Douglas; Nguyen, Hoa Mai; Kong, Fantao; Beyly-Adriano, Audrey; Légeret, Bertrand; Billon, Emmanuelle; Cuiné, Stéphan; Beisson, Fred; Peltier, Gilles; Li-Beisson, Yonghua

    2016-01-01

    Microalgae have emerged as a promising source for biofuel production. Massive oil and starch accumulation in microalgae is possible, but occurs mostly when biomass growth is impaired. The molecular networks underlying the negative correlation between growth and reserve formation are not known. Thus isolation of strains capable of accumulating carbon reserves during optimal growth would be highly desirable. To this end, we screened an insertional mutant library of Chlamydomonas reinhardtii for alterations in oil content. A mutant accumulating five times more oil and twice more starch than wild-type during optimal growth was isolated and named constitutive oil accumulator 1 (coa1). Growth in photobioreactors under highly controlled conditions revealed that the increase in oil and starch content in coa1 was dependent on light intensity. Genetic analysis and DNA hybridization pointed to a single insertional event responsible for the phenotype. Whole genome re-sequencing identified in coa1 a >200 kb deletion on chromosome 14 containing 41 genes. This study demonstrates that, 1), the generation of algal strains accumulating higher reserve amount without compromising biomass accumulation is feasible; 2), light is an important parameter in phenotypic analysis; and 3), a chromosomal region (Quantitative Trait Locus) acts as suppressor of carbon reserve accumulation during optimal growth. PMID:27141848

  16. Modelling accumulation of marine plastics in the coastal zone; what are the dominant physical processes?

    NASA Astrophysics Data System (ADS)

    Critchell, Kay; Lambrechts, Jonathan

    2016-03-01

    Anthropogenic marine debris, mainly of plastic origin, is accumulating in estuarine and coastal environments around the world causing damage to fauna, flora and habitats. Plastics also have the potential to accumulate in the food web, as well as causing economic losses to tourism and sea-going industries. If we are to manage this increasing threat, we must first understand where debris is accumulating and why these locations are different to others that do not accumulate large amounts of marine debris. This paper demonstrates an advection-diffusion model that includes beaching, settling, resuspension/re-floating, degradation and topographic effects on the wind in nearshore waters to quantify the relative importance of these physical processes governing plastic debris accumulation. The aim of this paper is to prioritise research that will improve modelling outputs in the future. We have found that the physical characteristic of the source location has by far the largest effect on the fate of the debris. The diffusivity, used to parameterise the sub-grid scale movements, and the relationship between debris resuspension/re-floating from beaches and the wind shadow created by high islands also has a dramatic impact on the modelling results. The rate of degradation of macroplastics into microplastics also have a large influence in the result of the modelling. The other processes presented (settling, wind drift velocity) also help determine the fate of debris, but to a lesser degree. These findings may help prioritise research on physical processes that affect plastic accumulation, leading to more accurate modelling, and subsequently management in the future.

  17. CD8+ T-cell immunosurveillance constrains lymphoid pre-metastatic myeloid cell accumulation

    PubMed Central

    Li, Wenzhao; Deng, Jiehui; Herrmann, Andreas; Priceman, Saul J.; Liang, Wei; Shen, Shudan; Pal, Sumanta K.; Hoon, Dave S.B.; Yu, Hua

    2014-01-01

    Increasing evidence suggests that pre-metastatic niches, consisting mainly of myeloid cells, provide microenvironment critical for cancer cell recruitment and survival to facilitate metastasis. While CD8+ T cells exert immunosurveillance in primary human tumors, whether they can exert similar effects on myeloid cells in the pre-metastatic environment is unknown. Here, we show that CD8+ T cells are capable of constraining pre-metastatic myeloid cell accumulation by inducing myeloid cell apoptosis in C57BL/6 mice. Antigen-specific CD8+ T-cell cytotoxicity against myeloid cells in pre-metastatic lymph nodes is compromised by Stat3. We demonstrate here that Stat3 ablation in myeloid cells leads to CD8+ T-cell activation and increased levels of IFN-γ and granzyme B in the pre-metastatic environment. Furthermore, Stat3 negatively regulates soluble antigen cross-presentation by myeloid cells to CD8+ T cells in the pre-metastatic niche. Importantly, in tumor-free lymph nodes of melanoma patients, infiltration of activated CD8+ T cells inversely correlates with STAT3 activity, which is associated with a decrease in number of myeloid cells. Our study suggested a novel role for CD8+ T cells in constraining myeloid cell activity through direct killing in the pre-metastatic environment, and the therapeutic potential by targeting Stat3 in myeloid cells to improve CD8+ T-cell immunosurveillance against metastasis. PMID:25310972

  18. Selenium accumulation by plants

    PubMed Central

    White, Philip J.

    2016-01-01

    Background Selenium (Se) is an essential mineral element for animals and humans, which they acquire largely from plants. The Se concentration in edible plants is determined by the Se phytoavailability in soils. Selenium is not an essential element for plants, but excessive Se can be toxic. Thus, soil Se phytoavailability determines the ecology of plants. Most plants cannot grow on seleniferous soils. Most plants that grow on seleniferous soils accumulate <100 mg Se kg–1 dry matter and cannot tolerate greater tissue Se concentrations. However, some plant species have evolved tolerance to Se, and commonly accumulate tissue Se concentrations >100 mg Se kg–1 dry matter. These plants are considered to be Se accumulators. Some species can even accumulate Se concentrations of 1000–15 000 mg Se kg–1 dry matter and are called Se hyperaccumulators. Scope This article provides an overview of Se uptake, translocation and metabolism in plants and highlights the possible genetic basis of differences in these between and within plant species. The review focuses initially on adaptations allowing plants to tolerate large Se concentrations in their tissues and the evolutionary origin of species that hyperaccumulate Se. It then describes the variation in tissue Se concentrations between and within angiosperm species and identifies genes encoding enzymes limiting the rates of incorporation of Se into organic compounds and chromosomal loci that might enable the development of crops with greater Se concentrations in their edible portions. Finally, it discusses transgenic approaches enabling plants to tolerate greater Se concentrations in the rhizosphere and in their tissues. Conclusions The trait of Se hyperaccumulation has evolved several times in separate angiosperm clades. The ability to tolerate large tissue Se concentrations is primarily related to the ability to divert Se away from the accumulation of selenocysteine and selenomethionine, which might be incorporated

  19. Selenium accumulation by plants.

    PubMed

    White, Philip J

    2016-02-01

    Selenium (Se) is an essential mineral element for animals and humans, which they acquire largely from plants. The Se concentration in edible plants is determined by the Se phytoavailability in soils. Selenium is not an essential element for plants, but excessive Se can be toxic. Thus, soil Se phytoavailability determines the ecology of plants. Most plants cannot grow on seleniferous soils. Most plants that grow on seleniferous soils accumulate <100 mg Se kg(-1) dry matter and cannot tolerate greater tissue Se concentrations. However, some plant species have evolved tolerance to Se, and commonly accumulate tissue Se concentrations >100 mg Se kg(-1) dry matter. These plants are considered to be Se accumulators. Some species can even accumulate Se concentrations of 1000-15 000 mg Se kg(-1 )dry matter and are called Se hyperaccumulators. This article provides an overview of Se uptake, translocation and metabolism in plants and highlights the possible genetic basis of differences in these between and within plant species. The review focuses initially on adaptations allowing plants to tolerate large Se concentrations in their tissues and the evolutionary origin of species that hyperaccumulate Se. It then describes the variation in tissue Se concentrations between and within angiosperm species and identifies genes encoding enzymes limiting the rates of incorporation of Se into organic compounds and chromosomal loci that might enable the development of crops with greater Se concentrations in their edible portions. Finally, it discusses transgenic approaches enabling plants to tolerate greater Se concentrations in the rhizosphere and in their tissues. The trait of Se hyperaccumulation has evolved several times in separate angiosperm clades. The ability to tolerate large tissue Se concentrations is primarily related to the ability to divert Se away from the accumulation of selenocysteine and selenomethionine, which might be incorporated into non-functional proteins

  20. Charge injection and accumulation in organic light-emitting diode with PEDOT:PSS anode

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Weis, Martin, E-mail: martin.weis@stuba.sk; Otsuka, Takako; Taguchi, Dai

    2015-04-21

    Organic light-emitting diode (OLED) displays using flexible substrates have many attractive features. Since transparent conductive oxides do not fit the requirements of flexible devices, conductive polymer poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) has been proposed as an alternative. The charge injection and accumulation in OLED devices with PEDOT:PSS anodes are investigated and compared with indium tin oxide anode devices. Higher current density and electroluminescence light intensity are achieved for the OLED device with a PEDOT:PSS anode. The electric field induced second-harmonic generation technique is used for direct observation of temporal evolution of electric fields. It is clearly demonstrated that the improvement in the devicemore » performance of the OLED device with a PEDOT:PSS anode is associated with the smooth charge injection and accumulation.« less

  1. Charge injection and accumulation in organic light-emitting diode with PEDOT:PSS anode

    NASA Astrophysics Data System (ADS)

    Weis, Martin; Otsuka, Takako; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa

    2015-04-01

    Organic light-emitting diode (OLED) displays using flexible substrates have many attractive features. Since transparent conductive oxides do not fit the requirements of flexible devices, conductive polymer poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) has been proposed as an alternative. The charge injection and accumulation in OLED devices with PEDOT:PSS anodes are investigated and compared with indium tin oxide anode devices. Higher current density and electroluminescence light intensity are achieved for the OLED device with a PEDOT:PSS anode. The electric field induced second-harmonic generation technique is used for direct observation of temporal evolution of electric fields. It is clearly demonstrated that the improvement in the device performance of the OLED device with a PEDOT:PSS anode is associated with the smooth charge injection and accumulation.

  2. Disruption of plastid acyl:acyl carrier protein synthetases increases medium chain fatty acid accumulation in seeds of transgenic Arabidopsis.

    PubMed

    Tjellström, Henrik; Strawsine, Merissa; Silva, Jillian; Cahoon, Edgar B; Ohlrogge, John B

    2013-04-02

    Engineering transgenic plants that accumulate high levels of medium-chain fatty acids (MCFA) has been least successful for shorter chain lengths (e.g., C8). We demonstrate that one limitation is the activity of acyl-ACP synthetase (AAE) that re-activates fatty acids released by acyl-ACP thioesterases. Seed expression of Cuphea pulcherrima FATB acyl-ACP thioesterase in a double mutant lacking AAE15/16 increased 8:0 accumulation almost 2-fold compared to expression in wild type. These results also provide an in planta demonstration that AAE enzymes participate not only in activation of exogenously added MCFA but also in activation of MCFA synthesized in plastids. Copyright © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  3. High-Density SNP Screening of the Major Histocompatibility Complex in Systemic Lupus Erythematosus Demonstrates Strong Evidence for Independent Susceptibility Regions

    PubMed Central

    Barcellos, Lisa F.; May, Suzanne L.; Ramsay, Patricia P.; Quach, Hong L.; Lane, Julie A.; Nititham, Joanne; Noble, Janelle A.; Taylor, Kimberly E.; Quach, Diana L.; Chung, Sharon A.; Kelly, Jennifer A.; Moser, Kathy L.; Behrens, Timothy W.; Seldin, Michael F.; Thomson, Glenys; Harley, John B.; Gaffney, Patrick M.; Criswell, Lindsey A.

    2009-01-01

    A substantial genetic contribution to systemic lupus erythematosus (SLE) risk is conferred by major histocompatibility complex (MHC) gene(s) on chromosome 6p21. Previous studies in SLE have lacked statistical power and genetic resolution to fully define MHC influences. We characterized 1,610 Caucasian SLE cases and 1,470 parents for 1,974 MHC SNPs, the highly polymorphic HLA-DRB1 locus, and a panel of ancestry informative markers. Single-marker analyses revealed strong signals for SNPs within several MHC regions, as well as with HLA-DRB1 (global p = 9.99×10−16). The most strongly associated DRB1 alleles were: *0301 (odds ratio, OR = 2.21, p = 2.53×10−12), *1401 (OR = 0.50, p = 0.0002), and *1501 (OR = 1.39, p = 0.0032). The MHC region SNP demonstrating the strongest evidence of association with SLE was rs3117103, with OR = 2.44 and p = 2.80×10−13. Conditional haplotype and stepwise logistic regression analyses identified strong evidence for association between SLE and the extended class I, class I, class III, class II, and the extended class II MHC regions. Sequential removal of SLE–associated DRB1 haplotypes revealed independent effects due to variation within OR2H2 (extended class I, rs362521, p = 0.006), CREBL1 (class III, rs8283, p = 0.01), and DQB2 (class II, rs7769979, p = 0.003, and rs10947345, p = 0.0004). Further, conditional haplotype analyses demonstrated that variation within MICB (class I, rs3828903, p = 0.006) also contributes to SLE risk independent of HLA-DRB1*0301. Our results for the first time delineate with high resolution several MHC regions with independent contributions to SLE risk. We provide a list of candidate variants based on biologic and functional considerations that may be causally related to SLE risk and warrant further investigation. PMID:19851445

  4. Enhanced Insight into the Autoimmune Component of Glaucoma: IgG Autoantibody Accumulation and Pro-Inflammatory Conditions in Human Glaucomatous Retina

    PubMed Central

    Gramlich, Oliver W.; Beck, Sabine; von Thun und Hohenstein-Blaul, Nadine; Boehm, Nils; Ziegler, Anika; Vetter, Jan M.; Pfeiffer, Norbert; Grus, Franz H.

    2013-01-01

    Background There is accumulating evidence that autoimmune components, such as autoantibodies and autoantibody depositions, play a role in the pathogenesis of neurodegenerative diseases like Alzheimeŕs disease or Multiple Sclerosis. Due to alterations of autoantibody patterns in sera and aqueous humor, an autoimmune component is also assumed in the pathogenesis of glaucoma, a common reason for irreversible blindness worldwide. So far there has been no convincing evidence that autoantibodies are accumulated in the retina of glaucoma patients and that the local immune homeostasis might be affected. Methods and Results Six human glaucomatous donor eyes and nine samples from donors with no recorded ocular disease were included. Antibody microarrays were used to examine the patterns of pro-inflammatory proteins and complement proteins. Analysis of TNF-α and interleukin levels revealed a slight up-regulation exclusively in the glaucomatous group, while complement protein levels were not altered. IgG autoantibody accumulations and/or cellular components were determined by immunohistology (n = 4 per group). A significantly reduced number of retinal ganglion cells was found in the glaucomatous group (healthy: 104±7 nuclei/mm, glaucoma: 67±9 nuclei/mm; p = 0.0007). Cell loss was accompanied by strong retinal IgG autoantibody accumulations, which were at least twice as high as in healthy subjects (healthy: 5.0±0.5 IgG deposits/100 cells, glaucoma: 9.4±1.9 IgG deposits/100 cells; p = 0.004). CD27+ cells and CD27+/IgG+ plasma cells were observed in all glaucomatous subjects, but not in controls. Conclusion This work provides serious evidence for the occurrence of IgG antibody deposition and plasma cells in human glaucomatous retina. Moreover, the results suggest that these IgG deposits occurred in a pro-inflammatory environment which seems to be maintained locally by immune-competent cells like microglia. Thereby, glaucoma features an immunological involvement

  5. Plastids and Carotenoid Accumulation.

    PubMed

    Li, Li; Yuan, Hui; Zeng, Yunliu; Xu, Qiang

    Plastids are ubiquitously present in plants and are the organelles for carotenoid biosynthesis and storage. Based on their morphology and function, plastids are classified into various types, i.e. proplastids, etioplasts, chloroplasts, amyloplasts, and chromoplasts. All plastids, except proplastids, can synthesize carotenoids. However, plastid types have a profound effect on carotenoid accumulation and stability. In this chapter, we discuss carotenoid biosynthesis and regulation in various plastids with a focus on carotenoids in chromoplasts. Plastid transition related to carotenoid biosynthesis and the different capacity of various plastids to sequester carotenoids and the associated effect on carotenoid stability are described in light of carotenoid accumulation in plants.

  6. Where Is the Evidence for "Evidence-Based" Therapy?

    PubMed

    Shedler, Jonathan

    2018-06-01

    The term evidence-based therapy is a de facto code word for manualized therapy, most often brief cognitive behavior therapy and its variants. It is widely asserted that "evidence-based" therapy is scientifically proven, superior to other forms of psychotherapy, and the gold standard of care. Research findings do not support such assertions. Research on evidence-based therapies demonstrates that they are weak treatments. They have not shown superiority to other forms of psychotherapy, few patients get well, and treatment benefits do not last. Questionable research practices create a distorted picture of the actual benefits of these therapies. Copyright © 2018 Jonathan Shedler. Published by Elsevier Inc. All rights reserved.

  7. Accumulation and distribution of α-synuclein and ubiquitin in the CNS of Gaucher disease mouse models

    PubMed Central

    Xu, YH; Sun, Y; Ran, H; Quinn, B; Witte, D; Grabowski, GA

    2011-01-01

    Gaucher disease, a prevalent lysosomal storage disease, is caused by insufficient activity of acid β-glucosidase (GCase) and resultant glucosylceramide accumulation. Recently in Parkinson disease (PD) patients, heterozygous mutations in GCase have been associated with earlier onset and more progressive PD. To understand the pathogenic relationships between GCase variants and Parkinsonism, α-synuclein and ubiquitin distributions and levels in the brains of several mouse models containing GCase variants were evaluated by immunohistochemistry. Progressive α-synuclein and ubiquitin aggregate accumulations were observed in the cortex, hippocampus, basal ganglia, brainstem, and some cerebellar regions between 4-24 wks in mice that were homozygous for GCase [D409H (9H) or V394L (4L)] variants and also had a prosaposin hypomorphic (PS-NA) transgene. In 4L/PS-NA and 9H/PS-NA mice, this was coincident with progressive neurological manifestations and brain glucosylceramide accumulation. Ultrastructural studies showed electron dense inclusion bodies in neurons and axons of 9H/PS-NA brains. α-Synuclein aggregates were also observed in ventricular, brainstem, and cerebellar regions of older mice (>42-wk) with the GCase variant (D409H/D409H) without overt neurological disease. In a chemically induced GCase deficiency, α-synuclein aggregates and glucosylceramide accumulation also occurred. These studies demonstrate a relationship between glucosylceramide accumulation and α-synuclein aggregates, and implicate glucosylceramide accumulation as risk factor for the α-synucleinopathies. PMID:21257328

  8. Grazing suppression of dimethylsulphoniopropionate (DMSP) accumulation in iron-fertilised, sub-Antarctic waters

    NASA Astrophysics Data System (ADS)

    Archer, S. D.; Safi, K.; Hall, A.; Cummings, D. G.; Harvey, M.

    2011-03-01

    considerably higher than for chlorophyll a, indicating higher cycling rates of the DMSP-producing taxa than for the bulk phytoplankton community. When compared to the total phytoplankton community, there was no evidence of selection against the DMSP-containing phytoplankton by the microzooplankton grazers; the opposite appeared to be the case. SAGE demonstrated that increased iron availability in the HNLC waters of the Southern Ocean does not invariably lead to enhanced DMS sea-air flux. The potential suppression of DMSPp accumulation by grazers needs to be taken into account in future attempts to elevate DMS emission through in situ iron fertilisation and in understanding the hypothesised link between levels of Aeolian iron deposition in the Southern Ocean, DMS emission and global albedo.

  9. Geomorphic control of landscape carbon accumulation

    USGS Publications Warehouse

    Rosenbloom, N.A.; Harden, J.W.; Neff, J.C.; Schimel, D.S.

    2006-01-01

    We use the CREEP process-response model to simulate soil organic carbon accumulation in an undisturbed prairie site in Iowa. Our primary objectives are to identify spatial patterns of carbon accumulation, and explore the effect of erosion on basin-scale C accumulation. Our results point to two general findings. First, redistribution of soil carbon by erosion results in a net increase in basin-wide carbon storage relative to a noneroding environment. Landscape-average mean residence times are increased in an eroding landscape owing to the burial/preservation of otherwise labile C. Second, field observations taken along a slope transect may overlook significant intraslope variations in carbon accumulation. Spatial patterns of modeled deep C accumulation are complex. While surface carbon with its relatively short equilibration time is predictable from surface properties, deep carbon is strongly influenced by the landscape's geomorphic and climatic history, resulting in wide spatial variability. Convergence and divergence associated with upland swales and interfluves result in bimodal carbon distributions in upper and mid slopes; variability in carbon storage within modeled mid slopes was as high as simulated differences between erosional shoulders and depositional valley bottoms. The bimodality of mid-slope C variability in the model suggests that a three-dimensional sampling strategy is preferable over the traditional two-dimensional analog or "catena" approach. Copyright 2006 by the American Geophysical Union.

  10. Self-Control Assessments of Capuchin Monkeys With the Rotating Tray Task and the Accumulation Task

    PubMed Central

    Beran, Michael J.; Perdue, Bonnie M.; Rossettie, Mattea S.; James, Brielle T.; Whitham, Will; Walker, Bradlyn; Futch, Sara E.; Parrish, Audrey E.

    2016-01-01

    Recent studies of delay of gratification in capuchin monkeys using a rotating tray (RT) task have shown improved self-control performance in these animals in comparison to the accumulation (AC) task. In this study, we investigated whether this improvement resulted from the difference in methods between the rotating tray task and previous tests, or whether it was the result of greater overall experience with delay of gratification tasks. Experiment 1 produced similar performance levels by capuchins monkeys in the RT and AC tasks when identical reward and temporal parameters were used. Experiment 2 demonstrated a similar result using reward amounts that were more similar to previous AC experiments with these monkeys. In Experiment 3, monkeys performed multiple versions of the AC task with varied reward and temporal parameters. Their self-control behavior was found to be dependent on the overall delay to reward consumption, rather than the overall reward amount ultimately consumed. These findings indicate that these capuchin monkeys’ self-control capacities were more likely to have improved across studies because of the greater experience they had with delay of gratification tasks. Experiment 4 and Experiment 5 tested new, task-naïve monkeys on both tasks, finding more limited evidence of self-control, and no evidence that one task was more beneficial than the other in promoting self-control. The results of this study suggest that future testing of this kind should focus on temporal parameters and reward magnitude parameters to establish accurate measures of delay of gratification capacity and development in this species and perhaps others. PMID:27298233

  11. TRANSPARENT TESTA GLABRA1 Regulates the Accumulation of Seed Storage Reserves in Arabidopsis.

    PubMed

    Chen, Mingxun; Zhang, Bin; Li, Chengxiang; Kulaveerasingam, Harikrishna; Chew, Fook Tim; Yu, Hao

    2015-09-01

    Seed storage reserves mainly consist of starch, triacylglycerols, and storage proteins. They not only provide energy for seed germination and seedling establishment, but also supply essential dietary nutrients for human beings and animals. So far, the regulatory networks that govern the accumulation of seed storage reserves in plants are still largely unknown. Here, we show that TRANSPARENT TESTA GLABRA1 (TTG1), which encodes a WD40 repeat transcription factor involved in many aspects of plant development, plays an important role in mediating the accumulation of seed storage reserves in Arabidopsis (Arabidopsis thaliana). The dry weight of ttg1-1 embryos significantly increases compared with that of wild-type embryos, which is accompanied by an increase in the contents of starch, total protein, and fatty acids in ttg1-1 seeds. FUSCA3 (FUS3), a master regulator of seed maturation, binds directly to the TTG1 genomic region and suppresses TTG1 expression in developing seeds. TTG1 negatively regulates the accumulation of seed storage proteins partially through transcriptional repression of 2S3, a gene encoding a 2S albumin precursor. TTG1 also indirectly suppresses the expression of genes involved in either seed development or synthesis/modification of fatty acids in developing seeds. In addition, we demonstrate that the maternal allele of the TTG1 gene suppresses the accumulation of storage proteins and fatty acids in seeds. Our results suggest that TTG1 is a direct target of FUS3 in the framework of the regulatory hierarchy controlling seed filling and regulates the accumulation of seed storage proteins and fatty acids during the seed maturation process. © 2015 American Society of Plant Biologists. All Rights Reserved.

  12. Evidence-based economic analysis demonstrates that ecosystem service benefits of water hyacinth management greatly exceed research and control costs

    PubMed Central

    Harms, Nathan E.; Magen, Cedric; Liang, Dong; Nesslage, Genevieve M.; McMurray, Anna M.; Cofrancesco, Al F.

    2018-01-01

    Invasive species management can be a victim of its own success when decades of effective control cause memories of past harm to fade and raise questions of whether programs should continue. Economic analysis can be used to assess the efficiency of investing in invasive species control by comparing ecosystem service benefits to program costs, but only if appropriate data exist. We used a case study of water hyacinth (Eichhornia crassipes (Mart.) Solms), a nuisance floating aquatic plant, in Louisiana to demonstrate how comprehensive record-keeping supports economic analysis. Using long-term data sets, we developed empirical and spatio-temporal simulation models of intermediate complexity to project invasive species growth for control and no-control scenarios. For Louisiana, we estimated that peak plant cover would be 76% higher without the substantial growth rate suppression (84% reduction) that appeared due primarily to biological control agents. Our economic analysis revealed that combined biological and herbicide control programs, monitored over an unusually long time period (1975–2013), generated a benefit-cost ratio of about 34:1 derived from the relatively modest costs of $124 million ($2013) compared to the $4.2 billion ($2013) in benefits to anglers, waterfowl hunters, boating-dependent businesses, and water treatment facilities over the 38-year analysis period. This work adds to the literature by: (1) providing evidence of the effectiveness of water hyacinth biological control; (2) demonstrating use of parsimonious spatio-temporal models to estimate benefits of invasive species control; and (3) incorporating activity substitution into economic benefit transfer to avoid overstating benefits. Our study suggests that robust and cost-effective economic analysis is enabled by good record keeping and generalizable models that can demonstrate management effectiveness and promote social efficiency of invasive species control. PMID:29844976

  13. Evidence-based economic analysis demonstrates that ecosystem service benefits of water hyacinth management greatly exceed research and control costs.

    PubMed

    Wainger, Lisa A; Harms, Nathan E; Magen, Cedric; Liang, Dong; Nesslage, Genevieve M; McMurray, Anna M; Cofrancesco, Al F

    2018-01-01

    Invasive species management can be a victim of its own success when decades of effective control cause memories of past harm to fade and raise questions of whether programs should continue. Economic analysis can be used to assess the efficiency of investing in invasive species control by comparing ecosystem service benefits to program costs, but only if appropriate data exist. We used a case study of water hyacinth ( Eichhornia crassipes (Mart.) Solms), a nuisance floating aquatic plant, in Louisiana to demonstrate how comprehensive record-keeping supports economic analysis. Using long-term data sets, we developed empirical and spatio-temporal simulation models of intermediate complexity to project invasive species growth for control and no-control scenarios. For Louisiana, we estimated that peak plant cover would be 76% higher without the substantial growth rate suppression (84% reduction) that appeared due primarily to biological control agents. Our economic analysis revealed that combined biological and herbicide control programs, monitored over an unusually long time period (1975-2013), generated a benefit-cost ratio of about 34:1 derived from the relatively modest costs of $124 million ($2013) compared to the $4.2 billion ($2013) in benefits to anglers, waterfowl hunters, boating-dependent businesses, and water treatment facilities over the 38-year analysis period. This work adds to the literature by: (1) providing evidence of the effectiveness of water hyacinth biological control; (2) demonstrating use of parsimonious spatio-temporal models to estimate benefits of invasive species control; and (3) incorporating activity substitution into economic benefit transfer to avoid overstating benefits. Our study suggests that robust and cost-effective economic analysis is enabled by good record keeping and generalizable models that can demonstrate management effectiveness and promote social efficiency of invasive species control.

  14. ACCUMULATION OF RADIOCESIUM BY MUSHROOMS IN THE ENVIRONMENT: A LITERATURE REVIEW AND IMAGE GALLERY

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Duff, M; Mary Ramsey, M

    2006-11-05

    During the last 50 years, a large amount of information on radionuclide accumulators or 'sentinel-type' organisms in the environment has been published. Much of this work focused on the risks of food-chain transfer of radionuclides to higher organisms such as reindeer and man. However, until the 1980's and 1990's, there has been little published data on the radiocesium ({sup 134}Cs and {sup 137}Cs) accumulation by mushrooms. This presentation will consist of a review of the published data for {sup 134,137}Cs accumulation by mushrooms in nature. The review will consider the time of sampling, sample location characteristics, the radiocesium source termmore » and other aspects that promote {sup 134,137}Cs uptake by mushrooms. This review will focus on published data for mushrooms that demonstrate a large propensity for use in the environmental biomonitoring of radiocesium contamination. It will also provide photographs and descriptions of habitats for many of these mushrooms to facilitate their collection for biomonitoring.« less

  15. Determinants of reinforcer accumulation during an operant task.

    PubMed

    McFarland, J M; Lattal, K A

    2001-11-01

    Responses by rats on an earn lever made available food pellets that were delivered to a food cup by responses on a second, collect, lever. The rats could either collect and immediately consume or accumulate (defined as the percentage of multiple earn responses and as the number of pellets earned before a collect response) earned pellets. In Experiment 1, accumulation varied as a function of variations in the earn or collect response requirements and whether the earn and collect levers were proximal (31 cm) or distal (248 cm) to one another. Some accumulation occurred under all but one of the conditions, but generally was higher when the earn and collect levers were distal to one another, particularly when the earn response requirement was fixed-ratio (FR) 1. In Experiment 2, the contributions of responses and time to accumulation were assessed by comparing an FR 20 earn response requirement to a condition in which only a single earn response was required at the end of a time interval nominally yoked to the FR interval. When 248 cm separated the earn and collect levers, accumulation was always greater in the FR condition, and it was not systematically related to reinforcement rate. In Experiment 3, increasing the earn response requirement with a progressive-ratio schedule that reset only with a collect response increased the likelihood of accumulation when the collect and earn levers were 248 cm apart, even though such accumulation increased the next earn response requirement. Reinforcer accumulation is an understudied dimension of operant behavior that relates to the analysis of such phenomena as hoarding and self-control, in that they too involve accumulating versus immediately collecting or consuming reinforcers.

  16. Flavonols Accumulate Asymmetrically and Affect Auxin Transport in Arabidopsis1[C][W][OA

    PubMed Central

    Kuhn, Benjamin M.; Geisler, Markus; Bigler, Laurent; Ringli, Christoph

    2011-01-01

    Flavonoids represent a class of secondary metabolites with diverse functions in plants including ultraviolet protection, pathogen defense, and interspecies communication. They are also known as modulators of signaling processes in plant and animal systems and therefore are considered to have beneficial effects as nutraceuticals. The rol1-2 (for repressor of lrx1) mutation of Arabidopsis (Arabidopsis thaliana) induces aberrant accumulation of flavonols and a cell-growth phenotype in the shoot. The hyponastic cotyledons, aberrant shape of pavement cells, and deformed trichomes in rol1-2 mutants are suppressed by blocking flavonoid biosynthesis, suggesting that the altered flavonol accumulation in these plants induces the shoot phenotype. Indeed, the identification of several transparent testa, myb, and fls1 (for flavonol synthase1) alleles in a rol1-2 suppressor screen provides genetic evidence that flavonols interfere with shoot development in rol1-2 seedlings. The increased accumulation of auxin in rol1-2 seedlings appears to be caused by a flavonol-induced modification of auxin transport. Quantification of auxin export from mesophyll protoplasts revealed that naphthalene-1-acetic acid but not indole-3-acetic acid transport is affected by the rol1-2 mutation. Inhibition of flavonol biosynthesis in rol1-2 fls1-3 restores naphthalene-1-acetic acid transport to wild-type levels, indicating a very specific mode of action of flavonols on the auxin transport machinery. PMID:21502189

  17. Progressive Retinal Degeneration and Accumulation of Autofluorescent Lipopigments in Progranulin Deficient Mice

    PubMed Central

    Hafler, Brian P.; Klein, Zoe A.; Zhou, Z. Jimmy; Strittmatter, Stephen M.

    2014-01-01

    Prior investigations have shown that patients with neuronal ceroid lipofuscinosis (NCL) develop neurodegeneration characterized by vision loss, motor dysfunction, seizures, and often early death. Neuropathological analysis of patients with NCL shows accumulation of intracellular autofluorescent storage material, lipopigment, throughout neurons in the central nervous system including in the retina. A recent study of a sibling pair with adult onset NCL and retinal degeneration showed linkage to the region of the progranulin (GRN) locus and a homozygous mutation was demonstrated in GRN. In particular, the sibling pair with a mutation in GRN developed retinal degeneration and optic atrophy. This locus for this form of adult onset neuronal ceroid lipofuscinosis was designated neuronal ceroid lipofuscinosis-11 (CLN11). Based on these clinical observations, we wished to determine whether Grn-null mice develop accumulation of autofluorescent particles and retinal degeneration. Retinas of both wild-type and Progranulin deficient mice were examined by immunostaining and autofluorescence. Accumulation of autofluorescent material was present in Progranulin deficient mice at 12 months. Degeneration of multiple classes of neurons including photoreceptors and retinal ganglion cells was noted in mice at 12 and 18 months. Our data shows that Grn−/− mice develop degenerative pathology similar to features of human CLN11. PMID:25234724

  18. Mercury bioremediation by mercury accumulating Enterobacter sp. cells and its alginate immobilized application.

    PubMed

    Sinha, Arvind; Khare, Sunil Kumar

    2012-02-01

    The effective microbial remediation of the mercury necessitates the mercury to be trapped within the cells without being recycled back to the environment. The study describes a mercury bioaccumulating strain of Enterobacter sp., which remediated mercury from the medium simultaneous to its growth. The transmission electron micrographs and electron dispersive X-ray analysis revealed the accumulation of remediated mercury as nano-size particles in the cytoplasm as well as on the cell wall. The Enterobacter sp. in the present work was able to accumulate mercury, without being engineered in its native form. The possibility of recovering the accumulated mercury from the cells is also indicated. The applicability of the alginate immobilized cells in removing mercury from synthetic and complex industrial effluent in a batch mode was amply demonstrated. The initial load of 7.3 mg l(-1) mercury in the industrial effluent was completely removed in 72 h. The cells immobilized in calcium alginate were similarly effective in the complete removal of 5 mg l(-1) HgCl(2) of mercury from the synthetic effluent in less than 72 h. The immobilized cells could be reused for multiple cycles.

  19. Nanoparticle accumulation and transcytosis in brain endothelial cell layers

    NASA Astrophysics Data System (ADS)

    Ye, Dong; Raghnaill, Michelle Nic; Bramini, Mattia; Mahon, Eugene; Åberg, Christoffer; Salvati, Anna; Dawson, Kenneth A.

    2013-10-01

    The blood-brain barrier (BBB) is a selective barrier, which controls and limits access to the central nervous system (CNS). The selectivity of the BBB relies on specialized characteristics of the endothelial cells that line the microvasculature, including the expression of intercellular tight junctions, which limit paracellular permeability. Several reports suggest that nanoparticles have a unique capacity to cross the BBB. However, direct evidence of nanoparticle transcytosis is difficult to obtain, and we found that typical transport studies present several limitations when applied to nanoparticles. In order to investigate the capacity of nanoparticles to access and transport across the BBB, several different nanomaterials, including silica, titania and albumin- or transferrin-conjugated gold nanoparticles of different sizes, were exposed to a human in vitro BBB model of endothelial hCMEC/D3 cells. Extensive transmission electron microscopy imaging was applied in order to describe nanoparticle endocytosis and typical intracellular localisation, as well as to look for evidence of eventual transcytosis. Our results show that all of the nanoparticles were internalised, to different extents, by the BBB model and accumulated along the endo-lysosomal pathway. Rare events suggestive of nanoparticle transcytosis were also observed for several of the tested materials.The blood-brain barrier (BBB) is a selective barrier, which controls and limits access to the central nervous system (CNS). The selectivity of the BBB relies on specialized characteristics of the endothelial cells that line the microvasculature, including the expression of intercellular tight junctions, which limit paracellular permeability. Several reports suggest that nanoparticles have a unique capacity to cross the BBB. However, direct evidence of nanoparticle transcytosis is difficult to obtain, and we found that typical transport studies present several limitations when applied to nanoparticles. In

  20. Abscisic acid-regulated protein degradation causes osmotic stress-induced accumulation of branched-chain amino acids in Arabidopsis thaliana.

    PubMed

    Huang, Tengfang; Jander, Georg

    2017-10-01

    Whereas proline accumulates through de novo biosynthesis in plants subjected to osmotic stress, leucine, isoleucine, and valine accumulation in drought-stressed Arabidopsis thaliana is caused by abscisic acid-regulated protein degradation. In response to several kinds of abiotic stress, plants greatly increase their accumulation of free amino acids. Although stress-induced proline increases have been studied the most extensively, the fold-increase of other amino acids, in particular branched-chain amino acids (BCAAs; leucine, isoleucine, and valine), is often higher than that of proline. In Arabidopsis thaliana (Arabidopsis), BCAAs accumulate in response to drought, salt, mannitol, polyethylene glycol, herbicide treatment, and nitrogen starvation. Plants that are deficient in abscisic acid signaling accumulate lower amounts of BCAAs, but not proline and most other amino acids. Previous bioinformatic studies had suggested that amino acid synthesis, rather than protein degradation, is responsible for the observed BCAA increase in osmotically stressed Arabidopsis. However, whereas treatment with the protease inhibitor MG132 decreased drought-induced BCAA accumulation, inhibition of BCAA biosynthesis with the acetolactate synthase inhibitors chlorsulfuron and imazapyr did not. Additionally, overexpression of BRANCHED-CHAIN AMINO ACID TRANSFERASE2 (BCAT2), which is upregulated in response to osmotic stress and functions in BCAA degradation, decreased drought-induced BCAA accumulation. Together, these results demonstrate that BCAA accumulation in osmotically stressed Arabidopsis is primarily the result of protein degradation. After relief of the osmotic stress, BCAA homeostasis is restored over time by amino acid degradation involving BCAT2. Thus, drought-induced BCAA accumulation is different from that of proline, which is accumulated due to de novo synthesis in an abscisic acid-independent manner and remains elevated for a more prolonged period of time after removal of

  1. Dynamically accumulated dose and 4D accumulated dose for moving tumors

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Li Heng; Li Yupeng; Zhang Xiaodong

    2012-12-15

    Purpose: The purpose of this work was to investigate the relationship between dynamically accumulated dose (dynamic dose) and 4D accumulated dose (4D dose) for irradiation of moving tumors, and to quantify the dose uncertainty induced by tumor motion. Methods: The authors established that regardless of treatment modality and delivery properties, the dynamic dose will converge to the 4D dose, instead of the 3D static dose, after multiple deliveries. The bounds of dynamic dose, or the maximum estimation error using 4D or static dose, were established for the 4D and static doses, respectively. Numerical simulations were performed (1) to prove themore » principle that for each phase, after multiple deliveries, the average number of deliveries for any given time converges to the total number of fractions (K) over the number of phases (N); (2) to investigate the dose difference between the 4D and dynamic doses as a function of the number of deliveries for deliveries of a 'pulsed beam'; and (3) to investigate the dose difference between 4D dose and dynamic doses as a function of delivery time for deliveries of a 'continuous beam.' A Poisson model was developed to estimate the mean dose error as a function of number of deliveries or delivered time for both pulsed beam and continuous beam. Results: The numerical simulations confirmed that the number of deliveries for each phase converges to K/N, assuming a random starting phase. Simulations for the pulsed beam and continuous beam also suggested that the dose error is a strong function of the number of deliveries and/or total deliver time and could be a function of the breathing cycle, depending on the mode of delivery. The Poisson model agrees well with the simulation. Conclusions: Dynamically accumulated dose will converge to the 4D accumulated dose after multiple deliveries, regardless of treatment modality. Bounds of the dynamic dose could be determined using quantities derived from 4D doses, and the mean dose

  2. Quantitation of cell-associated carbon nanotubes: selective binding and accumulation of carboxylated carbon nanotubes by macrophages.

    PubMed

    Wang, Ruhung; Lee, Michael; Kinghorn, Karina; Hughes, Tyler; Chuckaree, Ishwar; Lohray, Rishabh; Chow, Erik; Pantano, Paul; Draper, Rockford

    2018-05-26

    To understand the influence of carboxylation on the interaction of carbon nanotubes with cells, the amount of pristine multi-walled carbon nanotubes (P-MWNTs) or carboxylated multi-walled carbon nanotubes (C-MWNTs) coated with Pluronic ® F-108 that were accumulated by macrophages was measured by quantifying CNTs extracted from cells. Mouse RAW 264.7 macrophages and differentiated human THP-1 (dTHP-1) macrophages accumulated 80-100 times more C-MWNTs than P-MWNTs during a 24-h exposure at 37 °C. The accumulation of C-MWNTs by RAW 264.7 cells was not lethal; however, phagocytosis was impaired as subsequent uptake of polystyrene beads was reduced after a 20-h exposure to C-MWNTs. The selective accumulation of C-MWNTs suggested that there might be receptors on macrophages that bind C-MWNTs. The binding of C-MWNTs to macrophages was measured as a function of concentration at 4 °C in the absence of serum to minimize the potential interference by serum proteins or temperature-dependent uptake processes. The result was that the cells bound 8.7 times more C-MWNTs than P-MWNTs, consistent with the selective accumulation of C-MWNTs at 37 °C. In addition, serum strongly antagonized the binding of C-MWTS to macrophages, suggesting that serum contained inhibitors of binding. Moreover, inhibitors of class A scavenger receptor (SR-As) reduced the binding of C-MWNTs by about 50%, suggesting that SR-As contribute to the binding and endocytosis of C-MWNTs in macrophages but that other receptors may also be involved. Altogether, the evidence supports the hypothesis that macrophages contain binding sites selective for C-MWNTs that facilitate the high accumulation of C-MWNTs compared to P-MWNTs.

  3. Fungus Causing White-Nose Syndrome in Bats Accumulates Genetic Variability in North America with No Sign of Recombination.

    PubMed

    Trivedi, Jigar; Lachapelle, Josianne; Vanderwolf, Karen J; Misra, Vikram; Willis, Craig K R; Ratcliffe, John M; Ness, Rob W; Anderson, James B; Kohn, Linda M

    2017-01-01

    Emerging fungal diseases of wildlife are on the rise worldwide, and the white-nose syndrome (WNS) epidemic in North American bats is a catastrophic example. The causal agent of WNS is a single clone of the fungus Pseudogymnoascus destructans . Early evolutionary change in this clonal population has major implications for disease ecology and conservation. Accumulation of variation in the fungus through mutation, and shuffling of variation through recombination, could affect the virulence and transmissibility of the fungus and the durability of what appears to be resistance arising in some bat populations. Our genome-wide analysis shows that the clonal population of P. destructans has expanded in size from a single genotype, has begun to accumulate variation through mutation, and presents no evidence as yet of genetic exchange among individuals. IMPORTANCE Since its discovery in 2006, the emerging infectious disease known as white-nose syndrome has killed millions of bats in North America, making it one of the most devastating wildlife epidemics in recorded history. We demonstrate that there has been as yet only spontaneous mutation across the North American population of P. destructans , and we find no indication of recombination. Thus, selective forces, which might otherwise impact pathogenic virulence, have so far had essentially no genetic variation on which to act. Our study confirmed the time of origin for the first and, thus far, only introduction of P. destructans to North America. This system provides an unprecedented opportunity to follow the evolution of a host-pathogen interaction unfolding in real time.

  4. Plastic Accumulation in the Mediterranean Sea

    PubMed Central

    Cózar, Andrés; Sanz-Martín, Marina; Martí, Elisa; González-Gordillo, J. Ignacio; Ubeda, Bárbara; Gálvez, José Á.; Irigoien, Xabier; Duarte, Carlos M.

    2015-01-01

    Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region. PMID:25831129

  5. Plastic accumulation in the Mediterranean sea.

    PubMed

    Cózar, Andrés; Sanz-Martín, Marina; Martí, Elisa; González-Gordillo, J Ignacio; Ubeda, Bárbara; Gálvez, José Á; Irigoien, Xabier; Duarte, Carlos M

    2015-01-01

    Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region.

  6. Salinity-dependent nickel accumulation and oxidative stress responses in the euryhaline killifish (Fundulus heteroclitus).

    PubMed

    Blewett, Tamzin A; Wood, Chris M

    2015-02-01

    The mechanisms of nickel (Ni) toxicity in marine fish remain unclear, although evidence from freshwater (FW) fish suggests that Ni can act as a pro-oxidant. This study investigated the oxidative stress effects of Ni on the euryhaline killifish (Fundulus heteroclitus) as a function of salinity. Killifish were exposed to sublethal levels (5, 10, and 20 mg L(-1)) of waterborne Ni for 96 h in FW (0 ppt) and 100 % saltwater (SW) (35 ppt). In general, SW was protective against both Ni accumulation and indicators of oxidative stress [protein carbonyl formation and catalase (CAT) activity]. This effect was most pronounced at the highest Ni exposure level. For example, FW intestine showed increased Ni accumulation relative to SW intestine at 20 mg Ni L(-1), and this was accompanied by significantly greater protein carbonylation and CAT activity in this tissue. There were exceptions, however, in that although liver of FW killifish at the highest exposure concentration showed greater Ni accumulation relative to SW liver, levels of CAT activity were greatly decreased. This may relate to tissue- and salinity-specific differences in oxidative stress responses. The results of the present study suggest (1) that there was Ni-induced oxidative stress in killifish, (2) that the effects of salinity depend on differences in the physiology of the fish in FW versus SW, and (3) that increased levels of cations (sodium, calcium, potassium, and magnesium) and anions (SO4 and Cl) in SW are likely protective against Ni accumulation in tissues exposed to the aquatic environment.

  7. Stoichiometric Correlation of Malate Accumulation with Auxin-dependent K+-H+ Exchange and Growth in Avena Coleoptile Segments 12

    PubMed Central

    Haschke, Hans-Peter; Lüttge, Ulrich

    1975-01-01

    The action of auxin in the promotion of growth has been suggested in the literature to depend on cell wall acidification. In a former investigation by the present authors the electrochemical balance in auxin-induced proton extrusion was shown to be maintained by potassium net uptake. The present paper reports data demonstrating that the elongation of Avena coleoptile segments is accompanied by an accumulation of malate, which is stoichiometrically correlated with potassium uptake. We concluded that this malate accumulation is required in a mechanism regulating intracellular pH. PMID:16659374

  8. Effect of diurnal temperature difference on lipid accumulation and development in Calanus sinicus (Copepoda: Calanoida)

    NASA Astrophysics Data System (ADS)

    Zhou, Konglin; Sun, Song

    2017-07-01

    Calanus sinicus, the dominant copepod in the Yellow Sea, develops a large oil sac in late spring to prepare for over-summering in the Yellow Sea Cold Water Mass (YSCWM). The lipid accumulation mechanism for the initiation of over-summering is unknown. Here, we cultured C3 copepodites at four constant temperatures (10, 13, 16, and 19°C) and at three temperature regimes that mimicked the temperature variations experienced during diurnal vertical migration (10-13°C, 10-16°C, and 10-19°C) for 18 days to explore the effects of temperature differences on copepod development and lipid accumulation. C. sinicus stored more lipid at low than at high temperatures. A diurnal temperature difference (10-16°C and 10-19°C) promoted greater lipid accumulation (1.9-2.1 times) than a constant temperature of either 16°C or 19°C, by reducing the energy cost at colder temperatures and lengthening copepodite development. Thereafter, the lipid reserve supported gonad development after final molting. Only one male developed in these experiments. This highly female-skewed sex ratio may have been the result of the monotonous microalgae diet fed to the copepodites. This study provides the first evidence that diurnal temperature differences may promote lipid accumulation in C. sinicus, and provides a foundation for future investigations into the mechanisms involved in over-summering in the YSCWM.

  9. A mesocosm study using four native Hawaiian plants to assess nitrogen accumulation under varying surface water nitrogen concentrations.

    PubMed

    Unser, C U; Bruland, G L; Hood, A; Duin, K

    2010-01-01

    Accumulation of nitrogen (N) by native Hawaiian riparian plants from surface water was measured under a controlled experimental mesocosm setting. Four species, Cladium jamaicense, Cyperus javanicus, Cyperus laevigatus, and Cyperus polystachyos were tested for their ability to survive in coconut fiber coir log media with exposure to differing N concentrations. It was hypothesized that the selected species would have significantly different tissue total nitrogen (TN) concentrations, aboveground biomass, and TN accumulation rates because of habitat preference and physiological growth differences. A general linear model (GLM) analysis of variance (ANOVA) determined that species differences accounted for the greatest proportion of variance in tissue TN concentration, aboveground biomass growth, and accumulation rates, when compared with the other main effects (i.e. N concentration, time) and their interactions. A post hoc test of means demonstrated that C. jamaicense had significantly higher tissue TN concentration, aboveground biomass growth, and accumulation rates than the other species under all N concentrations. It was also hypothesized that tissue TN concentrations and biomass growth would increase in plants exposed to elevated N concentrations, however data did not support this hypothesis. Nitrogen accumulation rates by species were controlled by differences in plant biomass growth.

  10. Measurement of the surface charge accumulation using anodic aluminum oxide(AAO) structure in an inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Park, Ji-Hwan; Oh, Seung-Ju; Lee, Hyo-Chang; Kim, Yu-Sin; Kim, Young-Cheol; Kim, June Young; Ha, Chang-Seoung; Kwon, Soon-Ho; Lee, Jung-Joong; Chung, Chin-Wook

    2014-10-01

    As the critical dimension of the nano-device shrinks, an undesired etch profile occurs during plasma etch process. One of the reasons is the local electric field due to the surface charge accumulation. To demonstrate the surface charge accumulation, an anodic aluminum oxide (AAO) membrane which has high aspect ratio is used. The potential difference between top electrode and bottom electrode in an anodic aluminum oxide contact structure is measured during inductively coupled plasma exposure. The voltage difference is changed with external discharge conditions, such as gas pressure, input power, and gas species and the result is analyzed with the measured plasma parameters.

  11. Do Child Development Accounts Promote Account Holding, Saving, and Asset Accumulation for Children's Future? Evidence from a Statewide Randomized Experiment

    ERIC Educational Resources Information Center

    Nam, Yunju; Kim, Youngmi; Clancy, Margaret; Zager, Robert; Sherraden, Michael

    2013-01-01

    This study examines the impacts of Child Development Accounts (CDAs) on account holding, saving, and asset accumulation for children, using data from the SEED for Oklahoma Kids experiment (SEED OK). SEED OK, a policy test of universal and progressive CDAs, provides a 529 college savings plan account to every infant in the treatment group with…

  12. Variability in Proline-Accumulating Ability of Barley (Hordeum vulgare L.) Cultivars Induced by Vapor Pressure Deficit 1

    PubMed Central

    Naidu, Bodapati P.; Aspinall, Donald; Paleg, Leslie G.

    1992-01-01

    This work was undertaken in an effort to reconcile the conflicting proline-accumulating responses of the barley (Hordeum vulgare L.) cultivars, Excelsior and Proctor, reported by Singh et al. (1972) and Hanson et al. (1976). It deals with the effects of different vapor pressure deficits (VPD) during growth and subsequent drought stress on several barley cultivars. A higher VPD (1.2 kilopascals) during Clipper seedling growth resulted in higher solute-accumulating ability, seemingly independently of leaf water potential, than a lower VPD (0.12 kilopascals). The higher VPD during stress also resulted in higher solute contents, and this response may be more closely related to leaf water potential. When the responses of Excelsior and Proctor were examined in detail, it was found that the relative proline-accumulating ability of the two cultivars was dependent upon the VPD under which they were grown. At low VPD, Proctor accumulated significantly more proline than did Excelsior; whereas at higher VPD, Excelsior accumulated more proline than did Proctor. The crossover occurred at a VPD of about 0.72 kilopascals. This reversal of cultivar response was enhanced by multiplying seed under the two VPD extremes. Glycinebetaine accumulation did not demonstrate the crossover effect, although the concentration of this compound in all cultivars also depended on the VPD prevailing during growth and/or stress. Solute levels, in general, were more closely related to the decrease in relative water content than to a decrease in leaf water potential. It is concluded that the conflicting proline-accumulating responses of Excelsior and Proctor could be explained by these findings. PMID:16668700

  13. COP1 is required for UV-B–induced nuclear accumulation of the UVR8 photoreceptor

    PubMed Central

    Skvortsova, Mariya Y.; Loubéry, Sylvain

    2016-01-01

    The UV-B photoreceptor UV RESISTANCE LOCUS 8 (UVR8) promotes UV-B acclimation and tolerance in Arabidopsis thaliana. UVR8 localizes to both cytosol and nucleus, but its main activity is assumed to be nuclear. UV-B photoreception stimulates nuclear accumulation of UVR8 in a presently unknown manner. Here, we show that CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) is required for UV-B–induced nuclear accumulation of UVR8, but bypassing the COP1 requirement for UVR8 nuclear accumulation did not rescue the cop1 mutant UV-B phenotype. Using a glucocorticoid receptor (GR)-based fusion protein system to conditionally localize GR-UVR8 to the nucleus, we have demonstrated that both photoactivation and nuclear localization of UVR8 are required for UV-B–induced photomorphogenic responses. In contrast, there was no UV-B response when UV-B–activated UVR8 was artificially retained in the cytosol. In agreement with a predominantly nuclear activity, constitutively active UVR8W285A accumulated in the nucleus also in the absence of UV-B. Furthermore, GR-COP1 expression lines suggested that UV-B–activated UVR8 can be coimported into the nucleus by COP1. Our data strongly support localization of UVR8 signaling in the nucleus and a dual role for COP1 in the regulation of UV-B–induced UVR8 nuclear accumulation and in UVR8-mediated UV-B signaling. PMID:27407149

  14. Determinants of reinforcer accumulation during an operant task.

    PubMed Central

    McFarland, J M; Lattal, K A

    2001-01-01

    Responses by rats on an earn lever made available food pellets that were delivered to a food cup by responses on a second, collect, lever. The rats could either collect and immediately consume or accumulate (defined as the percentage of multiple earn responses and as the number of pellets earned before a collect response) earned pellets. In Experiment 1, accumulation varied as a function of variations in the earn or collect response requirements and whether the earn and collect levers were proximal (31 cm) or distal (248 cm) to one another. Some accumulation occurred under all but one of the conditions, but generally was higher when the earn and collect levers were distal to one another, particularly when the earn response requirement was fixed-ratio (FR) 1. In Experiment 2, the contributions of responses and time to accumulation were assessed by comparing an FR 20 earn response requirement to a condition in which only a single earn response was required at the end of a time interval nominally yoked to the FR interval. When 248 cm separated the earn and collect levers, accumulation was always greater in the FR condition, and it was not systematically related to reinforcement rate. In Experiment 3, increasing the earn response requirement with a progressive-ratio schedule that reset only with a collect response increased the likelihood of accumulation when the collect and earn levers were 248 cm apart, even though such accumulation increased the next earn response requirement. Reinforcer accumulation is an understudied dimension of operant behavior that relates to the analysis of such phenomena as hoarding and self-control, in that they too involve accumulating versus immediately collecting or consuming reinforcers. PMID:11768714

  15. Racial Differences in Patterns of Wealth Accumulation

    ERIC Educational Resources Information Center

    Gittleman, Maury; Wolff, Edward N.

    2004-01-01

    The race differences in patterns of asset accumulations were examined using PSD data for 1984, 1989 and 1994. The results indicate that inheritances led to wealth accumulations among whites as compared to the African Americans.

  16. Evaluation of a new chest physiotherapy technique in dogs with airway fluid accumulation hospitalized in an intensive care unit.

    PubMed

    Pouzot-Nevoret, Céline; Goy-Thollot, Isabelle; Billet, Didier; Barthélemy, Anthony; Blesch, Maïlys; Pin, Aurélie; Hopper, Kate

    2018-05-01

    To evaluate the feasibility, benefits, and adverse effects of prolonged slow expiration (PSE) and assisted cough (AC) as chest physiotherapy (CP) techniques in dogs with airway fluid accumulation. Prospective interventional study. University teaching hospital. Intervention group of 30 client-owned dogs and retrospective control group of 71 client-owned dogs. PSE was performed on dogs with evidence of airway fluid accumulation, identified based on physical examination and thoracic radiographs. AC was performed if spontaneous cough or swallowing were not evident. The PSE treatment was performed every 6 hours until normalization of respiratory status or hospital discharge. Animals were monitored for respiratory distress, discomfort, and SpO 2 during the procedure. A retrospective control group was identified by computer search. One hundred thirty-three sessions of CP were performed on 30 dogs. Discomfort frequency during physiotherapy was low (9%). The most commonly used position for CP was in lateral recumbency (95%) and this was well tolerated in most cases. There was no significant difference in the median SpO 2 before and after CP sessions (P = 0.24). Sixty percent of sessions had a spontaneous cough or swallowing evident, 21% had successful AC performed, and no cough or swallowing occurred in the remaining (19%) sessions despite attempts of AC being made. The length of hospitalization was significantly longer in the intervention group (6 days vs 4) (P = 0.02). There was no difference in survival between the intervention (76.7%) and the control (57.7%) group (P = 0.055). PSE associated with AC are easily adaptable, well-tolerated techniques in dogs. The benefit of CP in dogs with airway fluid accumulation remains to be determined and it is hoped that future randomized controlled prospective studies may help answer this line of inquiry. © Veterinary Emergency and Critical Care Society 2018.

  17. LipiD-QuanT: a novel method to quantify lipid accumulation in live cells.

    PubMed

    Varinli, Hilal; Osmond-McLeod, Megan J; Molloy, Peter L; Vallotton, Pascal

    2015-11-01

    Lipid droplets (LDs) are the main storage organelles for triglycerides. Elucidation of lipid accumulation mechanisms and metabolism are essential to understand obesity and associated diseases. Adipogenesis has been well studied in murine 3T3-L1 and human Simpson-Golabi-Behmel syndrome (SGBS) preadipocyte cell lines. However, most techniques for measuring LD accumulation are either not quantitative or can be destructive to samples. Here, we describe a novel, label-free LD quantification technique (LipiD-QuanT) to monitor lipid dynamics based on automated image analysis of phase contrast microscopy images acquired during in vitro human adipogenesis. We have applied LipiD-QuanT to measure LD accumulation during differentiation of SGBS cells. We demonstrate that LipiD-QuanT is a robust, nondestructive, time- and cost-effective method compared with other triglyceride accumulation assays based on enzymatic digest or lipophilic staining. Further, we applied LipiD-QuanT to measure the effect of four potential pro- or antiobesogenic substances: DHA, rosiglitazone, elevated levels of D-glucose, and zinc oxide nanoparticles. Our results revealed that 2 µmol/l rosiglitazone treatment during adipogenesis reduced lipid production and caused a negative shift in LD diameter size distribution, but the other treatments showed no effect under the conditions used here. Copyright © 2015 by the American Society for Biochemistry and Molecular Biology, Inc.

  18. LipiD-QuanT: a novel method to quantify lipid accumulation in live cells[S

    PubMed Central

    Varinli, Hilal; Osmond-McLeod, Megan J.; Molloy, Peter L.; Vallotton, Pascal

    2015-01-01

    Lipid droplets (LDs) are the main storage organelles for triglycerides. Elucidation of lipid accumulation mechanisms and metabolism are essential to understand obesity and associated diseases. Adipogenesis has been well studied in murine 3T3-L1 and human Simpson-Golabi-Behmel syndrome (SGBS) preadipocyte cell lines. However, most techniques for measuring LD accumulation are either not quantitative or can be destructive to samples. Here, we describe a novel, label-free LD quantification technique (LipiD-QuanT) to monitor lipid dynamics based on automated image analysis of phase contrast microscopy images acquired during in vitro human adipogenesis. We have applied LipiD-QuanT to measure LD accumulation during differentiation of SGBS cells. We demonstrate that LipiD-QuanT is a robust, nondestructive, time- and cost-effective method compared with other triglyceride accumulation assays based on enzymatic digest or lipophilic staining. Further, we applied LipiD-QuanT to measure the effect of four potential pro- or antiobesogenic substances: DHA, rosiglitazone, elevated levels of D-glucose, and zinc oxide nanoparticles. Our results revealed that 2 µmol/l rosiglitazone treatment during adipogenesis reduced lipid production and caused a negative shift in LD diameter size distribution, but the other treatments showed no effect under the conditions used here. PMID:26330056

  19. [Accelerated senescence of fresh-cut Chinese water chestnut tissues in relation to hydrogen peroxide accumulation].

    PubMed

    Peng, Li-Tao; Jiang, Yue-Ming; Yang, Shu-Zhen; Pan, Si-Yi

    2005-10-01

    Accelerated senescence of fresh-cut Chinese water chestnut (CWC) tissues in relation to active oxygen species (AOS) metabolism was investigated. Fresh-cut CWC (2 mm thick) and intact CWC were stored at 4 degrees C in trays wrapped with plastic films. Changes in superoxide anion production rate, activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were monitored, while contents of hydrogen peroxide, ascorbic acid, MDA as well as electrolyte leakage were measured. Fresh-cutting of CWC induced activities of SOD, CAT and APX to a certain extent (Fig. 2B and Fig. 3), but simultaneously stimulated superoxide anion production markedly (Fig. 2A), enhanced hydrogen peroxide accumulation and accelerated loss in ascorbic acid (Figs. 4 and 5), which resulted in increased lipid peroxidation indicated by malondialdehyde (MDA) content and electrolyte leakage (Fig. 1). Statistics analysis indicated that there was a significantly positive correlation among hydrogen peroxide accumulation, MDA content and electrolyte leakage (Table 1). Histochemical detection with 3, 3'-diaminobenzidine further demonstrated that hydrogen peroxide accumulation increased in fresh-cut CWC during storage (Fig. 5). AOS production rate and activities of SOD, CAT and APX changed little while no obvious hydrogen peroxide accumulation was observed, in intact CWC during storage.

  20. Streptomyces clavuligerus shows a strong association between TCA cycle intermediate accumulation and clavulanic acid biosynthesis.

    PubMed

    Ramirez-Malule, Howard; Junne, Stefan; Nicolás Cruz-Bournazou, Mariano; Neubauer, Peter; Ríos-Estepa, Rigoberto

    2018-05-01

    Clavulanic acid (CA) is produced by Streptomyces clavuligerus (S. clavuligerus) as a secondary metabolite. Knowledge about the carbon flux distribution along the various routes that supply CA precursors would certainly provide insights about metabolic performance. In order to evaluate metabolic patterns and the possible accumulation of tricarboxylic acid (TCA) cycle intermediates during CA biosynthesis, batch and subsequent continuous cultures with steadily declining feed rates were performed with glycerol as the main substrate. The data were used to in silico explore the metabolic capabilities and the accumulation of metabolic intermediates in S. clavuligerus. While clavulanic acid accumulated at glycerol excess, it steadily decreased at declining dilution rates; CA synthesis stopped when glycerol became the limiting substrate. A strong association of succinate, oxaloacetate, malate, and acetate accumulation with CA production in S. clavuligerus was observed, and flux balance analysis (FBA) was used to describe the carbon flux distribution in the network. This combined experimental and numerical approach also identified bottlenecks during the synthesis of CA in a batch and subsequent continuous cultivation and demonstrated the importance of this type of methodologies for a more advanced understanding of metabolism; this potentially derives valuable insights for future successful metabolic engineering studies in S. clavuligerus.

  1. Seasonality of snow accumulation at Mount Wrangell, Alaska, USA

    NASA Astrophysics Data System (ADS)

    Kanamori, Syosaku; Benson, Carl S.; Truffer, Martin; Matoba, Sumito; Solie, Daniel J.; Shiraiwa, Takayuki

    We recorded the burial times of temperature sensors mounted on a specially constructed tower to determine snow accumulation during individual storms in the summit caldera of Mount Wrangell, Alaska, USA, (62°N, 144°W; 4100 m a.s.l.) during the accumulation year June 2005 to June 2006. The experiment showed most of the accumulation occurred in episodic large storms, and half of the total accumulation was delivered in late summer. The timing of individual events correlated well with storms recorded upwind, at Cordova, the closest Pacific coastal weather station (200 km south-southeast), although the magnitude of events showed only poor correlation. Hence, snow accumulation at Mount Wrangell appears to be a reflection of synoptic-scale regional weather systems. The accumulation at Mount Wrangell's summit (>2.5 m w.e.) exceeded the precipitation at Cordova. Although the direct relationship between accumulation of individual storms at the summit of Mount Wrangell and precipitation events at Cordova may be unique in the region, it is useful for interpreting ice cores obtained on Mount Wrangell. This is especially the case here because the high rate of accumulation allows high time resolution within the core.

  2. Converging roads: evidence for an adult hemangioblast.

    PubMed

    Bailey, Alexis S; Fleming, William H

    2003-11-01

    Classical studies of the developing embryo first suggested the existence of the hemangioblast, a precursor cell with the potential to differentiate into both blood and blood vessels. Several lines of investigation demonstrated that many of the genes activated during early hematopoietic development are also expressed in the vascular endothelium. Gene-targeting studies using embryonic stem cells have identified Flk-1, SCL, and Runx-1 as important regulatory molecules that specify both hematopoietic and vascular outcomes. Although it was anticipated that the hemangioblast would be present only during the earliest stages of vascular development in the yolk sac, accumulating evidence now indicates that hematopoietic cells with hemangioblast activity persist into adulthood. In the adult, bone marrow-derived, circulating endothelial progenitors contribute to postnatal neovascularization and enhance vascular repair following ischemic injury. Highly purified populations of hematopoietic stem cells from humans and mice can differentiate into both blood cells and vascular tissue at the single cell level. These recent findings suggest that bone marrow-derived hematopoietic stem cells or their progeny may contribute to the maintenance and repair of both the hematopoietic and the vascular systems during adult life.

  3. The Cytoplasmic Zinc Finger Protein ZPR1 Accumulates in the Nucleolus of Proliferating Cells

    PubMed Central

    Galcheva-Gargova, Zoya; Gangwani, Laxman; Konstantinov, Konstantin N.; Mikrut, Monique; Theroux, Steven J.; Enoch, Tamar; Davis, Roger J.

    1998-01-01

    The zinc finger protein ZPR1 translocates from the cytoplasm to the nucleus after treatment of cells with mitogens. The function of nuclear ZPR1 has not been defined. Here we demonstrate that ZPR1 accumulates in the nucleolus of proliferating cells. The role of ZPR1 was examined using a gene disruption strategy. Cells lacking ZPR1 are not viable. Biochemical analysis demonstrated that the loss of ZPR1 caused disruption of nucleolar function, including preribosomal RNA expression. These data establish ZPR1 as an essential protein that is required for normal nucleolar function in proliferating cells. PMID:9763455

  4. Accumulation of Content Validation Evidence for the Critical Thinking Self-Assessment Scale.

    PubMed

    Nair, Girija Gopinathan; Hellsten, Laurie-Ann M; Stamler, Lynnette Leeseberg

    2017-04-01

    Critical thinking skills (CTS) are essential for nurses; assessing students' acquisition of these skills is a mandate of nursing curricula. This study aimed to develop a self-assessment instrument of critical thinking skills (Critical Thinking Self-Assessment Scale [CTSAS]) for students' self-monitoring. An initial pool of 196 items across 6 core cognitive skills and 16 subskills were generated using the American Philosophical Association definition of CTS. Experts' content review of the items and their ratings provided evidence of content relevance using the item-level content validity index (I-CVI) and Aiken's content validity coefficient (VIk). 115 items were retained (range of I-CVI values = .70 to .94 and range of VIk values = .69-.95; significant at p< .05). The CTSAS is the first CTS instrument designed specifically for self-assessment purposes.

  5. Divergent Evolutionary Pattern of Sugar Transporter Genes is Associated with the Difference in Sugar Accumulation between Grasses and Eudicots.

    PubMed

    Wang, Wei; Zhou, Hui; Ma, Baiquan; Owiti, Albert; Korban, Schuyler S; Han, Yuepeng

    2016-06-30

    Sugars play a variety of roles in plants, and their accumulation in seeds and/or surrounding pericarp tissues is distinctly different between grasses and eudicots. However, little is known about the evolutionary pattern of genes involved in sugar accumulation in these two major groups of flowering plants. Here, we compared evolutionary rates, gene duplication, and selective patterns of genes involved in sugar metabolism and transport between grasses and eudicots using six grass species and seven eudicot species as materials. Overall, sugar transporter genes exhibit divergent evolutionary patterns, whereas, sugar metabolism genes showing similar evolutionary pattern between monocots and eudicots. Sugar transporter genes have higher frequencies of recent duplication in eudicots than in grasses and their patterns of evolutionary rate are different. Evidence for divergent selection of these two groups of flowering plants is also observed in sugar transporter genes, wherein, these genes have undergone positive selection in eudicots, but not in grasses. Taken together, these findings suggest that sugar transporter genes rather than sugar metabolism genes play important roles in sugar accumulation in plants, and that divergent evolutionary patterns of sugar transporter genes are associated with the difference of sugar accumulation in storage tissues of grasses and eudicots.

  6. Efficacy and safety of topical NSAIDs in the management of osteoarthritis: Evidence from real-life setting trials and surveys.

    PubMed

    Rannou, François; Pelletier, Jean-Pierre; Martel-Pelletier, Johanne

    2016-02-01

    Topical non-steroidal anti-inflammatory drugs (NSAIDs) are recommended in international and national guidelines as an early treatment option for the symptomatic management of knee and hand osteoarthritis (OA), and may be used ahead of oral NSAIDs due to their superior safety profile. The European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) treatment algorithm recommends topical NSAIDs for knee OA in addition to the pharmacological background of symptomatic slow-acting drugs for osteoarthritis (SYSADOAs) and rescue analgesia with paracetamol and non-pharmacological treatment, if the patient is still symptomatic. Topical NSAIDs have a moderate effect on pain relief, with efficacy similar to that of oral NSAIDs, with the advantage of a better risk:benefit ratio. In real-life studies, topical and oral NSAIDs demonstrate an equivalent effect on knee pain over 1 year of treatment, with fewer adverse events due to lower systemic absorption of topical NSAIDs compared with oral NSAIDs. As a result, topical NSAIDs may be the preferred treatment option, especially in OA patients aged ≥75 years, and those with co-morbidities or at an increased risk of cardiovascular, gastrointestinal, or renal side effects. Furthermore, using topical NSAIDs in inflammatory rheumatic diseases leads to a 40% reduction in the need for concomitant oral NSAIDs. When selecting a topical NSAID, absorption and bioavailability are important because of heterogeneity among topical drug formulations. Molecules like etofenamate have a bioavailability of >20% and evidence for accumulation in synovial tissues, with efficacy demonstrated as improvement in pain and function in real-life studies of OA patients. Diclofenac also shows good efficacy alongside evidence that diclofenac accumulates in the synovium. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  7. Amyloid and intracellular accumulation of BRI2.

    PubMed

    Garringer, Holly J; Sammeta, Neeraja; Oblak, Adrian; Ghetti, Bernardino; Vidal, Ruben

    2017-04-01

    Familial British dementia (FBD) and familial Danish dementia (FDD) are caused by mutations in the BRI 2 gene. These diseases are characterized clinically by progressive dementia and ataxia and neuropathologically by amyloid deposits and neurofibrillary tangles. Herein, we investigate BRI 2 protein accumulation in FBD, FDD, Alzheimer disease and Gerstmann-Sträussler-Scheinker disease. In FBD and FDD, we observed reduced processing of the mutant BRI 2 pro-protein, which was found accumulating intracellularly in the Golgi of neurons and glial cells. In addition, we observed an accumulation of a mature form of BRI 2 protein in dystrophic neurites, surrounding amyloid cores. Accumulation of BRI 2 was also observed in dystrophic neurites of Alzheimer disease and Gerstmann-Sträussler-Scheinker disease cases. Although it remains to be determined whether intracellular accumulation of BRI 2 may lead to cell damage in these degenerative diseases, our study provides new insights into the role of mutant BRI 2 in the pathogenesis of FBD and FDD and implicates BRI 2 as a potential indicator of neuritic damage in diseases characterized by cerebral amyloid deposition. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Amyloid and intracellular accumulation of BRI2

    PubMed Central

    Garringer, Holly J.; Sammeta, Neeraja; Oblak, Adrian; Ghetti, Bernardino; Vidal, Ruben

    2016-01-01

    Familial British dementia (FBD) and familial Danish dementia (FDD) are caused by mutations in the BRI2 gene. These diseases are characterized clinically by progressive dementia and ataxia and neuropathologically by amyloid deposits and neurofibrillary tangles. Herein, we investigate BRI2 protein accumulation in FBD, FDD, Alzheimer disease and Gerstmann-Sträussler-Scheinker disease. In FBD and FDD, we observed reduced processing of the mutant BRI2 pro-protein, which was found accumulating intracellularly in the Golgi of neurons and glial cells. In addition, we observed an accumulation of a mature form of BRI2 protein in dystrophic neurites, surrounding amyloid cores. Accumulation of BRI2 was also observed in dystrophic neurites of Alzheimer disease and Gerstmann-Sträussler-Scheinker disease cases. Although it remains to be determined whether intracellular accumulation of BRI2 may lead to cell damage in these degenerative diseases, our study provides new insights into the role of mutant BRI2 in the pathogenesis of FBD and FDD and implicates BRI2 as a potential indicator of neuritic damage in diseases characterized by cerebral amyloid deposition. PMID:28131015

  9. Propylene glycol accumulation in critically ill patients receiving continuous intravenous lorazepam infusions.

    PubMed

    Horinek, Erica L; Kiser, Tyree H; Fish, Douglas N; MacLaren, Robert

    2009-12-01

    Lorazepam is recommended by the Society of Critical Care Medicine as the preferred agent for sedation of critically ill patients. Intravenous lorazepam contains propylene glycol, which has been associated with toxicity when high doses of lorazepam are administered. To evaluate the accumulation of propylene glycol in critically ill patients receiving lorazepam by continuous infusion and determine factors associated with propylene glycol concentration. A 6-month, retrospective, safety assessment was conducted of adults admitted to the medical intensive care unit who were receiving lorazepam by continuous infusion for 12 hours or more. Propylene glycol serum concentrations were obtained 24-48 hours after continuous-infusion lorazepam was initiated and every 3-5 days thereafter. Propylene glycol accumulation was defined as concentrations of 25 mg/dL or more. Groups with and without propylene glycol accumulation were compared and factors associated with propylene glycol concentration were determined using multivariate correlation regression analyses. Forty-eight propylene glycol serum samples were obtained from 33 patients. Fourteen (42%) patients had propylene glycol accumulation, representing 23 (48%) serum samples. Univariate analyses showed the following factors were related to propylene glycol accumulation: baseline renal dysfunction, presence of alcohol withdrawal, sex, age, Acute Physiology and Chronic Health Evaluation (APACHE II) score, rate of lorazepam continuous infusion, and 24-hour lorazepam dose. Multivariate linear regression modeling demonstrated that propylene glycol concentration was strongly associated with the continuous infusion rate and 24-hour dose (adjusted r(2) > or = 0.77; p < 0.001). Independent correlation analyses showed that these 2 variables were so strongly associated with propylene glycol concentration (r(2) > or = 0.71; p < 0.001) that they alone predicted propylene glycol concentration. Seven (21%) patients developed renal dysfunction

  10. Electrophysiological evidence for emotional valence and competitive arousal effects on insight problem solving.

    PubMed

    Li, Yadan; Xiao, Xiao; Ma, Wenjuan; Jiang, Jun; Qiu, Jiang; Zhang, Qinglin

    2013-11-13

    Accumulating evidence suggests that insight can be substantially influenced by task-irrelevant emotion stimuli and interpersonal competitive situation, and a close link might exist between them. Using a learning-testing paradigm and Event-Related Potentials (ERPs), the present study investigated the independent and joint effects of emotional and competitive information on insight problem solving especially their neural mechanisms. Subjects situated in either competitive or non-competitive condition learned heuristic logogriphs first and then viewed task-irrelevant positive or negative emotional pictures, which were followed by test logogriphs to solve. Both behavioral and ERP findings showed a more evident insight boost following negative emotional pictures in competitive context. Results demonstrated that negative emotion and competitive situation might promote insight by a defocused mode of attention (as indicated by N1 and P2), the enhanced semantic integration and breaking mental set (as indicated by N450), and the increased forming of novel associations activated by motivational arousal originating from competition (as indicated by P800-1600 and P1600-2500). These results indicate that the dynamic interactions between emotional valence and competitive arousal effects on insight. © 2013 Elsevier B.V. All rights reserved.

  11. Earliest accumulation history of the north polar layered deposits, Mars from SHARAD

    NASA Astrophysics Data System (ADS)

    Nerozzi, Stefano; Holt, John W.

    2018-07-01

    The approximately 2 km thick north polar layered deposits (NPLD) are often considered to contain the most complete and detailed stratigraphic records of recent climate of Mars. Exposures of the dense layering within troughs and scarps allowed detailed reconstructions of the latest accumulation history of these water ice deposits, but we lack knowledge of their initial emplacement. The Shallow Radar (SHARAD) onboard Mars Reconnaissance Orbiter (MRO) penetrates the NPLD to their base and detects their internal layering, overcoming the limitation of scarce and scattered visible outcrops of the lowermost sequences. In this study, we map reflectors in SHARAD data that result from discrete stratigraphic horizons in order to delineate the three-dimensional stratigraphy of the lowermost ∼500 m NPLD sequence and reconstruct their accumulation history. We confirm the large-scale lateral continuity and thickness uniformity of the deposits previously detected within the lowermost NPLD. However, stratigraphic complexity-in the form of pinch-outs and significant thickness variations-arises when we examine single radar units. We find evidence of an initially limited geographic stability of water ice within two deposits that are centered at the North Pole and present-day Gemina Lingula. A period of lateral ice sheet growth followed, interrupted only once by a retreat episode. Lower net accumulation is observed on pre-existing slopes, suggesting a reduction of water ice stability due to increased solar radiation incidence and/or transport by katabatic winds. Lateral transport of water ice by wind is also suggested by thickness undulations toward the top of the sequence, resembling cyclic steps. Water ice accumulation models based on orbital forcing predict a sequence of deposition and retreat events that is generally compatible with our reconstructed accumulation history. Therefore, we interpret the stratigraphic complexity that we observe as regional and, possibly global

  12. Molybdenum accumulation, tolerance and molybdenum-selenium-sulfur interactions in Astragalus selenium hyperaccumulator and nonaccumulator species.

    PubMed

    DeTar, Rachael Ann; Alford, Élan R; Pilon-Smits, Elizabeth A H

    2015-07-01

    Some species hyperaccumulate selenium (Se) upwards of 0.1% of dry weight. This study addressed whether Se hyperaccumulators also accumulate and tolerate more molybdenum (Mo). A field survey revealed on average 2-fold higher Mo levels in three hyperaccumulator Astragali compared to three nonaccumulator Astragali, which were not significantly different. Next, a controlled study was performed where hyperaccumulators Astragalus racemosus and Astragalus bisulcatus were compared with nonaccumulators Astragalus drummondii and Astragalus convallarius for Mo accumulation and tolerance, alone or in the presence of Se. When grown on agar media with 0, 12, 24 or 48 mg L(-1) molybdate and/or 0, 1.6 or 3.2 mg L(-1) selenate, all species decreased in biomass with increasing Mo supply. Selenium did not impact biomass at the supplied levels. All Astragali accumulated Mo upwards of 0.1% of dry weight. Selenium levels were up to 0.08% in Astragalus racemosus and 0.04% Se in the other species. Overall, there was no correlation between Se hyperaccumulation and Mo accumulation capacity. However, the hyperaccumulators and nonaccumulators differed in some respects. While none of the species had a higher tissue Mo to sulfur (S) ratio than the growth medium, nonaccumulators had a higher Mo/S ratio than hyperaccumulators. Also, while molybdate and selenate reduced S accumulation in nonaccumulators, it did not in hyperaccumulators. Furthermore, A. racemosus had a higher Se/S ratio than its medium, while the other species did not. Additionally, Mo and Se treatment affected S levels in nonaccumulators, but not in hyperaccumulators. In conclusion, there is no evidence of a link between Se and Mo accumulation and tolerance in Astragalus. Sulfate transporters in hyperaccumulating Astragali appear to have higher sulfate specificity over other oxyanions, compared to nonaccumulators, and A. racemosus may have a transporter with enhanced selenate specificity relative to sulfate or molybdate. Copyright

  13. U.S. Army Field Demonstration of the Single Common Powertrain Lubricant (SCPL)

    DTIC Science & Technology

    2015-02-01

    for a full 2-years without changes in the basic climate location demonstrating the SCPL’s extended drain capabilities. All three field...This was done to highlight any oil changes completed, whether they were required or not. 4.1 BASIC CLIMATE – FT. BENNING GA For the basic...were controlled tightly to determine actual changes . Table 20. Ft. Wainwright Arctic Climate Vehicle Fleet 4.2.2 Mileage Accumulation Overall

  14. High-field penning-malmberg trap: confinement properties and use in positron accumulation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hartley, J.H.

    1997-09-01

    This dissertation reports on the development of the 60 kG cryogenic positron trap at Lawrence Livermore National Laboratory, and compares the trap`s confinement properties with other nonneutral plasma devices. The device is designed for the accumulation of up to 2{times}10{sup 9} positrons from a linear-accelerator source. This positron plasma could then be used in Bhabha scattering experiments. Initial efforts at time-of-flight accumulation of positrons from the accelerator show rapid ({approximately}100 ms) deconfinement, inconsistent with the long electron lifetimes. Several possible deconfinement mechanisms have been explored, including annihilation on residual gas, injection heating, rf noise from the accelerator, magnet field curvature,more » and stray fields. Detailed studies of electron confinement demonstrate that the empirical scaling law used to design the trap cannot be extrapolated into the parameter regime of this device. Several possible methods for overcoming these limitations are presented.« less

  15. Mechanisms of soil organic carbon accumulation from long-term fertilization strategies in two soils: Evidence from nuclear magnetic resonance spectroscopy analysis

    USDA-ARS?s Scientific Manuscript database

    Long-term fertilization strategies have been proven to significantly influence soil organic carbon (SOC) accumulation, while the underlying mechanism remains unclear. Using two long-term (>20 y) field experiments of a double-cropped maize-wheat rotation on a Calcaric Fluvisol and paddy rice on a Hyd...

  16. Oxidative stress caused by ozone exposure induces β-amyloid 1-42 overproduction and mitochondrial accumulation by activating the amyloidogenic pathway.

    PubMed

    Hernández-Zimbrón, L F; Rivas-Arancibia, S

    2015-09-24

    Oxidative stress is a major risk factor for Alzheimer's disease (AD) that has been suggested to be the trigger of AD pathology. However, whether oxidative damage precedes and contributes directly to the intracellular accumulation of beta amyloid 1-42 (βA42) peptide remains a matter of debate. Chronic exposure to low doses of ozone similar to the levels during a day of high pollution in México City causes a state of oxidative stress that elicits progressive neurodegeneration in the hippocampi of rats. Several reports have demonstrated that the mitochondria are among the first organelles to be affected by oxidative stress and βA42 toxicity and act as sites of the accumulation of βA42, which affects energy metabolism. However, the mechanisms related to the neurodegeneration process and organelle damage that occur in conditions of chronic exposure to low doses of ozone have not been demonstrated. To analyze the effect of chronic ozone chronic exposure on changes in the production and accumulation of the βA42 and βA40 peptides in the mitochondria of hippocampal neurons of rats exposed to ozone, we examined the mitochondrial expression levels of Presenilins 1 and 2 and ADAM10 to detect changes related to the oxidative stress caused by low doses of ozone (0.25ppm). The results revealed significant accumulations of βA42 peptide in the mitochondrial fractions on days 60 and 90 of ozone exposure along with reductions in beta amyloid 1-40 accumulation, significant overexpressions of Pres2 and significant reductions in ADAM10 expression. Beta amyloid immunodetection revealed that there were some intracellular deposits of βA42 and that βA42 and the mitochondrial markers OPA1 and COX1 colocalized. These results indicate that the time of exposure to ozone and the accumulation of βA42 in the mitochondria of the hippocampal cells of rats were correlated. Our results suggest that the accumulation of the βA42 peptide may promote mitochondrial dysfunction due to its

  17. Host-pathogen interactions. XV. Fungal glucans which elicit phytoalexin accumulation in soybean also elicit the accumulation of phytoalexins in other plants

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cline, K.; Wade, M.; Albersheim, P.

    1978-01-01

    A ..beta..-glucan isolated from the mycelial walls of Phytophthora megasperma var. sojae and a glucan purified from yeast extract stimulate the accumulation of phytoalexins in red kidney bean, Phaseolus vulgaris, and stimulate the accumulation of the phytoalexin, rishitin, in potato tubers, Solanum tuberosum. Treatment of kidney bean cotyledons with the glucan elicitors resulted in the accumulation of at least five fungistatic compounds. These compounds migrate during thin layer chromatography identically to the fungistatic compounds which accumulate in kidney beans which have been inoculated with Colletotrichum lindemuthianum, a fungal pathogen of kidney beans. Potatoes accumulate as much as 29 micrograms ofmore » rishitin per gram fresh weight following exposure to the glucan from Phytophthora megasperma va. sojae and as much as 19.5 micrograms of rishitin per gram fresh weight following exposure to yeast glucan.« less

  18. Adaptive History Biases Result from Confidence-Weighted Accumulation of past Choices

    PubMed Central

    2018-01-01

    Perceptual decision-making is biased by previous events, including the history of preceding choices: observers tend to repeat (or alternate) their judgments of the sensory environment more often than expected by chance. Computational models postulate that these so-called choice history biases result from the accumulation of internal decision signals across trials. Here, we provide psychophysical evidence for such a mechanism and its adaptive utility. Male and female human observers performed different variants of a challenging visual motion discrimination task near psychophysical threshold. In a first experiment, we decoupled categorical perceptual choices and motor responses on a trial-by-trial basis. Choice history bias was explained by previous perceptual choices, not motor responses, highlighting the importance of internal decision signals in action-independent formats. In a second experiment, observers performed the task in stimulus environments containing different levels of autocorrelation and providing no external feedback about choice correctness. Despite performing under overall high levels of uncertainty, observers adjusted both the strength and the sign of their choice history biases to these environments. When stimulus sequences were dominated by either repetitions or alternations, the individual degree of this adjustment of history bias was about as good a predictor of individual performance as individual perceptual sensitivity. The history bias adjustment scaled with two proxies for observers' confidence about their previous choices (accuracy and reaction time). Together, our results are consistent with the idea that action-independent, confidence-modulated decision variables are accumulated across choices in a flexible manner that depends on decision-makers' model of their environment. SIGNIFICANCE STATEMENT Decisions based on sensory input are often influenced by the history of one's preceding choices, manifesting as a bias to systematically repeat

  19. Adaptive History Biases Result from Confidence-weighted Accumulation of Past Choices.

    PubMed

    Braun, Anke; Urai, Anne E; Donner, Tobias H

    2018-01-25

    Perceptual decision-making is biased by previous events, including the history of preceding choices: Observers tend to repeat (or alternate) their judgments of the sensory environment more often than expected by chance. Computational models postulate that these so-called choice history biases result from the accumulation of internal decision signals across trials. Here, we provide psychophysical evidence for such a mechanism and its adaptive utility. Male and female human observers performed different variants of a challenging visual motion discrimination task near psychophysical threshold. In a first experiment, we decoupled categorical perceptual choices and motor responses on a trial-by-trial basis. Choice history bias was explained by previous perceptual choices, not motor responses, highlighting the importance of internal decision signals in action-independent formats. In a second experiment, observers performed the task in stimulus environments containing different levels of auto-correlation and providing no external feedback about choice correctness. Despite performing under overall high levels of uncertainty, observers adjusted both the strength and the sign of their choice history biases to these environments. When stimulus sequences were dominated by either repetitions or alternations, the individual degree of this adjustment of history bias was about as good a predictor of individual performance as individual perceptual sensitivity. The history bias adjustment scaled with two proxies for observers' confidence about their previous choices (accuracy and reaction time). Taken together, our results are consistent with the idea that action-independent, confidence-modulated decision variables are accumulated across choices in a flexible manner that depends on decision-makers' model of their environment. Significance statement: Decisions based on sensory input are often influenced by the history of one's preceding choices, manifesting as a bias to

  20. Factors influencing the accumulation of ciprofloxacin in Pseudomonas aeruginosa.

    PubMed Central

    Celesk, R A; Robillard, N J

    1989-01-01

    Ciprofloxacin accumulation in Pseudomonas aeruginosa was measured by a bioassay. Drug accumulation in strain PAO2 was compared with that of three spontaneous ciprofloxacin-resistant mutants selected with 0.5 micrograms of ciprofloxacin per ml. PAO4701 cfxA2 contains a mutation in the gyrA gene, PAO4742 cfxB5 may represent a permeability mutant based on pleiotropic drug resistance, and PAO4700 cfxA1 cfxB1 contains both types of mutations. In all strains, drug accumulation was similar, reaching steady state during the first minute of exposure. Drug accumulation was unsaturable over a range of 5 to 80 micrograms/ml, suggesting that ciprofloxacin accumulates by diffusion in P. aeruginosa. Although all four strains accumulated two- to sevenfold more ciprofloxacin in the presence of the inhibitor carbonyl cyanide m-chlorophenylhydrazone, the cfxB mutants accumulated two- to fourfold less drug than either PAO2 or the cfxA2 mutant. Polyacrylamide gel analysis revealed a protein common to cfxB mutants only, while all strains had similar lipopolysaccharide profiles. The results suggest that ciprofloxacin accumulation in P. aeruginosa is a complex phenomenon that may be affected by both an energy-dependent drug efflux process and outer envelope composition. Images PMID:2514623

  1. In Vivo Inhibition of Lipid Accumulation in Caenorhabditis elegans

    NASA Astrophysics Data System (ADS)

    Sulistiyani; Purwakusumah, E. P.; Andrianto, D.

    2017-03-01

    This is a preliminary research report on the use of Caenorhabditis elegans as a model to establish anti-obesity screening assay of the natural plant resources. Nematode C. elegans has been used as experimental animal model for understanding lipid accumulation. The objective of this research was to investigate the effect of selected plant extracts on lipid accumulation in C. elegans. Currently no report could be found regarding lipid accumulation in C.elegans treated with ethanolic leaf extracts of jabon merah (Anthocephalus macrophyllus), jati belanda (Guazuma ulmifolia), and Mindi (Melia Azedarach) plants. Lipid accumulation was determined qualitatively using lipid staining method and quantitatively by colorimetry using sulpho-phospho-vanillin reagent. Data showed that lipid accumulation was inhibited up to 72% by extract of M. azedarach, about 35% by both of A. macrophyllus and G. ulmifolia extracts, and up to 25% by orlistat (a synthetic slimming drug). Ethanolic extract of A. macrophyllus, G. ulmifolia, and M. azedarach leaves were shown to inhibit lipid accumulation in C. elegans and M. azedarach leaves extracts was the most effective inhibitor. C.elegans were shown to be an effective model for in vivo lipid accumulation mechanism and potential to be used as a rapid screening assay for bioactive compounds with lipid accumulation inhibitory activity.

  2. Accumulation of cyanobacterial hepatotoxins by Daphnia in some Egyptian irrigation canals.

    PubMed

    Mohamed, Z A

    2001-09-01

    In this study, microcosm experiments were run in the laboratory to test the possibility of feeding of Daphnia parvula on toxic Microcystis aeruginosa in some Egyptian irrigation canal at Sohag city. The results demonstrated that Daphnia has a priority of feeding on green algae and the diatom Melosira granulata over toxic M. aeruginosa during the first 10 days. Thereafter, when the green algae and diatom were depleted from the water, Daphnia started to feed on toxic Microcystis. This presumably indicates that Daphnia feeds facultatively on toxic cyanobacteria under the conditions of depletion of edible food. Additionally, the results indicated that Daphnia accumulates the Microcystis toxins "microcystins" in its body with a level of 1.78 microg toxin/25 daphnids. No release of toxin into the water was detected during the experimental period. This emphasizes that the disappearance of toxic Microcystis was due to the feeding by Daphnia, not to death or cell lysis. Such an accumulation of cyanobacterial hepatotoxins in the primary consumers (Daphnia) should be taken into consideration when zooplankton are used in the biomanipulation of toxic phytoplankton. Copyright 2001 Academic Press.

  3. [99mTc(V)-DMSA accumulation in gynecomastia].

    PubMed

    Ohta, H

    1998-11-01

    The accumulation of 99mTc(V)-DMSA in bilateral breasts was recognized in a 60-year-old male with drug-induced gynecomastia. There are some reports describing 99mTc(V)-DMSA accumulation in normal female breast, fibrous dysplasia of the breast and metastatic lesions of breast carcinoma, but to my knowledge, there have been no reports describing 99mTc(V)-DMSA accumulation in gynecomastia.

  4. Distinctive accumulation patterns of heavy metals in Sardinella aurita (Clupeidae) and Mugil cephalus (Mugilidae) tissues.

    PubMed

    Annabi, Ali; El Mouadeb, Rahma; Herrel, Anthony

    2018-01-01

    The present study assessed the impact of metal pollution on two widely consumed types of wild fish Sardinella aurita and Mugil cephalus captured from the Gulf of Gabes (Tunisia) which is currently experiencing acute environmental problems. A study of the Cd, Cu, Zn, and Pb levels present in the studied site and vital in fish tissues (gills, liver, gonad, and muscle) was undertaken. As expected, muscle, liver, and gonad tissues contained the highest concentrations of all metals except for Zn. The metal levels showed a significant variation of accumulation between species with overall effects of the tested tissues. In addition, the results address the significant effects of the species/tissue interaction. Liver sections showed structural alterations consisting mainly of a significant desquamation of the tissue, a fibroblast proliferation, and a lipid droplet accumulation in both species. Additionally, the presence of skeletal abnormalities affecting the vertebral column was observed in the M. cephalus specimens. As a whole, our data provide the first evidence of distinctive metal accumulation patterns in vital fish tissues as well as the interspecific difference that can be correlated with the biological habits of the two selected models, S. aurita and M. cephalus, known respectively as pelagic and benthopelagic species.

  5. Unprecedented last-glacial mass accumulation rates determined by luminescence dating of loess from western Nebraska

    USGS Publications Warehouse

    Roberts, H.M.; Muhs, D.R.; Wintle, A.G.; Duller, G.A.T.; Bettis, E. Arthur

    2003-01-01

    A high-resolution chronology for Peoria (last glacial period) Loess from three sites in Nebraska, midcontinental North America, is determined by applying optically stimulated luminescence (OSL) dating to 35-50 ??m quartz. At Bignell Hill, Nebraska, an OSL age of 25,000 yr near the contact of Peoria Loess with the underlying Gilman Canyon Formation shows that dust accumulation occurred early during the last glacial maximum (LGM), whereas at Devil's Den and Eustis, Nebraska, basal OSL ages are significantly younger (18,000 and 21,000 yr, respectively). At all three localities, dust accumulation ended at some time after 14,000 yr ago. Mass accumulation rates (MARs) for western Nebraska, calculated using the OSL ages, are extremely high from 18,000 to 14,000 yr-much higher than those calculated for any other pre-Holocene location worldwide. These unprecedented MARs coincide with the timing of a mismatch between paleoenvironmental evidence from central North America, and the paleoclimate simulations from atmospheric global circulation models (AGCMs). We infer that the high atmospheric dust loading implied by these MARs may have played an important role, through radiative forcing, in maintaining a colder-than-present climate over central North America for several thousand years after summer insolation exceeded present-day values. ?? 2003 Elsevier Science (USA). All rights reserved.

  6. Evidence of leopard predation on bonobos (Pan paniscus).

    PubMed

    D'Amour, Danielle E; Hohmann, Gottfried; Fruth, Barbara

    2006-01-01

    Current models of social organization assume that predation is one of the major forces that promotes group living in diurnal primates. As large body size renders some protection against predators, gregariousness of great apes and other large primate species is usually related to other parameters. The low frequency of observed cases of nonhuman predation on great apes seems to support this assumption. However, recent efforts to study potential predator species have increasingly accumulated direct and indirect evidence of predation by leopards (Panthera pardus) on chimpanzees and gorillas. The following report provides the first evidence of predation by a leopard on bonobos (Pan paniscus). Copyright 2006 S. Karger AG, Basel.

  7. Evaluation of two models for predicting elemental accumulation by arthropods

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Webster, J.R.; Crossley, D.A. Jr.

    1978-06-15

    Two different models have been proposed for predicting elemental accumulation by arthropods. Parameters of both models can be quantified from radioisotope elimination experiments. Our analysis of the 2 models shows that both predict identical elemental accumulation for a whole organism, though differing in the accumulation in body and gut. We quantified both models with experimental data from /sup 134/Cs and /sup 85/Sr elimination by crickets. Computer simulations of radioisotope accumulation were then compared with actual accumulation experiments. Neither model showed exact fit to the experimental data, though both showed the general pattern of elemental accumulation.

  8. Bilirubin Binding to PPARα Inhibits Lipid Accumulation

    PubMed Central

    Stec, David E.; John, Kezia; Trabbic, Christopher J.; Luniwal, Amarjit; Hankins, Michael W.; Baum, Justin

    2016-01-01

    Numerous clinical and population studies have demonstrated that increased serum bilirubin levels protect against cardiovascular and metabolic diseases such as obesity and diabetes. Bilirubin is a potent antioxidant, and the beneficial actions of moderate increases in plasma bilirubin have been thought to be due to the antioxidant effects of this bile pigment. In the present study, we found that bilirubin has a new function as a ligand for PPARα. We show that bilirubin can bind directly to PPARα and increase transcriptional activity. When we compared biliverdin, the precursor to bilirubin, on PPARα transcriptional activation to known PPARα ligands, WY 14,643 and fenofibrate, it showed that fenofibrate and biliverdin have similar activation properties. Treatment of 3T3-L1 adipocytes with biliverdin suppressed lipid accumulation and upregulated PPARα target genes. We treated wild-type and PPARα KO mice on a high fat diet with fenofibrate or bilirubin for seven days and found that both signal through PPARα dependent mechanisms. Furthermore, the effect of bilirubin on lowering glucose and reducing body fat percentage was blunted in PPARα KO mice. These data demonstrate a new function for bilirubin as an agonist of PPARα, which mediates the protection from adiposity afforded by moderate increases in bilirubin. PMID:27071062

  9. La Deletion from Mouse Brain Alters Pre-tRNA Metabolism and Accumulation of Pre-5.8S rRNA, with Neuron Death and Reactive Astrocytosis

    PubMed Central

    Blewett, Nathan H.; Iben, James R.; Gaidamakov, Sergei

    2017-01-01

    ABSTRACT Human La antigen (Sjögren's syndrome antigen B [SSB]) is an abundant multifunctional RNA-binding protein. In the nucleoplasm, La binds to and protects from 3′ exonucleases, the ends of precursor tRNAs, and other transcripts synthesized by RNA polymerase III and facilitates their maturation, while a nucleolar isoform has been implicated in rRNA biogenesis by multiple independent lines of evidence. We showed previously that conditional La knockout (La cKO) from mouse cortex neurons results in defective tRNA processing, although the pathway(s) involved in neuronal loss thereafter was unknown. Here, we demonstrate that La is stably associated with a spliced pre-tRNA intermediate. Microscopic evidence of aberrant nuclear accumulation of 5.8S rRNA in La cKO is supported by a 10-fold increase in a pre-5.8S rRNA intermediate. To identify pathways involved in subsequent neurodegeneration and loss of brain mass in the cKO cortex, we employed mRNA sequencing (mRNA-Seq), immunohistochemistry, and other approaches. This revealed robust enrichment of immune and astrocyte reactivity in La cKO cortex. Immunohistochemistry, including temporal analyses, demonstrated neurodegeneration, followed by astrocyte invasion associated with immune response and decreasing cKO cortex size over time. Thus, deletion of La from postmitotic neurons results in defective pre-tRNA and pre-rRNA processing and progressive neurodegeneration with loss of cortical brain mass. PMID:28223366

  10. Evaluation of urban environment pollution based on the accumulation of macro- and trace elements in epiphytic lichens.

    PubMed

    Parzych, Agnieszka; Astel, Aleksander; Zduńczyk, Anna; Surowiec, Tomasz

    2016-01-01

    Nitrogen, phosphorus, potassium, magnesium, zinc, nickel, copper, manganese, iron and lead accumulation properties of three epiphytic lichen species (Hypogymnia physodes (L.) Nyl., Parmelia sulcata Taylor and Xanthoria parietina (L.) Th. Fr.) were compared. An assessment of pollution of the municipal environment in Słupsk (Poland) according to macro- and trace elements was also done. Lichen samples were taken in Autumn 2013 from Betula pendula, Fraxinus excelsior, Acer platanoides, A. pseudoplatanus and Populus sp. trees. Sampling stations comprised of house development areas, green urban parks, vicinity of streets with heavy traffic and industrial enterprises. It was found that lichens represent diverse accumulation properties to pollutants according to the species. X. parietina indicated the highest bioaccumulation in relation to N, K, Mg, Zn and Fe, the thalli of H. physodes accumulated the largest amounts of Ni and Pb, while P. sulcata P and Cu. Manganese was accumulated in similar quantities by all species. Evidences acquired by the use of factor analysis proved that pollution in Słupsk municipal environment is a serious issue with three major sources domination: street dust, marine factor and residual oil combustion. The high-risk areas were detected and visualized using surface maps based on Kriging algorithm. It was seen that the highest pollution occurs in the town centre, while the smallest happened on its outskirts and in urban parks.

  11. Chronic Alcohol Ingestion in Rats Alters Lung Metabolism, Promotes Lipid Accumulation, and Impairs Alveolar Macrophage Functions

    PubMed Central

    Romero, Freddy; Shah, Dilip; Duong, Michelle; Stafstrom, William; Hoek, Jan B.; Kallen, Caleb B.; Lang, Charles H.

    2014-01-01

    Chronic alcoholism impairs pulmonary immune homeostasis and predisposes to inflammatory lung diseases, including infectious pneumonia and acute respiratory distress syndrome. Although alcoholism has been shown to alter hepatic metabolism, leading to lipid accumulation, hepatitis, and, eventually, cirrhosis, the effects of alcohol on pulmonary metabolism remain largely unknown. Because both the lung and the liver actively engage in lipid synthesis, we hypothesized that chronic alcoholism would impair pulmonary metabolic homeostasis in ways similar to its effects in the liver. We reasoned that perturbations in lipid metabolism might contribute to the impaired pulmonary immunity observed in people who chronically consume alcohol. We studied the metabolic consequences of chronic alcohol consumption in rat lungs in vivo and in alveolar epithelial type II cells and alveolar macrophages (AMs) in vitro. We found that chronic alcohol ingestion significantly alters lung metabolic homeostasis, inhibiting AMP-activated protein kinase, increasing lipid synthesis, and suppressing the expression of genes essential to metabolizing fatty acids (FAs). Furthermore, we show that these metabolic alterations promoted a lung phenotype that is reminiscent of alcoholic fatty liver and is characterized by marked accumulation of triglycerides and free FAs within distal airspaces, AMs, and, to a lesser extent, alveolar epithelial type II cells. We provide evidence that the metabolic alterations in alcohol-exposed rats are mechanistically linked to immune impairments in the alcoholic lung: the elevations in FAs alter AM phenotypes and suppress both phagocytic functions and agonist-induced inflammatory responses. In summary, our work demonstrates that chronic alcohol ingestion impairs lung metabolic homeostasis and promotes pulmonary immune dysfunction. These findings suggest that therapies aimed at reversing alcohol-related metabolic alterations might be effective for preventing and

  12. Anion channels and the stimulation of anthocyanin accumulation by blue light in Arabidopsis seedlings

    NASA Technical Reports Server (NTRS)

    Noh, B.; Spalding, E. P.; Evans, M. H. (Principal Investigator)

    1998-01-01

    Activation of anion channels by blue light begins within seconds of irradiation in seedlings and is related to the ensuing growth inhibition. 5-Nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB) is a potent, selective, and reversible blocker of these anion channels in Arabidopsis thaliana. Here we show that 20 microM NPPB blocked 72% of the blue-light-induced accumulation of anthocyanin pigments in seedlings. Feeding biosynthetic intermediates to wild-type and tt5 seedlings provided evidence that NPPB prevented blue light from up-regulating one or more steps between and including phenylalanine ammonia lyase and chalcone isomerase. NPPB was found to have no significant effect on the blue-light-induced increase in transcript levels of PAL1, CHS, CHI, or DFR, which are genes that encode anthocyanin-biosynthetic enzymes. Immunoblots revealed that NPPB also did not inhibit the accumulation of the chalcone synthase, chalcone isomerase, or flavanone-3-hydroxylase proteins. This is in contrast to the reduced anthocyanin accumulation displayed by a mutant lacking the HY4 blue-light receptor, as hy4 displayed reduced expression of the above enzymes. Taken together, the data indicate that blue light acting through HY4 leads to an increase in the amount of biosynthetic enzymes but blue light must also act through a separate, anion-channel-dependent system to create a fully functional biosynthetic pathway.

  13. Increase methylmercury accumulation in Arabidopsis thaliana expressing bacterial broad-spectrum mercury transporter MerE

    PubMed Central

    2013-01-01

    The bacterial merE gene derived from the Tn21 mer operon encodes a broad-spectrum mercury transporter that governs the transport of methylmercury and mercuric ions across bacterial cytoplasmic membranes, and this gene is a potential molecular tool for improving the efficiency of methylmercury phytoremediation. A transgenic Arabidopsis engineered to express MerE was constructed and the impact of expression of MerE on methylmercury accumulation was evaluated. The subcellular localization of transiently expressed GFP-tagged MerE was examined in Arabidopsis suspension-cultured cells. The GFP-MerE was found to localize to the plasma membrane and cytosol. The transgenic Arabidopsis expressing MerE accumulated significantly more methymercury and mercuric ions into plants than the wild-type Arabidopsis did. The transgenic plants expressing MerE was significantly more resistant to mercuric ions, but only showed more resistant to methylmercury compared with the wild type Arabidopsis. These results demonstrated that expression of the bacterial mercury transporter MerE promoted the transport and accumulation of methylmercury in transgenic Arabidopsis, which may be a useful method for improving plants to facilitate the phytoremediation of methylmercury pollution. PMID:24004544

  14. THE SOURCE OF LIPID ACCUMULATION IN L CELLS

    PubMed Central

    Bensch, Klaus G.; King, Donald W.; Socolow, Edward L.

    1961-01-01

    Strain L cells accumulate lipid, concurrent with cessation of protein synthesis, in the stationary phase of growth from the extracellular medium and as a result of de novo synthesis. Cells which have been more severely damaged with an amino acid analogue also accumulate lipid from the extracellular medium, but synthesize very little lipid from labeled acetate. The possible roles which lipid accumulation may play in the cell are discussed. PMID:19866577

  15. Total carbon accumulation in a tropical forest landscape.

    PubMed

    Sierra, Carlos A; Del Valle, Jorge I; Restrepo, Hector I

    2012-12-19

    Regrowing tropical forests worldwide sequester important amounts of carbon and restore part of the C emissions emitted by deforestation. However, there are large uncertainties concerning the rates of carbon accumulation after the abandonment of agricultural and pasture land. We report here accumulation of total carbon stocks (TCS) in a chronosequence of secondary forests at a mid-elevation landscape (900-1200 m asl) in the Andean mountains of Colombia. We found positive accumulation rates for all ecosystem pools except soil carbon, which showed no significant trend of recovery after 36 years of secondary succession. We used these data to develop a simple model to predict accumulation of TCS over time. This model performed remarkably well predicting TCS at other chronosequences in the Americas (Root Mean Square Error < 40 Mg C ha-1), which provided an opportunity to explore different assumptions in the calculation of large-scale carbon budgets. Simulations of TCS with our empirical model were used to test three assumptions often made in carbon budgets: 1) the use of carbon accumulation in tree aboveground biomass as a surrogate for accumulation of TCS, 2) the implicit consideration of carbon legacies from previous land-use, and 3) the omission of landscape age in calculating accumulation rates of TCS. Our simulations showed that in many situations carbon can be released from regrowing secondary forests depending on the amount of carbon legacies and the average age of the landscape. In most cases, the rates used to predict carbon accumulation in the Americas were above the rates predicted in our simulations. These biome level rates seemed to be realistic only in landscapes not affected by carbon legacies from previous land-use and mean ages of around 10 years.

  16. Total carbon accumulation in a tropical forest landscape

    PubMed Central

    2012-01-01

    Background Regrowing tropical forests worldwide sequester important amounts of carbon and restore part of the C emissions emitted by deforestation. However, there are large uncertainties concerning the rates of carbon accumulation after the abandonment of agricultural and pasture land. We report here accumulation of total carbon stocks (TCS) in a chronosequence of secondary forests at a mid-elevation landscape (900-1200 m asl) in the Andean mountains of Colombia. Results We found positive accumulation rates for all ecosystem pools except soil carbon, which showed no significant trend of recovery after 36 years of secondary succession. We used these data to develop a simple model to predict accumulation of TCS over time. This model performed remarkably well predicting TCS at other chronosequences in the Americas (Root Mean Square Error < 40 Mg C ha-1), which provided an opportunity to explore different assumptions in the calculation of large-scale carbon budgets. Simulations of TCS with our empirical model were used to test three assumptions often made in carbon budgets: 1) the use of carbon accumulation in tree aboveground biomass as a surrogate for accumulation of TCS, 2) the implicit consideration of carbon legacies from previous land-use, and 3) the omission of landscape age in calculating accumulation rates of TCS. Conclusions Our simulations showed that in many situations carbon can be released from regrowing secondary forests depending on the amount of carbon legacies and the average age of the landscape. In most cases, the rates used to predict carbon accumulation in the Americas were above the rates predicted in our simulations. These biome level rates seemed to be realistic only in landscapes not affected by carbon legacies from previous land-use and mean ages of around 10 years. PMID:23249727

  17. Accumulation of the Antibiotic Phenazine-1-Carboxylic Acid in the Rhizosphere of Dryland Cereals

    PubMed Central

    Mavrodi, Dmitri V.; Mavrodi, Olga V.; Parejko, James A.; Bonsall, Robert F.; Kwak, Youn-Sig; Paulitz, Timothy C.; Weller, David M.

    2012-01-01

    Natural antibiotics are thought to function in the defense, fitness, competitiveness, biocontrol activity, communication, and gene regulation of microorganisms. However, the scale and quantitative aspects of antibiotic production in natural settings are poorly understood. We addressed these fundamental questions by assessing the geographic distribution of indigenous phenazine-producing (Phz+) Pseudomonas spp. and the accumulation of the broad-spectrum antibiotic phenazine-1-carboxylic acid (PCA) in the rhizosphere of wheat grown in the low-precipitation zone (<350 mm) of the Columbia Plateau and in adjacent, higher-precipitation areas. Plants were collected from 61 commercial wheat fields located within an area of about 22,000 km2. Phz+ Pseudomonas spp. were detected in all sampled fields, with mean population sizes ranging from log 3.2 to log 7.1 g−1 (fresh weight) of roots. Linear regression analysis demonstrated a significant inverse relationship between annual precipitation and the proportion of plants colonized by Phz+ Pseudomonas spp. (r2 = 0.36, P = 0.0001). PCA was detected at up to nanomolar concentrations in the rhizosphere of plants from 26 of 29 fields that were selected for antibiotic quantitation. There was a direct relationship between the amount of PCA extracted from the rhizosphere and the population density of Phz+ pseudomonads (r2 = 0.46, P = 0.0006). This is the first demonstration of accumulation of significant quantities of a natural antibiotic across a terrestrial ecosystem. Our results strongly suggest that natural antibiotics can transiently accumulate in the plant rhizosphere in amounts sufficient not only for inter- and intraspecies signaling but also for the direct inhibition of sensitive organisms. PMID:22138981

  18. Cigarette smoke-induced accumulation of lung dendritic cells is interleukin-1α-dependent in mice

    PubMed Central

    2012-01-01

    Background Evidence suggests that dendritic cells accumulate in the lungs of COPD patients and correlate with disease severity. We investigated the importance of IL-1R1 and its ligands IL-1α and β to dendritic cell accumulation and maturation in response to cigarette smoke exposure. Methods Mice were exposed to cigarette smoke using a whole body smoke exposure system. IL-1R1-, TLR4-, and IL-1α-deficient mice, as well as anti-IL-1α and anti-IL-1β blocking antibodies were used to study the importance of IL-1R1 and TLR4 to dendritic cell accumulation and activation. Results Acute and chronic cigarette smoke exposure led to increased frequency of lung dendritic cells. Accumulation and activation of dendritic cells was IL-1R1/IL-1α dependent, but TLR4- and IL-1β-independent. Corroborating the cellular data, expression of CCL20, a potent dendritic cells chemoattractant, was IL-1R1/IL-1α-dependent. Studies using IL-1R1 bone marrow-chimeric mice revealed the importance of IL-1R1 signaling on lung structural cells for CCL20 expression. Consistent with the importance of dendritic cells in T cell activation, we observed decreased CD4+ and CD8+ T cell activation in cigarette smoke-exposed IL-1R1-deficient mice. Conclusion Our findings convey the importance of IL-1R1/IL-1α to the recruitment and activation of dendritic cells in response to cigarette smoke exposure. PMID:22992200

  19. The Benefits of Attending Community College: A Review of the Evidence

    ERIC Educational Resources Information Center

    Belfield, Clive R.; Bailey, Thomas

    2011-01-01

    This article reviews the existing literature on the economic and other benefits of attending community college. First, the article reports on the earnings gains across all students and reviews the evidence for subgroups by gender, minority status, and credits accumulated. The article then reviews the methodological challenges associated with…

  20. Evidence-Based Language Practice

    ERIC Educational Resources Information Center

    Pollock, Eric J.

    2005-01-01

    The purpose of this paper was to examine evidence-based procedures in medicine and to demonstrate that the same protocols can be used in English language instruction. In the evidence-based methodology, studies are divided into those that address specific language problems. Integrated studies are presented as a systematic overview, meta-analysis,…

  1. Identification of oleaginous yeast strains able to accumulate high intracellular lipids when cultivated in alkaline pretreated corn stover

    PubMed Central

    Sitepu, Irnayuli R.; Jin, Mingjie; Fernandez, J. Enrique; da Costa Sousa, Leonardo; Balan, Venkatesh; Boundy-Mills, Kyria L.

    2015-01-01

    Microbial oil is a potential alternative to food/plant-derived biodiesel fuel. Our previous screening studies identified a wide range of oleaginous yeast species, using a defined laboratory medium known to stimulate lipid accumulation. In this study, the ability of these yeasts to grow and accumulate lipids was further investigated in synthetic hydrolysate (SynH) and authentic ammonia fiber expansion (AFEX™)-pretreated corn stover hydrolysate (ACSH). Most yeast strains tested were able to accumulate lipids in SynH, but only a few were able to grow and accumulate lipids in ACSH medium. Cryptococcus humicola UCDFST 10-1004 was able to accumulate as high as 15.5 g/L lipids, out of a total of 36 g/L cellular biomass when grown in ACSH, with a cellular lipid content of 40% of cell dry weight. This lipid production is among the highest reported values for oleaginous yeasts grown in authentic hydrolysate. Pre-culturing in SynH media with xylose as sole carbon source enabled yeasts to assimilate both glucose and xylose more efficiently in the subsequent hydrolysate medium. This study demonstrates that ACSH is a suitable medium for certain oleaginous yeasts to convert lignocellullosic sugars to triacylglycerols for production of biodiesel and other valuable oleochemicals. PMID:25052467

  2. Contribution of extracellular ATP on the cell-surface F1F0-ATP synthase-mediated intracellular triacylglycerol accumulation.

    PubMed

    Kita, Toshiyuki; Arakaki, Naokatu

    2015-01-01

    Cell-surface F1F0-ATP synthase was involved in the cell signaling mediating various biological functions. Recently, we found that cell-surface F1F0-ATP synthase plays a role on intracellular triacylglycerol accumulation in adipocytes, and yet, the underlying mechanisms remained largely unknown. In this study, we investigated the role of extracellular ATP on the intracellular triacylglycerol accumulation. We demonstrated that significant amounts of ATP were produced extracellularly by cultured 3T3-L1 adipocytes and that the antibodies against α and β subunits of F1F0-ATP synthase inhibited the extracellular ATP production. Piceatannol, a F1F0-ATP synthase inhibitor, and apyrase, an enzyme which degrades extracellular ATP, suppressed triacylglycerol accumulation. The selective P2Y1 receptor antagonist MRS2500 significantly inhibited triacylglycerol accumulation, whereas the selective P2X receptor antagonist NF279 has less effect. The present results indicate that cell-surface F1F0-ATP synthase on adipocytes is functional in extracellular ATP production and that the extracellular ATP produced contributes, at least in part, to the cell-surface F1F0-ATP synthase-mediated intracellular triacylglycerol accumulation in adipocytes through P2Y1 receptor.

  3. Interaction and accumulation of manganese and cadmium in the manganese accumulator Lupinus albus.

    PubMed

    Zornoza, Pilar; Sánchez-Pardo, Beatriz; Carpena, Ramón O

    2010-09-01

    The effects of the interaction between Mn and Cd on the growth of the white lupin (Lupinus albus), uptake of these metals, their accumulation, and effects on heavy metal stress indicators were studied under glasshouse conditions. Plants were grown with and without Mn and/or Cd for 4 weeks. The absence of Mn and Cd led to lipid peroxidation-induced loss of flavonoids and anthocyanins in the roots, reduced the size of the plant canopy, and led to the appearance of proteoid roots. Sensitivity to Cd in white lupin was enhanced by a low Mn supply, despite lower Cd uptake and accumulation (leaf Mn:Cd concentration ratio <3), as evidenced by increased lipid peroxidation in the leaves and strong inhibition of growth. However, when the Mn supply was adequate, the plants showed few symptoms of Cd toxicity, even though Cd uptake and accumulation increased. A Mn:Cd ratio of up to 20 was enough to minimize Cd stress in the leaf, reflecting the plants' relative tolerance to Cd under such conditions. Irrespective of the Mn supply, the increase in antioxidant compounds observed in the roots of Cd-treated plants might act as a protective mechanism by minimizing the oxidative stress caused by Cd exposure. In summary, high leaf Mn concentrations seem to render white lupins more tolerant to Cd stress. Copyright 2010 Elsevier GmbH. All rights reserved.

  4. Self-control assessments of capuchin monkeys with the rotating tray task and the accumulation task.

    PubMed

    Beran, Michael J; Perdue, Bonnie M; Rossettie, Mattea S; James, Brielle T; Whitham, Will; Walker, Bradlyn; Futch, Sara E; Parrish, Audrey E

    2016-08-01

    Recent studies of delay of gratification in capuchin monkeys using a rotating tray (RT) task have shown improved self-control performance in these animals in comparison to the accumulation (AC) task. In this study, we investigated whether this improvement resulted from the difference in methods between the rotating tray task and previous tests, or whether it was the result of greater overall experience with delay of gratification tasks. Experiment 1 produced similar performance levels by capuchins monkeys in the RT and AC tasks when identical reward and temporal parameters were used. Experiment 2 demonstrated a similar result using reward amounts that were more similar to previous AC experiments with these monkeys. In Experiment 3, monkeys performed multiple versions of the AC task with varied reward and temporal parameters. Their self-control behavior was found to be dependent on the overall delay to reward consumption, rather than the overall reward amount ultimately consumed. These findings indicate that these capuchin monkeys' self-control capacities were more likely to have improved across studies because of the greater experience they had with delay of gratification tasks. Experiment 4 and Experiment 5 tested new, task-naïve monkeys on both tasks, finding more limited evidence of self-control, and no evidence that one task was more beneficial than the other in promoting self-control. The results of this study suggest that future testing of this kind should focus on temporal parameters and reward magnitude parameters to establish accurate measures of delay of gratification capacity and development in this species and perhaps others. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Impact of slope inclination on salt accumulation

    NASA Astrophysics Data System (ADS)

    Nachshon, Uri

    2017-04-01

    Field measurements indicated on high variability in salt accumulation along natural and cultivated slopes, even for relatively homogeneous soil conditions. It was hypothesised that slope inclination has an impact on the location of salt accumulation along the slope. A set of laboratory experiments and numerical models were used to explore the impact of slope inclination on salt accumulation. It was shown, experimentally, that for conditions of saline water source at the lower boundary of the slope - salt accumulates in low concentrations and homogeneously along the entire slope, for moderate slopes. However, as inclination increases high salt concentrations were observed at the upper parts of the slope, leaving the lower parts of the slope relatively free of salt. The traditional flow and transport models did not predict the experimental observations as they indicated also for the moderate slopes on salt accumulation in the elevated parts of the slope, away of the saline water source. Consequently - a conceptual model was raised to explain the laboratory observations. It was suggested that the interactions between slope angle, evaporation rates, hydraulic conductivity of the medium and distribution of wetness along the slope affect the saline water flow path through the medium. This lead to preferential flow path close to the soil-atmosphere interface for the steep slopes, which leads to constant wash of the salts from the evaporation front upward towards the slope upper parts, whereas for the moderate slopes, flow path is below the soil-atmosphere interface, therefore salt that accumulates at the evaporation front is not being transported upward. Understanding of salt dynamics along slopes is important for agricultural and natural environments, as well as for civil engineering purposes. Better understanding of the salt transport processes along slopes will improve our ability to minimize and to cope with soil salinization processes. The laboratory experiments and

  6. Late 20th Century increase in South Pole snow accumulation

    USGS Publications Warehouse

    Mosley-Thompson, E.; Paskievitch, J.F.; Gow, A.J.; Thompson, L.G.

    1999-01-01

    A compilation of the 37-year history of net accumulation at the South Pole [Mosley-Thompson et al., 1995] suggests an increase in net annual accumulation since 1965. This record is sporadic and its quality is compromised by spatially restricted observations and nonsystematic measurement procedures. Results from a new, spatially extensive network of 236 accumulation poles document that the current 5-year (1992-1997) average annual net accumulation at the South Pole is 84.5??8.9 mm water equivalent (w.e.). This accumulation rate reflects a 30% increase since the 1960s when the best, although not optimal, records indicate that it was 65 mm w.e. Identification of two prominent beta radioactivity horizons (1954/1955 and 1964/1965) in six firn cores confirms an increase in accumulation since 1965. Viewed from a longer perspective of accumulation provided by ice cores and a snow mine study, the net accumulation of the 30-year period, 1965-1994, is the highest 30-year average of this millennium. Limited data suggest this recent accumulation increase extends beyond the South Pole region and may be characteristic of the high East Antarctic Plateau. Enhanced accumulation over the polar ice sheets has been identified as a potential early indicator of warmer sea surface temperatures and may offset a portion of the current rise in global sea level. Copyright 1999 by the American Geophysical Union.

  7. 26 CFR 1.263A-11 - Accumulated production expenditures.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 3 2011-04-01 2011-04-01 false Accumulated production expenditures. 1.263A-11... TAX (CONTINUED) INCOME TAXES (CONTINUED) Items Not Deductible § 1.263A-11 Accumulated production expenditures. (a) General rule. Accumulated production expenditures generally means the cumulative amount of...

  8. 26 CFR 1.263A-11 - Accumulated production expenditures.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 3 2013-04-01 2013-04-01 false Accumulated production expenditures. 1.263A-11... TAX (CONTINUED) INCOME TAXES (CONTINUED) Items Not Deductible § 1.263A-11 Accumulated production expenditures. (a) General rule. Accumulated production expenditures generally means the cumulative amount of...

  9. 26 CFR 1.263A-11 - Accumulated production expenditures.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 3 2014-04-01 2014-04-01 false Accumulated production expenditures. 1.263A-11... TAX (CONTINUED) INCOME TAXES (CONTINUED) Items Not Deductible § 1.263A-11 Accumulated production expenditures. (a) General rule. Accumulated production expenditures generally means the cumulative amount of...

  10. 26 CFR 1.263A-11 - Accumulated production expenditures.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 3 2012-04-01 2012-04-01 false Accumulated production expenditures. 1.263A-11... TAX (CONTINUED) INCOME TAXES (CONTINUED) Items Not Deductible § 1.263A-11 Accumulated production expenditures. (a) General rule. Accumulated production expenditures generally means the cumulative amount of...

  11. Quantitative Trait Loci for Mercury Accumulation in Maize (Zea mays L.) Identified Using a RIL Population

    PubMed Central

    Zhang, Qinbin; Wang, Long; Zhang, Xiaoxiang; Song, Guiliang; Fu, Zhiyuan; Ding, Dong; Liu, Zonghua; Tang, Jihua

    2014-01-01

    To investigate the genetic mechanism of mercury accumulation in maize (Zea mays L.), a population of 194 recombinant inbred lines derived from an elite hybrid Yuyu 22, was used to identify quantitative trait loci (QTLs) for mercury accumulation at two locations. The results showed that the average Hg concentration in the different tissues of maize followed the order: leaves > bracts > stems > axis > kernels. Twenty-three QTLs for mercury accumulation in five tissues were detected on chromosomes 1, 4, 7, 8, 9 and 10, which explained 6.44% to 26.60% of the phenotype variance. The QTLs included five QTLs for Hg concentration in kernels, three QTLs for Hg concentration in the axis, six QTLs for Hg concentration in stems, four QTLs for Hg concentration in bracts and five QTLs for Hg concentration in leaves. Interestingly, three QTLs, qKHC9a, qKHC9b, and qBHC9 were in linkage with two QTLs for drought tolerance. In addition, qLHC1 was in linkage with two QTLs for arsenic accumulation. The study demonstrated the concentration of Hg in Hg-contaminated paddy soil could be reduced, and maize production maintained simultaneously by selecting and breeding maize Hg pollution-safe cultivars (PSCs). PMID:25210737

  12. Sodium chloride decreases cadmium accumulation and changes the response of metabolites to cadmium stress in the halophyte Carpobrotus rossii.

    PubMed

    Cheng, Miaomiao; Wang, Anan; Liu, Zhiqian; Gendall, Anthony R; Rochfort, Simone; Tang, Caixian

    2018-05-18

    Salinity affects the bioavailability of cadmium (Cd) in soils and Cd accumulation in plants, but the associated mechanisms remain unclear. This study aimed to assess the metabolic response to NaCl and Cd and the relationship between metabolites and Cd accumulation in the halophyte Carpobrotus rossii, which has potential for Cd phytoextraction. Plants were grown in nutrient solution with 0-400 mm NaCl in the presence of 5 or 15 µm Cd, with varied or constant solution Cd2+ activity. Plant growth and Cd uptake were measured, and the accumulation of peptides, and organic and amino acids in plant tissues were assessed. The addition of NaCl to Cd-containing solutions improved plant growth along with 70-87 % less shoot Cd accumulation, resulting from decreases in Cd root uptake and root-to-shoot translocation irrespective of Cd2+ activity in solutions. Moreover, Cd exposure increased the concentration of phytochelatins, which correlated positively with Cd concentrations in plants regardless of NaCl addition. In comparison, Cd inhibited the synthesis of organic acids in shoots and roots in the absence of NaCl, but increased it in shoots in the presence of NaCl. While Cd increased the concentrations of amino acids in plant shoots, the effect of NaCl on the synthesis of amino acids was inconsistent. Our data provide the first evidence that NaCl decreased Cd shoot accumulation in C. rossii by decreasing Cd root uptake and root-to-shoot translocation even under constant Cd2+ activity. The present study also supports the important role of peptides and organic acids, particular of phytochelatins, in Cd tolerance and accumulation although the changes of those metabolites was not the main reason for the decreased Cd accumulation.

  13. Accumulation of free and covalently bound microcystins in tissues of Lymnaea stagnalis (Gastropoda) following toxic cyanobacteria or dissolved microcystin-LR exposure.

    PubMed

    Lance, Emilie; Neffling, Milla-Riina; Gérard, Claudia; Meriluoto, Jussi; Bormans, Myriam

    2010-03-01

    Accumulation of free microcystins (MCs) in freshwater gastropods has been demonstrated but accumulation of MCs covalently bound to tissues has never been considered so far. Here, we follow the accumulation of total (free and bound) MCs in Lymnaea stagnalis exposed to i) dissolved MC-LR (33 and 100 microg L(-1)) and ii) Planktothrix agardhii suspensions producing 5 and 33 microg MC-LR equivalents L(-1) over a 5-week period, and after a 3-week depuration period. Snails exposed to dissolved MC-LR accumulated up to 0.26 microg total MCs g(-1) dry weight (DW), with no detection of bound MCs. Snails exposed to MCs producing P. agardhii accumulated up to 69.9 microg total MCs g(-1) DW, of which from 17.7 to 66.7% were bound. After depuration, up to 15.3 microg g(-1) DW of bound MCs were detected in snails previously exposed to toxic cyanobacteria, representing a potential source of MCs transfer through the food web. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  14. Methodological approaches to developing and establishing the body of evidence on post-marketing Chinese medicine safety.

    PubMed

    Liao, Xing; Robinson, Nicola

    2013-07-01

    Evidence based medicine demands the highest form of scientific evidence to demonstrate the efficacy and clinical effectiveness for any therapeutic intervention in order to provide best care. It is however accepted that in the absence of scientific evidence, personal experience and expert opinion together with professional judgement are critical. Obtaining evidence for drug safety, postmarketing surveillance (PMS) has focussed on follow up of observational cohorts exposed to a particular drug in order to estimate the incidence of adverse drug reactions (ADRs). Evidence on PMS of Chinese herbal products is still limited, in particular for herbal injections. The aim of this article is to suggest a new model of ascertaining the safety of Chinese medicine using a more comprehensive approach for collecting data. To collect safety data on the Chinese herbal injection, Kudiezi, a mixed methods approach is proposed using 18 hospital information systems to detect ADRs in order to prospectively observe 30,000 patients over 3 years. Evidence will also be collected using a questionnaire survey and through a sample of semi structured interviews. This information based on the expert opinion and the experience of clinicians will produce additional data on the frequency and types of side effects in clinical practice. Furthermore semi structured interviews with a random sample of patients receiving the injection will be carried out to ascertain any potential side effects missed. It is hoped that this comprehensive approach to data collection will accumulate wider evidence based on individual traditional Chinese medicine care and treatment and provide important feedback to the national data collection system to ensure completeness of ADR data recording, monitoring and any potential wider effects through developing improved ADR guidelines.

  15. Mechanisms of intrahepatic triglyceride accumulation

    PubMed Central

    Ress, Claudia; Kaser, Susanne

    2016-01-01

    Hepatic steatosis defined as lipid accumulation in hepatocytes is very frequently found in adults and obese adolescents in the Western World. Etiologically, obesity and associated insulin resistance or excess alcohol intake are the most frequent causes of hepatic steatosis. However, steatosis also often occurs with chronic hepatitis C virus (HCV) infection and is also found in rare but potentially life-threatening liver diseases of pregnancy. Clinical significance and outcome of hepatic triglyceride accumulation are highly dependent on etiology and histological pattern of steatosis. This review summarizes current concepts of pathophysiology of common causes of hepatic steatosis, including non-alcoholic fatty liver disease (NAFLD), alcoholic fatty liver disease, chronic HCV infections, drug-induced forms of hepatic steatosis, and acute fatty liver of pregnancy. Regarding the pathophysiology of NAFLD, this work focuses on the close correlation between insulin resistance and hepatic triglyceride accumulation, highlighting the potential harmful effects of systemic insulin resistance on hepatic metabolism of fatty acids on the one side and the role of lipid intermediates on insulin signalling on the other side. Current studies on lipid droplet morphogenesis have identified novel candidate proteins and enzymes in NAFLD. PMID:26819531

  16. Divergent Evolutionary Pattern of Sugar Transporter Genes is Associated with the Difference in Sugar Accumulation between Grasses and Eudicots

    PubMed Central

    Wang, Wei; Zhou, Hui; Ma, Baiquan; Owiti, Albert; Korban, Schuyler S.; Han, Yuepeng

    2016-01-01

    Sugars play a variety of roles in plants, and their accumulation in seeds and/or surrounding pericarp tissues is distinctly different between grasses and eudicots. However, little is known about the evolutionary pattern of genes involved in sugar accumulation in these two major groups of flowering plants. Here, we compared evolutionary rates, gene duplication, and selective patterns of genes involved in sugar metabolism and transport between grasses and eudicots using six grass species and seven eudicot species as materials. Overall, sugar transporter genes exhibit divergent evolutionary patterns, whereas, sugar metabolism genes showing similar evolutionary pattern between monocots and eudicots. Sugar transporter genes have higher frequencies of recent duplication in eudicots than in grasses and their patterns of evolutionary rate are different. Evidence for divergent selection of these two groups of flowering plants is also observed in sugar transporter genes, wherein, these genes have undergone positive selection in eudicots, but not in grasses. Taken together, these findings suggest that sugar transporter genes rather than sugar metabolism genes play important roles in sugar accumulation in plants, and that divergent evolutionary patterns of sugar transporter genes are associated with the difference of sugar accumulation in storage tissues of grasses and eudicots. PMID:27356489

  17. Nutrient accumulation in planted red and jack pine.

    Treesearch

    David H. Alban

    1988-01-01

    Compares nutrient accumulation in adjacent plantations of red and jack pine in the upper Great Lakes. Describes equations developed to predict biomass and nutrient accumulation based on stand basal area and height.

  18. Ethanol accumulation in drought-stressed conifer seedlings

    Treesearch

    Daniel K. Manter; Rick G. Kelsey

    2008-01-01

    In this study, we investigated the effect of drought stress on ethanol production and accumulation in tissues from seedlings of three conifers (Douglas-fir, lodgepole pine, and ponderosa pine) with increasing degrees of tolerance to drought stress. Significant ethanol accumulation was only observed in their aerial tissues when severely stressed (water potential

  19. Flavonoid accumulation patterns of transparent testa mutants of arabidopsis

    NASA Technical Reports Server (NTRS)

    Peer, W. A.; Brown, D. E.; Tague, B. W.; Muday, G. K.; Taiz, L.; Murphy, A. S.

    2001-01-01

    Flavonoids have been implicated in the regulation of auxin movements in Arabidopsis. To understand when and where flavonoids may be acting to control auxin movement, the flavonoid accumulation pattern was examined in young seedlings and mature tissues of wild-type Arabidopsis. Using a variety of biochemical and visualization techniques, flavonoid accumulation in mature plants was localized in cauline leaves, pollen, stigmata, and floral primordia, and in the stems of young, actively growing inflorescences. In young Landsberg erecta seedlings, aglycone flavonols accumulated developmentally in three regions, the cotyledonary node, the hypocotyl-root transition zone, and the root tip. Aglycone flavonols accumulated at the hypocotyl-root transition zone in a developmental and tissue-specific manner with kaempferol in the epidermis and quercetin in the cortex. Quercetin localized subcellularly in the nuclear region, plasma membrane, and endomembrane system, whereas kaempferol localized in the nuclear region and plasma membrane. The flavonoid accumulation pattern was also examined in transparent testa mutants blocked at different steps in the flavonoid biosynthesis pathway. The transparent testa mutants were shown to have precursor accumulation patterns similar to those of end product flavonoids in wild-type Landsberg erecta, suggesting that synthesis and end product accumulation occur in the same cells.

  20. Selenium accumulation in plants--phytotechnological applications and ecological implications.

    PubMed

    Valdez Barillas, José Rodolfo; Quinn, Colin F; Pilon-Smits, Elizabeth A H

    2011-01-01

    Selenium (Se) is an essential trace element for many organisms including humans, yet toxic at higher levels. Both Se deficiency and toxicity are problems worldwide. Since plants readily accumulate and volatilize Se, they may be used both as a source of dietary Se and for removing excess Se from the environment. Plant species differ in their capacity to metabolize and accumulate Se, from non-Se accumulators (< 100 mg Se/kg DW), to Se-accumulators (100-1000 mg Se/kg DW) to Se hyperaccumulators (> 1,000 mg Se/kg DW). Here we review plant mechanisms of Se metabolism in these various plant types. We also summarize results from genetic engineering that have led to enhanced plant Se accumulation, volatilization, and/or tolerance, including field studies. Before using Se-accumulating plants at a large scale we need to evaluate the ecological implications. Research so far indicates that plant Se accumulation significantly affects the plant's ecological interactions below and above ground. Selenium canprotect plants from fungal pathogens and from a variety of invertebrate and vertebrate herbivores, due to both deterrence and toxicity. However, specialist (Se-tolerant herbivores), detritivores and endophytes appear to utilize Se hyperaccumulator plants as a resource. These findings are relevant for managing phytoremediation of Se and similar elements.

  1. Overexpression of PtABCC1 contributes to mercury tolerance and accumulation in Arabidopsis and poplar.

    PubMed

    Sun, Liping; Ma, Yifeng; Wang, Huihong; Huang, Weipeng; Wang, Xiaozhu; Han, Li; Sun, Wanmei; Han, Erqin; Wang, Bangjun

    2018-03-18

    Mercury (Hg) is a highly biotoxic heavy metal that contaminates the environment. Phytoremediation is a green technology for environmental remediation and is used to clean up Hg contaminated soil in recent years. In this study, we isolated an ATP-binding cassette (ABC) transporter gene PtABCC1 from Populus trichocarpa and overexpressed it in Arabidopsis and poplar. The transgenic plants conferred higher Hg tolerance than wild type (WT) plants, and overexpression of PtABCC1 could lead to 26-72% or 7-160% increase of Hg accumulation in Arabidopsis or poplar plants, respectively. These results demonstrated that PtABCC1 plays a crucial role in enhancing tolerance and accumulation to Hg in plants, which provides a promising way for phytoremediation of Hg contamination. Copyright © 2018 Elsevier Inc. All rights reserved.

  2. The Role of Interest in Physical Education: A Review of Research Evidence

    ERIC Educational Resources Information Center

    Chen, Ang; Wang, Yubing

    2017-01-01

    This article focuses on the research on interest, especially situational interest, in physical education. Interest has been considered a powerful motivator for children and adolescents. Based on a conceptualization of individual and situational interest, a reasonable size of evidence has been accumulated showing that situational interest motivates…

  3. Dynamic detection of spin accumulation in ferromagnet-semiconductor devices by ferromagnetic resonance (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Crowell, Paul A.; Liu, Changjiang; Patel, Sahil; Peterson, Tim; Geppert, Chad C.; Christie, Kevin; Stecklein, Gordon; Palmstrøm, Chris J.

    2016-10-01

    A distinguishing feature of spin accumulation in ferromagnet-semiconductor devices is its precession in a magnetic field. This is the basis for detection techniques such as the Hanle effect, but these approaches become ineffective as the spin lifetime in the semiconductor decreases. For this reason, no electrical Hanle measurement has been demonstrated in GaAs at room temperature. We show here that by forcing the magnetization in the ferromagnet to precess at resonance instead of relying only on the Larmor precession of the spin accumulation in the semiconductor, an electrically generated spin accumulation can be detected up to 300 K. The injection bias and temperature dependence of the measured spin signal agree with those obtained using traditional methods. We further show that this new approach enables a measurement of short spin lifetimes (< 100 psec), a regime that is not accessible in semiconductors using traditional Hanle techniques. The measurements were carried out on epitaxial Heusler alloy (Co2FeSi or Co2MnSi)/n-GaAs heterostructures. Lateral spin valve devices were fabricated by electron beam and photolithography. We compare measurements carried out by the new FMR-based technique with traditional non-local and three-terminal Hanle measurements. A full model appropriate for the measurements will be introduced, and a broader discussion in the context of spin pumping experimenments will be included in the talk. The new technique provides a simple and powerful means for detecting spin accumulation at high temperatures. Reference: C. Liu, S. J. Patel, T. A. Peterson, C. C. Geppert, K. D. Christie, C. J. Palmstrøm, and P. A. Crowell, "Dynamic detection of electron spin accumulation in ferromagnet-semiconductor devices by ferromagnetic resonance," Nature Communications 7, 10296 (2016). http://dx.doi.org/10.1038/ncomms10296

  4. Ionic charge accumulation at microscopic interfaces in filled composites

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhu Yutao; Wang Xinheng; Xie Hengkun

    1996-12-31

    In this paper the charge accumulation process at microscopic interfaces in insulating materials filled with inorganic fillers is analyzed by using a unit model. Dynamic equations of interfacial ionic charge accumulation are proposed by the authors. The charge accumulation and its regulations are proved by TSC test results obtained on silica filled EPDM samples.

  5. Enhanced accumulation of starch and total carbohydrates in alginate-immobilized Chlorella spp. induced by Azospirillum brasilense: I. Autotrophic conditions.

    PubMed

    Choix, Francisco J; de-Bashan, Luz E; Bashan, Yoav

    2012-10-10

    The effect of the microalgae-growth promoting bacterium Azospirillum brasilense on accumulation of total carbohydrates and starch in two species of Chlorella (Chlorella vulgaris and Chlorella sorokiniana), when the bacterium and each microalga were jointly immobilized in alginate beads was studied under autotrophic conditions for 144 h in synthetic medium. The interaction of the bacterium with the microalgae enhanced accumulation of total carbohydrate and starch. Cells of Chlorella accumulated the highest amounts of carbohydrate after incubation for 24h. Yet, this did not coincide with the highest affinity and volumetric productivity measured in these cultures. However, after incubation for 72 h, mainly in jointly immobilized treatments of both microalgae species, the cultures reached their highest total carbohydrate content (mainly as starch) and also the highest affinity and volumetric productivity. These results demonstrate the potential of A. brasilense to affect carbohydrates and starch accumulation in Chlorella spp. when both microorganisms are co-cultured, which can be an important tool for applications of microalgae. Copyright © 2012. Published by Elsevier Inc.

  6. Inhibition of Lysosome Membrane Recycling Causes Accumulation of Gangliosides that Contribute to Neurodegeneration.

    PubMed

    Boutry, Maxime; Branchu, Julien; Lustremant, Céline; Pujol, Claire; Pernelle, Julie; Matusiak, Raphaël; Seyer, Alexandre; Poirel, Marion; Chu-Van, Emeline; Pierga, Alexandre; Dobrenis, Kostantin; Puech, Jean-Philippe; Caillaud, Catherine; Durr, Alexandra; Brice, Alexis; Colsch, Benoit; Mochel, Fanny; El Hachimi, Khalid Hamid; Stevanin, Giovanni; Darios, Frédéric

    2018-06-26

    Lysosome membrane recycling occurs at the end of the autophagic pathway and requires proteins that are mostly encoded by genes mutated in neurodegenerative diseases. However, its implication in neuronal death is still unclear. Here, we show that spatacsin, which is required for lysosome recycling and whose loss of function leads to hereditary spastic paraplegia 11 (SPG11), promotes clearance of gangliosides from lysosomes in mouse and human SPG11 models. We demonstrate that spatacsin acts downstream of clathrin and recruits dynamin to allow lysosome membrane recycling and clearance of gangliosides from lysosomes. Gangliosides contributed to the accumulation of autophagy markers in lysosomes and to neuronal death. In contrast, decreasing ganglioside synthesis prevented neurodegeneration and improved motor phenotype in a SPG11 zebrafish model. Our work reveals how inhibition of lysosome membrane recycling leads to the deleterious accumulation of gangliosides, linking lysosome recycling to neurodegeneration. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

  7. Activity and Accumulation of Cell Division-Promoting Phenolics in Tobacco Tissue Cultures 1

    PubMed Central

    Teutonico, Rita A.; Dudley, Matthew W.; Orr, John D.; Lynn, David G.; Binns, Andrew N.

    1991-01-01

    Dehydrodiconiferyl alcohol glucosides (DCGs) are derivatives of the phenylpropanoid pathway that have been isolated from Catharansus roseus L. (Vinca rosea) crown gall tumors. Fractions containing purified DCGs have been shown previously to promote the growth of cytokinin-requiring tissues of tobacco in the absence of exogenous cytokinins. In this study, we utilized synthetic DCG isomers to confirm the cell division-promoting activity of DCG isomers A and B and show that they neither promote shoot meristem initiation on Nicotiana tabacum L., cv Havana 425, leaf explants nor induce betacyanin synthesis in amaranth seedlings. Analysis of cultured tobacco pith tissue demonstrated that DCG accumulation was stimulated by cytokinin treatment and correlated with cytokinin-induced cell division. Thus, the accumulation of metabolites that could replace cytokinin in cell division bioassays is stimulated by cytokinins. These data support the model that DCGs are a component of a cytokinin-mediated regulatory circuit controlling cell division. ImagesFigure 2 PMID:16668384

  8. MdSOS2L1 phosphorylates MdVHA-B1 to modulate malate accumulation in response to salinity in apple.

    PubMed

    Hu, Da-Gang; Sun, Cui-Hui; Sun, Mei-Hong; Hao, Yu-Jin

    2016-03-01

    Salt-induced phosphorylation of MdVHA-B1 protein was mediated by MdSOS2L1 protein kinase, and thereby increasing malate content in apple. Salinity is an important environmental factor that influences malate accumulation in apple. However, the molecular mechanism by which salinity regulates this process is poorly understood. In this work, we found that MdSOS2L1, a novel AtSOS2-LIKE protein kinase, interacts with V-ATPase subunit MdVHA-B1. Furthermore, MdSOS2L1 directly phosphorylates MdVHA-B1 at Ser(396) site to modulate malate accumulation in response to salt stress. Meanwhile, a series of transgenic analyses in apple calli showed that the MdSOS2L1-MdVHAB1 pathway was involved in the regulation of malate accumulation. Finally, a viral vector-based transformation approach demonstrated that the MdSOS2L1-MdVHAB1 pathway also modulated malate accumulation in apple fruits with or without salt stress. Collectively, our findings provide a new insight into the mechanism by which MdSOS2L1 phosphorylates MdVHA-B1 to modulate malate accumulation in response to salinity in apple.

  9. Organic carbon accumulation in Brazilian mangal sediments

    NASA Astrophysics Data System (ADS)

    Sanders, Christian J.; Smoak, Joseph M.; Sanders, Luciana M.; Sathy Naidu, A.; Patchineelam, Sambasiva R.

    2010-12-01

    This study reviews the organic carbon (OC) accumulation rates in mangrove forests, margins and intertidal mudflats in geographically distinct areas along the Brazilian coastline (Northeastern to Southern). Our initial results indicate that the mangrove forests in the Northeastern region of Brazil are accumulating more OC (353 g/m 2/y) than in the Southeastern areas (192 g/m 2/y) being that the sediment accumulation rates, 2.8 and 2.5 mm/y, and OC content ˜7.1% and ˜5.8% (dry sediment weight) were contributing factors to the discrepancies between the forests. The intertidal mudflats on the other hand showed substantially greater OC accumulation rates, sedimentation rates and content 1129 g/m 2/y and 234 g/m 2/y; 7.3 and 3.4 mm/y; 10.3% and ˜2.7% (OC of dry sediment weight content), respectively, in the Northeastern compared to the Southeastern region. Mangrove forests in the South-Southeastern regions of Brazil may be more susceptible to the rising sea level, as they are geographically constricted by the vast mountain ranges along the coastline.

  10. Genetic variation of the weaning weight of beef cattle as a function of accumulated heat stress.

    PubMed

    Santana, M L; Bignardi, A B; Eler, J P; Ferraz, J B S

    2016-04-01

    The objective of this study was to identify the genetic variation in the weaning weight (WW) of beef cattle as a function of heat stress. The WWs were recorded at approximately 205 days of age in three Brazilian beef cattle populations: Nelore (93,616), Brangus (18,906) and Tropical Composite (62,679). In view of the cumulative nature of WW, the effect of heat stress was considered as the accumulation of temperature and humidity index units (ACTHI) from the animal's birth to weaning. A reaction norm model was used to estimate the (co)variance components of WW across the ACTHI scale. The accumulation of THI units from birth to weaning negatively affected the WW. The definition of accumulated THI units as an environmental descriptor permitted to identify important genetic variation in the WW as a function of heat stress. As evidence of genotype by environment interaction, substantial heterogeneity was observed in the (co)variance components for WW across the environmental gradient. In this respect, the best animals in less stressful environments are not necessarily the best animals in more stressful environments. Furthermore, the response to selection for WW is expected to be lower in more stressful environments. © 2015 Blackwell Verlag GmbH.

  11. LcMYB1 Is a Key Determinant of Differential Anthocyanin Accumulation among Genotypes, Tissues, Developmental Phases and ABA and Light Stimuli in Litchi chinensis

    PubMed Central

    Lai, Biao; Li, Xiao-Jing; Hu, Bing; Qin, Yong-Hua; Huang, Xu-Ming; Wang, Hui-Cong; Hu, Gui-Bing

    2014-01-01

    The red coloration of litchi fruit depends on the accumulation of anthocyanins. The anthocyanins level in litchi fruit varies widely among cultivars, developmental stages and environmental stimuli. Previous studies on various plant species demonstrate that anthocyanin biosynthesis is controlled at the transcriptional level. Here, we describe a litchi R2R3-MYB transcription factor gene, LcMYB1, which demonstrates a similar sequence as other known anthocyanin regulators. The transcription levels of the LcMYB1 and anthocyanin biosynthetic genes were investigated in samples with different anthocyanin levels. The expression of LcMYB1 was strongly associated with tissue anthocyanin content. LcMYB1 transcripts were only detected in anthocyanin-accumulating tissues and were positively correlated with anthocyanin accumulation in the pericarps of 12 genotypes. ABA and sunlight exposure promoted, whereas CPPU and bagging inhibited the expression of LcMYB1 and anthocyanin accumulation in the pericarp. Cis-elements associated with light responsiveness and abscisic acid responsiveness were identified in the promoter region of LcMYB1. Among the 6 structural genes tested, only LcUFGT was highly correlated with LcMYB1. These results suggest that LcMYB1 controls anthocyanin biosynthesis in litchi and LcUFGT might be the structural gene that is targeted and regulated by LcMYB1. Furthermore, the overexpression of LcMYB1 induced anthocyanin accumulation in all tissues in tobacco, confirming the function of LcMYB1 in the regulation of anthocyanin biosynthesis. The upregulation of NtAn1b in response to LcMYB1 overexpression seems to be essential for anthocyanin accumulation in the leaf and pedicel. In the reproductive tissues of transgenic tobacco, however, increased anthocyanin accumulation is independent of tobacco's endogenous MYB and bHLH transcriptional factors, but associated with the upregulation of specific structural genes. PMID:24466010

  12. When Good Evidence Goes Bad: The Weak Evidence Effect in Judgment and Decision-Making

    ERIC Educational Resources Information Center

    Fernbach, Philip M.; Darlow, Adam; Sloman, Steven A.

    2011-01-01

    An indispensable principle of rational thought is that positive evidence should increase belief. In this paper, we demonstrate that people routinely violate this principle when predicting an outcome from a weak cause. In Experiment 1 participants given weak positive evidence judged outcomes of public policy initiatives to be less likely than…

  13. Testing multi-alternative decision models with non-stationary evidence.

    PubMed

    Tsetsos, Konstantinos; Usher, Marius; McClelland, James L

    2011-01-01

    Recent research has investigated the process of integrating perceptual evidence toward a decision, converging on a number of sequential sampling choice models, such as variants of race and diffusion models and the non-linear leaky competing accumulator (LCA) model. Here we study extensions of these models to multi-alternative choice, considering how well they can account for data from a psychophysical experiment in which the evidence supporting each of the alternatives changes dynamically during the trial, in a way that creates temporal correlations. We find that participants exhibit a tendency to choose an alternative whose evidence profile is temporally anti-correlated with (or dissimilar from) that of other alternatives. This advantage of the anti-correlated alternative is well accounted for in the LCA, and provides constraints that challenge several other models of multi-alternative choice.

  14. TRANSPARENT TESTA GLABRA1 Regulates the Accumulation of Seed Storage Reserves in Arabidopsis1[OPEN

    PubMed Central

    Chen, Mingxun; Zhang, Bin; Li, Chengxiang; Kulaveerasingam, Harikrishna; Chew, Fook Tim; Yu, Hao

    2015-01-01

    Seed storage reserves mainly consist of starch, triacylglycerols, and storage proteins. They not only provide energy for seed germination and seedling establishment, but also supply essential dietary nutrients for human beings and animals. So far, the regulatory networks that govern the accumulation of seed storage reserves in plants are still largely unknown. Here, we show that TRANSPARENT TESTA GLABRA1 (TTG1), which encodes a WD40 repeat transcription factor involved in many aspects of plant development, plays an important role in mediating the accumulation of seed storage reserves in Arabidopsis (Arabidopsis thaliana). The dry weight of ttg1-1 embryos significantly increases compared with that of wild-type embryos, which is accompanied by an increase in the contents of starch, total protein, and fatty acids in ttg1-1 seeds. FUSCA3 (FUS3), a master regulator of seed maturation, binds directly to the TTG1 genomic region and suppresses TTG1 expression in developing seeds. TTG1 negatively regulates the accumulation of seed storage proteins partially through transcriptional repression of 2S3, a gene encoding a 2S albumin precursor. TTG1 also indirectly suppresses the expression of genes involved in either seed development or synthesis/modification of fatty acids in developing seeds. In addition, we demonstrate that the maternal allele of the TTG1 gene suppresses the accumulation of storage proteins and fatty acids in seeds. Our results suggest that TTG1 is a direct target of FUS3 in the framework of the regulatory hierarchy controlling seed filling and regulates the accumulation of seed storage proteins and fatty acids during the seed maturation process. PMID:26152712

  15. Anthropogenic N deposition increases soil organic matter accumulation without altering its biochemical composition.

    PubMed

    Zak, Donald R; Freedman, Zachary B; Upchurch, Rima A; Steffens, Markus; Kögel-Knabner, Ingrid

    2017-02-01

    Accumulating evidence indicates that future rates of atmospheric N deposition have the potential to increase soil C storage by reducing the decay of plant litter and soil organic matter (SOM). Although the microbial mechanism underlying this response is not well understood, a decline in decay could alter the amount, as well as biochemical composition of SOM. Here, we used size-density fractionation and solid-state 13 C-NMR spectroscopy to explore the extent to which declines in microbial decay in a long-term (ca. 20 yrs.) N deposition experiment have altered the biochemical composition of forest floor, bulk mineral soil, as well as free and occluded particulate organic matter. Significant amounts of organic matter have accumulated in occluded particulate organic matter (~20%; oPOM); however, experimental N deposition had not altered the abundance of carboxyl, aryl, alkyl, or O/N-alkyl C in forest floor, bulk mineral soil, or any soil fraction. These observations suggest that biochemically equivalent organic matter has accumulated in oPOM at a greater rate under experimental N deposition, relative to the ambient treatment. Although we do not understand the process by which experimental N deposition has fostered the occlusion of organic matter by mineral soil particles, our results highlight the importance of interactions among the products of microbial decay and the chemical and physical properties of silt and clay particles that occlude organic matter from microbial attack. Because oPOM can reside in soils for decades to centuries, organic matter accumulating under future rates of anthropogenic N deposition could remain in soil for long periods of time. If temperate forest soils in the Northern Hemisphere respond like those in our experiment, then unabated deposition of anthropogenic N from the atmosphere has the potential to foster greater soil C storage, especially in fine-texture forest soils. © 2016 John Wiley & Sons Ltd.

  16. Do acid volatile sulfides (AVS) influence the accumulation of sediment-bound metals to benthic invertebrates under natural field conditions?

    PubMed

    De Jonge, Maarten; Dreesen, Freja; De Paepe, Josefina; Blust, Ronny; Bervoets, Lieven

    2009-06-15

    The present study evaluates the influence of acid volatile sulfides (AVS) on accumulation of sediment-bound metals in benthic invertebrates under natural field conditions. Natural sediments, pore water, surface water, and two species of widespread benthic invertebrates (Chironomus gr. thummi and Tubifex tubifex) were collected from 17 historical polluted Flemish lowland rivers and measured for metal concentrations. Different sediment characteristics were determined (AVS, organic matter, clay content) and multiple regression was used to study their relationship with accumulated metals in the invertebrates. Physical and chemical analysis of the field samples indicated low metal concentrations in the water and pore water, but very high metal concentrations in the sediment and the invertebrates, especially for Pb (5.99 micromol/ g). In general, metal accumulation in chironomids and tubificid worms was most strongly correlated with total metal concentrations in the sediment and sediment metal concentrations normalized for organic matter and clay content. Following the results of the linear regression model, AVS did not turn out to be a significant variable in describing variation in metal accumulation. Our study clearly demonstrates that, in addition to the results gained from experiments under lab conditions, benthic invertebrates can accumulate metals from unspiked field sediments even when there's an excess of AVS.

  17. Acclimation to NaCl and light stress of heterotrophic Chlamydomonas reinhardtii for lipid accumulation.

    PubMed

    Fan, Jianhua; Zheng, Lvhong

    2017-09-01

    Salt stress has been proven very effective in enhancing the lipid content among many photoautotrophically grown microalgae species including marine and freshwater algae. Nevertheless, its effect on heterotrophic grown cells and lipid accumulation is scarcely known. This study sought to demonstrate a new train of thought for cost-effective biofuels production by heterotrophic culture of Chlamydomonas reinhardtii coupling with subsequent salt and light stress. NaCl treatments (25-200 mM) gradually suppressed the cell growth. After one day's acclimation, the cells restored slow growth with light supplement (200 μmol/m2/s) in low salt concentration (0-50 mM). However, high concentration of NaCl (200 mM) dose caused permanent damage, with over 47% cells death after 3 days treatment. The highest lipid content of 35.8% and lipid productivity of 28.6 mg/L/d were achieved by 50 mM NaCl stress and light treatment upon heterotrophic grown cells. Cells lost their green pigmentation and became yellowish under 100-200 mM NaCl conditions, whereas cells grown in 0-50 mM NaCl retained their dark-green pigmentation. Variable-to-maximum fluorescence ratio (Fv/Fm) and non-photochemical quenching (NPQ) value were markedly influenced under salt and light stress, indicating that severe inhibition of photosynthetic ability was occurred. Moreover, we further demonstrated the dynamic changes of cell growth and lipid accumulation would potentially be caused by the increase of intracellular redox state. To our knowledge, this study is the first instance in which C. reinhardtii was applied to oil accumulation by using combination of heterotrophic culture and multiple stress, and opened up a new territory for the further development of microalgae-based biofuels production. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  18. Tensile behavior and flow stress anisotropy of accumulative roll bonded Cu-Nb nanolaminates

    DOE PAGES

    Nizolek, Thomas; Beyerlein, Irene J.; Mara, Nathan A.; ...

    2016-02-01

    The flow stress, ductility, and in-plane anisotropy are evaluated for bulk accumulative roll bonded copper-niobium nanolaminates with layer thicknesses ranging from 1.8 μm to 15 nm. Uniaxial tensile tests conducted parallel to the rolling direction and transverse direction demonstrate that ductility generally decreases with decreasing layer thickness; however, at 30 nm, both high strengths (1200 MPa) and significant ductility (8%) are achieved. The yield strength increases monotonically with decreasing layer thickness, consistent with the Hall-Petch relationship, and significant in-plane flow stress anisotropy is observed. As a result, Taylor polycrystal modeling is used to demonstrate that crystallographic texture is responsible formore » the in-plane anisotropy and that the effects of texture dominate even at nanoscale layer thicknesses.« less

  19. Accumulation of Major Life Events in Childhood and Adult Life and Risk of Type 2 Diabetes Mellitus

    PubMed Central

    Masters Pedersen, Jolene; Hulvej Rod, Naja; Andersen, Ingelise; Lange, Theis; Poulsen, Gry; Prescott, Eva; Lund, Rikke

    2015-01-01

    Background The aim of the study was to estimate the effect of the accumulation of major life events (MLE) in childhood and adulthood, in both the private and working domains, on risk of type 2 diabetes mellitus (T2DM). Furthermore, we aimed to test the possible interaction between childhood and adult MLE and to investigate modification of these associations by educational attainment. Methods The study was based on 4,761 participants from the Copenhagen City Heart Study free of diabetes at baseline and followed for 10 years. MLE were categorized as 0, 1, 2, 3 or more events. Multivariate logistic regression models adjusted for age, sex, education and family history of diabetes were used to estimate the association between MLE and T2DM. Results In childhood, experiencing 3 or more MLE was associated with a 69% higher risk of developing T2DM (Odds Ratio (OR) 1.69; 95% Confidence Interval (CI) 1.60, 3.27). The accumulation of MLE in adult private (p-trend = 0.016) and work life (p-trend = 0.049) was associated with risk of T2DM in a dose response manner. There was no evidence that experiencing MLE in both childhood and adult life was more strongly associated with T2DM than experiencing events at only one time point. There was some evidence that being simultaneously exposed to childhood MLE and short education (OR 2.28; 95% C.I. 1.45, 3.59) and work MLE and short education (OR 2.86; 95% C.I. 1.62, 5.03) was associated with higher risk of T2DM, as the joint effects were greater than the sum of their individual effects. Conclusions Findings from this study suggest that the accumulation of MLE in childhood, private adult life and work life, respectively, are risk factors for developing T2DM. PMID:26394040

  20. Practical device-independent quantum cryptography via entropy accumulation.

    PubMed

    Arnon-Friedman, Rotem; Dupuis, Frédéric; Fawzi, Omar; Renner, Renato; Vidick, Thomas

    2018-01-31

    Device-independent cryptography goes beyond conventional quantum cryptography by providing security that holds independently of the quality of the underlying physical devices. Device-independent protocols are based on the quantum phenomena of non-locality and the violation of Bell inequalities. This high level of security could so far only be established under conditions which are not achievable experimentally. Here we present a property of entropy, termed "entropy accumulation", which asserts that the total amount of entropy of a large system is the sum of its parts. We use this property to prove the security of cryptographic protocols, including device-independent quantum key distribution, while achieving essentially optimal parameters. Recent experimental progress, which enabled loophole-free Bell tests, suggests that the achieved parameters are technologically accessible. Our work hence provides the theoretical groundwork for experimental demonstrations of device-independent cryptography.

  1. Accumulation of Inertial Sensory Information in the Perception of Whole Body Yaw Rotation.

    PubMed

    Nesti, Alessandro; de Winkel, Ksander; Bülthoff, Heinrich H

    2017-01-01

    While moving through the environment, our central nervous system accumulates sensory information over time to provide an estimate of our self-motion, allowing for completing crucial tasks such as maintaining balance. However, little is known on how the duration of the motion stimuli influences our performances in a self-motion discrimination task. Here we study the human ability to discriminate intensities of sinusoidal (0.5 Hz) self-rotations around the vertical axis (yaw) for four different stimulus durations (1, 2, 3 and 5 s) in darkness. In a typical trial, participants experienced two consecutive rotations of equal duration and different peak amplitude, and reported the one perceived as stronger. For each stimulus duration, we determined the smallest detectable change in stimulus intensity (differential threshold) for a reference velocity of 15 deg/s. Results indicate that differential thresholds decrease with stimulus duration and asymptotically converge to a constant, positive value. This suggests that the central nervous system accumulates sensory information on self-motion over time, resulting in improved discrimination performances. Observed trends in differential thresholds are consistent with predictions based on a drift diffusion model with leaky integration of sensory evidence.

  2. In vivo visualization and attenuation of oxidized lipid accumulation in hypercholesterolemic zebrafish

    PubMed Central

    Fang, Longhou; Green, Simone R.; Baek, Ji Sun; Lee, Sang-Hak; Ellett, Felix; Deer, Elena; Lieschke, Graham J.; Witztum, Joseph L.; Tsimikas, Sotirios; Miller, Yury I.

    2011-01-01

    Oxidative modification of LDL is an early pathological event in the development of atherosclerosis. Oxidation events such as malondialdehyde (MDA) formation may produce specific, immunogenic epitopes. Indeed, antibodies to MDA-derived epitopes are widely used in atherosclerosis research and have been demonstrated to enable cardiovascular imaging. In this study, we engineered a transgenic zebrafish with temperature-inducible expression of an EGFP-labeled single-chain human monoclonal antibody, IK17, which binds to MDA-LDL, and used optically transparent zebrafish larvae for imaging studies. Feeding a high-cholesterol diet (HCD) supplemented with a red fluorescent lipid marker to the transgenic zebrafish resulted in vascular lipid accumulation, quantified in live animals using confocal microscopy. After heat shock–induced expression of IK17-EGFP, we measured the time course of vascular accumulation of IK17-specific MDA epitopes. Treatment with either an antioxidant or a regression diet resulted in reduced IK17 binding to vascular lesions. Interestingly, homogenates of IK17-EGFP–expressing larvae bound to MDA-LDL and inhibited MDA-LDL binding to macrophages. Moreover, sustained expression of IK17-EGFP effectively prevented HCD-induced lipid accumulation in the vascular wall, suggesting that the antibody itself may have therapeutic effects. Thus, we conclude that HCD-fed zebrafish larvae with conditional expression of EGFP-labeled oxidation-specific antibodies afford an efficient method of testing dietary and/or other therapeutic antioxidant strategies that may ultimately be applied to humans. PMID:22105168

  3. Calcite-accumulating large sulfur bacteria of the genus Achromatium in Sippewissett Salt Marsh

    PubMed Central

    Salman, Verena; Yang, Tingting; Berben, Tom; Klein, Frieder; Angert, Esther; Teske, Andreas

    2015-01-01

    Large sulfur bacteria of the genus Achromatium are exceptional among Bacteria and Archaea as they can accumulate high amounts of internal calcite. Although known for more than 100 years, they remain uncultured, and only freshwater populations have been studied so far. Here we investigate a marine population of calcite-accumulating bacteria that is primarily found at the sediment surface of tide pools in a salt marsh, where high sulfide concentrations meet oversaturated oxygen concentrations during the day. Dynamic sulfur cycling by phototrophic sulfide-oxidizing and heterotrophic sulfate-reducing bacteria co-occurring in these sediments creates a highly sulfidic environment that we propose induces behavioral differences in the Achromatium population compared with reported migration patterns in a low-sulfide environment. Fluctuating intracellular calcium/sulfur ratios at different depths and times of day indicate a biochemical reaction of the salt marsh Achromatium to diurnal changes in sedimentary redox conditions. We correlate this calcite dynamic with new evidence regarding its formation/mobilization and suggest general implications as well as a possible biological function of calcite accumulation in large bacteria in the sediment environment that is governed by gradients. Finally, we propose a new taxonomic classification of the salt marsh Achromatium based on their adaptation to a significantly different habitat than their freshwater relatives, as indicated by their differential behavior as well as phylogenetic distance on 16S ribosomal RNA gene level. In future studies, whole-genome characterization and additional ecophysiological factors could further support the distinctive position of salt marsh Achromatium. PMID:25909974

  4. Calcite-accumulating large sulfur bacteria of the genus Achromatium in Sippewissett Salt Marsh.

    PubMed

    Salman, Verena; Yang, Tingting; Berben, Tom; Klein, Frieder; Angert, Esther; Teske, Andreas

    2015-11-01

    Large sulfur bacteria of the genus Achromatium are exceptional among Bacteria and Archaea as they can accumulate high amounts of internal calcite. Although known for more than 100 years, they remain uncultured, and only freshwater populations have been studied so far. Here we investigate a marine population of calcite-accumulating bacteria that is primarily found at the sediment surface of tide pools in a salt marsh, where high sulfide concentrations meet oversaturated oxygen concentrations during the day. Dynamic sulfur cycling by phototrophic sulfide-oxidizing and heterotrophic sulfate-reducing bacteria co-occurring in these sediments creates a highly sulfidic environment that we propose induces behavioral differences in the Achromatium population compared with reported migration patterns in a low-sulfide environment. Fluctuating intracellular calcium/sulfur ratios at different depths and times of day indicate a biochemical reaction of the salt marsh Achromatium to diurnal changes in sedimentary redox conditions. We correlate this calcite dynamic with new evidence regarding its formation/mobilization and suggest general implications as well as a possible biological function of calcite accumulation in large bacteria in the sediment environment that is governed by gradients. Finally, we propose a new taxonomic classification of the salt marsh Achromatium based on their adaptation to a significantly different habitat than their freshwater relatives, as indicated by their differential behavior as well as phylogenetic distance on 16S ribosomal RNA gene level. In future studies, whole-genome characterization and additional ecophysiological factors could further support the distinctive position of salt marsh Achromatium.

  5. The Csr System Regulates Escherichia coli Fitness by Controlling Glycogen Accumulation and Energy Levels.

    PubMed

    Morin, Manon; Ropers, Delphine; Cinquemani, Eugenio; Portais, Jean-Charles; Enjalbert, Brice; Cocaign-Bousquet, Muriel

    2017-10-31

    In the bacterium Escherichia coli , the posttranscriptional regulatory system Csr was postulated to influence the transition from glycolysis to gluconeogenesis. Here, we explored the role of the Csr system in the glucose-acetate transition as a model of the glycolysis-to-gluconeogenesis switch. Mutations in the Csr system influence the reorganization of gene expression after glucose exhaustion and disturb the timing of acetate reconsumption after glucose exhaustion. Analysis of metabolite concentrations during the transition revealed that the Csr system has a major effect on the energy levels of the cells after glucose exhaustion. This influence was demonstrated to result directly from the effect of the Csr system on glycogen accumulation. Mutation in glycogen metabolism was also demonstrated to hinder metabolic adaptation after glucose exhaustion because of insufficient energy. This work explains how the Csr system influences E. coli fitness during the glycolysis-gluconeogenesis switch and demonstrates the role of glycogen in maintenance of the energy charge during metabolic adaptation. IMPORTANCE Glycogen is a polysaccharide and the main storage form of glucose from bacteria such as Escherichia coli to yeasts and mammals. Although its function as a sugar reserve in mammals is well documented, the role of glycogen in bacteria is not as clear. By studying the role of posttranscriptional regulation during metabolic adaptation, for the first time, we demonstrate the role of sugar reserve played by glycogen in E. coli Indeed, glycogen not only makes it possible to maintain sufficient energy during metabolic transitions but is also the key component in the capacity of cells to resume growth. Since the essential posttranscriptional regulatory system Csr is a major regulator of glycogen accumulation, this work also sheds light on the central role of posttranscriptional regulation in metabolic adaptation. Copyright © 2017 Morin et al.

  6. Enterobacter cloacae administration induces hepatic damage and subcutaneous fat accumulation in high-fat diet fed mice.

    PubMed

    Keskitalo, Anniina; Munukka, Eveliina; Toivonen, Raine; Hollmén, Maija; Kainulainen, Heikki; Huovinen, Pentti; Jalkanen, Sirpa; Pekkala, Satu

    2018-01-01

    Accumulating evidence indicates that gut microbiota plays a significant role in obesity, insulin resistance and associated liver disorders. Family Enterobacteriaceae and especially Enterobacter cloacae strain B29 have been previously linked to obesity and hepatic damage. The underlying mechanisms, however, remain unclear. Therefore, we comprehensively examined the effects of E. cloacae subsp. cloacae (ATCC® 13047™) administration on host metabolism of mice fed with high-fat diet (HFD). C57BL/6N mice were randomly divided into HFD control, chow control, and E. cloacae treatment groups. The E. cloacae treatment group received live bacterial cells in PBS intragastrically twice a week, every other week for 13 weeks. Both control groups received PBS intragastrically. After the 13-week treatment period, the mice were sacrificed for gene and protein expression and functional analyses. Our results show that E. cloacae administration increased subcutaneous fat mass and the relative proportion of hypertrophic adipocytes. Both subcutaneous and visceral fat had signs of decreased insulin signaling and elevated lipolysis that was reflected in higher serum glycerol levels. In addition, E. cloacae -treated mice had significantly higher hepatic AST and AST/ALT ratio, and their liver histology indicated fibrosis, demonstrating that E. cloacae subsp. cloacae administration promotes hepatic damage in HFD fed mice.

  7. Arsenic uptake and accumulation in rice (Oryza sativa L.) with selenite fertilization and water management.

    PubMed

    Wan, Yanan; Camara, Aboubacar Younoussa; Huang, Qingqing; Yu, Yao; Wang, Qi; Li, Huafen

    2018-07-30

    The accumulation of arsenic (As) in rice grain is a potential threat to human health. Our study investigated the possible mediatory role of selenite fertilization on As uptake and accumulation by rice (Oryza sativa L.) under different water management regimes (aerobic or flooded) in a pot experiment. Soil solutions were also extracted during the growing season to monitor As dynamics. Results showed that As contents in the soil solutions, seedlings, and mature rice were higher under flooded than under aerobic water management. Under aerobic conditions, selenite additions slightly increased As concentrations in soil solutions (in the last two samplings), but decreased As levels in rice plants. Relative to the control, 0.5 mg kg -1 selenite decreased rice grain As by 27.5%. Under flooded conditions, however, selenite additions decreased As in soil solutions, while increased As in rice grain. Tendencies also showed that selenite additions decreased the proportion of As in rice shoots both at the seedling stage and maturity, and were more effective in aerobic soil. Our results demonstrate that the effect of selenite fertilizer on As accumulation by rice is related to water management. Copyright © 2018 Elsevier Inc. All rights reserved.

  8. Arsenic accumulation and speciation in rice are affected by root aeration and variation of genotypes.

    PubMed

    Wu, Chuan; Ye, Zhihong; Shu, Wensheng; Zhu, Yongguan; Wong, Minghung

    2011-05-01

    Root aeration, arsenic (As) accumulation, and speciation in rice of 20 different genotypes with regular irrigation of water containing 0.4 mg As l(-1) were investigated. Different genotypes had different root anatomy demonstrated by entire root porosity (ranging from 12.43% to 33.21%), which was significantly correlated with radial oxygen loss (ROL) (R=0.64, P<0.01). Arsenic accumulation differed between genotypes, but there were no significant differences between Indica and Japonica subspecies, as well as paddy and upland rice. Total ROL from entire roots was correlated with metal tolerance (expressed as percentage mean of control straw biomass, R=0.69, P<0.01) among the 20 genotypes; total As concentration (R=-0.67, P<0.01) and inorganic As concentration (R=-0.47, P<0.05) in rice grains of different genotypes were negatively correlated with ROL. There were also significant genotype effects in percentage inorganic As (F=15.8, P<0.001) and percentage cacodylic acid (F=22.1, P<0.001), respectively. Root aeration of different genotypes and variation of genotypes on As accumulation and speciation would be useful for selecting genotypes to grow in areas contaminated by As.

  9. The maize brown midrib2 (bm2) gene encodes a methylenetetrahydrofolate reductase that contributes to lignin accumulation

    PubMed Central

    Tang, Ho Man; Liu, Sanzhen; Hill-Skinner, Sarah; Wu, Wei; Reed, Danielle; Yeh, Cheng-Ting; Nettleton, Dan; Schnable, Patrick S

    2014-01-01

    The midribs of maize brown midrib (bm) mutants exhibit a reddish-brown color associated with reductions in lignin concentration and alterations in lignin composition. Here, we report the mapping, cloning, and functional and biochemical analyses of the bm2 gene. The bm2 gene was mapped to a small region of chromosome 1 that contains a putative methylenetetrahydrofolate reductase (MTHFR) gene, which is down-regulated in bm2 mutant plants. Analyses of multiple Mu-induced bm2-Mu mutant alleles confirmed that this constitutively expressed gene is bm2. Yeast complementation experiments and a previously published biochemical characterization show that the bm2 gene encodes a functional MTHFR. Quantitative RT-PCR analyses demonstrated that the bm2 mutants accumulate substantially reduced levels of bm2 transcript. Alteration of MTHFR function is expected to influence accumulation of the methyl donor S-adenosyl-l-methionine (SAM). Because SAM is consumed by two methyltransferases in the lignin pathway (Ye et al., 1994), the finding that bm2 encodes a functional MTHFR is consistent with its lignin phenotype. Consistent with this functional assignment of bm2, the expression patterns of genes in a variety of SAM-dependent or -related pathways, including lignin biosynthesis, are altered in the bm2 mutant. Biochemical assays confirmed that bm2 mutants accumulate reduced levels of lignin with altered composition compared to wild-type. Hence, this study demonstrates a role for MTHFR in lignin biosynthesis. PMID:24286468

  10. S1PR1 is crucial for accumulation of regulatory T cells in tumors via STAT3.

    PubMed

    Priceman, Saul J; Shen, Shudan; Wang, Lin; Deng, Jiehui; Yue, Chanyu; Kujawski, Maciej; Yu, Hua

    2014-03-27

    S1PR1 signaling has been shown to restrain the number and function of regulatory T (Treg) cells in the periphery under physiological conditions and in colitis models, but its role in regulating tumor-associated T cells is unknown. Here, we show that S1PR1 signaling in T cells drives Treg accumulation in tumors, limits CD8(+) T cell recruitment and activation, and promotes tumor growth. T-cell-intrinsic S1PR1 affects Treg cells, but not CD8(+) T cells, as demonstrated by adoptive transfer models and transient pharmacological S1PR1 modulation. An increase in S1PR1 in CD4(+) T cells promotes STAT3 activation and JAK/STAT3-dependent Treg tumor migration, whereas STAT3 ablation in T cells diminishes tumor-associated Treg accumulation and tumor growth. Our study demonstrates a stark contrast between the consequences of S1PR1 signaling in Treg cells in the periphery versus tumors. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  11. Absorption, accumulation and biological effects of depleted uranium in Peyer's patches of rats.

    PubMed

    Dublineau, I; Grison, S; Grandcolas, L; Baudelin, C; Tessier, C; Suhard, D; Frelon, S; Cossonnet, C; Claraz, M; Ritt, J; Paquet, P; Voisin, P; Gourmelon, P

    2006-10-29

    The digestive tract is the entry route for radionuclides following the ingestion of contaminated food and/or water wells. It was recently characterized that the small intestine was the main area of uranium absorption throughout the gastrointestinal tract. This study was designed to determine the role played by the Peyer's patches in the intestinal absorption of uranium, as well as the possible accumulation of this radionuclide in lymphoid follicles and the toxicological or pathological consequences on the Peyer's patch function subsequent to the passage and/or accumulation of uranium. Results of experiments performed in Ussing chambers indicate that the apparent permeability to uranium in the intestine was higher (10-fold) in the mucosa than in Peyer's patches ((6.21+/-1.21 to 0.55+/-0.35)x10(-6)cm/s, respectively), demonstrating that the small intestinal epithelium was the preferential pathway for the transmucosal passage of uranium. A quantitative analysis of uranium by ICP-MS following chronic contamination with depleted uranium during 3 or 9 months showed a preferential accumulation of uranium in Peyer's patches (1355% and 1266%, respectively, at 3 and 9 months) as compared with epithelium (890% and 747%, respectively, at 3 and 9 months). Uranium was also detected in the mesenteric lymph nodes ( approximately 5-fold after contamination with DU). The biological effects of this accumulation of depleted uranium after chronic contamination were investigated in Peyer's patches. There was no induction of the apoptosis pathway after chronic DU contamination in Peyer's patches. The results indicate no change in the cytokine expression (Il-10, TGF-beta, IFN-gamma, TNF-alpha, MCP-1) in Peyer's patches and in mesenteric lymph nodes, and no modification in the uptake of yeast cells by Peyer's patches. In conclusion, this study shows that the Peyer's patches were a site of retention for uranium following the chronic ingestion of this radionuclide, without any biological

  12. Accumulation of Polychlorinated Biphenyls in Adipocytes: Selective Targeting to Lipid Droplets and Role of Caveolin-1

    PubMed Central

    Bourez, Sophie; Le Lay, Soazig; Van den Daelen, Carine; Louis, Caroline; Larondelle, Yvan; Thomé, Jean-Pierre; Schneider, Yves-Jacques; Dugail, Isabelle; Debier, Cathy

    2012-01-01

    Background Polychlorinated biphenyls (PCBs) are persistent environmental pollutants that preferentially accumulate in lipid-rich tissues of contaminated organisms. Although the adipose tissue constitutes a major intern reservoir of PCBs and recent epidemiological studies associate PCBs to the development of obesity and its related disorders, little is known about the mechanisms involved in their uptake by the adipose tissue and their intracellular localization in fat cells. Methodology/Principal Findings We have examined the intracellular distribution of PCBs in mouse cultured adipocytes and tested the potential involvement of caveolin-1, an abundant adipocyte membrane protein, in the uptake of these compounds by fat cells. We show that 2,4,4′-trichlorobiphenyl (PCB-28), 2,3′,4,4′,5-pentachlorobiphenyl (PCB-118) and 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB-153) congeners rapidly and extensively accumulate in 3T3-L1 or mouse embryonic fibroblast (MEF) derived cultured adipocytes. The dynamics of accumulation differed between the 3 congeners tested. By subcellular fractionation of primary adipocytes, we demonstrate that these pollutants were almost exclusively recovered within the lipid droplet fraction and practically not associated to cell membranes. The absence of caveolin-1 expression in primary adipocytes from cav-1 deficient mice did not modify lipid droplet selective targeting of PCBs. In cav-1 KO MEF differentiated adipocytes, PCB accumulation was decreased, which correlated with reduced cell triglyceride content. Conversely, adenoviral mediated cav-1 overexpressing in 3T3-L1 cells, which had no impact on total cell lipid content, did not change PCB accumulation. Conclusion/Significance Our data indicate that caveolin-1 per se is not required for selective PCB accumulation, but rather point out a primary dependence on adipocyte triglyceride content. If the crucial role of lipid droplets in energy homeostasis is considered, the almost exclusive

  13. Brain mitochondrial iron accumulates in Huntington's disease, mediates mitochondrial dysfunction, and can be removed pharmacologically.

    PubMed

    Agrawal, Sonal; Fox, Julia; Thyagarajan, Baskaran; Fox, Jonathan H

    2018-05-20

    Mitochondrial bioenergetic dysfunction is involved in neurodegeneration in Huntington's disease (HD). Iron is critical for normal mitochondrial bioenergetics but can also contribute to pathogenic oxidation. The accumulation of iron in the brain occurs in mouse models and in human HD. Yet the role of mitochondria-related iron dysregulation as a contributor to bioenergetic pathophysiology in HD is unclear. We demonstrate here that human HD and mouse model HD (12-week R6/2 and 12-month YAC128) brains accumulated mitochondrial iron and showed increased expression of iron uptake protein mitoferrin 2 and decreased iron-sulfur cluster synthesis protein frataxin. Mitochondria-enriched fractions from mouse HD brains had deficits in membrane potential and oxygen uptake and increased lipid peroxidation. In addition, the membrane-permeable iron-selective chelator deferiprone (1 μM) rescued these effects ex-vivo, whereas hydrophilic iron and copper chelators did not. A 10-day oral deferiprone treatment in 9-week R6/2 HD mice indicated that deferiprone removed mitochondrial iron, restored mitochondrial potentials, decreased lipid peroxidation, and improved motor endurance. Neonatal iron supplementation potentiates neurodegeneration in mouse models of HD by unknown mechanisms. We found that neonatal iron supplementation increased brain mitochondrial iron accumulation and potentiated markers of mitochondrial dysfunction in HD mice. Therefore, bi-directional manipulation of mitochondrial iron can potentiate and protect against markers of mouse HD. Our findings thus demonstrate the significance of iron as a mediator of mitochondrial dysfunction and injury in mouse models of human HD and suggest that targeting the iron-mitochondrial pathway may be protective. Copyright © 2018 Elsevier Inc. All rights reserved.

  14. The Evidence Value Matrix for Diagnostic Imaging.

    PubMed

    Seidel, David; Frank, Richard A; Schmidt, Sebastian

    2016-10-01

    Evidence and value are independent factors that together affect the adoption of diagnostic imaging. For example, noncoverage decisions by reimbursement authorities can be justified by a lack of evidence and/or value. To create transparency and a common understanding among various stakeholders, we have proposed a two-dimensional matrix that allows classification of imaging devices into three distinct categories based on the available evidence and value: "question marks" (low value demonstrated in studies of any evidence level), "candidates" (high value demonstrated in retrospective case-control studies and smaller case series), and "stars" (high value demonstrated in large prospective cohort studies or, preferably, randomized controlled trials). We use several examples to illustrate the application of our matrix. A major benefit of the matrix includes the development of specific strategies for evidence and value generation. High-evidence/low-value studies are expensive and unlikely to convince decision makers, given the uncertainty of the impact on patient management and outcomes. Developing question marks into candidates first and then into stars will often be quicker and less expensive ("success sequence"). Only this more sophisticated and objective approach can justify the additional funding necessary to generate the evidence base to inform reimbursement by payers and adoption by providers. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  15. Selective accumulation of cytosol CDP-choline as an isolated erythrocyte defect in chronic hemolysis.

    PubMed Central

    Paglia, D E; Valentine, W N; Nakatani, M; Rauth, B J

    1983-01-01

    Erythrocytes from a young woman with chronic hemolytic anemia were found to contain 0.31-0.45 mM CDP-choline, concentrations that are 15-25 times those in normal erythrocytes and equivalent to 20-30% of the total adenine nucleotide content. Accumulation of CDP-choline has been reported only in erythrocytes from subjects with severe (homozygous) pyrimidine nucleotidase deficiency. In the latter syndrome, however, pyrimidine nucleotidase activity is very low and a spectrum of uridine- and cytidine-containing nucleotides is present along with epiphenomena involving glutathione and ribosephosphate pyrophosphokinase. By contrast, selective accumulation of CDP-choline was the only abnormality demonstrable in proband erythrocytes. Membrane phospholipids were quantitatively and qualitatively normal, compatible with the observation that mature erythrocytes maintain membrane phospholipids largely by passive exchange with plasma components or by acylation of lysophospholipids. Although the presence of small amounts of other CDP-containing cofactors, such as CDP-ethanolamine, could not be entirely excluded, the cytidine/choline ratio closely approximated 1:1 in all studies. These data are compatible with the view that choline phosphotransferase and ethanolamine phosphotransferase are separate enzymes in erythroid cells. Selective accumulation of CDP-choline in proband erythrocytes is also compatible with an inherited deficiency of choline phosphotransferase in erythroid precursors, though this hypothesis remains unproved. PMID:6574471

  16. Higher accumulation of F1-V fusion recombinant protein in plants after induction of protein body formation.

    PubMed

    Alvarez, M Lucrecia; Topal, Emel; Martin, Federico; Cardineau, Guy A

    2010-01-01

    Improving foreign protein accumulation is crucial for enhancing the commercial success of plant-based production systems since product yields have a major influence on process economics. Cereal grain evolved to store large amounts of proteins in tightly organized aggregates. In maize, gamma-Zein is the major storage protein synthesized by the rough endoplasmic reticulum (ER) and stored in specialized organelles called protein bodies (PB). Zera (gamma-Zein ER-accumulating domain) is the N-terminal proline-rich domain of gamma-zein that is sufficient to induce the assembly of PB formation. Fusion of the Zera domain to proteins of interest results in assembly of dense PB-like, ER-derived organelles, containing high concentration of recombinant protein. Our main goal was to increase recombinant protein accumulation in plants in order to enhance the efficiency of orally-delivered plant-made vaccines. It is well known that oral vaccination requires substantially higher doses than parental formulations. As a part of a project to develop a plant-made plague vaccine, we expressed our model antigen, the Yersinia pestis F1-V antigen fusion protein, with and without a fused Zera domain. We demonstrated that Zera-F1-V protein accumulation was at least 3x higher than F1-V alone when expressed in three different host plant systems: Ncotiana benthamiana, Medicago sativa (alfalfa) and Nicotiana tabacum NT1 cells. We confirmed the feasibility of using Zera technology to induce protein body formation in non-seed tissues. Zera expression and accumulation did not affect plant development and growth. These results confirmed the potential exploitation of Zera technology to substantially increase the accumulation of value-added proteins in plants.

  17. Metabolic Adaptation in Transplastomic Plants Massively Accumulating Recombinant Proteins

    PubMed Central

    Bally, Julia; Job, Claudette; Belghazi, Maya; Job, Dominique

    2011-01-01

    Background Recombinant chloroplasts are endowed with an astonishing capacity to accumulate foreign proteins. However, knowledge about the impact on resident proteins of such high levels of recombinant protein accumulation is lacking. Methodology/Principal Findings Here we used proteomics to characterize tobacco (Nicotiana tabacum) plastid transformants massively accumulating a p-hydroxyphenyl pyruvate dioxygenase (HPPD) or a green fluorescent protein (GFP). While under the conditions used no obvious modifications in plant phenotype could be observed, these proteins accumulated to even higher levels than ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), the most abundant protein on the planet. This accumulation occurred at the expense of a limited number of leaf proteins including Rubisco. In particular, enzymes involved in CO2 metabolism such as nuclear-encoded plastidial Calvin cycle enzymes and mitochondrial glycine decarboxylase were found to adjust their accumulation level to these novel physiological conditions. Conclusions/Significance The results document how protein synthetic capacity is limited in plant cells. They may provide new avenues to evaluate possible bottlenecks in recombinant protein technology and to maintain plant fitness in future studies aiming at producing recombinant proteins of interest through chloroplast transformation. PMID:21966485

  18. Reduced arsenic accumulation in indica rice (Oryza sativa L.) cultivar with ferromanganese oxide impregnated biochar composites amendments.

    PubMed

    Lin, Lina; Gao, Minling; Qiu, Weiwen; Wang, Di; Huang, Qing; Song, Zhengguo

    2017-12-01

    The effects of biochar (BC) and ferromanganese oxide biochar composites (FMBC 1 and FMBC 2 ) on As (Arsenic) accumulation in rice were determined using a pot experiment. Treatments with BC or FMBC improved the dry weights of rice roots, stems, leaves, and grains in soils containing different As contamination levels. Compared to BC treatment, FMBC treatments significantly reduced As accumulation in different parts of the rice plants (P < 0.05), and FMBC 2 performed better than FMBC 1 did. Furthermore, exposure to 2% FMBC 2 decreased the total As concentration in the grain by 68.9-78.3%. The addition of FMBC increased the ratio of essential amino acids in the grain, decreased As availability in the soil, and significantly increased the Fe and Mn plaque contents. The reduced As accumulation in rice can be attributed to As(III) to As(V) oxidation by ferro - manganese binary oxide, which increased the As adsorbed by FMBC. Furthermore, Fe and Mn plaques on the rice root surface decreased the transport of As in rice. Taken together, our results demonstrated the applicability of FMBC as a potential measure for reducing As accumulation in rice, improving the amino acid content of rice grains, and effectively remediating As-polluted soil. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Osmoregulation in Agrobacterium tumefaciens: accumulation of a novel disaccharide is controlled by osmotic strength and glycine betaine.

    PubMed Central

    Smith, L T; Smith, G M; Madkour, M A

    1990-01-01

    We have investigated the mechanism of osmotic stress adaptation (osmoregulation) in Agrobacterium tumefaciens biotype I (salt-tolerant) and biotype II (salt-sensitive) strains. Using natural-abundance 13C nuclear magnetic resonance spectroscopy, we identified all organic solutes that accumulated to significant levels in osmotically stressed cultures. When stressed, biotype I strains (C58, NT1, and A348) accumulated glutamate and a novel disaccharide, beta-fructofuranosyl-alpha-mannopyranoside, commonly known as mannosucrose. In the salt-sensitive biotype II strain K84, glutamate was observed but mannosucrose was not. We speculate that mannosucrose confers the extra osmotic tolerance observed in the biotype I strains. In addition to identifying the osmoregulated solutes that this species synthesizes, we investigated the ability of A. tumefaciens to utilize the powerful osmotic stress protectant glycine betaine when it is supplied in the medium. Results from growth experiments, nuclear magnetic resonance spectroscopy, and a 14C labeling experiment demonstrated that in the absence of osmotic stress, glycine betaine was metabolized, while in stressed cultures, glycine betaine accumulated intracellularly and conferred enhanced osmotic stress tolerance. Furthermore, when glycine betaine was taken up in stressed cells, its accumulation caused the intracellular concentration of mannosucrose to drop significantly. The possible role of osmoregulation of A. tumefaciens in the transformation of plants is discussed. PMID:2254260

  20. Implications of metal accumulation mechanisms to phytoremediation.

    PubMed

    Memon, Abdul R; Schröder, Peter

    2009-03-01

    Trace elements (heavy metals and metalloids) are important environmental pollutants, and many of them are toxic even at very low concentrations. Pollution of the biosphere with trace elements has accelerated dramatically since the Industrial Revolution. Primary sources are the burning of fossil fuels, mining and smelting of metalliferous ores, municipal wastes, agrochemicals, and sewage. In addition, natural mineral deposits containing particularly large quantities of heavy metals are found in many regions. These areas often support characteristic plant species thriving in metal-enriched environments. Whereas many species avoid the uptake of heavy metals from these soils, some of them can accumulate significantly high concentrations of toxic metals, to levels which by far exceed the soil levels. The natural phenomenon of heavy metal tolerance has enhanced the interest of plant ecologists, plant physiologists, and plant biologists to investigate the physiology and genetics of metal tolerance in specialized hyperaccumulator plants such as Arabidopsis halleri and Thlaspi caerulescens. In this review, we describe recent advances in understanding the genetic and molecular basis of metal tolerance in plants with special reference to transcriptomics of heavy metal accumulator plants and the identification of functional genes implied in tolerance and detoxification. Plants are susceptible to heavy metal toxicity and respond to avoid detrimental effects in a variety of different ways. The toxic dose depends on the type of ion, ion concentration, plant species, and stage of plant growth. Tolerance to metals is based on multiple mechanisms such as cell wall binding, active transport of ions into the vacuole, and formation of complexes with organic acids or peptides. One of the most important mechanisms for metal detoxification in plants appears to be chelation of metals by low-molecular-weight proteins such as metallothioneins and peptide ligands, the phytochelatins. For

  1. Molecular evidence that the eukaryotic THO/TREX complex is required for efficient transcription elongation.

    PubMed

    Rondón, Ana G; Jimeno, Sonia; García-Rubio, María; Aguilera, Andrés

    2003-10-03

    THO/TREX is a conserved eukaryotic complex formed by the core THO complex plus proteins involved in mRNA metabolism and export such as Sub2 and Yra1. Mutations in any of the THO/TREX structural genes cause pleiotropic phenotypes such as transcription impairment, increased transcription-associated recombination, and mRNA export defects. To assay the relevance of THO/TREX complex in transcription, we performed in vitro transcription elongation assays in mutant cell extracts using supercoiled DNA templates containing two G-less cassettes. With these assays, we demonstrate that hpr1delta, tho2delta, and mft1delta mutants of the THO complex and sub2 mutants show significant reductions in the efficiency of transcription elongation. The mRNA expression defect of hpr1delta mutants was not due to an increase in mRNA decay, as determined by mRNA half-life measurements and mRNA time course accumulation experiments in the absence of Rrp6p exoribonuclease. This work demonstrates that THO and Sub2 are required for efficient transcription elongation, providing further evidence for the coupling between transcription and mRNA metabolism and export.

  2. Rice choline monooxygenase (OsCMO) protein functions in enhancing glycine betaine biosynthesis in transgenic tobacco but does not accumulate in rice (Oryza sativa L. ssp. japonica).

    PubMed

    Luo, Di; Niu, Xiangli; Yu, Jinde; Yan, Jun; Gou, Xiaojun; Lu, Bao-Rong; Liu, Yongsheng

    2012-09-01

    Glycine betaine (GB) is a compatible quaternary amine that enables plants to tolerate abiotic stresses, including salt, drought and cold. In plants, GB is synthesized through two-step of successive oxidations from choline, catalyzed by choline monooxygenase (CMO) and betaine aldehyde dehydrogenase (BADH), respectively. Rice is considered as a typical non-GB accumulating species, although the entire genome sequencing revealed rice contains orthologs of both CMO and BADH. Several studies unraveled that rice has a functional BADH gene, but whether rice CMO gene (OsCMO) is functional or a pseudogene remains to be elucidated. In the present study, we report the functional characterization of rice CMO gene. The OsCMO gene was isolated from rice cv. Nipponbare (Oryza sativa L. ssp. japonica) using RT-PCR. Northern blot demonstrated the transcription of OsCMO is enhanced by salt stress. Transgenic tobacco plants overexpressing OsCMO results in increased GB content and elevated tolerance to salt stress. Immunoblotting analysis demonstrates that a functional OsCMO protein with correct size was present in transgenic tobacco but rarely accumulated in wild-type rice plants. Surprisingly, a large amount of truncated proteins derived from OsCMO was induced in the rice seedlings in response to salt stresses. This suggests that it is the lack of a functional OsCMO protein that presumably results in non-GB accumulation in the tested rice plant. Expression and transgenic studies demonstrate OsCMO is transcriptionally induced in response to salt stress and functions in increasing glycinebetaine accumulation and enhancing tolerance to salt stress. Immunoblotting analysis suggests that no accumulation of glycinebetaine in the Japonica rice plant presumably results from lack of a functional OsCMO protein.

  3. The relative contribution of near-bed vs. intragravel horizontal transport to fine sediment accumulation processes in river gravel beds

    NASA Astrophysics Data System (ADS)

    Casas-Mulet, Roser; Lakhanpal, Garima; Stewardson, Michael J.

    2018-02-01

    Understanding flow-sediment interactions is important for comprehending river functioning. Fine sediment accumulation processes, in particular, have key implications for ecosystem health. However, the amount of fines generated by intragravel flows and later accumulated in gravel streambeds may have been underestimated, as the hydraulic-related driving transport mechanisms in play are not clearly identified. Specifically, the relative contribution of fines from upper vs. lower sediment layers in gravel beds is not well understood. By recreating flooded and dewatered conditions in an experimental flume filled with natural sediment, we estimated such contributions by observing and collecting intragravel transported fines that were later accumulated into a void in the middle of the sediment matrix. Near-bed transport in the upper sediment layers (named Brinkman load) during flooded conditions accounted for most (90%) of the accumulated fines. Intragravel transport in the lower sediment layers (named Interstitial load) was the sole source of transport and accumulation during dewatered conditions with steeper hydraulic gradients. Interstitial load accounted for 10% of the total transport during flooded conditions. Although small, such estimations demonstrate that hydraulic-gradient transport in the lower sediment layers occurs in spite of the contradicting analytical assessments. We provide a case study to challenge the traditional approaches of assessing intragravel transport, and a useful framework to understand the origin and relative contribution of fine sediment accumulation in gravel beds. Such knowledge will be highly useful for the design of monitoring programs aiding river management, particularly in regulated rivers.

  4. Bicarbonate trigger for inducing lipid accumulation in algal systems

    DOEpatents

    Gardner, Robert; Peyton, Brent; Cooksey, Keith E.

    2015-08-04

    The present invention provides bicarbonate containing and/or bicarbonate-producing compositions and methods to induce lipid accumulation in an algae growth system, wherein the algae growth system is under light-dark cycling condition. By adding said compositions at a specific growth stage, said methods lead to much higher lipid accumulation and/or significantly reduced total time required for accumulating lipid in the algae growth system.

  5. Formalizing Evidence Type Definitions for Drug-Drug Interaction Studies to Improve Evidence Base Curation.

    PubMed

    Utecht, Joseph; Brochhausen, Mathias; Judkins, John; Schneider, Jodi; Boyce, Richard D

    2017-01-01

    In this research we aim to demonstrate that an ontology-based system can categorize potential drug-drug interaction (PDDI) evidence items into complex types based on a small set of simple questions. Such a method could increase the transparency and reliability of PDDI evidence evaluation, while also reducing the variations in content and seriousness ratings present in PDDI knowledge bases. We extended the DIDEO ontology with 44 formal evidence type definitions. We then manually annotated the evidence types of 30 evidence items. We tested an RDF/OWL representation of answers to a small number of simple questions about each of these 30 evidence items and showed that automatic inference can determine the detailed evidence types based on this small number of simpler questions. These results show proof-of-concept for a decision support infrastructure that frees the evidence evaluator from mastering relatively complex written evidence type definitions.

  6. Instability of bottom-water redox conditions during accumulation of Quaternary sediment in the Japan Sea

    USGS Publications Warehouse

    Piper, D.Z.; Isaacs, C.M.

    1996-01-01

    The concentrations of Cd, Cr, Cu, Mo, Ni, Sb, U, V, and Zn were measured in early Quaternary sediment (1.32 to 1.08 Ma) from the Oki Ridge in the Japan Sea. The elements were partitioned between a detrital fraction, composed of terrigenous and volcaniclastic aluminosilicate debris, and a marine fraction, composed of biogenic and hydrogenous debris derived from seawater. The most important factors controlling minor-element accumulation rates in the marine fraction were (1) primary productivity in the photic zone, which largely controlled the flux of particulate organic-matter-bound minor elements settling through the water column and onto the seafloor, and (2) bottom-water redox, which determined the suite of elements that accumulated directly from seawater. This marine fraction of minor elements on Oki Ridge recorded six periods of high minor-element abundance. Assuming a constant bulk sediment accumulation rate, each period lasted roughly 5,000 to 10,000 years with a 41,000-year cycle. Accumulation rates of individual elements such as Cd, Mo, and U suggest sulfate-reducing conditions were established in the bottom water during the 10,000-year periods; accumulation rates of Cr and V during the intervening periods are indicative of less reducing, denitrifying conditions. Interelement ratios, for example, Cu:Mo, V:Cr, and Sb:Mo, further reflect bottom-water instability, such that bottom-water redox actually varied from sulfate reducing to denitrifying during the periods of highest minor-element accumulation rates; it varied from denitrifying to oxidizing during the intervening periods. Sediment lithology supports these interpretations of the minor-element distributions; the sediment is finely laminated for several of the periods represented by Cd, Mo, and U maxima and weakly laminated to bioturbated for the intervening periods. The geochemistry of this sediment demonstrates the unambiguous signal of Mo, principally, but of several other minor elements as well in

  7. Synoptic controls on precipitation pathways and snow delivery to high-accumulation ice core sites in the Ross Sea region, Antarctica

    NASA Astrophysics Data System (ADS)

    Sinclair, K. E.; Bertler, N. A. N.; Trompetter, W. J.

    2010-11-01

    Dominant storm tracks to two ice core sites on the western margin of the Ross Sea, Antarctica (Skinner Saddle (SKS) and Evans Piedmont Glacier), are investigated to establish key synoptic controls on snow accumulation. This is critical in terms of understanding the seasonality, source regions, and transport pathways of precipitation delivered to these sites. In situ snow depth and meteorological observations are used to identify major accumulation events in 2007-2008, which differ considerably between sites in terms of their magnitude and seasonal distribution. While snowfall at Evans Piedmont Glacier occurs almost exclusively during summer and spring, Skinner Saddle receives precipitation year round with a lull during the months of April and May. Cluster analysis of daily back trajectories reveals that the highest-accumulation days at both sites result from fast-moving air masses, associated with synoptic-scale low-pressure systems. There is evidence that short-duration pulses of snowfall at SKS also originate from mesocyclone development over the Ross Ice Shelf and local moisture sources. Changes in the frequency and seasonal distribution of these mechanisms of precipitation delivery will have a marked impact on annual accumulation over time and will therefore need careful consideration during the interpretation of stable isotope and geochemical records from these ice cores.

  8. High accumulation of anthocyanins via the ectopic expression of AtDFR confers significant salt stress tolerance in Brassica napus L.

    PubMed

    Kim, Jihye; Lee, Won Je; Vu, Tien Thanh; Jeong, Chan Young; Hong, Suk-Whan; Lee, Hojoung

    2017-08-01

    The ectopic expression of AtDFR results in increased accumulation of anthocyanins leading to enhanced salinity and drought stress tolerance in B. napus plants. Flavonoids with antioxidant effects confer many additional benefits to plants. Evidence indicates that flavonoids, including anthocyanins, protect tissues against oxidative stress from various abiotic stressors. We determined whether increases in anthocyanins increased abiotic stress tolerance in Brassica napus, because the values of B. napus L. and its cultivation area are increasing worldwide. We overexpressed Arabidopsis dihydroflavonol-4-reductase (DFR) in B. napus. Increased DFR transcript levels for AtDFR-OX B. shoots correlated with higher anthocyanin accumulation. AtDFR-OX Brassica shoots exhibited lower reactive oxygen species (ROS) accumulation than wild-type (WT) shoots under high NaCl and mannitol concentrations. This was corroborated by 3,3-diaminobenzidine staining for ROS scavenging activity in 1,1-diphenyl-2-picryl-hydrazyl assays. Shoots of the AtDFR-OX B. napus lines grown in a high salt medium exhibited enhanced salt tolerance and higher chlorophyll content than similarly grown WT plants. Our observations suggested that the AtDFR gene can be effectively manipulated to modulate salinity and drought stress tolerance by directing to high accumulation of anthocyanins in oilseed plants.

  9. Accumulation of sediment-associated viruses in shellfish.

    PubMed Central

    Landry, E F; Vaughn, J M; Vicale, T J; Mann, R

    1983-01-01

    The present study focused on the importance of contaminated sediments in shellfish accumulation of human viruses. Epifaunal (Crassostrea virginica) and infaunal (Mercenaria mercenaria) shellfish, placed on or in cores, were exposed to either resuspended or undisturbed sediments containing bound poliovirus type 1 (LSc 2ab). Consistent bioaccumulation by oysters (four of five trials) was only noted when sediment-bound viruses occurred in the water column. Virus accumulation was observed in a single instance where sediments remained in an undisturbed state. While the incidence of bioaccumulation was higher with resuspended rather than undisturbed contaminated sediment, the actual concentration of accumulated viruses was not significantly different. The accumulation of viruses from oysters residing on uninoculated sediments. When clams were exposed to undisturbed, virus-contaminated sediments, two of five shellfish pools yielded viral isolates. Bioaccumulation of undisturbed sediments by these bivalves was considered marginal when related to the concentration of virus in contaminated sediments; they would only represent a significant threat when suspended in the water column. Arguments were advanced for water-column sampling in the region of the water-sediment interface to provide an accurate determination of the virological quality of shellfish harvesting waters. PMID:6297392

  10. Asynchronous accumulation of lettuce infectious yellows virus RNAs 1 and 2 and identification of an RNA 1 trans enhancer of RNA 2 accumulation.

    PubMed

    Yeh, H H; Tian, T; Rubio, L; Crawford, B; Falk, B W

    2000-07-01

    Time course and mutational analyses were used to examine the accumulation in protoplasts of progeny RNAs of the bipartite Crinivirus, Lettuce infectious yellow virus (LIYV; family Closteroviridae). Hybridization analyses showed that simultaneous inoculation of LIYV RNAs 1 and 2 resulted in asynchronous accumulation of progeny LIYV RNAs. LIYV RNA 1 progeny genomic and subgenomic RNAs could be detected in protoplasts as early as 12 h postinoculation (p.i.) and accumulated to high levels by 24 h p.i. The LIYV RNA 1 open reading frame 2 (ORF 2) subgenomic RNA was the most abundant of all LIYV RNAs detected. In contrast, RNA 2 progeny were not readily detected until ca. 36 h p.i. Mutational analyses showed that in-frame stop codons introduced into five of seven RNA 2 ORFs did not affect accumulation of progeny LIYV RNA 1 or RNA 2, confirming that RNA 2 does not encode proteins necessary for LIYV RNA replication. Mutational analyses also supported that LIYV RNA 1 encodes proteins necessary for replication of LIYV RNAs 1 and 2. A mutation introduced into the LIYV RNA 1 region encoding the overlapping ORF 1B and ORF 2 was lethal. However, mutations introduced into only LIYV RNA 1 ORF 2 resulted in accumulation of progeny RNA 1 near or equal to wild-type RNA 1. In contrast, the RNA 1 ORF 2 mutants did not efficiently support the trans accumulation of LIYV RNA 2. Three distinct RNA 1 ORF 2 mutants were analyzed and all exhibited a similar phenotype for progeny LIYV RNA accumulation. These data suggest that the LIYV RNA 1 ORF 2 encodes a trans enhancer for RNA 2 accumulation.

  11. Asynchronous Accumulation of Lettuce Infectious Yellows Virus RNAs 1 and 2 and Identification of an RNA 1 trans Enhancer of RNA 2 Accumulation

    PubMed Central

    Yeh, Hsin-Hung; Tian, Tongyan; Rubio, Luis; Crawford, Brett; Falk, Bryce W.

    2000-01-01

    Time course and mutational analyses were used to examine the accumulation in protoplasts of progeny RNAs of the bipartite Crinivirus, Lettuce infectious yellow virus (LIYV; family Closteroviridae). Hybridization analyses showed that simultaneous inoculation of LIYV RNAs 1 and 2 resulted in asynchronous accumulation of progeny LIYV RNAs. LIYV RNA 1 progeny genomic and subgenomic RNAs could be detected in protoplasts as early as 12 h postinoculation (p.i.) and accumulated to high levels by 24 h p.i. The LIYV RNA 1 open reading frame 2 (ORF 2) subgenomic RNA was the most abundant of all LIYV RNAs detected. In contrast, RNA 2 progeny were not readily detected until ca. 36 h p.i. Mutational analyses showed that in-frame stop codons introduced into five of seven RNA 2 ORFs did not affect accumulation of progeny LIYV RNA 1 or RNA 2, confirming that RNA 2 does not encode proteins necessary for LIYV RNA replication. Mutational analyses also supported that LIYV RNA 1 encodes proteins necessary for replication of LIYV RNAs 1 and 2. A mutation introduced into the LIYV RNA 1 region encoding the overlapping ORF 1B and ORF 2 was lethal. However, mutations introduced into only LIYV RNA 1 ORF 2 resulted in accumulation of progeny RNA 1 near or equal to wild-type RNA 1. In contrast, the RNA 1 ORF 2 mutants did not efficiently support the trans accumulation of LIYV RNA 2. Three distinct RNA 1 ORF 2 mutants were analyzed and all exhibited a similar phenotype for progeny LIYV RNA accumulation. These data suggest that the LIYV RNA 1 ORF 2 encodes a trans enhancer for RNA 2 accumulation. PMID:10846054

  12. Identification of potential barriers to nurse-sensitive outcome demonstration.

    PubMed

    Beckel, Jean; Wolf, Gail; Wilson, Roxanne; Hoolahan, Susan

    2013-12-01

    The objective of this study was to determine differences in chief nursing officer, Magnet(®) program director, nurse leader, and direct care RN perspectives of potential barriers to demonstration of nurse-sensitive outcomes. The Magnet Recognition Program(®) and other designations are focusing on patient outcomes. No evidence is available addressing barriers to demonstration of nursing outcomes at multiple levels of practice. A Likert scale tool was developed and administered to 526 attendees at the 2012 national Magnet conference. Questions related to available resources, benchmarks, outcome demonstration process understanding, perception of value, and competing priorities. Significant perception differences by role were demonstrated related to available resources, competing priorities, and process understanding supporting demonstration of nurse-sensitive outcomes. No significant differences were identified related to benchmarks or perception of process value to the organization. This study provides new information demonstrating potential barriers to demonstration of nurse-sensitive outcomes differing by role. Opportunity exists to develop systems and processes to reduce perceived barriers among the nursing workforce.

  13. Atmospheric mercury accumulation and washoff processes on impervious urban surfaces

    USGS Publications Warehouse

    Eckley, C.S.; Branfireun, B.; Diamond, M.; Van Metre, P.C.; Heitmuller, F.

    2008-01-01

    The deposition and transport of mercury (Hg) has been studied extensively in rural environments but is less understood in urbanized catchments, where elevated atmospheric Hg concentrations and impervious surfaces may efficiently deliver Hg to waterways in stormwater runoff. We determined the rate at which atmospheric Hg accumulates on windows, identified the importance of washoff in removing accumulated Hg, and measured atmospheric Hg concentrations to help understand the relationship between deposition and surface accumulation. The main study location was Toronto, Ontario. Similar samples were also collected from Austin, Texas for comparison of Hg accumulation between cities. Windows provided a good sampling surface because they are ubiquitous in urban environments and are easy to clean/blank allowing the assessment of contemporary Hg accumulation. Hg Accumulation rates were spatially variable ranging from 0.82 to 2.7 ng m-2 d-1 in Toronto and showed similar variability in Austin. The highest accumulation rate in Toronto was at the city center and was 5?? higher than the rural comparison site (0.58 ng m-2 d-1). The atmospheric total gaseous mercury (TGM) concentrations were less than 2?? higher between the rural and urban locations (1.7 ?? 0.3 and 2.7 ?? 1.1 ng m-3, respectively). The atmospheric particulate bound fraction (HgP), however, was more than 3?? higher between the rural and urban sites, which may have contributed to the higher urban Hg accumulation rates. Windows exposed to precipitation had 73 ?? 9% lower accumulation rates than windows sheltered from precipitation. Runoff collected from simulated rain events confirmed that most Hg accumulated on windows was easily removed and that most of the Hg in washoff was HgP. Our results indicate that the Hg flux from urban catchments will respond rapidly to changes in atmospheric concentrations due to the mobilization of the majority of the surface accumulated Hg during precipitation events. ?? 2008 Elsevier

  14. Accumulation of fatty acids in Chlorella vulgaris under heterotrophic conditions in relation to activity of acetyl-CoAcarboxylase, temperature, and co-immobilization with Azospirillum brasilense [corrected].

    PubMed

    Leyva, Luis A; Bashan, Yoav; Mendoza, Alberto; de-Bashan, Luz E

    2014-10-01

    The relation between fatty acid accumulation, activity of acetyl-CoA carboxylase (ACC), and consequently lipid accumulation was studied in the microalgae Chlorella vulgaris co-immobilized with the plant growth-promoting bacterium Azospirillum brasilense under dark heterotrophic conditions with Na acetate as a carbon source. In C. vulgaris immobilized alone, cultivation experiments for 6 days showed that ACC activity is directly related to fatty acid accumulation, especially in the last 3 days. In co-immobilization experiments, A. brasilense exerted a significant positive effect over ACC activity, increased the quantity in all nine main fatty acids, increased total lipid accumulation in C. vulgaris, and mitigated negative effects of nonoptimal temperature for growth. No correlation between ACC activity and lipid accumulation in the cells was established for three different temperatures. This study demonstrated that the interaction between A. brasilense and C. vulgaris has a significant effect on fatty acid and lipid accumulation in the microalgae.

  15. Accumulation fatty acids of in Chlorella vulgaris under heterotrophic conditions in relation to activity of acetyl-CoA carboxylase, temperature, and co-immobilization with Azospirillum brasilense

    NASA Astrophysics Data System (ADS)

    Leyva, Luis A.; Bashan, Yoav; Mendoza, Alberto; de-Bashan, Luz E.

    2014-10-01

    The relation between fatty acid accumulation, activity of acetyl-CoA carboxylase (ACC), and consequently lipid accumulation was studied in the microalgae Chlorella vulgaris co-immobilized with the plant growth-promoting bacterium Azospirillum brasilense under dark heterotrophic conditions with Na acetate as a carbon source. In C. vulgaris immobilized alone, cultivation experiments for 6 days showed that ACC activity is directly related to fatty acid accumulation, especially in the last 3 days. In co-immobilization experiments, A. brasilense exerted a significant positive effect over ACC activity, increased the quantity in all nine main fatty acids, increased total lipid accumulation in C. vulgaris, and mitigated negative effects of nonoptimal temperature for growth. No correlation between ACC activity and lipid accumulation in the cells was established for three different temperatures. This study demonstrated that the interaction between A. brasilense and C. vulgaris has a significant effect on fatty acid and lipid accumulation in the microalgae.

  16. Early diagenesis and trace element accumulation in North American Arctic margin sediments

    NASA Astrophysics Data System (ADS)

    Kuzyk, Zou Zou A.; Gobeil, Charles; Goñi, Miguel A.; Macdonald, Robie W.

    2017-04-01

    Concentrations of redox-sensitive elements (S, Mn, Mo, U, Cd, Re) were analyzed in a set of 27 sediment cores collected along the North American Arctic margin (NAAM) from the North Bering Sea to Davis Strait via the Canadian Archipelago. Sedimentary distributions and accumulation rates of the elements were used to evaluate early diagenesis in sediments along this section and to estimate the importance of this margin as a sink for key elements in the polar and global oceans. Distributions of Mn, total S and reduced inorganic S demonstrated that diagenetic conditions and thus sedimentary carbon turnover in the NAAM is organized regionally: undetectable or very thin layers (<0.5 cm) of surface Mn enrichment occurred in the Bering-Chukchi shelves; thin layers (1-5 cm) of surface Mn enrichment occurred in Barrow Canyon and Lancaster Sound; and thick layers (5-20 cm) of surface Mn enrichment occurred in the Beaufort Shelf, Canadian Archipelago, and Davis Strait. Inventories of authigenic S below the Mn-rich layer decreased about fivefold from Bering-Chukchi shelf and Barrow Canyon to Lancaster Sound and more than ten-fold from Bering-Chukchi shelf to Beaufort Shelf, Canadian Archipelago and Davis Strait. The Mn, total S and reduced inorganic S distributions imply strong organic carbon (OC) flux and metabolism in the Bering-Chukchi shelves, lower aerobic OC metabolism in Barrow Canyon and Lancaster Sound, and deep O2 penetration and much lower OC metabolism in the Beaufort Shelf, Canadian Archipelago, and Davis Strait. Accumulation rates of authigenic S, Mo, Cd, Re, and U displayed marked spatial variability along the NAAM reflecting the range in sedimentary redox conditions. Strong relationships between the accumulation rates and vertical carbon flux, estimated from regional primary production values and water depth at the coring sites, indicate that the primary driver in the regional patterns is the supply of labile carbon to the seabed. Thus, high primary production

  17. [A review of the current research on prions. The evidence suggests the possibility of transmission of the mad cow disease to humans].

    PubMed

    Grandien, M; Wahren, B

    1998-11-25

    Further evidence of the transmissibility of bovine spongiform encephalopathy (BSE) across the species barrier from cow to man has been derived from epidemiological analysis and the characterisation of prion strains. Recent research has shown the persistence of prions after experimental transmission to resistant murine species, and subclinical persistence in cows. The accumulation of pathological prion proteins in tonsils and appendix has been demonstrated prior to clinical confirmation of the presence of the new variant of Creutzfeldt-Jakob disease. Current prion research is focused on the involvement of B lymphocytes as carriers, on the species barrier and cellular receptors, and on macromolecules involved in the conformational change from normal to pathological prion proteins.

  18. From evidence-based medicine to genomic medicine

    PubMed Central

    2007-01-01

    The concept of ‘evidence-based medicine’ dates back to mid-19th century or even earlier. It remains pivotal in planning, funding and in delivering the health care. Clinicians, public health practitioners, health commissioners/purchasers, health planners, politicians and public seek formal ‘evidence’ in approving any form of health care provision. Essentially ‘evidence-based medicine’ aims at the conscientious, explicit and judicious use of the current best evidence in making decisions about the care of individual patients. It is in fact the ‘personalised medicine’ in practice. Since the completion of the human genome project and the rapid accumulation of huge amount of data, scientists and physicians alike are excited on the prospect of ‘personalised health care’ based on individual’s genotype and phenotype. The first decade of the new millennium now witnesses the transition from ‘evidence-based medicine’ to the ‘genomic medicine’. The practice of medicine, including health promotion and prevention of disease, stands now at a wide-open road as the scientific and medical community embraces itself with the rapidly expanding and revolutionising field of genomic medicine. This article reviews the rapid transformation of modern medicine from the ‘evidence-based medicine’ to ‘genomic medicine’. PMID:18923934

  19. Free Trehalose Accumulation in Dormant Mycobacterium smegmatis Cells and Its Breakdown in Early Resuscitation Phase

    PubMed Central

    Shleeva, Margarita O.; Trutneva, Kseniya A.; Demina, Galina R.; Zinin, Alexander I.; Sorokoumova, Galina M.; Laptinskaya, Polina K.; Shumkova, Ekaterina S.; Kaprelyants, Arseny S.

    2017-01-01

    Under gradual acidification of growth medium resulting in the formation of dormant Mycobacterium smegmatis, a significant accumulation of free trehalose in dormant cells was observed. According to 1H- and 13C-NMR spectroscopy up to 64% of total organic substances in the dormant cell extract was represented by trehalose whilst the trehalose content in an extract of active cells taken from early stationary phase was not more than 15%. Trehalose biosynthesis during transition to the dormant state is provided by activation of genes involved in the OtsA-OtsB and TreY-TreZ pathways (according to RT-PCR). Varying the concentration of free trehalose in dormant cells by expression of MSMEG_4535 coding for trehalase we found that cell viability depends on trehalose level: cells with a high amount of trehalose survive much better than cells with a low amount. Upon resuscitation of dormant M. smegmatis, a decrease of free trehalose and an increase in glucose concentration occurred in the early period of resuscitation (after 2 h). Evidently, breakdown of trehalose by trehalase takes place at this time as a transient increase in trehalase activity was observed between 1 and 3 h of resuscitation. Activation of trehalase was not due to de novo biosynthesis but because of self-activation of the enzyme from the inactive state in dormant cells. Because, even a low concentration of ATP (2 mM) prevents self-activation of trehalase in vitro and after activation the enzyme is still sensitive to ATP we suggest that the transient character of trehalase activation in cells is due to variation in intracellular ATP concentration found in the early resuscitation period. The negative influence of the trehalase inhibitor validamycin A on the resuscitation of dormant cells proves the importance of trehalase for resuscitation. These experiments demonstrate the significance of free trehalose accumulation for the maintenance of dormant mycobacterial viability and the involvement of trehalose

  20. Balanced activation of IspG and IspH to eliminate MEP intermediate accumulation and improve isoprenoids production in Escherichia coli.

    PubMed

    Li, Qingyan; Fan, Feiyu; Gao, Xiang; Yang, Chen; Bi, Changhao; Tang, Jinlei; Liu, Tao; Zhang, Xueli

    2017-11-01

    The MEP pathway genes were modulated to investigate whether there were new rate-limiting steps and toxic intermediates in this pathway. Activating IspG led to significant decrease of cell growth and β-carotene production. It was found that ispG overexpression led to accumulation of intermediate HMBPP, which seriously interfered with synthesis machinery of nucleotide and protein in Escherichia coli. Activation of the downstream enzyme IspH could solve HMBPP accumulation problem and eliminate the negative effects of ispG overexpression. In addition, intermediate MECPP accumulated in the starting strain, while balanced activation of IspG and IspH could push the carbon flux away from MECPP and led to 73% and 77% increase of β-carotene and lycopene titer respectively. Our work for the first time identified HMBPP to be a cytotoxic intermediate in MEP pathway and demonstrated that balanced activation of IspG and IspH could eliminate accumulation of HMBPP and MECPP and improve isoprenoids production. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.