The pursuit of optimal distinctiveness and consumer preferences.

Science.gov (United States)

He, Lingnan; Cong, Feng; Liu, Yanping; Zhou, Xinyue

2010-10-01

This article investigates the effect of optimal distinctiveness on consumer product consumption. The authors argue that consumers acquire and display material possessions to restore their optimal levels of distinctiveness. Results showed that placing consumers in a state of low distinctiveness increased desire to acquire distinctive products, whereas perceptions of high distinctiveness reduced desire to acquire such products. Consumers' desire for distinctiveness-related products held true for various consumer choices, including willingness to pay more for limited-edition products and preference for unpopular gifts. This finding has implications for understanding consumer choice in expressing identity. © 2010 The Authors. Scandinavian Journal of Psychology © 2010 The Scandinavian Psychological Associations.

Active zone proteins are transported via distinct mechanisms regulated by Par-1 kinase.

Directory of Open Access Journals (Sweden)

Kara R Barber

2017-02-01

Full Text Available Disruption of synapses underlies a plethora of neurodevelopmental and neurodegenerative disease. Presynaptic specialization called the active zone plays a critical role in the communication with postsynaptic neuron. While the role of many proteins at the active zones in synaptic communication is relatively well studied, very little is known about how these proteins are transported to the synapses. For example, are there distinct mechanisms for the transport of active zone components or are they all transported in the same transport vesicle? Is active zone protein transport regulated? In this report we show that overexpression of Par-1/MARK kinase, a protein whose misregulation has been implicated in Autism spectrum disorders (ASDs and neurodegenerative disorders, lead to a specific block in the transport of an active zone protein component- Bruchpilot at Drosophila neuromuscular junctions. Consistent with a block in axonal transport, we find a decrease in number of active zones and reduced neurotransmission in flies overexpressing Par-1 kinase. Interestingly, we find that Par-1 acts independently of Tau-one of the most well studied substrates of Par-1, revealing a presynaptic function for Par-1 that is independent of Tau. Thus, our study strongly suggests that there are distinct mechanisms that transport components of active zones and that they are tightly regulated.

Phenotype specific analyses reveal distinct regulatory mechanism for chronically activated p53.

Directory of Open Access Journals (Sweden)

Kristina Kirschner

2015-03-01

Full Text Available The downstream functions of the DNA binding tumor suppressor p53 vary depending on the cellular context, and persistent p53 activation has recently been implicated in tumor suppression and senescence. However, genome-wide information about p53-target gene regulation has been derived mostly from acute genotoxic conditions. Using ChIP-seq and expression data, we have found distinct p53 binding profiles between acutely activated (through DNA damage and chronically activated (in senescent or pro-apoptotic conditions p53. Compared to the classical 'acute' p53 binding profile, 'chronic' p53 peaks were closely associated with CpG-islands. Furthermore, the chronic CpG-island binding of p53 conferred distinct expression patterns between senescent and pro-apoptotic conditions. Using the p53 targets seen in the chronic conditions together with external high-throughput datasets, we have built p53 networks that revealed extensive self-regulatory 'p53 hubs' where p53 and many p53 targets can physically interact with each other. Integrating these results with public clinical datasets identified the cancer-associated lipogenic enzyme, SCD, which we found to be directly repressed by p53 through the CpG-island promoter, providing a mechanistic link between p53 and the 'lipogenic phenotype', a hallmark of cancer. Our data reveal distinct phenotype associations of chronic p53 targets that underlie specific gene regulatory mechanisms.

Lin28a uses distinct mechanisms of binding to RNA and affects miRNA levels positively and negatively.

Science.gov (United States)

Nowak, Jakub Stanislaw; Hobor, Fruzsina; Downie Ruiz Velasco, Angela; Choudhury, Nila Roy; Heikel, Gregory; Kerr, Alastair; Ramos, Andres; Michlewski, Gracjan

2017-03-01

Lin28a inhibits the biogenesis of let-7 miRNAs by triggering the polyuridylation and degradation of their precursors by terminal uridylyltransferases TUT4/7 and 3'-5' exoribonuclease Dis3l2, respectively. Previously, we showed that Lin28a also controls the production of neuro-specific miRNA-9 via a polyuridylation-independent mechanism. Here we reveal that the sequences and structural characteristics of pre-let-7 and pre-miRNA-9 are eliciting two distinct modes of binding to Lin28a. We present evidence that Dis3l2 controls miRNA-9 production. Finally, we show that the constitutive expression of untagged Lin28a during neuronal differentiation in vitro positively and negatively affects numerous other miRNAs. Our findings shed light on the role of Lin28a in differentiating cells and on the ways in which one RNA-binding protein can perform multiple roles in the regulation of RNA processing. © 2017 Nowak et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

The Biology of Atherosclerosis: General Paradigms and Distinct Pathogenic Mechanisms Among HIV-Infected Patients

OpenAIRE

Lo, Janet; Plutzky, Jorge

2012-01-01

Complications of atherosclerosis, including myocardial infarction and stroke, are the leading cause of death and disability worldwide. Recent data strongly implicate cardiovascular death as a contributor to mortality among patients with human immunodeficiency virus (HIV) infection, with evidence suggesting increased incidence of atherosclerosis among these patients. Therefore, greater understanding of atherosclerotic mechanisms and how these responses may be similar or distinct in HIV-infecte...

Antibody-mediated neutralization of Ebola virus can occur by two distinct mechanisms

International Nuclear Information System (INIS)

Shedlock, Devon J.; Bailey, Michael A.; Popernack, Paul M.; Cunningham, James M.; Burton, Dennis R.; Sullivan, Nancy J.

2010-01-01

Human Ebola virus causes severe hemorrhagic fever disease with high mortality and there is no vaccine or treatment. Antibodies in survivors occur early, are sustained, and can delay infection when transferred into nonhuman primates. Monoclonal antibodies (mAbs) from survivors exhibit potent neutralizing activity in vitro and are protective in rodents. To better understand targets and mechanisms of neutralization, we investigated a panel of mAbs shown previously to react with the envelope glycoprotein (GP). While one non-neutralizing mAb recognized a GP epitope in the nonessential mucin-like domain, the rest were specific for GP1, were neutralizing, and could be further distinguished by reactivity with secreted GP. We show that survivor antibodies, human KZ52 and monkey JP3K11, were specific for conformation-dependent epitopes comprising residues in GP1 and GP2 and that neutralization occurred by two distinct mechanisms; KZ52 inhibited cathepsin cleavage of GP whereas JP3K11 recognized the cleaved, fusion-active form of GP.

Development of distinction method of production area of ginsengs by using a neutron activation analysis

Energy Technology Data Exchange (ETDEWEB)

Kim, Youngjin; Chung, Yongsam; Sim, Chulmuu; Sun, Gwangmin; Lee, Yuna; Yoo, Sangho

2011-01-15

During the last 2 years of the project, we have tried to develop the technology to make a distinction of the production areas for Korean ginsengs cultivated in the various provinces in Korea and foreign countries. It will contribute to secure the health food safety for public and stability of its market. In this year, we collected ginseng samples cultivated in the northeastern province in Chinese mainland such as Liaoning province, Jilin province and Baekdu mountain within Jilin province. 10 ginseng samples were collected at each province. The elemental concentrations in the ginseng were analyzed by using a neutron activation analysis technique at the HANARO research reactor. The distinction of production area was made by using a statistical software. As a result, the Chinese Korean ginsengs were certainly differentiated from those cultivated in the famous province in Korea though there was a limitation that the number of our sample we analyzed is very small.

Development of distinction method of production area of ginsengs by using a neutron activation analysis

International Nuclear Information System (INIS)

Kim, Youngjin; Chung, Yongsam; Sim, Chulmuu; Sun, Gwangmin; Lee, Yuna; Yoo, Sangho

2011-01-01

During the last 2 years of the project, we have tried to develop the technology to make a distinction of the production areas for Korean ginsengs cultivated in the various provinces in Korea and foreign countries. It will contribute to secure the health food safety for public and stability of its market. In this year, we collected ginseng samples cultivated in the northeastern province in Chinese mainland such as Liaoning province, Jilin province and Baekdu mountain within Jilin province. 10 ginseng samples were collected at each province. The elemental concentrations in the ginseng were analyzed by using a neutron activation analysis technique at the HANARO research reactor. The distinction of production area was made by using a statistical software. As a result, the Chinese Korean ginsengs were certainly differentiated from those cultivated in the famous province in Korea though there was a limitation that the number of our sample we analyzed is very small

Distinct mechanisms eliminate mother and daughter centrioles in meiosis of starfish oocytes.

Science.gov (United States)

Borrego-Pinto, Joana; Somogyi, Kálmán; Karreman, Matthia A; König, Julia; Müller-Reichert, Thomas; Bettencourt-Dias, Mónica; Gönczy, Pierre; Schwab, Yannick; Lénárt, Péter

2016-03-28

Centriole elimination is an essential process that occurs in female meiosis of metazoa to reset centriole number in the zygote at fertilization. How centrioles are eliminated remains poorly understood. Here we visualize the entire elimination process live in starfish oocytes. Using specific fluorescent markers, we demonstrate that the two older, mother centrioles are selectively removed from the oocyte by extrusion into polar bodies. We show that this requires specific positioning of the second meiotic spindle, achieved by dynein-driven transport, and anchorage of the mother centriole to the plasma membrane via mother-specific appendages. In contrast, the single daughter centriole remaining in the egg is eliminated before the first embryonic cleavage. We demonstrate that these distinct elimination mechanisms are necessary because if mother centrioles are artificially retained, they cannot be inactivated, resulting in multipolar zygotic spindles. Thus, our findings reveal a dual mechanism to eliminate centrioles: mothers are physically removed, whereas daughters are eliminated in the cytoplasm, preparing the egg for fertilization. © 2016 Borrego-Pinto et al.

Negative hydrogen ion production mechanisms

Energy Technology Data Exchange (ETDEWEB)

Bacal, M. [UPMC, LPP, Ecole Polytechnique, UMR CNRS 7648, Palaiseau (France); Wada, M. [School of Science and Engineering, Doshisha University, Kyoto 610-0321 (Japan)

2015-06-15

Negative hydrogen/deuterium ions can be formed by processes occurring in the plasma volume and on surfaces facing the plasma. The principal mechanisms leading to the formation of these negative ions are dissociative electron attachment to ro-vibrationally excited hydrogen/deuterium molecules when the reaction takes place in the plasma volume, and the direct electron transfer from the low work function metal surface to the hydrogen/deuterium atoms when formation occurs on the surface. The existing theoretical models and reported experimental results on these two mechanisms are summarized. Performance of the negative hydrogen/deuterium ion sources that emerged from studies of these mechanisms is reviewed. Contemporary negative ion sources do not have negative ion production electrodes of original surface type sources but are operated with caesium with their structures nearly identical to volume production type sources. Reasons for enhanced negative ion current due to caesium addition to these sources are discussed.

Mechanics of coalbed methane production

Energy Technology Data Exchange (ETDEWEB)

Creel, J C; Rollins, J B [Crawley, Gillespie and Associates, Inc. (United Kingdom)

1994-12-31

Understanding the behaviour of coalbed methane reservoirs and the mechanics of production is crucial to successful management of coalbed methane resources and projects. This paper discusses the effects of coal properties and coalbed methane reservoir characteristics on gas production rates and recoveries with a review of completion techniques for coalbed methane wells. 4 refs., 17 figs.

The biology of atherosclerosis: general paradigms and distinct pathogenic mechanisms among HIV-infected patients.

Science.gov (United States)

Lo, Janet; Plutzky, Jorge

2012-06-01

Complications of atherosclerosis, including myocardial infarction and stroke, are the leading cause of death and disability worldwide. Recent data strongly implicate cardiovascular death as a contributor to mortality among patients with human immunodeficiency virus (HIV) infection, with evidence suggesting increased incidence of atherosclerosis among these patients. Therefore, greater understanding of atherosclerotic mechanisms and how these responses may be similar or distinct in HIV-infected patients is needed. Key concepts in atherosclerosis are reviewed, including the evidence that inflammation and abnormal metabolism are major drivers of atherosclerosis, and connected to the current literature regarding atherosclerosis in the context of HIV.

Amphetamine and cocaine suppress social play behavior in rats through distinct mechanisms.

Science.gov (United States)

Achterberg, E J Marijke; Trezza, Viviana; Siviy, Stephen M; Schrama, Laurens; Schoffelmeer, Anton N M; Vanderschuren, Louk J M J

2014-04-01

Social play behavior is a characteristic form of social behavior displayed by juvenile and adolescent mammals. This social play behavior is highly rewarding and of major importance for social and cognitive development. Social play is known to be modulated by neurotransmitter systems involved in reward and motivation. Interestingly, psychostimulant drugs, such as amphetamine and cocaine, profoundly suppress social play, but the neural mechanisms underlying these effects remain to be elucidated. In this study, we investigated the pharmacological underpinnings of amphetamine- and cocaine-induced suppression of social play behavior in rats. The play-suppressant effects of amphetamine were antagonized by the alpha-2 adrenoreceptor antagonist RX821002 but not by the dopamine receptor antagonist alpha-flupenthixol. Remarkably, the effects of cocaine on social play were not antagonized by alpha-2 noradrenergic, dopaminergic, or serotonergic receptor antagonists, administered either alone or in combination. The effects of a subeffective dose of cocaine were enhanced by a combination of subeffective doses of the serotonin reuptake inhibitor fluoxetine, the dopamine reuptake inhibitor GBR12909, and the noradrenaline reuptake inhibitor atomoxetine. Amphetamine, like methylphenidate, exerts its play-suppressant effect through alpha-2 noradrenergic receptors. On the other hand, cocaine reduces social play by simultaneous increases in dopamine, noradrenaline, and serotonin neurotransmission. In conclusion, psychostimulant drugs with different pharmacological profiles suppress social play behavior through distinct mechanisms. These data contribute to our understanding of the neural mechanisms of social behavior during an important developmental period, and of the deleterious effects of psychostimulant exposure thereon.

Pyridine-pyrimidine amides that prevent HGF-induced epithelial scattering by two distinct mechanisms.

Science.gov (United States)

Siddiqui-Jain, Adam; Hoj, Jacob P; Hargiss, J Blade; Hoj, Taylor H; Payne, Carter J; Ritchie, Collin A; Herron, Steven R; Quinn, Colette; Schuler, Jeffrey T; Hansen, Marc D H

2017-09-01

Stimulation of cultured epithelial cells with scatter factor/hepatocyte growth factor (HGF) results in individual cells detaching and assuming a migratory and invasive phenotype. Epithelial scattering recapitulates cancer progression and studies have implicated HGF signaling as a driver of cancer metastasis. Inhibitors of HGF signaling have been proposed to act as anti-cancer agents. We previously screened a small molecule library for compounds that block HGF-induced epithelial scattering. Most hits identified in this screen exhibit anti-mitotic properties. Here we assess the biological mechanism of a compound that blocks HGF-induced scattering with limited anti-mitotic activity. Analogs of this compound have one of two distinct activities: inhibiting either cell migration or cell proliferation with cell cycle arrest in G2/M. Each activity bears unique structure-activity relationships. The mechanism of action of anti-mitotic compounds is by inhibition of microtubule polymerization; these compounds entropically and enthalpically bind tubulin in the colchicine binding site, generating a conformational change in the tubulin dimer. Copyright © 2017 Elsevier Ltd. All rights reserved.

Distinct Mechanisms of Nuclease-Directed DNA-Structure-Induced Genetic Instability in Cancer Genomes.

Science.gov (United States)

Zhao, Junhua; Wang, Guliang; Del Mundo, Imee M; McKinney, Jennifer A; Lu, Xiuli; Bacolla, Albino; Boulware, Stephen B; Zhang, Changsheng; Zhang, Haihua; Ren, Pengyu; Freudenreich, Catherine H; Vasquez, Karen M

2018-01-30

Sequences with the capacity to adopt alternative DNA structures have been implicated in cancer etiology; however, the mechanisms are unclear. For example, H-DNA-forming sequences within oncogenes have been shown to stimulate genetic instability in mammals. Here, we report that H-DNA-forming sequences are enriched at translocation breakpoints in human cancer genomes, further implicating them in cancer etiology. H-DNA-induced mutations were suppressed in human cells deficient in the nucleotide excision repair nucleases, ERCC1-XPF and XPG, but were stimulated in cells deficient in FEN1, a replication-related endonuclease. Further, we found that these nucleases cleaved H-DNA conformations, and the interactions of modeled H-DNA with ERCC1-XPF, XPG, and FEN1 proteins were explored at the sub-molecular level. The results suggest mechanisms of genetic instability triggered by H-DNA through distinct structure-specific, cleavage-based replication-independent and replication-dependent pathways, providing critical evidence for a role of the DNA structure itself in the etiology of cancer and other human diseases. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Monoclonal Antibodies Follow Distinct Aggregation Pathways During Production-Relevant Acidic Incubation and Neutralization

DEFF Research Database (Denmark)

Pedersen, Thomas Skamris; Tian, Xinsheng; Thorolfsson, Matthias

2016-01-01

and orthogonal analytical methods, including small-angle X-ray scattering and dynamic light scattering and supplemented the experimental data with crystal structure-based spatial aggregation propensity (SAP) calculations. RESULTS: We revealed distinct solution behaviors between the three mAb models: At acidic p......PURPOSE: Aggregation aspects of therapeutic monoclonal antibodies (mAbs) are of common concern to the pharmaceutical industry. Low pH treatment is applied during affinity purification and to inactivate endogenous retroviruses, directing interest to the mechanisms of acid-induced antibody...... distinguish between reversible and irreversible mAb aggregation pathways at early stages of acidic treatment....

Perceptual learning shapes multisensory causal inference via two distinct mechanisms.

Science.gov (United States)

McGovern, David P; Roudaia, Eugenie; Newell, Fiona N; Roach, Neil W

2016-04-19

To accurately represent the environment, our brains must integrate sensory signals from a common source while segregating those from independent sources. A reasonable strategy for performing this task is to restrict integration to cues that coincide in space and time. However, because multisensory signals are subject to differential transmission and processing delays, the brain must retain a degree of tolerance for temporal discrepancies. Recent research suggests that the width of this 'temporal binding window' can be reduced through perceptual learning, however, little is known about the mechanisms underlying these experience-dependent effects. Here, in separate experiments, we measure the temporal and spatial binding windows of human participants before and after training on an audiovisual temporal discrimination task. We show that training leads to two distinct effects on multisensory integration in the form of (i) a specific narrowing of the temporal binding window that does not transfer to spatial binding and (ii) a general reduction in the magnitude of crossmodal interactions across all spatiotemporal disparities. These effects arise naturally from a Bayesian model of causal inference in which learning improves the precision of audiovisual timing estimation, whilst concomitantly decreasing the prior expectation that stimuli emanate from a common source.

NSAID gastropathy and enteropathy: distinct pathogenesis likely necessitates distinct prevention strategies.

Science.gov (United States)

Wallace, John L

2012-01-01

The mechanisms underlying the ability of nonsteroidal anti-inflammatory drugs (NSAIDs) to cause ulceration in the stomach and proximal duodenum are well understood, and this injury can largely be prevented through suppression of gastric acid secretion (mainly with proton pump inhibitors). In contrast, the pathogenesis of small intestinal injury induced by NSAIDs is less well understood, involving more complex mechanisms than those in the stomach and proximal duodenum. There is clear evidence for important contributions to NSAID enteropathy of enteric bacteria, bile and enterohepatic recirculation of the NSAID. There is no evidence that suppression of gastric acid secretion will reduce the incidence or severity of NSAID enteropathy. Indeed, clinical data suggest little, if any, benefit. Animal studies suggest a significant exacerbation of NSAID enteropathy when proton pump inhibitors are co-administered with the NSAID. This worsening of damage appears to be linked to changes in the number and types of bacteria in the small intestine during proton pump inhibitor therapy. The distinct mechanisms of NSAID-induced injury in the stomach/proximal duodenum versus the more distal small intestine likely dictate distinct strategies for prevention. © 2011 The Author. British Journal of Pharmacology © 2011 The British Pharmacological Society.

Analysis of the Lifecycle of Mechanical Engineering Products

OpenAIRE

Gubaidulina, Rauza Khamidovna; Gruby, S. V.; Davlatov, G. D.

2016-01-01

Principal phases of the lifecycle of mechanical engineering products are analyzed in the paper. The authors have developed methods and procedures to improve designing, manufacturing, operating and recycling of the machine. It has been revealed that economic lifecycle of the product is a base for appropriate organization of mechanical engineering production. This lifecycle is calculated as a minimal sum total of consumer and producer costs. The machine construction and its manufacturing techno...

Distinct signaling mechanisms in multiple developmental pathways by the SCRAMBLED receptor of Arabidopsis.

Science.gov (United States)

Kwak, Su-Hwan; Woo, Sooah; Lee, Myeong Min; Schiefelbein, John

2014-10-01

SCRAMBLED (SCM), a leucine-rich repeat receptor-like kinase in Arabidopsis (Arabidopsis thaliana), is required for positional signaling in the root epidermis and for tissue/organ development in the shoot. To further understand SCM action, we generated a series of kinase domain variants and analyzed their ability to complement scm mutant defects. We found that the SCM kinase domain, but not kinase activity, is required for its role in root epidermal patterning, supporting the view that SCM is an atypical receptor kinase. We also describe a previously uncharacterized role for SCM in fruit dehiscence, because mature siliques from scm mutants fail to open properly. Interestingly, the kinase domain of SCM appears to be dispensable for this developmental process. Furthermore, we found that most of the SCM kinase domain mutations dramatically inhibit inflorescence development. Because this process is not affected in scm null mutants, it is likely that SCM acts redundantly to regulate inflorescence size. The importance of distinct kinase residues for these three developmental processes provides an explanation for the maintenance of the conserved kinase domain in the SCM protein, and it may generally explain its conservation in other atypical kinases. Furthermore, these results indicate that individual leucine-rich repeat receptor-like kinases may participate in multiple pathways using distinct signaling mechanisms to mediate diverse cellular communication events. © 2014 American Society of Plant Biologists. All Rights Reserved.

The Effect of Headquarter Integration Mechanisms on Subsidiaries’ New Product Success: From Control to Coordination Mechanism

Directory of Open Access Journals (Sweden)

Firmanzah Firmanzah

2013-07-01

Full Text Available New product launching (NPL to the local market by subsidiary managers is a strategic activity, which requires organizational supports from MNC global network. The NPL activity is marked by high level of uncertainty, risk, and market failure. Thus, a headquarter needs to integrate the subsidiary NPL into global strategy. There are two mechanisms to integrate subsidiaries’ activities during NPL process; coordination and control process. By testing the effect of each mechanism on role clarity and functional conflict, I found that coordination mechanism increase role clarity between headquarter and subsidiaries’ managers. In contrast, exercising control mechanism reduces role clarity and functional conflict between headquarter and subsidiaries’ managers during NPL. This research shows that both role clarity and functional conflict increase new product commercial performance introduced by subsidiary in the local market. Keywords: new product launching (NPL, coordination mechanism, control mechanism, and new product performance

On interference of cumulative proton production mechanisms

International Nuclear Information System (INIS)

Braun, M.A.; Vechernin, V.V.

1993-01-01

The dynamical picture of the cumulative proton production in hA-collisions by means of diagram analysis with NN interaction described by a non-relativistic NN potential is considered. The contributions of the various mechanisms (spectator, direct and rescattering) for backward hemisphere proton production within the framework of this common approach is calculated. The emphasis is on the comparison of the relative contributions of these mechanisms for various angles, taking into account the interference of these contributions. Comparison with experimental data is also presented. (author)

Distinct mechanisms of a phosphotyrosyl peptide binding to two SH2 domains.

Science.gov (United States)

Pang, Xiaodong; Zhou, Huan-Xiang

2014-05-01

Protein phosphorylation is very common post-translational modification, catalyzed by kinases, for signaling and regulation. Phosphotyrosines frequently target SH2 domains. The spleen tyrosine kinase (Syk) is critical for tyrosine phosphorylation of multiple proteins and for regulation of important pathways. Phosphorylation of both Y342 and Y346 in Syk linker B is required for optimal signaling. The SH2 domains of Vav1 and PLC-γ both bind this doubly phosphorylated motif. Here we used a recently developed method to calculate the effects of Y342 and Y346 phosphorylation on the rate constants of a peptide from Syk linker B binding to the SH2 domains of Vav1 and PLC-γ. The predicted effects agree well with experimental observations. Moreover, we found that the same doubly phosphorylated peptide binds the two SH2 domains via distinct mechanisms, with apparent rigid docking for Vav1 SH2 and dock-and-coalesce for PLC-γ SH2.

Distinct mechanisms underlying tolerance to intermittent and constant hypoxia in Drosophila melanogaster.

Directory of Open Access Journals (Sweden)

Priti Azad

Full Text Available BACKGROUND: Constant hypoxia (CH and intermittent hypoxia (IH occur during several pathological conditions such as asthma and obstructive sleep apnea. Our research is focused on understanding the molecular mechanisms that lead to injury or adaptation to hypoxic stress using Drosophila as a model system. Our current genome-wide study is designed to investigate gene expression changes and identify protective mechanism(s in D. melanogaster after exposure to severe (1% O(2 intermittent or constant hypoxia. METHODOLOGY/PRINCIPAL FINDINGS: Our microarray analysis has identified multiple gene families that are up- or down-regulated in response to acute CH or IH. We observed distinct responses to IH and CH in gene expression that varied in the number of genes and type of gene families. We then studied the role of candidate genes (up-or down-regulated in hypoxia tolerance (adult survival for longer periods (CH-7 days, IH-10 days under severe CH or IH. Heat shock proteins up-regulation (specifically Hsp23 and Hsp70 led to a significant increase in adult survival (as compared to controls of P-element lines during CH. In contrast, during IH treatment the up-regulation of Mdr49 and l(208717 genes (P-element lines provided survival advantage over controls. This suggests that the increased transcript levels following treatment with either paradigm play an important role in tolerance to severe hypoxia. Furthermore, by over-expressing Hsp70 in specific tissues, we found that up-regulation of Hsp70 in heart and brain play critical role in tolerance to CH in flies. CONCLUSIONS/SIGNIFICANCE: We observed that the gene expression response to IH or CH is specific and paradigm-dependent. We have identified several genes Hsp23, Hsp70, CG1600, l(208717 and Mdr49 that play an important role in hypoxia tolerance whether it is in CH or IH. These data provide further clues about the mechanisms by which IH or CH lead to cell injury and morbidity or adaptation and survival.

Mechanics of human voice production and control.

Science.gov (United States)

Zhang, Zhaoyan

2016-10-01

As the primary means of communication, voice plays an important role in daily life. Voice also conveys personal information such as social status, personal traits, and the emotional state of the speaker. Mechanically, voice production involves complex fluid-structure interaction within the glottis and its control by laryngeal muscle activation. An important goal of voice research is to establish a causal theory linking voice physiology and biomechanics to how speakers use and control voice to communicate meaning and personal information. Establishing such a causal theory has important implications for clinical voice management, voice training, and many speech technology applications. This paper provides a review of voice physiology and biomechanics, the physics of vocal fold vibration and sound production, and laryngeal muscular control of the fundamental frequency of voice, vocal intensity, and voice quality. Current efforts to develop mechanical and computational models of voice production are also critically reviewed. Finally, issues and future challenges in developing a causal theory of voice production and perception are discussed.

Mechanisms for the Production of Fast HI from Dissociation of H2 on Saturn

Science.gov (United States)

Liu, Xianming; Johnson, Paul; Malone, Charles; Young, Jason; Kanik, Isik; Shemansky, Donald

2010-05-01

Images of the Saturn system obtained by the Cassini UVIS at a pixel resolution of 0.1 × 0.1 Saturn radii (Rs) reveal atomic hydrogen in ballistic and escaping trajectories sourced at the top of the thermosphere, primarily in the southern sunlit hemisphere. The main feature in the image is a distinctive H Lyman-α plume structure with FWHM of 0.56 Rs at the exobase sub-solar limb at ~ -13.5° latitude constituting the core of the distributed outward flow of atomic hydrogen from the sunlit hemisphere, with a counterpart on the anti-solar side peaking near the equator above the exobase limb. The structure of the image indicates that part of the out-flowing population is sub-orbital and re-enters the thermosphere in ~ 5 hour time scale. A larger and more broadly distributed component fills the magnetosphere to beyond 45 Rs in the orbital plane and 20 Rs latitudinally above and below the plane in an asymmetric distribution in local time. Molecular hydrogen emission in extreme and far ultraviolet regions collected with the H Lyman-α into the image mosaic reveals a distinctive resonance property correlated with the atomic hydrogen plume and shows a strong deviation of H2 X 1Σg+ from local thermodynamic equilibrium in the main source region. The inferred approximate globally averaged energy deposition at the top of the thermosphere from the production of the hot atomic hydrogen accounts for the measured atmospheric temperature. Possible processes for the fast atomic hydrogen formation from dissociation of H2 include the excitation of singlet-ungerade states and doubly excited states by photons and electrons, and the excitation of the singlet-gerade and triplet states by electrons, and chemical reactions involving the formation and dissociative recombination of H3+. Based on the available laboratory measurements and quantum mechanics calculations, the assessment of various mechanisms for H2 - H production, especially those producing H atoms with sufficient energy to

Mechanisms of multiple production processes

International Nuclear Information System (INIS)

Dremin, I.M.

1977-01-01

Theoretical approaches to multiple production processes are discussed. A large number of models proceeds from the notion about common excited system produced by colliding hadrons. This class of models includes the hydrodynamical, statistical, thermodynamical and statistical bootstrap models. Sometimes the production process is due to excitation and decay of two colliding particles. The fragmentation bremsstrahlung and inelastic diffraction models belong to this group. The largest group of models describes the multiple production process as a result of formation of many excited centers. The typical example is the multiperipheral model. An interesting direction is given by the attempts to interrelate the mechanism of multiple production with internal structure of particles that is with their constituents (C-group)'-quarks, gluons, etc. Besides the models there are phenomenological (p group) attempts to connect different features of multiple production. Experimental data indicate the existence of leading and pionization particles thus giving an evidence for applications of different models. The data about increase of total and inclusive cross sections, the behaviour of the mean multiplicity and correlations at high energies provide a clue for further development of multiple production theory

A Resource Sharing Mechanism for Sustainable Production in the Garment Industry

Directory of Open Access Journals (Sweden)

Ke Ma

2017-12-01

Full Text Available With the development of mass customization, the traditional garment production model needs to be optimized to have a more sustainable structure. To meet demand for flexibility, low-cost, and high-efficiency, an innovative resource sharing mechanism was proposed in this paper to form a new sustainable type of garment production. Different from the individual production in traditional models, the new mechanism involves resources being shared among various manufacturers. The tradeoff between positive and negative effects of the proposed mechanism is a key issue for sustainable production. In the present study, an overall sustainable index, integrating four production performance indicators, was defined on the basis of an Analytical Network Process to assess various production scenarios. According to the discrete-event simulation results of the different scenarios, we found that garment manufacturers could obtain comprehensive improvements in sustainable production by implementing the proposed resource sharing mechanism under the threshold of an increasing production failure rate.

ABOUT DIGITAL MOCK-UP FOR MECHANICAL PRODUCTS

Directory of Open Access Journals (Sweden)

GHERGHINA George

2015-06-01

The digital mock-up of the product is built at a design stage, and is applicable to the whole life-cycle of the product, including design, manufacture, marketing and aftermarket. The digital mock-up could achieve interference check, motion analysis, simulation of performance and manufacturing, technical training, advertising and maintenance, planning etc. The DMU of mechanical products, as important engineering data in a company, is supposed to be able to support all the activities in the whole life-cycle of the product including design, manufacture, marketing and aftermarket

Beta2- and beta3-adrenoceptors activate glucose uptake in chick astrocytes by distinct mechanisms: a mechanism for memory enhancement?

Science.gov (United States)

Hutchinson, Dana S; Summers, Roger J; Gibbs, Marie E

2007-11-01

Isoprenaline, acting at beta-adrenoceptors (ARs), enhances memory formation in single trial discriminated avoidance learning in day-old chicks by mechanisms involving alterations in glucose and glycogen metabolism. Earlier studies of memory consolidation in chicks indicated that beta3-ARs enhanced memory by increasing glucose uptake, whereas beta2-ARs enhance memory by increasing glycogenolysis. This study examines the ability of beta-ARs to increase glucose uptake in chick forebrain astrocytes. The beta-AR agonist isoprenaline increased glucose uptake in a concentration-dependent manner, as did insulin. Glucose uptake was increased by the beta2-AR agonist zinterol and the beta3-AR agonist CL316243, but not by the beta1-AR agonist RO363. In chick astrocytes, reverse transcription-polymerase chain reaction studies showed that beta1-, beta2-, and beta3-AR mRNA were present, whereas radioligand-binding studies showed the presence of only beta2- and beta3-ARs. beta-AR or insulin-mediated glucose uptake was inhibited by phosphatidylinositol-3 kinase and protein kinase C inhibitors, suggesting a possible interaction between the beta-AR and insulin pathways. However beta2- and beta3-ARs increase glucose uptake by two different mechanisms: beta2-ARs via a Gs-cAMP-protein kinase A-dependent pathway, while beta3-ARs via interactions with Gi. These results indicate that activation of beta2- and beta3-ARs causes glucose uptake in chick astrocytes by distinct mechanisms, which may be relevant for memory enhancement.

Development of Distinction Method of Production Area of Ginsengs by Using a Neutron Activation Analysis

Energy Technology Data Exchange (ETDEWEB)

Kim, Young Jin; Chung, Yong Sam; Sun, Gwang Min; Lee, Yu Na; Yoo, Sang Ho [KAERI, Daejeon (Korea, Republic of)

2010-05-15

Distinction of production area of Korean ginsengs has been tried by using neutron activation techniques such as an instrumental neutron activation analysis (INAA) and a prompt gamma activation analysis (PGAA). A distribution of elements has varied according to the part of plant clue to the difference of enrichment effect and influence from a soil where the plants have been grown. So correlation study between plants and soil has been an Issue. In this study, the distribution of trace elements within a Korean ginseng was investigated by using an instrumental neutron activation analysis

Neonatal plasma polarizes TLR4-mediated cytokine responses towards low IL-12p70 and high IL-10 production via distinct factors.

Directory of Open Access Journals (Sweden)

Mirjam E Belderbos

Full Text Available Human neonates are highly susceptible to infection, which may be due in part to impaired innate immune function. Neonatal Toll-like receptor (TLR responses are biased against the generation of pro-inflammatory/Th1-polarizing cytokines, yet the underlying mechanisms are incompletely defined. Here, we demonstrate that neonatal plasma polarizes TLR4-mediated cytokine production. When exposed to cord blood plasma, mononuclear cells (MCs produced significantly lower TLR4-mediated IL-12p70 and higher IL-10 compared to MC exposed to adult plasma. Suppression by neonatal plasma of TLR4-mediated IL-12p70 production, but not induction of TLR4-mediated IL-10 production, was maintained up to the age of 1 month. Cord blood plasma conferred a similar pattern of MC cytokine responses to TLR3 and TLR8 agonists, demonstrating activity towards both MyD88-dependent and MyD88-independent agonists. The factor causing increased TLR4-mediated IL-10 production by cord blood plasma was heat-labile, lost after protein depletion and independent of lipoprotein binding protein (LBP or soluble CD14 (sCD14. The factor causing inhibition of TLR4-mediated IL-12p70 production by cord blood plasma was resistant to heat inactivation or protein depletion and was independent of IL-10, vitamin D and prostaglandin E2. In conclusion, human neonatal plasma contains at least two distinct factors that suppress TLR4-mediated IL-12p70 production or induce IL-10 or production. Further identification of these factors will provide insight into the ontogeny of innate immune development and might identify novel targets for the prevention and treatment of neonatal infection.

Neonatal Plasma Polarizes TLR4-Mediated Cytokine Responses towards Low IL-12p70 and High IL-10 Production via Distinct Factors

Science.gov (United States)

Belderbos, Mirjam E.; Levy, Ofer; Stalpers, Femke; Kimpen, Jan L.; Meyaard, Linde; Bont, Louis

2012-01-01

Human neonates are highly susceptible to infection, which may be due in part to impaired innate immune function. Neonatal Toll-like receptor (TLR) responses are biased against the generation of pro-inflammatory/Th1-polarizing cytokines, yet the underlying mechanisms are incompletely defined. Here, we demonstrate that neonatal plasma polarizes TLR4-mediated cytokine production. When exposed to cord blood plasma, mononuclear cells (MCs) produced significantly lower TLR4-mediated IL-12p70 and higher IL-10 compared to MC exposed to adult plasma. Suppression by neonatal plasma of TLR4-mediated IL-12p70 production, but not induction of TLR4-mediated IL-10 production, was maintained up to the age of 1 month. Cord blood plasma conferred a similar pattern of MC cytokine responses to TLR3 and TLR8 agonists, demonstrating activity towards both MyD88-dependent and MyD88-independent agonists. The factor causing increased TLR4-mediated IL-10 production by cord blood plasma was heat-labile, lost after protein depletion and independent of lipoprotein binding protein (LBP) or soluble CD14 (sCD14). The factor causing inhibition of TLR4-mediated IL-12p70 production by cord blood plasma was resistant to heat inactivation or protein depletion and was independent of IL-10, vitamin D and prostaglandin E2. In conclusion, human neonatal plasma contains at least two distinct factors that suppress TLR4-mediated IL-12p70 production or induce IL-10 or production. Further identification of these factors will provide insight into the ontogeny of innate immune development and might identify novel targets for the prevention and treatment of neonatal infection. PMID:22442690

Production of olefins from bioethanol. Catalysts, mechanism

Directory of Open Access Journals (Sweden)

Kusman Dossumov

2012-12-01

Full Text Available This review describes methods of catalytic obtaining from bioethanol of valuable industrial products – olefins, particularly ethylene. Аmong olefins, ethylene is the most popular key raw material of petrochemical synthesis. The scope of appllication of ethylene is almost unlimited in petrochemical products: polyethylene, ethylbenzene, styrene, ethylene dichloride, vinyl chloride etc. It also examines catalysts for the production of olefins and their properties. The most promising and commercially advantageous process of ethylene production by catalytic dehydration of ethanol on catalysts based on modified alumina. And this review discusses the mechanisms of catalytic conversion of ethanol to ethylene.

ERP evidence of distinct processes underlying semantic facilitation and interference in word production.

Science.gov (United States)

Python, Grégoire; Fargier, Raphaël; Laganaro, Marina

2018-02-01

In everyday conversations, we take advantage of lexical-semantic contexts to facilitate speech production, but at the same time, we also have to reduce interference and inhibit semantic competitors. The blocked cyclic naming paradigm (BCNP) has been used to investigate such context effects. Typical results on production latencies showed semantic facilitation (or no effect) during the first presentation cycle, and interference emerging in subsequent cycles. Even if semantic contexts might be just as facilitative as interfering, previous BCNP studies focused on interference, which was interpreted as reflecting lemma selection and self-monitoring processes. Facilitation in the first cycle was rarely considered/analysed, although it potentially informs on word production to the same extent as interference. Here we contrasted the event-related potential (ERP) signatures of both semantic facilitation and interference in a BCNP. ERPs differed between homogeneous and heterogeneous blocks from about 365 msec post picture onset in the first cycle (facilitation) and in an earlier time-window (270 msec post picture onset) in the third cycle (interference). Three different analyses of the ERPs converge towards distinct processes underlying semantic facilitation and interference (post-lexical vs lexical respectively). The loci of semantic facilitation and interference are interpreted in the context of different theoretical frameworks of language production: the post-lexical locus of semantic facilitation involves interactive phonological-semantic processes and/or self-monitoring, whereas the lexical locus of semantic interference is in line with selection through increased lexical competition. Copyright © 2017 Elsevier Ltd. All rights reserved.

Distinct Signaling Mechanisms in Multiple Developmental Pathways by the SCRAMBLED Receptor of Arabidopsis1[OPEN

Science.gov (United States)

Kwak, Su-Hwan; Woo, Sooah; Lee, Myeong Min; Schiefelbein, John

2014-01-01

SCRAMBLED (SCM), a leucine-rich repeat receptor-like kinase in Arabidopsis (Arabidopsis thaliana), is required for positional signaling in the root epidermis and for tissue/organ development in the shoot. To further understand SCM action, we generated a series of kinase domain variants and analyzed their ability to complement scm mutant defects. We found that the SCM kinase domain, but not kinase activity, is required for its role in root epidermal patterning, supporting the view that SCM is an atypical receptor kinase. We also describe a previously uncharacterized role for SCM in fruit dehiscence, because mature siliques from scm mutants fail to open properly. Interestingly, the kinase domain of SCM appears to be dispensable for this developmental process. Furthermore, we found that most of the SCM kinase domain mutations dramatically inhibit inflorescence development. Because this process is not affected in scm null mutants, it is likely that SCM acts redundantly to regulate inflorescence size. The importance of distinct kinase residues for these three developmental processes provides an explanation for the maintenance of the conserved kinase domain in the SCM protein, and it may generally explain its conservation in other atypical kinases. Furthermore, these results indicate that individual leucine-rich repeat receptor-like kinases may participate in multiple pathways using distinct signaling mechanisms to mediate diverse cellular communication events. PMID:25136062

Distinct patterns of brain activity characterise lexical activation and competition in spoken word production.

Directory of Open Access Journals (Sweden)

Vitória Piai

Full Text Available According to a prominent theory of language production, concepts activate multiple associated words in memory, which enter into competition for selection. However, only a few electrophysiological studies have identified brain responses reflecting competition. Here, we report a magnetoencephalography study in which the activation of competing words was manipulated by presenting pictures (e.g., dog with distractor words. The distractor and picture name were semantically related (cat, unrelated (pin, or identical (dog. Related distractors are stronger competitors to the picture name because they receive additional activation from the picture relative to other distractors. Picture naming times were longer with related than unrelated and identical distractors. Phase-locked and non-phase-locked activity were distinct but temporally related. Phase-locked activity in left temporal cortex, peaking at 400 ms, was larger on unrelated than related and identical trials, suggesting differential activation of alternative words by the picture-word stimuli. Non-phase-locked activity between roughly 350-650 ms (4-10 Hz in left superior frontal gyrus was larger on related than unrelated and identical trials, suggesting differential resolution of the competition among the alternatives, as reflected in the naming times. These findings characterise distinct patterns of activity associated with lexical activation and competition, supporting the theory that words are selected by competition.

Trimethylamine N-oxide stabilizes proteins via a distinct mechanism compared with betaine and glycine

Science.gov (United States)

Liao, Yi-Ting; Manson, Anthony C.; DeLyser, Michael R.; Noid, William G.; Cremer, Paul S.

2017-01-01

We report experimental and computational studies investigating the effects of three osmolytes, trimethylamine N-oxide (TMAO), betaine, and glycine, on the hydrophobic collapse of an elastin-like polypeptide (ELP). All three osmolytes stabilize collapsed conformations of the ELP and reduce the lower critical solution temperature (LSCT) linearly with osmolyte concentration. As expected from conventional preferential solvation arguments, betaine and glycine both increase the surface tension at the air–water interface. TMAO, however, reduces the surface tension. Atomically detailed molecular dynamics (MD) simulations suggest that TMAO also slightly accumulates at the polymer–water interface, whereas glycine and betaine are strongly depleted. To investigate alternative mechanisms for osmolyte effects, we performed FTIR experiments that characterized the impact of each cosolvent on the bulk water structure. These experiments showed that TMAO red-shifts the OH stretch of the IR spectrum via a mechanism that was very sensitive to the protonation state of the NO moiety. Glycine also caused a red shift in the OH stretch region, whereas betaine minimally impacted this region. Thus, the effects of osmolytes on the OH spectrum appear uncorrelated with their effects upon hydrophobic collapse. Similarly, MD simulations suggested that TMAO disrupts the water structure to the least extent, whereas glycine exerts the greatest influence on the water structure. These results suggest that TMAO stabilizes collapsed conformations via a mechanism that is distinct from glycine and betaine. In particular, we propose that TMAO stabilizes proteins by acting as a surfactant for the heterogeneous surfaces of folded proteins. PMID:28228526

Carbon dioxide production during mechanical ventilation

DEFF Research Database (Denmark)

Henneberg, S; Söderberg, D; Groth, T

1987-01-01

studied CO2 production (VCO2) and oxygen consumption (VO2) in mechanically ventilated ICU patients, where CO2 stores were altered by: a) changing minute ventilation by 15%, b) reducing body temperature, and c) changing the level of sedation. Expired gases went through a mixing chamber and were analyzed...

Reduction of excess sludge production using mechanical disintegration devices.

Science.gov (United States)

Strünkmann, G W; Müller, J A; Albert, F; Schwedes, J

2006-01-01

The usability of mechanical disintegration techniques for the reduction of excess sludge production in the activated sludge process was investigated. Using three different disintegration devices (ultrasonic homogeniser, stirred media mill, high pressure homogeniser) and different operational parameters of the disintegration, the effect of mechanical disintegration on the excess sludge production and on the effluent quality was studied within a continuously operated, laboratory scale wastewater treatment system with pre-denitrification. Depending on the operational conditions and the disintegration device used, a reduction of excess sludge production of up to 70% was achieved. A combination of mechanical disintegration with a membrane bioreactor process with high sludge age is more energy effective concerning reduction of sludge production than with a conventional activated sludge process at lower sludge ages. Depending on the disintegration parameters, the disintegration has no, or only minor, negative effect on the soluble effluent COD and on the COD-removal capacity of the activated sludge process. Nitrogen-removal was slightly deteriorated by the disintegration, whereas the system used was not optimised for nitrogen removal before disintegration was implemented.

Social conformity despite individual preferences for distinctiveness.

Science.gov (United States)

Smaldino, Paul E; Epstein, Joshua M

2015-03-01

We demonstrate that individual behaviours directed at the attainment of distinctiveness can in fact produce complete social conformity. We thus offer an unexpected generative mechanism for this central social phenomenon. Specifically, we establish that agents who have fixed needs to be distinct and adapt their positions to achieve distinctiveness goals, can nevertheless self-organize to a limiting state of absolute conformity. This seemingly paradoxical result is deduced formally from a small number of natural assumptions and is then explored at length computationally. Interesting departures from this conformity equilibrium are also possible, including divergence in positions. The effect of extremist minorities on these dynamics is discussed. A simple extension is then introduced, which allows the model to generate and maintain social diversity, including multimodal distinctiveness distributions. The paper contributes formal definitions, analytical deductions and counterintuitive findings to the literature on individual distinctiveness and social conformity.

The Process of Optimizing Mechanical Sound Quality in Product Design

DEFF Research Database (Denmark)

Eriksen, Kaare; Holst, Thomas

2011-01-01

The research field concerning optimizing product sound quality is a relatively unexplored area, and may become difficult for designers to operate in. To some degree, sound is a highly subjective parameter, which is normally targeted sound specialists. This paper describes the theoretical...... and practical background for managing a process of optimizing the mechanical sound quality in a product design by using simple tools and workshops systematically. The procedure is illustrated by a case study of a computer navigation tool (computer mouse or mouse). The process is divided into 4 phases, which...... clarify the importance of product sound, defining perceptive demands identified by users, and, finally, how to suggest mechanical principles for modification of an existing sound design. The optimized mechanical sound design is followed by tests on users of the product in its use context. The result...

Distinct Mechanism Evolved for Mycobacterial RNA Polymerase and Topoisomerase I Protein-Protein Interaction.

Science.gov (United States)

Banda, Srikanth; Cao, Nan; Tse-Dinh, Yuk-Ching

2017-09-15

We report here a distinct mechanism of interaction between topoisomerase I and RNA polymerase in Mycobacterium tuberculosis and Mycobacterium smegmatis that has evolved independently from the previously characterized interaction between bacterial topoisomerase I and RNA polymerase. Bacterial DNA topoisomerase I is responsible for preventing the hyper-negative supercoiling of genomic DNA. The association of topoisomerase I with RNA polymerase during transcription elongation could efficiently relieve transcription-driven negative supercoiling. Our results demonstrate a direct physical interaction between the C-terminal domains of topoisomerase I (TopoI-CTDs) and the β' subunit of RNA polymerase of M. smegmatis in the absence of DNA. The TopoI-CTDs in mycobacteria are evolutionarily unrelated in amino acid sequence and three-dimensional structure to the TopoI-CTD found in the majority of bacterial species outside Actinobacteria, including Escherichia coli. The functional interaction between topoisomerase I and RNA polymerase has evolved independently in mycobacteria and E. coli, with distinctively different structural elements of TopoI-CTD utilized for this protein-protein interaction. Zinc ribbon motifs in E. coli TopoI-CTD are involved in the interaction with RNA polymerase. For M. smegmatis TopoI-CTD, a 27-amino-acid tail that is rich in basic residues at the C-terminal end is responsible for the interaction with RNA polymerase. Overexpression of recombinant TopoI-CTD in M. smegmatis competed with the endogenous topoisomerase I for protein-protein interactions with RNA polymerase. The TopoI-CTD overexpression resulted in decreased survival following treatment with antibiotics and hydrogen peroxide, supporting the importance of the protein-protein interaction between topoisomerase I and RNA polymerase during stress response of mycobacteria. Copyright © 2017 Elsevier Ltd. All rights reserved.

Structure-mechanism-based engineering of chemical regulators targeting distinct pathological factors in Alzheimer's disease.

Science.gov (United States)

Beck, Michael W; Derrick, Jeffrey S; Kerr, Richard A; Oh, Shin Bi; Cho, Woo Jong; Lee, Shin Jung C; Ji, Yonghwan; Han, Jiyeon; Tehrani, Zahra Aliakbar; Suh, Nayoung; Kim, Sujeong; Larsen, Scott D; Kim, Kwang S; Lee, Joo-Yong; Ruotolo, Brandon T; Lim, Mi Hee

2016-10-13

The absence of effective therapeutics against Alzheimer's disease (AD) is a result of the limited understanding of its multifaceted aetiology. Because of the lack of chemical tools to identify pathological factors, investigations into AD pathogenesis have also been insubstantial. Here we report chemical regulators that demonstrate distinct specificity towards targets linked to AD pathology, including metals, amyloid-β (Aβ), metal-Aβ, reactive oxygen species, and free organic radicals. We obtained these chemical regulators through a rational structure-mechanism-based design strategy. We performed structural variations of small molecules for fine-tuning their electronic properties, such as ionization potentials and mechanistic pathways for reactivity towards different targets. We established in vitro and/or in vivo efficacies of the regulators for modulating their targets' reactivities, ameliorating toxicity, reducing amyloid pathology, and improving cognitive deficits. Our chemical tools show promise for deciphering AD pathogenesis and discovering effective drugs.

Fission product release mechanisms and groupings

International Nuclear Information System (INIS)

Iglesia, F.C.; Brito, A.C.; Liu, Y.

1995-01-01

During CANDU postulated accidents the reactor fuel is estimated to be exposed to a variety of conditions. These conditions are dynamic and, during the course of an accident, the fuel may experience a wide range of temperatures and conditions from highly oxidizing to mildly reducing environments. The exposure of the reactor fuel to these environments and temperatures may affect its stoichiometry and release performance. In this paper a review of the important fission product release mechanisms is presented, the results of three out-of-pile experimental programs are summarized, and fission product release groups, for both oxidizing and reducing conditions are proposed. (author)

One-carbon substrate-based biohydrogen production: microbes, mechanism, and productivity.

Science.gov (United States)

Rittmann, Simon K-M R; Lee, Hyun Sook; Lim, Jae Kyu; Kim, Tae Wan; Lee, Jung-Hyun; Kang, Sung Gyun

2015-01-01

Among four basic mechanisms for biological hydrogen (H2) production, dark fermentation has been considered to show the highest hydrogen evolution rate (HER). H2 production from one-carbon (C1) compounds such as formate and carbon monoxide (CO) is promising because formate is an efficient H2 carrier, and the utilization of CO-containing syngas or industrial waste gas may render the industrial biohydrogen production process cost-effective. A variety of microbes with the formate hydrogen lyase (FHL) system have been identified from phylogenetically diverse groups of archaea and bacteria, and numerous efforts have been undertaken to improve the HER for formate through strain optimization and bioprocess development. CO-dependent H2 production has been investigated to enhance the H2 productivity of various carboxydotrophs via an increase in CO gas-liquid mass transfer rates and the construction of genetically modified strains. Hydrogenogenic CO-conversion has been applied to syngas and by-product gas of the steel-mill process, and this low-cost feedstock has shown to be promising in the production of biomass and H2. Here, we focus on recent advances in the isolation of novel phylogenetic groups utilizing formate or CO, the remarkable genetic engineering that enhances H2 productivity, and the practical implementation of H2 production from C1 substrates. Copyright © 2014 Elsevier Inc. All rights reserved.

TCRs Used in Cancer Gene Therapy Cross-React with MART-1/Melan-A Tumor Antigens via Distinct Mechanisms

Energy Technology Data Exchange (ETDEWEB)

Borbulevych, Oleg Y.; Santhanagopolan, Sujatha M.; Hossain, Moushumi; Baker, Brian M. (Notre)

2013-09-18

T cells engineered to express TCRs specific for tumor Ags can drive cancer regression. The first TCRs used in cancer gene therapy, DMF4 and DMF5, recognize two structurally distinct peptide epitopes of the melanoma-associated MART-1/Melan-A protein, both presented by the class I MHC protein HLA-A*0201. To help understand the mechanisms of TCR cross-reactivity and provide a foundation for the further development of immunotherapy, we determined the crystallographic structures of DMF4 and DMF5 in complex with both of the MART-1/Melan-A epitopes. The two TCRs use different mechanisms to accommodate the two ligands. Although DMF4 binds the two with a different orientation, altering its position over the peptide/MHC, DMF5 binds them both identically. The simpler mode of cross-reactivity by DMF5 is associated with higher affinity toward both ligands, consistent with the superior functional avidity of DMF5. More generally, the observation of two diverging mechanisms of cross-reactivity with the same Ags and the finding that TCR-binding orientation can be determined by peptide alone extend our understanding of the mechanisms underlying TCR cross-reactivity.

Mechanisms for production of highly charged ions

International Nuclear Information System (INIS)

McGuire, J.H.

1987-01-01

Various experimental data at high collision velocity are interpreted in terms of direct (D) and rearrangement (R) mechanisms for production of multiply charged ions. We consider double ionization in helium by protons, electrons, heavy ions, antiprotons, positrons and photons. Qualitative differences are discussed in the context of the R and D mechanisms. Multiple ionization in many electron atoms is considered as is simultaneous capture and ionization and fragmentation of methane molecules. Some other theoretical methods are briefly discussed. (orig.)

On the mechanism of hadron cumulative production on nucleus

International Nuclear Information System (INIS)

Efremov, A.V.

1976-01-01

A mechanism of cumulative production of hadrons on nucleus is proposed which is similar to that of high perpendicular hadron production. The cross section obtained describes the main qualitative features of such prosesses, e.g., initial energy dependence atomic number behaviour, dependence on the rest mass of the produced particle and its production angle

Pathways and mechanisms for product release in the engineered haloalkane dehalogenases explored using classical and random acceleration molecular dynamics simulations.

Science.gov (United States)

Klvana, Martin; Pavlova, Martina; Koudelakova, Tana; Chaloupkova, Radka; Dvorak, Pavel; Prokop, Zbynek; Stsiapanava, Alena; Kuty, Michal; Kuta-Smatanova, Ivana; Dohnalek, Jan; Kulhanek, Petr; Wade, Rebecca C; Damborsky, Jiri

2009-10-09

Eight mutants of the DhaA haloalkane dehalogenase carrying mutations at the residues lining two tunnels, previously observed by protein X-ray crystallography, were constructed and biochemically characterized. The mutants showed distinct catalytic efficiencies with the halogenated substrate 1,2,3-trichloropropane. Release pathways for the two dehalogenation products, 2,3-dichloropropane-1-ol and the chloride ion, and exchange pathways for water molecules, were studied using classical and random acceleration molecular dynamics simulations. Five different pathways, denoted p1, p2a, p2b, p2c, and p3, were identified. The individual pathways showed differing selectivity for the products: the chloride ion releases solely through p1, whereas the alcohol releases through all five pathways. Water molecules play a crucial role for release of both products by breakage of their hydrogen-bonding interactions with the active-site residues and shielding the charged chloride ion during its passage through a hydrophobic tunnel. Exchange of the chloride ions, the alcohol product, and the waters between the buried active site and the bulk solvent can be realized by three different mechanisms: (i) passage through a permanent tunnel, (ii) passage through a transient tunnel, and (iii) migration through a protein matrix. We demonstrate that the accessibility of the pathways and the mechanisms of ligand exchange were modified by mutations. Insertion of bulky aromatic residues in the tunnel corresponding to pathway p1 leads to reduced accessibility to the ligands and a change in mechanism of opening from permanent to transient. We propose that engineering the accessibility of tunnels and the mechanisms of ligand exchange is a powerful strategy for modification of the functional properties of enzymes with buried active sites.

Distinct roles of two anaplerotic pathways in glutamate production induced by biotin limitation in Corynebacterium glutamicum.

Science.gov (United States)

Sato, Hiroki; Orishimo, Keita; Shirai, Tomokazu; Hirasawa, Takashi; Nagahisa, Keisuke; Shimizu, Hiroshi; Wachi, Masaaki

2008-07-01

Corynebacterium glutamicum is a biotin auxotrophic bacterium in which glutamate production is induced under biotin-limited conditions. During glutamate production, anaplerotic reactions catalyzed by phosphoenolpyruvate carboxylase (PEPC) and a biotin-containing enzyme pyruvate carboxylase (PC) are believed to play an important role in supplying oxaloacetate in the tricarboxylic acid cycle. To understand the distinct roles of PEPC and PC on glutamate production by C. glutamicum, we observed glutamate production induced under biotin-limited conditions in the disruptants of the genes encoding PEPC (ppc) and PC (pyc), respectively. The pyc disruptant retained the ability to produce high amounts of glutamate, and lactate was simultaneously produced probably due to the increased intracellular pyruvate levels. On the other hand, the ppc knockout mutant could not produce glutamate. Additionally, glutamate production in the pyc disruptant was enhanced by overexpression of ppc rather than disruption of the lactate dehydrogenase gene (ldh), which is involved in lactate production. Metabolic flux analysis based on the 13C-labeling experiment and measurement of 13C-enrichment in glutamate using nuclear magnetic resonance spectroscopy revealed that the flux for anaplerotic reactions in the pyc disruptant was lower than that in the wild type, concomitantly increasing the flux for lactate formation. Moreover, overexpression of ppc increased this flux in both the pyc disruptant and the wild type. Our results suggest that the PEPC-catalyzed anaplerotic reaction is necessary for glutamate production induced under biotin-limited conditions, because PC is not active during glutamate production, and overexpression of ppc effectively enhances glutamate production under biotin-limited conditions.

Fission product release mechanisms and groupings

Energy Technology Data Exchange (ETDEWEB)

Iglesia, F C; Brito, A C; Liu, Y [Ontario Hydro, Toronto, ON (Canada); and others

1996-12-31

During CANDU postulated accidents the reactor fuel is estimated to be exposed to a variety of conditions. These conditions are dynamic and, during the course of an accident, the fuel may experience a wide range of temperatures and conditions from highly oxidizing to mildly reducing environments. The exposure of the reactor fuel to these environments and temperatures may affect its stoichiometry and release performance. In this paper a review of the important fission product release mechanisms is presented, the results of three out-of-pile experimental programs are summarized, and fission product release groups, for both oxidizing and reducing conditions are proposed. (author) 92 refs., 6 tabs.

Reactor design for minimizing product inhibition during enzymatic lignocellulose hydrolysis: I. Significance and mechanism of cellobiose and glucose inhibition on cellulolytic enzymes

DEFF Research Database (Denmark)

Andric, Pavle; Meyer, Anne S.; Jensen, Peter Arendt

2010-01-01

Achievement of efficient enzymatic degradation of cellulose to glucose is one of the main prerequisites and one of the main challenges in the biological conversion of lignocellulosic biomass to liquid fuels and other valuable products. The specific inhibitory interferences by cellobiose and glucose...... on enzyme-catalyzed cellulose hydrolysis reactions impose significant limitations on the efficiency of lignocellulose conversion especially at high-biomass dry matter conditions. To provide the base for selecting the optimal reactor conditions, this paper reviews the reaction kinetics, mechanisms......, and significance of this product inhibition, notably the cellobiose and glucose inhibition, on enzymatic cellulose hydrolysis. Particular emphasis is put on the distinct complexity of cellulose as a substrate, the multi-enzymatic nature of the cellulolytic degradation, and the particular features of cellulase...

Study of mechanical properties and fracture mechanisms of synthetic fibers nylon-and-polyester type, used in engineering products

International Nuclear Information System (INIS)

Cardoso, Sergio Gomes

2009-01-01

Fibers are groups formed by molecular-chain-oriented filaments. Fibers play a fundamental role in human being's daily life and they can be found in several forms and geometries, such as filaments, yarns, beams, rope, fabric, composite, coatings, others. They are used in various segments such as civil, mechanical, electrical, electronics, military, naval, nautical, aviation, health, medicine, environment, communications, safety, space, others. Fibers are divided into two distinct classes: natural and chemical ones, which cover synthetic and man-made sub-classes. They can be produced from several materials, such as wool, cotton, rayon, flax, silk, rock, nylon, polyester, polyethylene, poly-propylene, aramid, glass, carbon, steel, ceramic, others. Globally, the participation of chemical fibers corresponds to approximately 59,9%, and the synthetic fiber polyester, the most used one, represents approximately 63% of the world market. Vital needs have led to the development of multi-function fibers and the focus has changed in the last 10 years with the use of nano technology for environmental responsibility and smart fibers. The study of mechanical properties and fracture mechanisms of fibers is of great relevance for characterization and understanding of causes as consequence of failures. For such reason, it was selected technical fabrics made of high performance synthetic fiber nylon-and-polyester type, used in engineered products such as tires, belts, hoses and pneumatic springs, which have been analyzed in each processing phase. Fiber samples were extracted after each processing phase to be analyzed, by traction destructive tests and scanning electron microscopy. The results of analysis of mechanical properties showed loss of resistance to temperature and multi axial stress during fiber processing phase. Through microscopy tests, it was possible to find contamination, surface stains, plastic deformations, scaling, variations in the fracture faces of the filaments and

Hippocampus duality: Memory and novelty detection are subserved by distinct mechanisms.

Science.gov (United States)

Barbeau, Emmanuel J; Chauvel, Patrick; Moulin, Christopher J A; Regis, Jean; Liégeois-Chauvel, Catherine

2017-04-01

The hippocampus plays a pivotal role both in novelty detection and in long-term memory. The physiological mechanisms underlying these behaviors have yet to be understood in humans. We recorded intracerebral evoked potentials within the hippocampus of epileptic patients (n = 10) during both memory and novelty detection tasks (targets in oddball tasks). We found that memory and detection tasks elicited late local field potentials in the hippocampus during the same period, but of opposite polarity (negative during novelty detection tasks, positive during memory tasks, ∼260-600 ms poststimulus onset, P < 0.05). Critically, these potentials had maximal amplitude on the same contact in the hippocampus for each patient. This pattern did not depend on the task as different types of memory and novelty detection tasks were used. It did not depend on the novelty of the stimulus or the difficulty of the task either. Two different hypotheses are discussed to account for this result: it is either due to the activation of CA1 pyramidal neurons by two different pathways such as the monosynaptic and trisynaptic entorhinal-hippocampus pathways, or to the activation of different neuronal populations, that is, differing either functionally (e.g., novelty/familiarity neurons) or located in different regions of the hippocampus (e.g., CA1/subiculum). In either case, these activities may integrate the activity of two distinct large-scale networks implementing externally or internally oriented, mutually exclusive, brain states. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Common and distinct neural mechanisms of attentional switching and response conflict.

Science.gov (United States)

Kim, Chobok; Johnson, Nathan F; Gold, Brian T

2012-08-21

The human capacities for overcoming prepotent actions and flexibly switching between tasks represent cornerstones of cognitive control. Functional neuroimaging has implicated a diverse set of brain regions contributing to each of these cognitive control processes. However, the extent to which attentional switching and response conflict draw on shared or distinct neural mechanisms remains unclear. The current study examined the neural correlates of response conflict and attentional switching using event-related functional magnetic resonance imaging (fMRI) and a fully randomized 2×2 design. We manipulated an arrow-word version of the Stroop task to measure conflict and switching in the context of a single task decision, in response to a common set of stimuli. Under these common conditions, both behavioral and imaging data showed significant main effects of conflict and switching but no interaction. However, conjunction analyses identified frontal regions involved in both switching and response conflict, including the dorsal anterior cingulate cortex (dACC) and left inferior frontal junction. In addition, connectivity analyses demonstrated task-dependent functional connectivity patterns between dACC and inferior temporal cortex for attentional switching and between dACC and posterior parietal cortex for response conflict. These results suggest that the brain makes use of shared frontal regions, but can dynamically modulate the connectivity patterns of some of those regions, to deal with attentional switching and response conflict. Copyright © 2012 Elsevier B.V. All rights reserved.

Suppressive versus augmenting effect of the same pretreatment regimen in two murine tumor systems with distinct effector mechanisms

International Nuclear Information System (INIS)

Fujiwara, Hiromi; Hamaoka, Toshiyuki; Kitagawa, Masayasu

1978-01-01

The effect of presensitization with x-irradiated tumor cells on the development of host's immune resistance against the tumor-associated transplantation antigens (TATA) was investigated in two syngeneic tumor systems with distinct effector mechanisms. When X5563 plasmacytoma, to which immune resistance was mediated exclusively by killer T lymphocytes, was intravenously inoculated into syngeneic C3H/He mice with lower number after 7000 R x-irradiation, the mice failed to exhibit any protective immunity against the subsequent challenge with viable tumor cells. Moreover, these mice lost their capability to develop any immune resistance even after an appropriate immunization procedure. The immunodepression induced by such a pretreatment regimen was specific for X5563 tumor. While no suppressor cell activity was detected in the above pretreated mice, serum factor(s) from these mice was virtually responsible for this suppression. When the serum factor mediating this tumor-specific suppression was fractionated on the Sephadex G-200 column, the suppressive activity was found in albumin-corresponding fraction, free of any immunoglobulin component. In contrast, in MM102 mammary tumor system, in which immune resistance is solely mediated by tumor-specific antibody, the pretreatment with x-irradiated MM102 cells augmented the induction of anti-tumor immunity. These results indicate that while tumor antigens given in the form of x-irradiated tumor cells suppress the induction of killer T cell-mediated immunity in one system, the same presensitization regimen of tumor antigens augments the antibody-mediated immunity in another system, thus giving a divergent effect on the distinct effector mechanisms of syngeneic tumor immunity. (author)

Two Silene vulgaris copper transporters residing in different cellular compartments confer copper hypertolerance by distinct mechanisms when expressed in Arabidopsis thaliana.

Science.gov (United States)

Li, Yanbang; Iqbal, Mazhar; Zhang, Qianqian; Spelt, Cornelis; Bliek, Mattijs; Hakvoort, Henk W J; Quattrocchio, Francesca M; Koes, Ronald; Schat, Henk

2017-08-01

Silene vulgaris is a metallophyte of calamine, cupriferous and serpentine soils all over Europe. Its metallicolous populations are hypertolerant to zinc (Zn), cadmium (Cd), copper (Cu) or nickel (Ni), compared with conspecific nonmetallicolous populations. These hypertolerances are metal-specific, but the underlying mechanisms are poorly understood. We investigated the role of HMA5 copper transporters in Cu-hypertolerance of a S. vulgaris copper mine population. Cu-hypertolerance in Silene is correlated and genetically linked with enhanced expression of two HMA5 paralogs, SvHMA5I and SvHMA5II, each of which increases Cu tolerance when expressed in Arabidopsis thaliana. Most Spermatophytes, except Brassicaceae, possess homologs of SvHMA5I and SvHMA5II, which originate from an ancient duplication predating the appearance of spermatophytes. SvHMA5II and the A. thaliana homolog AtHMA5 localize in the endoplasmic reticulum and upon Cu exposure move to the plasma membrane, from where they are internalized and degraded in the vacuole. This resembles trafficking of mammalian homologs and is apparently an extremely ancient mechanism. SvHMA5I, instead, neofunctionalized and always resides on the tonoplast, likely sequestering Cu in the vacuole. Adaption of Silene to a Cu-polluted soil is at least in part due to upregulation of two distinct HMA5 transporters, which contribute to Cu hypertolerance by distinct mechanisms. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Laboratory and 3-D-distinct element analysis of failure mechanism of slope under external surcharge

Science.gov (United States)

Li, N.; Cheng, Y. M.

2014-09-01

Landslide is a major disaster resulting in considerable loss of human lives and property damages in hilly terrain in Hong Kong, China and many other countries. The factor of safety and the critical slip surface for slope stabilization are the main considerations for slope stability analysis in the past, while the detailed post-failure conditions of the slopes have not been considered in sufficient details. There are however increasing interest on the consequences after the initiation of failure which includes the development and propagation of the failure surfaces, the amount of failed mass and runoff and the affected region. To assess the development of slope failure in more details and to consider the potential danger of slopes after failure has initiated, the slope stability problem under external surcharge is analyzed by the distinct element method (DEM) and laboratory model test in the present research. A more refined study about the development of failure, microcosmic failure mechanism and the post-failure mechanism of slope will be carried out. The numerical modeling method and the various findings from the present work can provide an alternate method of analysis of slope failure which can give additional information not available from the classical methods of analysis.

The Effect of Headquarter Integration Mechanisms on Subsidiaries’ New Product Success: From Control to Coordination Mechanism

Directory of Open Access Journals (Sweden)

Firmanzah

2007-10-01

Full Text Available New product launching (NPL to the local market by subsidiary managers is a strategic activity, which requires organizational supports from MNC global network. The NPL activity is marked by high level of uncertainty, risk, and market failure. Thus, a headquarter needs to integrate the subsidiary NPL into global strategy. There are two mechanisms to integrate subsidiaries’ activities during NPL process; coordination and control process. By testing the effect of each mechanism on role clarity and functional conflict, I found that coordination mechanism increase role clarity between headquarter and subsidiaries’ managers. In contrast, exercising control mechanism reduces role clarity and functional conflict between headquarter and subsidiaries’ managers during NPL. This research shows that both role clarity and functional conflict increase new product commercial performance introduced by subsidiary in the local market.

Mechanism of management of competitiveness of production of agrarian and industrial complex

Directory of Open Access Journals (Sweden)

Buryak E. A.

2016-04-01

Full Text Available the concept of competitiveness and mechanisms of management of competitiveness of production is considered. Major factors of ensuring competitiveness of production of agrarian and industrial complex are allocated. The main problems of production of wheat in the Republic of Crimea making negative impact on the level of her competitiveness are revealed. The mechanism of management of competitiveness of production of agrarian and industrial complex is developed.

A comparison of chemical mechanisms using tagged ozone production potential (TOPP analysis

Directory of Open Access Journals (Sweden)

J. Coates

2015-08-01

Full Text Available Ground-level ozone is a secondary pollutant produced photochemically from reactions of NOx with peroxy radicals produced during volatile organic compound (VOC degradation. Chemical transport models use simplified representations of this complex gas-phase chemistry to predict O3 levels and inform emission control strategies. Accurate representation of O3 production chemistry is vital for effective prediction. In this study, VOC degradation chemistry in simplified mechanisms is compared to that in the near-explicit Master Chemical Mechanism (MCM using a box model and by "tagging" all organic degradation products over multi-day runs, thus calculating the tagged ozone production potential (TOPP for a selection of VOCs representative of urban air masses. Simplified mechanisms that aggregate VOC degradation products instead of aggregating emitted VOCs produce comparable amounts of O3 from VOC degradation to the MCM. First-day TOPP values are similar across mechanisms for most VOCs, with larger discrepancies arising over the course of the model run. Aromatic and unsaturated aliphatic VOCs have the largest inter-mechanism differences on the first day, while alkanes show largest differences on the second day. Simplified mechanisms break VOCs down into smaller-sized degradation products on the first day faster than the MCM, impacting the total amount of O3 produced on subsequent days due to secondary chemistry.

Investigation of mechanisms of production of argon, krypton and xenon isotopes formed in heavy targets by protons with an energy ranging from 0.15 to 24 GeV

International Nuclear Information System (INIS)

Sauvageon, Henri

1981-01-01

As experimental results of the investigation of interactions between high-energy protons and nucleus generally lead to the distinction between four types of reaction mechanisms (spallation, fission, fragmentation and isotope production), this research thesis reports the study of this mechanisms by using the so-called 'thick target - thick collector' experiment and by studying the production of various isotopes of rare gases (argon, krypton, xenon). These isotopes are produced by using platinum, gold, bismuth and thorium targets bombarded by protons with an energy ranging from 0.15 to 24 GeV. The author presents the experimental methods (target preparation and irradiation, rare gas analysis system), reports the analysis of thick target - thick-collector experiments (vector-based representation, path determination, path-curve energy, corrections of experimental data, excitation energy of the intermediate nucleus), presents the experimental results, and discusses their interpretation (two-stage model of high energy nuclear reactions, isotopes produced by spallation and by fission, isotopes produced by deep spallation, representations of mechanisms of fragmentation and deep spallation)

Fragile X Proteins FMRP and FXR2P Control Synaptic GluA1 Expression and Neuronal Maturation via Distinct Mechanisms

Directory of Open Access Journals (Sweden)

Weixiang Guo

2015-06-01

Full Text Available Fragile X mental retardation protein (FMRP and its autosomal paralog FXR2P are selective neuronal RNA-binding proteins, and mice that lack either protein exhibit cognitive deficits. Although double-mutant mice display more severe learning deficits than single mutants, the molecular mechanism behind this remains unknown. In the present study, we discovered that FXR2P (also known as FXR2 is important for neuronal dendritic development. FMRP and FXR2P additively promote the maturation of new neurons by regulating a common target, the AMPA receptor GluA1, but they do so via distinct mechanisms: FXR2P binds and stabilizes GluA1 mRNA and enhances subsequent protein expression, whereas FMRP promotes GluA1 membrane delivery. Our findings unveil important roles for FXR2P and GluA1 in neuronal development, uncover a regulatory mechanism of GluA1, and reveal a functional convergence between fragile X proteins in neuronal development.

Ire1 Has Distinct Catalytic Mechanisms for XBP1/HAC1 Splicing and RIDD

Directory of Open Access Journals (Sweden)

Arvin B. Tam

2014-11-01

Full Text Available An evolutionarily conserved unfolded protein response (UPR component, IRE1, cleaves XBP1/HAC1 introns in order to generate spliced mRNAs that are translated into potent transcription factors. IRE1 also cleaves endoplasmic-reticulum-associated RNAs leading to their decay, an activity termed regulated IRE1-dependent decay (RIDD; however, the mechanism by which IRE1 differentiates intron cleavage from RIDD is not well understood. Using in vitro experiments, we found that IRE1 has two different modes of action: XBP1/HAC1 is cleaved by IRE1 subunits acting cooperatively within IRE1 oligomers, whereas a single subunit of IRE1 performs RIDD without cooperativity. Furthermore, these distinct activities can be separated by complementation of catalytically inactive IRE1 RNase and mutations at oligomerization interfaces. Using an IRE1 RNase inhibitor, STF-083010, selective inhibition of XBP1 splicing indicates that XBP1 promotes cell survival, whereas RIDD leads to cell death, revealing modulation of IRE1 activities as a drug-development strategy.

Bacterial protease uses distinct thermodynamic signatures for substrate recognition.

Science.gov (United States)

Bezerra, Gustavo Arruda; Ohara-Nemoto, Yuko; Cornaciu, Irina; Fedosyuk, Sofiya; Hoffmann, Guillaume; Round, Adam; Márquez, José A; Nemoto, Takayuki K; Djinović-Carugo, Kristina

2017-06-06

Porphyromonas gingivalis and Porphyromonas endodontalis are important bacteria related to periodontitis, the most common chronic inflammatory disease in humans worldwide. Its comorbidity with systemic diseases, such as type 2 diabetes, oral cancers and cardiovascular diseases, continues to generate considerable interest. Surprisingly, these two microorganisms do not ferment carbohydrates; rather they use proteinaceous substrates as carbon and energy sources. However, the underlying biochemical mechanisms of their energy metabolism remain unknown. Here, we show that dipeptidyl peptidase 11 (DPP11), a central metabolic enzyme in these bacteria, undergoes a conformational change upon peptide binding to distinguish substrates from end products. It binds substrates through an entropy-driven process and end products in an enthalpy-driven fashion. We show that increase in protein conformational entropy is the main-driving force for substrate binding via the unfolding of specific regions of the enzyme ("entropy reservoirs"). The relationship between our structural and thermodynamics data yields a distinct model for protein-protein interactions where protein conformational entropy modulates the binding free-energy. Further, our findings provide a framework for the structure-based design of specific DPP11 inhibitors.

On the intrinsic charm and the recombination mechanisms in charm hadron production

International Nuclear Information System (INIS)

Anjos, J.C.; Magnin, J.; Herrera, G.

2001-09-01

We study Λ c ± production in pN and π - N interactions. Recent experimental data from the SELEX and E791 Collaborations at FNAL provide important information on the production mechanism of charm hadrons. In particular, the production of the Λ c baryon provides a good test of the intrinsic charm and the recombination mechanisms, which have been proposed to explain the so called leading particle effects. (author)

Mechanical design of a magnetic fusion production reactor

International Nuclear Information System (INIS)

Neef, W.S.; Jassby, D.L.

1986-01-01

The mechanical aspects of a tandem mirror and tokamak concepts for the tritium production mission are compared, and a proposed breeding blanket configuration for each type of reactor is presented in detail, along with a design outline of the complete fusion reaction system. In both cases, the reactor design is developed sufficiently to permit preliminary cost estimates of all components. A qualitative comparison is drawn between both concepts from the view of mechanical design and serviceability, and suggestions are made for technology proof tests on unique mechanical features. Detailed cost breakdowns indicate less than 10% difference in the overall costs of the two reactors

Chemical and mechanical control of corrosion product transport

Energy Technology Data Exchange (ETDEWEB)

Hede Larsen, O; Blum, R [I/S Fynsvaerket, Faelleskemikerne, Odense (Denmark); Daucik, K [I/S Skaerbaekvaerket, Faelleskemikerne, Fredericia (Denmark)

1996-12-01

The corrosion products formed in the condensate and feedwater system of once-through boilers are precipitated and deposited inside the evaporator tubes mainly in the burner zone at the highest heat flux. Depositions lead to increased oxidation rate and increased metal temperature of the evaporator tubes, hereby decreasing tube lifetime. This effect is more important in the new high efficiency USC boilers due to increased feedwater temperature and hence higher thermal load on the evaporator tubes. The only way to reduce the load on the evaporator tubes is to minimise corrosion product transport to the boiler. Two general methods for minimising corrosion product transport to the boiler have been evaluated through measurement campaigns for Fe in the water/steam cycle in supercritical boilers within the ELSAM area. One method is to reduce corrosion in the low temperature condensate system by changing conditioning mode from alkaline volatile treatment (AVT) to oxygenated treatment (OT). The other method is to filtrate part of the condensate with a mechanical filter at the deaerator. The results show, that both methods are effective at minimising Fe-transport to the boiler, but changing to OT has the highest effect and should always be used, whenever high purity condensate is maintained. Whether mechanical filtration also is required, depends on the boiler, specifically the load on the evaporator. A simplified calculation model for lifetime evaluation of evaporator tubes has been developed. This model has been used for evaluating the effect of corrosion product transport to the boiler on evaporator tube lifetime. Conventional supercritical boilers generally can achieve sufficient lifetime by AVT and even better by OT, whereas all measures to reduce Fe-content of feedwater, including OT and mechanical filtration, should be taken, to ensure sufficient lifetime for the new boilers with advanced steam data - 290 bar/580 deg. C and above. (au)

Production compilation : A simple mechanism to model complex skill acquisition

NARCIS (Netherlands)

Taatgen, N.A.; Lee, F.J.

2003-01-01

In this article we describe production compilation, a mechanism for modeling skill acquisition. Production compilation has been developed within the ACT-Rational (ACT-R; J. R. Anderson, D. Bothell, M. D. Byrne, & C. Lebiere, 2002) cognitive architecture and consists of combining and specializing

Motor learning in childhood reveals distinct mechanisms for memory retention and re-learning.

Science.gov (United States)

Musselman, Kristin E; Roemmich, Ryan T; Garrett, Ben; Bastian, Amy J

2016-05-01

Adults can easily learn and access multiple versions of the same motor skill adapted for different conditions (e.g., walking in water, sand, snow). Following even a single session of adaptation, adults exhibit clear day-to-day retention and faster re-learning of the adapted pattern. Here, we studied the retention and re-learning of an adapted walking pattern in children aged 6-17 yr. We found that all children, regardless of age, showed adult-like patterns of retention of the adapted walking pattern. In contrast, children under 12 yr of age did not re-learn faster on the next day after washout had occurred-they behaved as if they had never adapted their walking before. Re-learning could be improved in younger children when the adaptation time on day 1 was increased to allow more practice at the plateau of the adapted pattern, but never to adult-like levels. These results show that the ability to store a separate, adapted version of the same general motor pattern does not fully develop until adolescence, and furthermore, that the mechanisms underlying the retention and rapid re-learning of adapted motor patterns are distinct. © 2016 Musselman et al.; Published by Cold Spring Harbor Laboratory Press.

U.S. Residential Miscellaneous Refrigeration Products: Results from Amazon Mechanical Turk Surveys

Energy Technology Data Exchange (ETDEWEB)

Greenblatt, Jeffery B.; Young, Scott J.; Yang, Hung-Chia; Long, Timothy; Beraki, Bereket; Price, Sarah K.; Pratt, Stacy; Willem, Henry; Desroches, Louis-Benoit

2013-11-14

Amazon Mechanical Turk was used, for the first time, to collect statistically representative survey data from U.S. households on the presence, number, type and usage of refrigerators, freezers, and various “miscellaneous” refrigeration products (wine/beverage coolers, residential icemakers and non-vapor compression refrigerators and freezers), along with household and demographic information. Such products have been poorly studied to date, with almost no information available about shipments, stocks, capacities, energy use, etc. A total of 9,981 clean survey responses were obtained from five distinct surveys deployed in 2012. General refrigeration product survey responses were weighted to demographics in the U.S. Energy Information Administration’s Residential Energy Consumption Survey 2009 dataset. Miscellaneous refrigeration product survey responses were weighted according to demographics of product ownership found in the general refrigeration product surveys. Model number matching for a portion of miscellaneous refrigeration product responses allowed validation of refrigeration product characteristics, which enabled more accurate estimates of the penetrations of these products in U.S. households. We estimated that there were 12.3±1.0 million wine/beverage coolers, 5.5(–3.5,+3.2) million residential icemakers and 4.4(–2.7,+2.3) million non-vapor compression refrigerators in U.S. households in 2012. (All numerical results are expressed with ranges indicating the 95% confidence interval.) No evidence was found for the existence of non-vapor compression freezers. Moreover, we found that 15% of wine/beverage coolers used vapor compression cooling technology, while 85% used thermoelectric cooling technology, with the vast majority of thermoelectric units having capacities of less than 30 wine bottles (approximately 3.5 cubic feet). No evidence was found for the existence of wine/beverage coolers with absorption cooling technology. Additionally, we estimated

U.S. Residential Miscellaneous Refrigeration Products: Results from Amazon Mechanical Turk Surveys

Energy Technology Data Exchange (ETDEWEB)

Greenblatt, Jeffery B. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Young, Scott J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Yang, Hung-Chia [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Long, Timothy [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Beraki, Bereket [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Price, Sarah K. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Pratt, Stacy [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Willem, Henry [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Desroches, Louis-Benoit [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2013-04-01

Amazon Mechanical Turk was used, for the first time, to collect statistically representative survey data from U.S. households on the presence, number, type and usage of refrigerators, freezers, and various “miscellaneous” refrigeration products (wine/beverage coolers, residential icemakers and non-vapor compression refrigerators and freezers), along with household and demographic information. Such products have been poorly studied to date, with almost no information available about shipments, stocks, capacities, energy use, etc. A total of 9,820 clean survey responses were obtained from four distinct surveys deployed in 2012. General refrigeration product survey responses were weighted to demographics in the U.S. Energy Information Administration’s Residential Energy Consumption Survey 2009 dataset. Miscellaneous refrigeration product survey responses were weighted according to demographics of product ownership found in the general refrigeration product surveys. Model number matching for a portion of miscellaneous refrigeration product responses allowed validation of refrigeration product characteristics, which enabled more accurate estimates of the penetrations of these products in U.S. households. We estimated that there were 12.3±1.0 million wine/beverage coolers, 5.5(–3.5,+3.2) million residential icemakers and 2.9(–2.5,+4.5) million non-vapor compression refrigerators in U.S. households in 2012. (All numerical results are expressed with ranges indicating the 95% confidence interval.) No evidence was found for the existence of non-vapor compression freezers. Moreover, we found that 15% of wine/beverage coolers used vapor compression cooling technology, while 85% used thermoelectric cooling technology, with the vast majority of thermoelectric units having capacities of less than 30 wine bottles (approximately 3.5 cubic feet). No evidence was found for the existence of wine/beverage coolers with absorption cooling technology. Additionally, we estimated

Feline immunodeficiency virus envelope glycoproteins antagonize tetherin through a distinctive mechanism that requires virion incorporation.

Science.gov (United States)

Morrison, James H; Guevara, Rebekah B; Marcano, Adriana C; Saenz, Dyana T; Fadel, Hind J; Rogstad, Daniel K; Poeschla, Eric M

2014-03-01

also its Env protein, but the mechanism is distinctive. Unlike other tetherin antagonists, FIV Env cannot act in trans to rescue vpu-deficient HIV-1. It must be incorporated specifically into FIV virions to be active. Also unlike other retroviral antagonists, but similar to Ebola virus Env, it does not act by downregulating or degrading tetherin. FIV Env might exclude tetherin locally or direct assembly to tetherin-negative membrane domains. Other distinctive features are apparent, including evidence that this virus evolved an equilibrium in which tetherin is both restriction factor and cofactor, as FIV requires tetherin for optimal particle release.

THE IMPACT OF A MECHANICAL PRESS ON THE ACCURACY OF PRODUCTS IN COLD FORGING

DEFF Research Database (Denmark)

Krusic, V.; Arentoft, Mogens; Rodic, T.

2005-01-01

Cold extrusion is an economic production process for the production of elements of complex forms and accurate dimensions. The first part of the article explains the impact that a mechanical press has on the accuracy of products. It describes the mechanical press main characteristics and in additi...

Amnesia, rehearsal, and temporal distinctiveness models of recall.

Science.gov (United States)

Brown, Gordon D A; Della Sala, Sergio; Foster, Jonathan K; Vousden, Janet I

2007-04-01

Classical amnesia involves selective memory impairment for temporally distant items in free recall (impaired primacy) together with relative preservation of memory for recency items. This abnormal serial position curve is traditionally taken as evidence for a distinction between different memory processes, with amnesia being associated with selectively impaired long-term memory. However recent accounts of normal serial position curves have emphasized the importance of rehearsal processes in giving rise to primacy effects and have suggested that a single temporal distinctiveness mechanism can account for both primacy and recency effects when rehearsal is considered. Here we explore the pattern of strategic rehearsal in a patient with very severe amnesia. When the patient's rehearsal pattern is taken into account, a temporal distinctiveness model can account for the serial position curve in both amnesic and control free recall. The results are taken as consistent with temporal distinctiveness models of free recall, and they motivate an emphasis on rehearsal patterns in understanding amnesic deficits in free recall.

A Novel Algorithm for the Generation of Distinct Kinematic Chain

Science.gov (United States)

Medapati, Sreenivasa Reddy; Kuchibhotla, Mallikarjuna Rao; Annambhotla, Balaji Srinivasa Rao

2016-07-01

Generation of distinct kinematic chains is an important topic in the design of mechanisms for various industrial applications i.e., robotic manipulator, tractor, crane etc. Many researchers have intently focused on this area and explained various processes of generating distinct kinematic chains which are laborious and complex. It is desirable to enumerate the kinematic chains systematically to know the inherent characteristics of a chain related to its structure so that all the distinct chains can be analyzed in depth, prior to the selection of a chain for a purpose. This paper proposes a novel and simple method with set of rules defined to eliminate isomorphic kinematic chains generating distinct kinematic chains. Also, this method simplifies the process of generating distinct kinematic chains even at higher levels i.e., 10-link, 11-link with single and multiple degree of freedom.

Grammar-Lexicon Distinction in a Neurocognitive Context

DEFF Research Database (Denmark)

Ishkhanyan, Byurakn

hypotheses and testing them through using various methods. The grammar-lexicon distinction and working memory are thus central topics of this thesis. The results suggest a potential for a successful integration of the two theories. The findings further provide evidence for Boye & Harder’s (2012......) understanding of the grammar-lexicon distinction, and for the involvement of working memory in language production, as the REF-model would predict. As a starting point for integrating the two theories, the present thesis gives directions for future research on the neurocognitive underpinning of language and its...... relation to working memory....

Using contract mechanisms to coordinate product line decisions

NARCIS (Netherlands)

Nalla, V.R.; Venugopal, V.; Veen, van der J.A.A.

2008-01-01

In this paper we design contract mechanisms to increase the efficiency of product line decisions in a Supply Chain (SC). A two stage SC with a buyer and the supplier is considered. The end consumers are comprised of two segments with different willingness to pay. The final demand and the segments’

Binding of the cSH3 domain of Grb2 adaptor to two distinct RXXK motifs within Gab1 docker employs differential mechanisms.

Science.gov (United States)

McDonald, Caleb B; Seldeen, Kenneth L; Deegan, Brian J; Bhat, Vikas; Farooq, Amjad

2011-01-01

A ubiquitous component of cellular signaling machinery, Gab1 docker plays a pivotal role in routing extracellular information in the form of growth factors and cytokines to downstream targets such as transcription factors within the nucleus. Here, using isothermal titration calorimetry (ITC) in combination with macromolecular modeling (MM), we show that although Gab1 contains four distinct RXXK motifs, designated G1, G2, G3, and G4, only G1 and G2 motifs bind to the cSH3 domain of Grb2 adaptor and do so with distinct mechanisms. Thus, while the G1 motif strictly requires the PPRPPKP consensus sequence for high-affinity binding to the cSH3 domain, the G2 motif displays preference for the PXVXRXLKPXR consensus. Such sequential differences in the binding of G1 and G2 motifs arise from their ability to adopt distinct polyproline type II (PPII)- and 3(10) -helical conformations upon binding to the cSH3 domain, respectively. Collectively, our study provides detailed biophysical insights into a key protein-protein interaction involved in a diverse array of signaling cascades central to health and disease. Copyright © 2010 John Wiley & Sons, Ltd.

Distinct uptake mechanisms but similar intracellular processing of two different toll-like receptor ligand-peptide conjugates in dendritic cells.

Science.gov (United States)

Khan, Selina; Bijker, Martijn S; Weterings, Jimmy J; Tanke, Hans J; Adema, Gosse J; van Hall, Thorbald; Drijfhout, Jan W; Melief, Cornelis J M; Overkleeft, Hermen S; van der Marel, Gijsbert A; Filippov, Dmitri V; van der Burg, Sjoerd H; Ossendorp, Ferry

2007-07-20

Covalent conjugation of Toll-like receptor ligands (TLR-L) to synthetic antigenic peptides strongly improves antigen presentation in vitro and T lymphocyte priming in vivo. These molecularly well defined TLR-L-peptide conjugates, constitute an attractive vaccination modality, sharing the peptide antigen and a defined adjuvant in one single molecule. We have analyzed the intracellular trafficking and processing of two TLR-L conjugates in dendritic cells (DCs). Long synthetic peptides containing an ovalbumin cytotoxic T-cell epitope were chemically conjugated to two different TLR-Ls the TLR2 ligand, Pam(3)CysSK(4) (Pam) or the TLR9 ligand CpG. Rapid and enhanced uptake of both types of TLR-L-conjugated peptide occurred in DCs. Moreover, TLR-L conjugation greatly enhanced antigen presentation, a process that was dependent on endosomal acidification, proteasomal cleavage, and TAP translocation. The uptake of the CpG approximately conjugate was independent of endosomally-expressed TLR9 as reported previously. Unexpectedly, we found that Pam approximately conjugated peptides were likewise internalized independently of the expression of cell surface-expressed TLR2. Further characterization of the uptake mechanisms revealed that TLR2-L employed a different uptake route than TLR9-L. Inhibition of clathrin- or caveolin-dependent endocytosis greatly reduced uptake and antigen presentation of the Pam-conjugate. In contrast, internalization and antigen presentation of CpG approximately conjugates was independent of clathrin-coated pits but partly dependent on caveolae formation. Importantly, in contrast to the TLR-independent uptake of the conjugates, TLR expression and downstream TLR signaling was required for dendritic cell maturation and for priming of naïve CD8(+) T-cells. Together, our data show that targeting to two distinct TLRs requires distinct uptake mechanism but follows similar trafficking and intracellular processing pathways leading to optimal antigen

Laboratory and 3-D distinct element analysis of the failure mechanism of a slope under external surcharge

Science.gov (United States)

Li, N.; Cheng, Y. M.

2015-01-01

Landslide is a major disaster resulting in considerable loss of human lives and property damages in hilly terrain in Hong Kong, China and many other countries. The factor of safety and the critical slip surface for slope stabilization are the main considerations for slope stability analysis in the past, while the detailed post-failure conditions of the slopes have not been considered in sufficient detail. There is however increasing interest in the consequences after the initiation of failure that includes the development and propagation of the failure surfaces, the amount of failed mass and runoff and the affected region. To assess the development of slope failure in more detail and to consider the potential danger of slopes after failure has initiated, the slope stability problem under external surcharge is analyzed by the distinct element method (DEM) and a laboratory model test in the present research. A more refined study about the development of failure, microcosmic failure mechanisms and the post-failure mechanisms of slopes will be carried out. The numerical modeling method and the various findings from the present work can provide an alternate method of analysis of slope failure, which can give additional information not available from the classical methods of analysis.

Do Payment Mechanisms Change the Way Consumers Perceive Products?

OpenAIRE

Promothesh Chatterjee; Randall L. Rose

2012-01-01

Do payment mechanisms change the way consumers perceive products? We argue that consumers for whom credit cards (cash) have been primed focus more on benefits (costs) when evaluating a product. In study 1, credit card (cash) primed participants made more (fewer) recall errors regarding cost attributes. In a word recognition task (study 2), participants primed with credit card (cash) identified more words related to benefits (costs) than those in the cash (credit card) condition. In study 3, p...

TLR2-dependent inhibition of macrophage responses to IFN-gamma is mediated by distinct, gene-specific mechanisms.

Directory of Open Access Journals (Sweden)

Sarah A Benson

2009-07-01

Full Text Available Mycobacterium tuberculosis uses multiple mechanisms to avoid elimination by the immune system. We have previously shown that M. tuberculosis can inhibit selected macrophage responses to IFN-gamma through TLR2-dependent and -independent mechanisms. To specifically address the role of TLR2 signaling in mediating this inhibition, we stimulated macrophages with the specific TLR2/1 ligand Pam(3CSK(4 and assayed responses to IFN-gamma. Pam(3CSK(4 stimulation prior to IFN-gamma inhibited transcription of the unrelated IFN-gamma-inducible genes, CIITA and CXCL11. Surface expression of MHC class II and secretion of CXCL11 were greatly reduced as well, indicating that the reduction in transcripts had downstream effects. Inhibition of both genes required new protein synthesis. Using chromatin immunoprecipitation, we found that TLR2 stimulation inhibited IFN-gamma-induced RNA polymerase II binding to the CIITA and CXCL11 promoters. Furthermore, TATA binding protein was unable to bind the TATA box of the CXCL11 promoter, suggesting that assembly of transcriptional machinery was disrupted. However, TLR2 stimulation affected chromatin modifications differently at each of the inhibited promoters. Histone H3 and H4 acetylation was reduced at the CIITA promoter but unaffected at the CXCL11 promoter. In addition, NF-kappaB signaling was required for inhibition of CXCL11 transcription, but not for inhibition of CIITA. Taken together, these results indicate that TLR2-dependent inhibition of IFN-gamma-induced gene expression is mediated by distinct, gene-specific mechanisms that disrupt binding of the transcriptional machinery to the promoters.

Commonalities and distinctions among mechanisms of addiction to alcohol and other drugs

Science.gov (United States)

Ozburn, Angela R.; Janowsky, Aaron J.; Crabbe, John C.

2015-01-01

Alcohol abuse is comorbid with abuse of many other drugs, some with similar pharmacology and others quite different. This leads to the hypothesis of an underlying, unitary dysfunctional neurobiological basis for substance abuse risk and consequences. In this review, we discuss commonalities and distinctions of addiction to alcohol and other drugs. We focus on recent advances in pre-clinical studies using rodent models of drug self-administration. While there are specific behavioral and molecular manifestations common to alcohol, psychostimulant, opioid, and nicotine dependence, attempts to propose a unifying theory of the addictions inevitably face details where distinctions are found among classes of drugs. For alcohol, versus other drugs of abuse, we discuss and compare advances in: 1) neurocircuitry important for the different stages of drug dependence; 2) transcriptomics and genetical genomics; and 3) enduring effects. We note in particular the contributions of behavioral genetics and animal models: discussions of progress specifically relevant to treatment development can be found in the accompanying review (Karoly et al, this issue). PMID:26431116

Modeling of Gas Production from Shale Reservoirs Considering Multiple Transport Mechanisms.

Directory of Open Access Journals (Sweden)

Chaohua Guo

Full Text Available Gas transport in unconventional shale strata is a multi-mechanism-coupling process that is different from the process observed in conventional reservoirs. In micro fractures which are inborn or induced by hydraulic stimulation, viscous flow dominates. And gas surface diffusion and gas desorption should be further considered in organic nano pores. Also, the Klinkenberg effect should be considered when dealing with the gas transport problem. In addition, following two factors can play significant roles under certain circumstances but have not received enough attention in previous models. During pressure depletion, gas viscosity will change with Knudsen number; and pore radius will increase when the adsorption gas desorbs from the pore wall. In this paper, a comprehensive mathematical model that incorporates all known mechanisms for simulating gas flow in shale strata is presented. The objective of this study was to provide a more accurate reservoir model for simulation based on the flow mechanisms in the pore scale and formation geometry. Complex mechanisms, including viscous flow, Knudsen diffusion, slip flow, and desorption, are optionally integrated into different continua in the model. Sensitivity analysis was conducted to evaluate the effect of different mechanisms on the gas production. The results showed that adsorption and gas viscosity change will have a great impact on gas production. Ignoring one of following scenarios, such as adsorption, gas permeability change, gas viscosity change, or pore radius change, will underestimate gas production.

Distinct pharmacology and metabolism of K2 synthetic cannabinoids compared to Δ9-THC: Mechanism underlying greater toxicity?

Science.gov (United States)

Fantegrossi, William E.; Moran, Jeffery H.; Radominska-Pandya, Anna; Prather, Paul L.

2013-01-01

K2 or Spice products are emerging drugs of abuse that contain synthetic cannabinoids (SCBs). Although assumed by many teens and first time drug users to be a “safe” and “legal” alternative to marijuana, many recent reports indicate that SCBs present in K2 produce toxicity not associated with the primary psychoactive component of marijuana, Δ9-tetrahydrocannabinol (Δ9-THC). This mini-review will summarize recent evidence that use of K2 products poses greater health risks relative to marijuana, and suggest that distinct pharmacological properties and metabolism of SCBs relative to Δ9-THC may contribute to the observed toxicity. Studies reviewed will indicate that in contrast to partial agonist properties of Δ9-THC typically observed in vitro, SCBs in K2 products act as full cannabinoid receptor type 1 (CB1R) and type 2 (CB2R) agonists in both cellular assays and animal studies. Furthermore, unlike Δ9-THC metabolism, several SCB metabolites retain high affinity for, and exhibit a range of intrinsic activities at, CB1 and CB2Rs. Finally, several reports indicate that although quasi-legal SCBs initially evaded detection and legal consequences, these presumed “advantages” have been limited by new legislation and development of product and human testing capabilities. Collectively, evidence reported in this mini-review suggests that K2 products are neither safe nor legal alternatives to marijuana. Instead, enhanced toxicity of K2 products relative to marijuana, perhaps resulting from the combined actions of a complex mixture of different SCBs present and their active metabolites that retain high affinity for CB1 and CB2Rs, highlights the inherent danger that may accompany use of these substances. PMID:24084047

Distinct pharmacology and metabolism of K2 synthetic cannabinoids compared to Δ(9)-THC: mechanism underlying greater toxicity?

Science.gov (United States)

Fantegrossi, William E; Moran, Jeffery H; Radominska-Pandya, Anna; Prather, Paul L

2014-02-27

K2 or Spice products are emerging drugs of abuse that contain synthetic cannabinoids (SCBs). Although assumed by many teens and first time drug users to be a "safe" and "legal" alternative to marijuana, many recent reports indicate that SCBs present in K2 produce toxicity not associated with the primary psychoactive component of marijuana, ∆(9)-tetrahydrocannabinol (Δ(9)-THC). This mini-review will summarize recent evidence that use of K2 products poses greater health risks relative to marijuana, and suggest that distinct pharmacological properties and metabolism of SCBs relative to Δ(9)-THC may contribute to the observed toxicity. Studies reviewed will indicate that in contrast to partial agonist properties of Δ(9)-THC typically observed in vitro, SCBs in K2 products act as full cannabinoid receptor type 1 (CB1R) and type 2 (CB2R) agonists in both cellular assays and animal studies. Furthermore, unlike Δ(9)-THC metabolism, several SCB metabolites retain high affinity for, and exhibit a range of intrinsic activities at, CB1 and CB2Rs. Finally, several reports indicate that although quasi-legal SCBs initially evaded detection and legal consequences, these presumed "advantages" have been limited by new legislation and development of product and human testing capabilities. Collectively, evidence reported in this mini-review suggests that K2 products are neither safe nor legal alternatives to marijuana. Instead, enhanced toxicity of K2 products relative to marijuana, perhaps resulting from the combined actions of a complex mixture of different SCBs present and their active metabolites that retain high affinity for CB1 and CB2Rs, highlights the inherent danger that may accompany use of these substances. © 2013.

Mechanical properties of layers of corrosion products at steel / concrete interface

International Nuclear Information System (INIS)

Dehoux, Anita

2012-01-01

To take account of the development of corrosion products layers in residual lifetime calculations of reinforced concrete structures requires a good knowledge of the mechanical properties of these products. Our study aims to determine the mechanical properties of layers of corrosion products. The approach consists of an identification of the microstructure properties complemented by homogenization calculations to calculate a mesoscopic behavior in linear elasticity of layers of corrosion products. The study includes a series of experimental campaigns at the microscopic scale. Vickers micro indentation tests analyzed by a Gaussian mixture model approach allowed the acquisition of hardness and elastic moduli at the microscale. An identification of the microstructure products is performed by Raman microspectrometry. The microstructure's characterization brings valuable information for homogenization calculations. The first approach has consisted of calculations of random media homogenization by self-consistent and generalized self-consistent schemes. In the second approach, effective modulus calculations were performed using numerical microstructures resulting from 2D images taken with an optical microscope. The corpus is composed of samples of different ages and origins, their microstructures were compared. (author) [fr

Effort Flow Analysis: A Methodology for Directed Product Evolution Using Rigid Body and Compliant Mechanisms

National Research Council Canada - National Science Library

Greer, James

2002-01-01

This dissertation presents a systematic design methodology for directed product evolution that uses both rigid body and compliant mechanisms to facilitate component combination in the domain of mechanical products...

Integrative modelling reveals mechanisms linking productivity and plant species richness.

Science.gov (United States)

Grace, James B; Anderson, T Michael; Seabloom, Eric W; Borer, Elizabeth T; Adler, Peter B; Harpole, W Stanley; Hautier, Yann; Hillebrand, Helmut; Lind, Eric M; Pärtel, Meelis; Bakker, Jonathan D; Buckley, Yvonne M; Crawley, Michael J; Damschen, Ellen I; Davies, Kendi F; Fay, Philip A; Firn, Jennifer; Gruner, Daniel S; Hector, Andy; Knops, Johannes M H; MacDougall, Andrew S; Melbourne, Brett A; Morgan, John W; Orrock, John L; Prober, Suzanne M; Smith, Melinda D

2016-01-21

How ecosystem productivity and species richness are interrelated is one of the most debated subjects in the history of ecology. Decades of intensive study have yet to discern the actual mechanisms behind observed global patterns. Here, by integrating the predictions from multiple theories into a single model and using data from 1,126 grassland plots spanning five continents, we detect the clear signals of numerous underlying mechanisms linking productivity and richness. We find that an integrative model has substantially higher explanatory power than traditional bivariate analyses. In addition, the specific results unveil several surprising findings that conflict with classical models. These include the isolation of a strong and consistent enhancement of productivity by richness, an effect in striking contrast with superficial data patterns. Also revealed is a consistent importance of competition across the full range of productivity values, in direct conflict with some (but not all) proposed models. The promotion of local richness by macroecological gradients in climatic favourability, generally seen as a competing hypothesis, is also found to be important in our analysis. The results demonstrate that an integrative modelling approach leads to a major advance in our ability to discern the underlying processes operating in ecological systems.

Mechanisms of yeast stress tolerance and its manipulation for efficient fuel ethanol production.

Science.gov (United States)

Zhao, X Q; Bai, F W

2009-10-12

Yeast strains of Saccharomyces cerevisiae have been extensively studied in recent years for fuel ethanol production, in which yeast cells are exposed to various stresses such as high temperature, ethanol inhibition, and osmotic pressure from product and substrate sugars as well as the inhibitory substances released from the pretreatment of lignocellulosic biomass. An in-depth understanding of the mechanism of yeast stress tolerance contributes to breeding more robust strains for ethanol production, especially under very high gravity conditions. Taking advantage of the "omics" technology, the stress response and defense mechanism of yeast cells during ethanol fermentation were further explored, and the newly emerged tools such as genome shuffling and global transcription machinery engineering have been applied to breed stress resistant yeast strains for ethanol production. In this review, the latest development of stress tolerance mechanisms was focused, and improvement of yeast stress tolerance by both random and rational tools was presented.

Appropriability mechanisms, innovation and productivity: Evidence from the UK

NARCIS (Netherlands)

Hall, B.H.; Sena, V.

2014-01-01

We use an extended version of the well-established Crepon, Duguet and Mairesse model (1998) to model the relationship between appropriability mechanisms, innovation and firm-level productivity. We enrich this model in several ways. First, we consider different types of innovation spending and study

Quantum mechanical signature in exclusive coherent pion production

Science.gov (United States)

Deutchman, P. A.; Buvel, R. L.; Maung, K. M.; Norbury, J. W.; Townsend, L. W.

1986-01-01

We calculate the coherent production of pions from subthreshold to relativistic energies in heavy-ion collisions using a quantum, microscopic, many-body model. For the first time, in this approach, we use harmonic oscillator wave functions to describe shell-model information. The theoretical quantum mechanical results obtained for the pion spectra represent an important improvement over our previous microscopic, many-body calculations.

Understanding and imitating unfamiliar actions: distinct underlying mechanisms.

Directory of Open Access Journals (Sweden)

Joana C Carmo

Full Text Available The human "mirror neuron system" has been proposed to be the neural substrate that underlies understanding and, possibly, imitating actions. However, since the brain activity with mirror properties seems insufficient to provide a good description for imitation of actions outside one's own repertoire, the existence of supplementary processes has been proposed. Moreover, it is unclear whether action observation requires the same neural mechanisms as the explicit access to their meaning. The aim of this study was two-fold as we investigated whether action observation requires different processes depending on 1 whether the ultimate goal is to imitate or understand the presented actions and 2 whether the to-be-imitated actions are familiar or unfamiliar to the subject. Participants were presented with both meaningful familiar actions and meaningless unfamiliar actions that they had to either imitate or discriminate later. Event-related Potentials were used as differences in brain activity could have been masked by the use of other techniques with lower temporal resolution. In the imitation task, a sustained left frontal negativity was more pronounced for meaningless actions than for meaningful ones, starting from an early time-window. Conversely, observing unfamiliar versus familiar actions with the intention of discriminating them led to marked differences over right centro-posterior scalp regions, in both middle and latest time-windows. These findings suggest that action imitation and action understanding may be sustained by dissociable mechanisms: while imitation of unfamiliar actions activates left frontal processes, that are likely to be related to learning mechanisms, action understanding involves dedicated operations which probably require right posterior regions, consistent with their involvement in social interactions.

Distinct mechanisms act in concert to mediate cell cycle arrest.

Science.gov (United States)

Toettcher, Jared E; Loewer, Alexander; Ostheimer, Gerard J; Yaffe, Michael B; Tidor, Bruce; Lahav, Galit

2009-01-20

In response to DNA damage, cells arrest at specific stages in the cell cycle. This arrest must fulfill at least 3 requirements: it must be activated promptly; it must be sustained as long as damage is present to prevent loss of genomic information; and after the arrest, cells must re-enter into the appropriate cell cycle phase to ensure proper ploidy. Multiple molecular mechanisms capable of arresting the cell cycle have been identified in mammalian cells; however, it is unknown whether each mechanism meets all 3 requirements or whether they act together to confer specific functions to the arrest. To address this question, we integrated mathematical models describing the cell cycle and the DNA damage signaling networks and tested the contributions of each mechanism to cell cycle arrest and re-entry. Predictions from this model were then tested with quantitative experiments to identify the combined action of arrest mechanisms in irradiated cells. We find that different arrest mechanisms serve indispensable roles in the proper cellular response to DNA damage over time: p53-independent cyclin inactivation confers immediate arrest, whereas p53-dependent cyclin downregulation allows this arrest to be sustained. Additionally, p21-mediated inhibition of cyclin-dependent kinase activity is indispensable for preventing improper cell cycle re-entry and endoreduplication. This work shows that in a complex signaling network, seemingly redundant mechanisms, acting in a concerted fashion, can achieve a specific cellular outcome.

The Code Aster: a product for mechanical engineers

International Nuclear Information System (INIS)

Levesque, J.R.

1998-01-01

The Code Aster is a 2D or 3D structural finite element software: analysis of structures and thermo-mechanics for evaluation and research with linear for non linear modelling. Since 1989, it has been the host structure that capitalizes on developments made by the Research and Development Division in the field of numerical modelling in structural mechanics, and user experience feedback. It is an industrial design tool, particularly for engineering of facilities in operation and for the evaluation of new projects. This software was developed using a quality Assurance methodology with independent validation. Upgrades to this product are guided by the objective of satisfying the needs of expertise studies, attempting to make functions coherent and complete. (author)

Movement goals and feedback and feedforward control mechanisms in speech production.

Science.gov (United States)

Perkell, Joseph S

2012-09-01

Studies of speech motor control are described that support a theoretical framework in which fundamental control variables for phonemic movements are multi-dimensional regions in auditory and somatosensory spaces. Auditory feedback is used to acquire and maintain auditory goals and in the development and function of feedback and feedforward control mechanisms. Several lines of evidence support the idea that speakers with more acute sensory discrimination acquire more distinct goal regions and therefore produce speech sounds with greater contrast. Feedback modification findings indicate that fluently produced sound sequences are encoded as feedforward commands, and feedback control serves to correct mismatches between expected and produced sensory consequences.

Relative importance of nitrate and sulfate aerosol production mechanisms in urban atmospheres

International Nuclear Information System (INIS)

Middleton, P.; Kiang, C.S.

1979-01-01

The relative importance of the various sulfate and nitrate aerosol production mechanisms is calculated for different atmospheric conditions. The calculation scheme used to determine the rates of nitrate and sulfate production, based on the concept that vapor transfer to the aerosols and nitrate and sulfate formation within the aerosols are coupled kinetic processes, considers sulfate formation by ozone and hydrogen peroxide oxidation and catalytic oxidation in the presence of soot, iron and manganese of sulfite solutions and sulfuric acid condensation and nitrate formation by the liquid-phase oxidation of dissolved nitrogen oxides for different initial gas concentrations and particle compositions and sizes. It is found that sulfate production is higher under daytime conditions, primarily proceeding by mechanisms involving sulfuric acid and hydrogen peroxide, while at night oxidation processes on the surface of the aerosol film are more important. Nitrate tends to decrease nighttime sulfate production due to an increase in aerosol acidity and nitrate production is found to be higher under nighttime conditions and in the winter

Medically important differences in snake venom composition are dictated by distinct postgenomic mechanisms.

Science.gov (United States)

Casewell, Nicholas R; Wagstaff, Simon C; Wüster, Wolfgang; Cook, Darren A N; Bolton, Fiona M S; King, Sarah I; Pla, Davinia; Sanz, Libia; Calvete, Juan J; Harrison, Robert A

2014-06-24

Variation in venom composition is a ubiquitous phenomenon in snakes and occurs both interspecifically and intraspecifically. Venom variation can have severe outcomes for snakebite victims by rendering the specific antibodies found in antivenoms ineffective against heterologous toxins found in different venoms. The rapid evolutionary expansion of different toxin-encoding gene families in different snake lineages is widely perceived as the main cause of venom variation. However, this view is simplistic and disregards the understudied influence that processes acting on gene transcription and translation may have on the production of the venom proteome. Here, we assess the venom composition of six related viperid snakes and compare interspecific changes in the number of toxin genes, their transcription in the venom gland, and their translation into proteins secreted in venom. Our results reveal that multiple levels of regulation are responsible for generating variation in venom composition between related snake species. We demonstrate that differential levels of toxin transcription, translation, and their posttranslational modification have a substantial impact upon the resulting venom protein mixture. Notably, these processes act to varying extents on different toxin paralogs found in different snakes and are therefore likely to be as important as ancestral gene duplication events for generating compositionally distinct venom proteomes. Our results suggest that these processes may also contribute to altering the toxicity of snake venoms, and we demonstrate how this variability can undermine the treatment of a neglected tropical disease, snakebite.

Increased serum advanced glycation end-products is a distinct finding in lean women with polycystic ovary syndrome (PCOS).

Science.gov (United States)

Diamanti-Kandarakis, Evanthia; Katsikis, Ilias; Piperi, Christina; Kandaraki, Eleni; Piouka, Athanasia; Papavassiliou, Athanasios G; Panidis, Dimitrios

2008-10-01

Nonenzymatic advanced glycation and oxidation end-products, advanced glycation end-products (AGEs), impart a potent impact on vessels and other tissues in diabetic state and in euglycaemic conditions with increased oxidative stress. Insulin resistant (IR) polycystic ovary syndrome (PCOS) women, have elevated serum AGEs, increased receptor (RAGE) expression, and increased deposition with differential localization in the polycystic ovarian tissue (theca and granulosa) compared to normal. To determine whether the raised AGE levels in noninsulin resistant women with PCOS is a distinct finding compared with those presenting the isolated components of the syndrome and among PCOS subphenotypes. Noninsulin resistant women were selected in order to show that serum AGEs are elevated in PCOS independently of the presence of IR. Clinical trial. One hundred and ninety-three age- and BMI-matched young lean noninsulin resistant women were studied. Among them, 100 women were diagnosed with PCOS according to Rotterdam criteria, and divided to subphenotypes (hyperandrogenaemia with or without PCO morphology and with or without anovulation). Sixty-eight women with the isolated components of the PCOS phenotype were also studied along with 25 healthy women. Serum AGE levels, metabolic, hormonal profiles and intravaginal ultrasound were determined in all subjects. The studied population did not differ in BMI, fasting insulin concentration, waist : hip and glucose : insulin ratios. PCOS women exhibited statistically higher AGEs levels (7.96 +/- 1.87 U/ml, P PCOS, serum AGEs are distinctly elevated compared with women having the isolated characteristics of the syndrome. No difference was observed between PCOS subphenotypes. As chronic inflammation and increased oxidant stress have been incriminated in the pathophysiology of PCOS, the role of AGEs as inflammatory and oxidant mediators, may be linked with the metabolic and reproductive abnormalities of the syndrome.

Radial frequency stimuli and sine-wave gratings seem to be processed by distinct contrast brain mechanisms

Directory of Open Access Journals (Sweden)

M.L.B. Simas

2005-03-01

Full Text Available An assumption commonly made in the study of visual perception is that the lower the contrast threshold for a given stimulus, the more sensitive and selective will be the mechanism that processes it. On the basis of this consideration, we investigated contrast thresholds for two classes of stimuli: sine-wave gratings and radial frequency stimuli (i.e., j0 targets or stimuli modulated by spherical Bessel functions. Employing a suprathreshold summation method, we measured the selectivity of spatial and radial frequency filters using either sine-wave gratings or j0 target contrast profiles at either 1 or 4 cycles per degree of visual angle (cpd, as the test frequencies. Thus, in a forced-choice trial, observers chose between a background spatial (or radial frequency alone and the given background stimulus plus the test frequency (1 or 4 cpd sine-wave grating or radial frequency. Contrary to our expectations, the results showed elevated thresholds (i.e., inhibition for sine-wave gratings and decreased thresholds (i.e., summation for radial frequencies when background and test frequencies were identical. This was true for both 1- and 4-cpd test frequencies. This finding suggests that sine-wave gratings and radial frequency stimuli are processed by different quasi-linear systems, one working at low luminance and contrast level (sine-wave gratings and the other at high luminance and contrast levels (radial frequency stimuli. We think that this interpretation is consistent with distinct foveal only and foveal-parafoveal mechanisms involving striate and/or other higher visual areas (i.e., V2 and V4.

Distinct evolutionary mechanisms for genomic imbalances in high-risk and low-risk neuroblastomas

Directory of Open Access Journals (Sweden)

Gisselsson David

2007-09-01

Full Text Available Abstract Background Neuroblastoma (NB is the most common extracranial solid tumour of childhood. Several genomic imbalances correlate to prognosis in NB, with structural rearrangements, including gene amplification, in a near-diploid setting typically signifying high-risk tumours and numerical changes in a near-triploid setting signifying low-risk tumours. Little is known about the temporal sequence in which these imbalances occur during the carcinogenic process. Methods We have reconstructed the appearance of cytogenetic imbalances in 270 NBs by first grouping tumours and imbalances through principal component analysis and then using the number of imbalances in each tumour as an indicator of evolutionary progression. Results Tumours clustered in four sub-groups, dominated respectively by (1 gene amplification in double minute chromosomes and few other aberrations, (2 gene amplification and loss of 1p sequences, (3 loss of 1p and other structural aberrations including gain of 17q, and (4 whole-chromosome gains and losses. Temporal analysis showed that the structural changes in groups 1–3 were acquired in a step-wise fashion, with loss of 1p sequences and the emergence of double minute chromosomes as the earliest cytogenetic events. In contrast, the gains and losses of whole chromosomes in group 4 occurred through multiple simultaneous events leading to a near-triploid chromosome number. Conclusion The finding of different temporal patterns for the acquisition of genomic imbalances in high-risk and low-risk NBs lends strong support to the hypothesis that these tumours are biologically diverse entities, evolving through distinct genetic mechanisms.

Soluble immune complexes shift the TLR-induced cytokine production of distinct polarized human macrophage subsets towards IL-10.

Directory of Open Access Journals (Sweden)

Carmen A Ambarus

Full Text Available BACKGROUND: Costimulation of murine macrophages with immune complexes (ICs and TLR ligands leads to alternative activation. Studies on human myeloid cells, however, indicate that ICs induce an increased pro-inflammatory cytokine production. This study aimed to clarify the effect of ICs on the pro- versus anti-inflammatory profile of human polarized macrophages. MATERIALS AND METHODS: Monocytes isolated from peripheral blood of healthy donors were polarized for four days with IFN-γ, IL-4, IL-10, GM-CSF, M-CSF, or LPS, in the presence or absence of heat aggregated gamma-globulins (HAGGs. Phenotypic polarization markers were measured by flow cytometry. Polarized macrophages were stimulated with HAGGs or immobilized IgG alone or in combination with TLR ligands. TNF, IL-6, IL-10, IL-12, and IL-23 were measured by Luminex and/or RT-qPCR. RESULTS: HAGGs did not modulate the phenotypic polarization and the cytokine production of macrophages. However, HAGGs significantly altered the TLR-induced cytokine production of all polarized macrophage subsets, with the exception of MΦ(IL-4. In particular, HAGGs consistently enhanced the TLR-induced IL-10 production in both classically and alternatively polarized macrophages (M1 and M2. The effect of HAGGs on TNF and IL-6 production was less pronounced and depended on the polarization status, while IL-23p19 and IL-12p35 expression was not affected. In contrast with HAGGs, immobilized IgG induced a strong upregulation of not only IL-10, but also TNF and IL-6. CONCLUSION: HAGGs alone do not alter the phenotype and cytokine production of in vitro polarized human macrophages. In combination with TLR-ligands, however, HAGGs but not immobilized IgG shift the cytokine production of distinct macrophage subsets toward IL-10.

Corrosion mechanisms of containment glasses for fission products

International Nuclear Information System (INIS)

Nogues, J.L.

1984-01-01

After a review of nuclear energy production and waste vitrification principles, the aqueous corrosion mechanisms of the containment glasses and the various parameters affecting the corrosion are studied: effects of glass composition, temperature, lixiviation agent pH, lixiviation duration and mode. Conventional mass loss measurement and solution analyses are coupled to sophisticated surface analysis techniques. The hydrolyzed layer formation and the solubility limits are discussed. 87 figs., 30 tabs., 144 refs

Distinct mechanisms regulate Lck spatial organization in activated T cells

Directory of Open Access Journals (Sweden)

Natasha eKapoor-Kaushik

2016-03-01

Full Text Available Phosphorylation of the T cell receptor (TCR by the kinase Lck is the first detectable signaling event upon antigen engagement. The distribution of Lck within the plasma membrane, its conformational state, kinase activity and protein interactions all contribute to determine how efficiently Lck phosphorylates the engaged TCR. Here we used cross-correlation raster image spectroscopy (ccRICS and photoactivated localization microscopy (PALM to identify two mechanisms of Lck clustering: an intrinsic mechanism of Lck clustering induced by locking Lck in its open conformation, and an extrinsic mechanism of clustering controlled by the phosphorylation of tyrosine 192, which regulates the affinity of Lck SH2 domain. Both mechanisms of clustering were differently affected by the absence of the kinase Zap70 or the adaptor Lat. We further observed that the adaptor TSAd bound to and promoted the diffusion of Lck when it is phosphorylated on tyrosine 192. Our data suggest that while Lck open conformation drives aggregation and clustering, the spatial organization of Lck is further controlled by signaling events downstream of TCR phosphorylation.

Particle-production mechanism in relativistic heavy-ion collisions

International Nuclear Information System (INIS)

Bush, B.W.; Nix, J.R.

1994-01-01

We discuss the production of particles in relativistic heavy-ion collisions through the mechanism of massive bremsstrahlung, in which massive mesons are emitted during rapid nucleon acceleration. This mechanism is described within the framework of classical hadrodynamics for extended nucleons, corresponding to nucleons of finite size interacting with massive meson fields. This new theory provides a natural covariant microscopic approach to relativistic heavy-ion collisions that includes automatically spacetime nonlocality and retardation, nonequilibrium phenomena, interactions among all nucleons, and particle production. Inclusion of the finite nucleon size cures the difficulties with preacceleration and runaway solutions that have plagued the classical theory of self-interacting point particles. For the soft reactions that dominate nucleon-nucleon collisions, a significant fraction of the incident center-of-mass energy is radiated through massive bremsstrahlung. In the present version of the theory, this radiated energy is in the form of neutral scalar (σ) and neutral vector (ω) mesons, which subsequently decay primarily into pions with some photons also. Additional meson fields that are known to be important from nucleon-nucleon scattering experiments should be incorporated in the future, in which case the radiated energy would also contain isovector pseudoscalar (π + , π - , π 0 ), isovector scalar (δ + , δ - , δ 0 ), isovector vector (ρ + , ρ - , ρ 0 ), and neutral pseudoscalar (η) mesons

Congenital amusics use a secondary pitch mechanism to identify lexical tones.

Science.gov (United States)

Bones, Oliver; Wong, Patrick C M

2017-09-01

Amusia is a pitch perception disorder associated with deficits in processing and production of both musical and lexical tones, which previous reports have suggested may be constrained to fine-grained pitch judgements. In the present study speakers of tone-languages, in which lexical tones are used to convey meaning, identified words present in chimera stimuli containing conflicting pitch-cues in the temporal fine-structure and temporal envelope, and which therefore conveyed two distinct utterances. Amusics were found to be more likely than controls to judge the word according to the envelope pitch-cues. This demonstrates that amusia is not associated with fine-grained pitch judgements alone, and is consistent with there being two distinct pitch mechanisms and with amusics having an atypical reliance on a secondary mechanism based upon envelope cues. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

(η-η'-ι)-mixing, decay and production mechanisms

International Nuclear Information System (INIS)

Geiger, K.; Mueller, B.; Greiner, W.

1990-01-01

We present a phenomenoligcal model for meson-glueball mixing and apply it to the mixing of the pseudoscalar mesons η and η' with the ι(1440)-particle as the prime candidate for a O -+ -glueball. Using the MIT bag model framework, our model incorporates, among other elements, configuration mixing effects due to virtually excited states, as well as mixing of quark and gluon components. We evaluate the portions of quark-antiquark and two-gluon admixtures in η, η' and ι. The results are used to study various decay and production processes involving these particles. In particular, we calculate the radiative and the 2γ-decay widths of the light mesons and make predictions for the widths of the ι in these channels. Furthermore, production mechanisms of the light mesons in electromagnetic and hadronic J/ψ-decays are used to evaluate the branching ratios for the production of the ι in various J/ψ-transitions. Our results are generally in reasonable agreement with experimental data. Especially we predict a rather large width for the decay ι→ργ and a sizable production rate for the ι in the transition J/ψ-ωι. (orig.)

Both differences in encoding processes and monitoring at retrieval reduce false alarms when distinctive information is studied.

Science.gov (United States)

Hanczakowski, Maciej; Mazzoni, Giuliana

2011-04-01

A reduction in false alarms to critical lures is observed in the DRM paradigm (Roediger & McDermott, 1995) when distinctive information is presented at encoding. Two mechanisms have been proposed to account for this reduction. According to the monitoring theory (e.g., the distinctiveness heuristic), lack of diagnostic recollection serves as a basis for discarding non-presented lures. According to the encoding theory, presenting distinctive information at study leads to impoverished relational processing, which results in a reduction in memorial information elicited by critical lures. In the present study a condition was created in which the use of the distinctiveness heuristic was precluded by associating, within the same study, lures with distinctive information in a context different from the study session. Under that condition reduction in false alarms to distinctive critical lures was still observed. This result supports the predictions of the encoding theory. However, when in the same study the use of the distinctiveness heuristic was not precluded, reductions in false alarms to unrelated lures were also observed when distinctive information was presented at study, indicating that both mechanisms are likely to contribute to the rejection of false memories.

Increasing energy efficiency level of building production based on applying modern mechanization facilities

Science.gov (United States)

Prokhorov, Sergey

2017-10-01

Building industry in a present day going through the hard times. Machine and mechanism exploitation cost, on a field of construction and installation works, takes a substantial part in total building construction expenses. There is a necessity to elaborate high efficient method, which allows not only to increase production, but also to reduce direct costs during machine fleet exploitation, and to increase its energy efficiency. In order to achieve the goal we plan to use modern methods of work production, hi-tech and energy saving machine tools and technologies, and use of optimal mechanization sets. As the optimization criteria there are exploitation prime cost and set efficiency. During actual task-solving process we made a conclusion, which shows that mechanization works, energy audit with production juxtaposition, prime prices and costs for energy resources allow to make complex machine fleet supply, improve ecological level and increase construction and installation work quality.

Embryo mechanics: balancing force production with elastic resistance during morphogenesis.

Science.gov (United States)

Davidson, Lance A

2011-01-01

Morphogenesis requires the spatial and temporal control of embryo mechanics, including force production and mechanical resistance to those forces, to coordinate tissue deformation and large-scale movements. Thus, biomechanical processes play a key role in directly shaping the embryo. Additional roles for embryo mechanics during development may include the patterning of positional information and to provide feedback to ensure the success of morphogenetic movements in shaping the larval body and organs. To understand the multiple roles of mechanics during development requires familiarity with engineering principles of the mechanics of structures, the viscoelastic properties of biomaterials, and the integration of force and stress within embryonic structures as morphogenesis progresses. In this chapter, we review the basic engineering principles of biomechanics as they relate to morphogenesis, introduce methods for quantifying embryo mechanics and the limitations of these methods, and outline a formalism for investigating the role of embryo mechanics in birth defects. We encourage the nascent field of embryo mechanics to adopt standard engineering terms and test methods so that studies of diverse organisms can be compared and universal biomechanical principles can be revealed. Copyright © 2011 Elsevier Inc. All rights reserved.

Pattern production through a chiral chasing mechanism

Science.gov (United States)

Woolley, Thomas E.

2017-09-01

Recent experiments on zebrafish pigmentation suggests that their typical black and white striped skin pattern is made up of a number of interacting chromatophore families. Specifically, two of these cell families have been shown to interact through a nonlocal chasing mechanism, which has previously been modeled using integro-differential equations. We extend this framework to include the experimentally observed fact that the cells often exhibit chiral movement, in that the cells chase, and run away, at angles different to the line connecting their centers. This framework is simplified through the use of multiple small limits leading to a coupled set of partial differential equations which are amenable to Fourier analysis. This analysis results in the production of dispersion relations and necessary conditions for a patterning instability to occur. Beyond the theoretical development and the production of new pattern planiforms we are able to corroborate the experimental hypothesis that the global pigmentation patterns can be dependent on the chirality of the chromatophores.

Mechanisms of Furfural Reduction on Metal Electrodes: Distinguishing Pathways for Selective Hydrogenation of Bioderived Oxygenates

International Nuclear Information System (INIS)

Chadderdon, Xiaotong H.; Chadderdon, David J.; Matthiesen, John E.

2017-01-01

Electrochemical reduction of biomass-derived platform molecules is an emerging route for the sustainable production of fuels and chemicals. Understanding gaps between reaction conditions, underlying mechanisms, and product selectivity have limited the rational design of active, stable, and selective catalyst systems. Here, the mechanisms of electrochemical reduction of furfural, an important biobased platform molecule and model for aldehyde reduction, are explored through a combination of voltammetry, preparative electrolysis, thiol-electrode modifications, and kinetic isotope studies. It is demonstrated that two distinct mechanisms are operable on metallic Cu electrodes in acidic electrolytes: (i) electrocatalytic hydrogenation (ECH) and (ii) direct electroreduction. The contributions of each mechanism to the observed product distribution are clarified by evaluating the requirement for direct chemical interactions with the electrode surface and the role of adsorbed hydrogen. Further analysis reveals that hydrogenation and hydrogenolysis products are generated by parallel ECH pathways. By understanding the underlying mechanisms it enables the manipulation of furfural reduction by rationally tuning the electrode potential, electrolyte pH, and furfural concentration to promote selective formation of important biobased polymer precursors and fuels.

Mechanisms of Furfural Reduction on Metal Electrodes: Distinguishing Pathways for Selective Hydrogenation of Bioderived Oxygenates.

Science.gov (United States)

Chadderdon, Xiaotong H; Chadderdon, David J; Matthiesen, John E; Qiu, Yang; Carraher, Jack M; Tessonnier, Jean-Philippe; Li, Wenzhen

2017-10-11

Electrochemical reduction of biomass-derived platform molecules is an emerging route for the sustainable production of fuels and chemicals. However, understanding gaps between reaction conditions, underlying mechanisms, and product selectivity have limited the rational design of active, stable, and selective catalyst systems. In this work, the mechanisms of electrochemical reduction of furfural, an important biobased platform molecule and model for aldehyde reduction, are explored through a combination of voltammetry, preparative electrolysis, thiol-electrode modifications, and kinetic isotope studies. It is demonstrated that two distinct mechanisms are operable on metallic Cu electrodes in acidic electrolytes: (i) electrocatalytic hydrogenation (ECH) and (ii) direct electroreduction. The contributions of each mechanism to the observed product distribution are clarified by evaluating the requirement for direct chemical interactions with the electrode surface and the role of adsorbed hydrogen. Further analysis reveals that hydrogenation and hydrogenolysis products are generated by parallel ECH pathways. Understanding the underlying mechanisms enables the manipulation of furfural reduction by rationally tuning the electrode potential, electrolyte pH, and furfural concentration to promote selective formation of important biobased polymer precursors and fuels.

Mechanism of Action of Lung Damage Caused by a Nanofilm Spray Product

DEFF Research Database (Denmark)

Larsen, Søren T.; Dallot, Constantin; Larsen, Susan W

2014-01-01

and identification of toxicological targets are important to perform rational and cost-effective toxicological studies. Thus, because the pulmonary surfactant system appears to be an important toxicological target for waterproofing spray products, study of surfactant inhibition could be included in toxicological...... during respiration. The active film-forming component used in the present spray product is also found in several other products on the market. Hence, it may be expected that these products may have a toxicity similar to the waterproofing product studied here. Elucidation of the toxicological mechanism...

Evidence and characterization of a glide-vowel distinction in American English

Directory of Open Access Journals (Sweden)

Zachary Scott Jaggers

2018-02-01

Full Text Available This study tests whether native speakers of American English exhibit a glide-vowel distinction ([j]-[i] in a speech elicitation experiment. When reading sentences out loud, participants’ pronunciations of 4 near-minimal pairs of pre-existing lexical items (e.g., 'Eston'[iə] vs. 'pneumon'[jə] exhibit significant differences when acoustically measured, confirming the presence of a [j]-[i] distinction. This distinction is also found to be productively extended to the production of 20 near-minimal pairs of nonce words (e.g., 'Súmia '→ [sumiə] vs. 'Fímya '→ [fimjə], diversified and balanced along different phonologically relevant factors of the surrounding environment. Multiple acoustic measurements are compared to test what aspects most consistently convey the distinction: F2 (frontness, F1 (height, intensity, vocalic sequence duration, transition earliness, and transition speed. This serves the purpose of documenting the distinction’s acoustic phonetic realization. It also serves in the comparison of phonological representations. Multiple types of previously proposed phonological representations are considered along with the competing predictions they generate regarding the acoustic measurements performed. Results suggest that the primary and most consistent characteristic of the distinction is earliness of transition into the following vowel, with results also suggesting that the [j] glide has a greater degree of constriction. The [j] glide is found to have a significantly 'less 'anterior articulation, challenging the application of a representation based on place or articulator differences that would predict [j] to be 'more 'anterior.

Mechanism of ascorbic acid interference in biochemical tests that use peroxide and peroxidase to generate chromophore.

Science.gov (United States)

Martinello, Flávia; Luiz da Silva, Edson

2006-11-01

Ascorbic acid interferes negatively in peroxidase-based tests (Trinder method). However, the precise mechanism remains unclear for tests that use peroxide, a phenolic compound and 4-aminophenazone (4-AP). We determined the chemical mechanism of this interference, by examining the effects of ascorbic acid in the reaction kinetics of the production and reduction of the oxidized chromophore in urate, cholesterol, triglyceride and glucose tests. Reaction of ascorbic acid with the Trinder method constituents was also verified. Ascorbic acid interfered stoichiometrically with all tests studied. However, it had two distinct effects on the reaction rate. In the urate test, ascorbic acid decreased the chromophore formation with no change in its production kinetics. In contrast, in cholesterol, triglyceride and glucose tests, an increase in the lag phase of color development occurred. Of all the Trinder constituents, only peroxide reverted the interference. In addition, ascorbic acid did not interfere with oxidase activity nor reduce significantly the chromophore formed. Peroxide depletion was the predominant chemical mechanism of ascorbic acid interference in the Trinder method with phenolics and 4-AP. Distinctive effects of ascorbic acid on the reaction kinetics of urate, cholesterol, glucose and triglyceride might be due to the rate of peroxide production by oxidases.

Force decay of elastomeric chains - a mechanical design and product comparison study.

Science.gov (United States)

Balhoff, David A; Shuldberg, Matthew; Hagan, Joseph L; Ballard, Richard W; Armbruster, Paul C

2011-03-01

To evaluate the percentage force decay of elastomeric chain products utilizing three different design mechanisms simulating canine retraction; and to evaluate the percentage force decay of elastomeric chain products from four different companies. In vitro, laboratory study. LSUHSC Dental School, New Orleans, LA, USA. Closed (non-spaced), grey elastomeric chains from four companies were selected for the study. Three acrylic resin jigs were constructed to provide a framework for three simulated space closure mechanisms. The 6-5-3, the chain loop, and the 6-3 were the configuration mechanisms used in the study. An electronic force gauge was used to measure the percentage force decay associated with each elastomeric chain over 28 days at preselected times. There was a significant difference in the mean percentage force decay for the three different mechanisms (P < 0·001). For all four companies, the 6-3 mechanical design had the smallest mean percentage force decay. There was a significant difference in the mean percentage force decay for the different companies (P < 0·001). For all three mechanisms, Ormco had the smallest percentage force decay while Unitek had the highest percentage force decay. The significant difference in the mean percentage force decay for the different mechanisms suggests that the 6-3 design is a more efficient means of closing extraction spaces utilizing elastomeric chains.

Therapeutic γ-globin inducers reduce transcriptional repression in hemoglobinopathy erythroid progenitors through distinct mechanisms

Science.gov (United States)

Dai, Yan; Sangerman, Jose; Hong, Yuan Luo; Fuchareon, Suthat; Chui, David H.K.; Faller, Douglas V.; Perrine, Susan P.

2015-01-01

Pharmacologic augmentation of γ-globin expression sufficient to reduce anemia and clinical severity in patients with diverse hemoglobinopathies has been challenging. In studies here, representative molecules from four chemical classes, representing several distinct primary mechanisms of action, were investigated for effects on γ-globin transcriptional repressors, including components of the NuRD complex (LSD1 and HDACs 2-3), and the downstream repressor BCL11A, in erythroid progenitors from hemoglobinopathy patients. Two HDAC inhibitors (MS-275 and SB939), a short-chain fatty acid derivative (sodium dimethylbutyrate [SDMB]), and an agent identified in high-throughput screening, Benserazide, were studied. These therapeutics induced γ globin mRNA in progenitors above same subject controls up to 20-fold, and increased F-reticulocytes up to 20%. Cellular protein levels of BCL11A, LSD-1, and KLF1 were suppressed by the compounds. Chromatin immunoprecipitation assays demonstrated a 3.6-fold reduction in LSD1 and HDAC3 occupancy in the γ-globin gene promoter with Benserazide exposure, 3-fold reduction in LSD-1 and HDAC2 occupancy in the γ-globin gene promoter with SDMB exposure, while markers of gene activation (histone H3K9 acetylation and H3K4 demethylation), were enriched 5.7-fold. These findings identify clinical-stage oral therapeutics which inhibit or displace major co-repressors of γ-globin gene transcription and may suggest a rationale for combination therapy to produce enhanced efficacy. PMID:26603726

Distinct Dasatinib-Induced Mechanisms of Apoptotic Response and Exosome Release in Imatinib-Resistant Human Chronic Myeloid Leukemia Cells

Directory of Open Access Journals (Sweden)

Juan Liu

2016-04-01

Full Text Available Although dasatinib is effective in most imatinib mesylate (IMT-resistant chronic myeloid leukemia (CML patients, the underlying mechanism of its effectiveness in eliminating imatinib-resistant cells is only partially understood. This study investigated the effects of dasatinib on signaling mechanisms driving-resistance in imatinib-resistant CML cell line K562 (K562RIMT. Compared with K562 control cells, exsomal release, the phosphoinositide 3-kinase (PI3K/protein kinase B (Akt/ mammalian target of rapamycin (mTOR signaling and autophagic activity were increased significantly in K562RIMT cells and mTOR-independent beclin-1/Vps34 signaling was shown to be involved in exosomal release in these cells. We found that Notch1 activation-mediated reduction of phosphatase and tensin homolog (PTEN was responsible for the increased Akt/mTOR activities in K562RIMT cells and treatment with Notch1 γ-secretase inhibitor prevented activation of Akt/mTOR. In addition, suppression of mTOR activity by rapamycin decreased the level of activity of p70S6K, induced upregulation of p53 and caspase 3, and led to increase of apoptosis in K562RIMT cells. Inhibition of autophagy by spautin-1 or beclin-1 knockdown decreased exosomal release, but did not affect apoptosis in K562RIMT cells. In summary, in K562RIMT cells dasatinib promoted apoptosis through downregulation of Akt/mTOR activities, while preventing exosomal release and inhibiting autophagy by downregulating expression of beclin-1 and Vps34. Our findings reveal distinct dasatinib-induced mechanisms of apoptotic response and exosomal release in imatinib-resistant CML cells.

Flavin-catalyzed redox tailoring reactions in natural product biosynthesis.

Science.gov (United States)

Teufel, Robin

2017-10-15

Natural products are distinct and often highly complex organic molecules that constitute not only an important drug source, but have also pushed the field of organic chemistry by providing intricate targets for total synthesis. How the astonishing structural diversity of natural products is enzymatically generated in biosynthetic pathways remains a challenging research area, which requires detailed and sophisticated approaches to elucidate the underlying catalytic mechanisms. Commonly, the diversification of precursor molecules into distinct natural products relies on the action of pathway-specific tailoring enzymes that catalyze, e.g., acylations, glycosylations, or redox reactions. This review highlights a selection of tailoring enzymes that employ riboflavin (vitamin B2)-derived cofactors (FAD and FMN) to facilitate unusual redox catalysis and steer the formation of complex natural product pharmacophores. Remarkably, several such recently reported flavin-dependent tailoring enzymes expand the classical paradigms of flavin biochemistry leading, e.g., to the discovery of the flavin-N5-oxide - a novel flavin redox state and oxygenating species. Copyright © 2017 Elsevier Inc. All rights reserved.

Establishment of the carbon label mechanism of coal chemical products based oncarbon footprint

Directory of Open Access Journals (Sweden)

Wu Bishan

Full Text Available ABSTRACT After redefining the carbon footprint and carbon label, the paper analyzesthe significance of the carbon labels under the background of the low carbon economy development, and establishes the concept of model of the carbon labels mechanism to chemical products. At the same time, the paper quantitatively studies carbon label data sourceof three kinds of coal chemical industry power products, which are fromhaving not CCS technologies of supercritical boiler of coal, using CCS technologies of supercritical boiler of coal and adopting CCS and IGCC technologies to power generation in CCI. Based on the three kinds of differences, the paper puts forward of establishing the carbon labels mechanism of chemical products under the low carbon consumption.

Peptidomic and transcriptomic profiling of four distinct spider venoms.

Directory of Open Access Journals (Sweden)

Vera Oldrati

Full Text Available Venom based research is exploited to find novel candidates for the development of innovative pharmacological tools, drug candidates and new ingredients for cosmetic and agrochemical industries. Moreover, venomics, as a well-established approach in systems biology, helps to elucidate the genetic mechanisms of the production of such a great molecular biodiversity. Today the advances made in the proteomics, transcriptomics and bioinformatics fields, favor venomics, allowing the in depth study of complex matrices and the elucidation even of minor compounds present in minute biological samples. The present study illustrates a rapid and efficient method developed for the elucidation of venom composition based on NextGen mRNA sequencing of venom glands and LC-MS/MS venom proteome profiling. The analysis of the comprehensive data obtained was focused on cysteine rich peptide toxins from four spider species originating from phylogenetically distant families for comparison purposes. The studied species were Heteropoda davidbowie (Sparassidae, Poecilotheria formosa (Theraphosidae, Viridasius fasciatus (Viridasiidae and Latrodectus mactans (Theridiidae. This led to a high resolution profiling of 284 characterized cysteine rich peptides, 111 of which belong to the Inhibitor Cysteine Knot (ICK structural motif. The analysis of H. davidbowie venom revealed a high richness in term of venom diversity: 95 peptide sequences were identified; out of these, 32 peptides presented the ICK structural motif and could be classified in six distinct families. The profiling of P. formosa venom highlighted the presence of 126 peptide sequences, with 52 ICK toxins belonging to three structural distinct families. V. fasciatus venom was shown to contain 49 peptide sequences, out of which 22 presented the ICK structural motif and were attributed to five families. The venom of L. mactans, until now studied for its large neurotoxins (Latrotoxins, revealed the presence of 14

Novel consortium of Klebsiella variicola and Lactobacillus species enhances the functional potential of fermented dairy products by increasing the availability of branched-chain amino acids and the amount of distinctive volatiles.

Science.gov (United States)

Rosales-Bravo, H; Morales-Torres, H C; Vázquez-Martínez, J; Molina-Torres, J; Olalde-Portugal, V; Partida-Martínez, L P

2017-11-01

Identify novel bacterial taxa that could increase the availability of branched-chain amino acids and the amount of distinctive volatiles during skim milk fermentation. We recovered 344 bacterial isolates from stool samples of healthy and breastfed infants. Five were selected based on their ability to produce branched-chain amino acids. Three strains were identified as Escherichia coli, one as Klebsiella pneumoniae and other as Klebsiella variicola by molecular and biochemical methods. HPLC and solid-phase microextraction with GC-MS were used for the determination of free amino acids and volatile compounds respectively. The consortium formed by K. variicola and four Lactobacillus species showed the highest production of Leu and Ile in skim milk fermentation. In addition, the production of volatile compounds, such as acetoin, ethanol, 2-nonanone, and acetic, hexanoic and octanoic acids, increased in comparison to commercial yogurt, Emmental and Gouda cheese. Also, distinctive volatiles, such as 2,3-butanediol, 4-methyl-2- hexanone and octanol, were identified. The use of K. variicola in combination with probiotic Lactobacillus species enhances the availability of Leu and Ile and the amount of distinctive volatiles during skim milk fermentation. The identified consortium increases the functional potential of fermented dairy products. © 2017 The Society for Applied Microbiology.

Distinct mechanisms of loss of IFN-gamma mediated HLA class I inducibility in two melanoma cell lines

International Nuclear Information System (INIS)

Rodríguez, Teresa; Méndez, Rosa; Del Campo, Ana; Jiménez, Pilar; Aptsiauri, Natalia; Garrido, Federico; Ruiz-Cabello, Francisco

2007-01-01

The inability of cancer cells to present antigen on the cell surface via MHC class I molecules is one of the mechanisms by which tumor cells evade anti-tumor immunity. Alterations of Jak-STAT components of interferon (IFN)-mediated signaling can contribute to the mechanism of cell resistance to IFN, leading to lack of MHC class I inducibility. Hence, the identification of IFN-γ-resistant tumors may have prognostic and/or therapeutic relevance. In the present study, we investigated a mechanism of MHC class I inducibility in response to IFN-γ treatment in human melanoma cell lines. Basal and IFN-induced expression of HLA class I antigens was analyzed by means of indirect immunofluorescence flow cytometry, Western Blot, RT-PCR, and quantitative real-time RT-PCR (TaqMan ® Gene Expression Assays). In demethylation studies cells were cultured with 5-aza-2'-deoxycytidine. Electrophoretic Mobility Shift Assay (EMSA) was used to assay whether IRF-1 promoter binding activity is induced in IFN-γ-treated cells. Altered IFN-γ mediated HLA-class I induction was observed in two melanoma cells lines (ESTDAB-004 and ESTDAB-159) out of 57 studied, while treatment of these two cell lines with IFN-α led to normal induction of HLA class I antigen expression. Examination of STAT-1 in ESTDAB-004 after IFN-γ treatment demonstrated that the STAT-1 protein was expressed but not phosphorylated. Interestingly, IFN-α treatment induced normal STAT-1 phosphorylation and HLA class I expression. In contrast, the absence of response to IFN-γ in ESTDAB-159 was found to be associated with alterations in downstream components of the IFN-γ signaling pathway. We observed two distinct mechanisms of loss of IFN-γ inducibility of HLA class I antigens in two melanoma cell lines. Our findings suggest that loss of HLA class I induction in ESTDAB-004 cells results from a defect in the earliest steps of the IFN-γ signaling pathway due to absence of STAT-1 tyrosine-phosphorylation, while absence

Vaccine and Wild-Type Strains of Yellow Fever Virus Engage Distinct Entry Mechanisms and Differentially Stimulate Antiviral Immune Responses.

Science.gov (United States)

Fernandez-Garcia, Maria Dolores; Meertens, Laurent; Chazal, Maxime; Hafirassou, Mohamed Lamine; Dejarnac, Ophélie; Zamborlini, Alessia; Despres, Philippe; Sauvonnet, Nathalie; Arenzana-Seisdedos, Fernando; Jouvenet, Nolwenn; Amara, Ali

2016-02-09

The live attenuated yellow fever virus (YFV) vaccine 17D stands as a "gold standard" for a successful vaccine. 17D was developed empirically by passaging the wild-type Asibi strain in mouse and chicken embryo tissues. Despite its immense success, the molecular determinants for virulence attenuation and immunogenicity of the 17D vaccine are poorly understood. 17D evolved several mutations in its genome, most of which lie within the envelope (E) protein. Given the major role played by the YFV E protein during virus entry, it has been hypothesized that the residues that diverge between the Asibi and 17D E proteins may be key determinants of attenuation. In this study, we define the process of YFV entry into target cells and investigate its implication in the activation of the antiviral cytokine response. We found that Asibi infects host cells exclusively via the classical clathrin-mediated endocytosis, while 17D exploits a clathrin-independent pathway for infectious entry. We demonstrate that the mutations in the 17D E protein acquired during the attenuation process are sufficient to explain the differential entry of Asibi versus 17D. Interestingly, we show that 17D binds to and infects host cells more efficiently than Asibi, which culminates in increased delivery of viral RNA into the cytosol and robust activation of the cytokine-mediated antiviral response. Overall, our study reveals that 17D vaccine and Asibi enter target cells through distinct mechanisms and highlights a link between 17D attenuation, virus entry, and immune activation. The yellow fever virus (YFV) vaccine 17D is one of the safest and most effective live virus vaccines ever developed. The molecular determinants for virulence attenuation and immunogenicity of 17D are poorly understood. 17D was generated by serially passaging the virulent Asibi strain in vertebrate tissues. Here we examined the entry mechanisms engaged by YFV Asibi and the 17D vaccine. We found the two viruses use different entry

Existence and equivalence of twisted products on a symplectic manifold

International Nuclear Information System (INIS)

Lichnerowicz, A.

1979-01-01

The twisted products play an important role in Quantum Mechanics. A distinction is introduced between Vey *sub(γ) products and strong Vey *sub(γ) products and it is proved that each *sub(γ) product is equivalent to a Vey *sub(γ) product. If b 3 (W) = 0, the symplectic manifold (W,F) admits strong Vey *sub(Gn) products. If b 2 (W) = 0, all *sub(γ) products are equivalent as well as the Vey Lie algebras. In the general case the formal Lie algebras are characterized which are generated by a *sub(γ) product and it proved that the existance of a *sub(γ)-product is equivalent to the existance of a formal Lie algebra infinitesimally equivalent to a Vey Lie algebra at the first order. (Auth.)

Mechanism of Mg2+-Accompanied Product Release in Sugar Nucleotidyltransferases.

Science.gov (United States)

Vithani, Neha; Ankush Jagtap, Pravin Kumar; Verma, Sunil Kumar; Tripathi, Ravi; Awasthi, Shalini; Nair, Nisanth N; Prakash, Balaji

2018-03-06

The nucleotidyl transfer reaction, catalyzed by sugar nucleotidyltransferases (SNTs), is assisted by two active site Mg 2+ ions. While studying this reaction using X-ray crystallography, we captured snapshots of the pyrophosphate (product) as it exits along a pocket. Surprisingly, one of the active site Mg 2+ ions remains coordinated to the exiting pyrophosphate. This hints at the participation of Mg 2+ in the process of product release, besides its role in catalyzing nucleotidyl transfer. These observations are further supported by enhanced sampling molecular dynamics simulations. Free energy computations suggest that the product release is likely to be rate limiting in SNTs, and the origin of the high free energy barrier for product release could be traced back to the "slow" conformational change of an Arg residue at the exit end of the pocket. These results establish a dual role for Mg 2+ , and propose a general mechanism of product release during the nucleotidyl transfer by SNTs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Isotope Effects Associated with N2O Production by Fungal and Bacterial Nitric Oxide Reductases: Implications for Enzyme Mechanisms

Science.gov (United States)

Hegg, E. L.; Yang, H.; Gandhi, H.; McQuarters, A.; Lehnert, N.; Ostrom, N. E.

2014-12-01

Nitrous oxide (N2O) is both a powerful greenhouse gas and a key participant in ozone destruction. Microbial activity accounts for over 70% of the N2O produced annually, and the atmospheric concentration of N2O continues to rise. Because the fungal and bacterial denitrification pathways are major contributors to microbial N2O production, understanding the mechanism by which NO is reduced to N2O will contribute to both N2O source tracing and quantification. Our strategy utilizes stable isotopes to probe the enzymatic mechanism of microbial N2O production. Although the use of stable isotopes to study enzyme mechanisms is not new, our approach is distinct in that we employ both measurements of isotopic preferences of purified enzyme and DFT calculations, thereby providing a synergistic combination of experimental and computational approaches. We analyzed δ18O, δ15Nα (central N atom in N2O), and δ15Nβ (terminal N atom) of N2O produced by purified fungal cytochrome P450 nitric oxide reductase (P450nor) from Histoplasma capsulatum as well as bacterial cytochrome c dependent nitric oxide reductase (cNOR) from Paracoccus denitrificans. P450nor exhibits an inverse kinetic isotope effect for Nβ (KIE = 0.9651) but a normal isotope effect for both Nα (KIE = 1.0127) and the oxygen atom (KIE = 1.0264). These results suggest a mechanism where NO binds to the ferric heme in the P450nor active site and becomes Nβ. Analysis of the NO-binding step indicated a greater difference in zero point energy in the transition state than the ground state, resulting in the inverse KIE observed for Nβ. Following protonation and rearrangement, it is speculated that this complex forms a FeIV-NHOH- species as a key intermediate. Our data are consistent with the second NO (which becomes Nα and O in the N2O product) attacking the FeIV-NHOH- species to generate a FeIII-N2O2H2 complex that enzymatically (as opposed to abiotically) breaks down to release N2O. Conversely, our preliminary data

A comparison of the mechanical and sensory properties of baked and extruded confectionery products

Science.gov (United States)

Butt, Saba; Charalambides, Maria; Mohammed, Idris K.; Powell, Hugh

2017-10-01

Traditional baking is the most common way of producing confectionery wafers, however over the past few decades, the extrusion process has become an increasingly important food manufacturing method and is commonly used in the manufacturing of breakfast cereals and filled snack products. This study aims to characterise products made via each of these manufacturing processes in order to understand the important parameters involved in the resulting texture of confectionery products such as wafers. Both of the named processes result in brittle, cellular foams comprising of cell walls and cell pores which may contain some of the confectionery filling. The mechanical response of the cell wall material and the geometry of the products influence the consumer perception and preference. X-Ray micro tomography (XRT) was used to generate geometry of the microstructure which was then fed to Finite Element (FE) for numerical analysis on both products. The FE models were used to determine properties such as solid modulus of the cell walls, Young's modulus of the entire foam and to investigate and compare the microstructural damage of baked wafers and extruded products. A sensory analysis study was performed on both products by a qualified sensory panel. The results of this study were then used to draw links between the mechanical behaviour and sensory perception of a consumer. The extruded product was found to be made up of a stiffer solid material and had a higher compressive modulus and fracture stress when compared to the baked wafer. The sensory panel observed textural differences between the baked and extruded products which were also found in the differences of the mechanical properties of the two products.

OPTIMIZATION OF THE ORGANIZATIONAL AND ECONOMICAL MECHANISM BETWEEN SMALL AND LARGE COMPANIES IN THE PRODUCTION AND SALE OF DAIRY PRODUCTS SPHERE

Directory of Open Access Journals (Sweden)

K. B. Dobrova

2012-01-01

Full Text Available This paper analyzes the main directions to optimize the organizational and economical mechanism between small and large companies in the production and sale of dairy products sphere in the Russian practice.

Paralinguistic mechanisms of production in human "beatboxing": a real-time magnetic resonance imaging study.

Science.gov (United States)

Proctor, Michael; Bresch, Erik; Byrd, Dani; Nayak, Krishna; Narayanan, Shrikanth

2013-02-01

Real-time magnetic resonance imaging (rtMRI) was used to examine mechanisms of sound production by an American male beatbox artist. rtMRI was found to be a useful modality with which to study this form of sound production, providing a global dynamic view of the midsagittal vocal tract at frame rates sufficient to observe the movement and coordination of critical articulators. The subject's repertoire included percussion elements generated using a wide range of articulatory and airstream mechanisms. Many of the same mechanisms observed in human speech production were exploited for musical effect, including patterns of articulation that do not occur in the phonologies of the artist's native languages: ejectives and clicks. The data offer insights into the paralinguistic use of phonetic primitives and the ways in which they are coordinated in this style of musical performance. A unified formalism for describing both musical and phonetic dimensions of human vocal percussion performance is proposed. Audio and video data illustrating production and orchestration of beatboxing sound effects are provided in a companion annotated corpus.

Frame transforms, star products and quantum mechanics on phase space

International Nuclear Information System (INIS)

Aniello, P; Marmo, G; Man'ko, V I

2008-01-01

Using the notions of frame transform and of square integrable projective representation of a locally compact group G, we introduce a class of isometries (tight frame transforms) from the space of Hilbert-Schmidt operators in the carrier Hilbert space of the representation into the space of square integrable functions on the direct product group G x G. These transforms have remarkable properties. In particular, their ranges are reproducing kernel Hilbert spaces endowed with a suitable 'star product' which mimics, at the level of functions, the original product of operators. A 'phase space formulation' of quantum mechanics relying on the frame transforms introduced in the present paper, and the link of these maps with both the Wigner transform and the wavelet transform are discussed

Quantum Distinction: Quantum Distinctiones!

OpenAIRE

Zeps, Dainis

2009-01-01

10 pages; How many distinctions, in Latin, quantum distinctiones. We suggest approach of anthropic principle based on anthropic reference system which should be applied equally both in theoretical physics and in mathematics. We come to principle that within reference system of life subject of mathematics (that of thinking) should be equated with subject of physics (that of nature). For this reason we enter notions of series of distinctions, quantum distinction, and argue that quantum distinct...

Monitoring the effect of mechanical stress on mesenchymal stem cell collagen production by multiphoton microscopy

Science.gov (United States)

Chen, Wei-Liang; Chang, Chia-Cheng; Chiou, Ling-Ling; Li, Tsung-Hsien; Liu, Yuan; Lee, Hsuan-Shu; Dong, Chen-Yuan

2008-02-01

Tissue engineering is emerging as a promising method for repairing damaged tissues. Due to cartilage's common wear and injury, in vitro production of cartilage replacements have been an active area of research. Finding the optimal condition for the generation of the collagen matrix is crucial in reproducing cartilages that closely match those found in human. Using multiphoton autofluorescence and second-harmonic generation (SHG) microscopy we monitored the effect of mechanical stress on mesenchymal stem cell collagen production. Bone marrow mesenchymal stem cells in the form of pellets were cultured and periodically placed under different mechanical stress by centrifugation over a period of four weeks. The differently stressed samples were imaged several times during the four week period, and the collagen production under different mechanical stress is characterized.

On the mechanism of high product selectivity for HCOOH using Pb in CO2 electroreduction.

Science.gov (United States)

Back, Seoin; Kim, Jun-Hyuk; Kim, Yong-Tae; Jung, Yousung

2016-04-14

While achieving high product selectivity is one of the major challenges of the CO2 electroreduction technology in general, Pb is one of the few examples with high selectivity that produces formic acid almost exclusively (versus H2, CO, or other byproducts). In this work, we study the mechanism of CO2 electroreduction reactions using Pb to understand the origin of high formic acid selectivity. In particular, we first assess the proton-assisted mechanism proposed in the literature using density functional calculations and find that it cannot fully explain the previous selectivity experiments for the Pb electrode. We then suggest an alternative proton-coupled-electron-transfer mechanism consistent with existing observations, and further validate a new mechanism by experimentally measuring and comparing the onset potentials for CO2 reduction vs. H2 production. We find that the origin of a high selectivity of the Pb catalyst for HCOOH production over CO and H2 lies in the strong O-affinitive and weak C-, H-affinitive characteristics of Pb, leading to the involvement of the *OCHO species as a key intermediate to produce HCOOH exclusively and preventing unwanted H2 production at the same time.

A cascade mechanism of three-particle resonance production

International Nuclear Information System (INIS)

Badalyan, A.M.; Polikarpov, M.I.; Simonov, Yu.A.

1976-01-01

We study the mechanism of the three-particle resonance production in a system consisting of a two-particle resonance and of one particle, the resonance and the particle permanently exchanging the decay product particle. The N/D method is used to show that the solution of the unitarity for the resonance-particle amplitude reduces to solving a one-dimensional nonsingular integral equation for the denominator of the amplitude D(y). The contribution from the right-hand cut of the exchange decay diagram is considered explicitly and the final equation contains only the integral over an arbitrary left-hand cut as in the case of the interaction amplitude of stable particles. It is as well shown that if only the right-hand cut is present, than the denominator D(y) for L=0 has no singularities, whereas the amplitude may have virtual or real poles at L=1

Regulated production of free radicals by the mitochondrial electron transport chain: Cardiac ischemic preconditioning.

Science.gov (United States)

Matsuzaki, Satoshi; Szweda, Pamela A; Szweda, Luke I; Humphries, Kenneth M

2009-11-30

Excessive production of free radicals by mitochondria is associated with, and likely contributes to, the progression of numerous pathological conditions. Nevertheless, the production of free radicals by the mitochondria may have important biological functions under normal or stressed conditions by activating or modulating redox-sensitive cellular signaling pathways. This raises the intriguing possibility that regulated mitochondrial free radical production occurs via mechanisms that are distinct from pathologies associated with oxidative damage. Indeed, the capacity of mitochondria to produce free radicals in a limited manner may play a role in ischemic preconditioning, the phenomenon whereby short bouts of ischemia protect from subsequent prolonged ischemia and reperfusion. Ischemic preconditioning can thus serve as an important model system for defining regulatory mechanisms that allow for transient, signal-inducing, production of free radicals by mitochondria. Defining how these mechanism(s) occur will provide insight into therapeutic approaches that minimize oxidative damage without altering normal cellular redox biology. The aim of this review is to present and discuss evidence for the regulated production of superoxide by the electron transport chain within the ischemic preconditioning paradigm of redox regulation.

The origin of the distinction between microscopic formulas for stress and Cauchy stress

OpenAIRE

Chen, Youping

2016-01-01

Stress is calculated routinely in atomistic simulations. The widely used microscopic stress formulas derived from classical or quantum mechanics, however, are distinct from the concept of Cauchy stress, i.e., the true mechanical tress. This work examines various atomistic stress formulations and their inconsistencies. Using standard mathematic theorems and the law of mechanics, we show that Cauchy stress results unambiguously from the definition of internal force density, thereby removing the...

Implement of the Owner Distinction Function for Healing-Type Pet Robots

Science.gov (United States)

Nambo, Hidetaka; Kimura, Haruhiko; Hirose, Sadaki

In recent years, a robotics technology is extremely progressive, and robots are widely applied in many fields. One of the most typical robots is a pet robot. The pet robot is based on an animal pet, such as a dog or a cat. Also, it is known that an animal pet has a healing effect. Therefore, the study to apply pet robots to Animal Assisted Therapy instead of an animal pet has begun to be investigated. We, also, have investigated a method of an owner distinction for pet robot, to emphasize a healing effect of pet robots. In this paper, taking account of implementation into pet robots, a real-time owner distinction method is proposed. In the concrete, the method provides a real-time matching algorithm and an oblivion mechanism. The real-time matching means that a matching and a data acquisition are processed simultaneously. The oblivion mechanism is deleting features of owners in the database of the pet robots. Additionally, the mechanism enables to reduce matching costs or size of database and it enables to follow a change of owners. Furthermore, effectivity and a practicality of the method are evaluated by experiments.

Appropriability mechanisms, innovation and productivity: Evidence from the UK

OpenAIRE

Hall, B.H.; Sena, V.

2014-01-01

We use an extended version of the well-established Crepon, Duguet and Mairesse model (1998) to model the relationship between appropriability mechanisms, innovation and firm-level productivity. We enrich this model in several ways. First, we consider different types of innovation spending and study the differences in estimates when innovation spending (rather than R&D spending) is used to predict innovation in the CDM model. Second, we assume that a firm simultaneously innovates and chooses a...

Dynamical parasupersymmetries in quantum mechanics

International Nuclear Information System (INIS)

Durand, S.; Vinet, L.

1990-01-01

This paper reports on supersymmetric field theories that have the distinctive feature of being invariant under transformations that mix bosonic and fermionic variables. Reduction to 0 + 1 dimensions yields mechanical models with an analogous invariance. In this case, the Grassmannian variables are interpreted as describing (classically) the spin degrees of freedom of the particles involved. After canonical quantization, the corresponding quantities obey the standard anticommutation relations of fermionic creation and annihilation operators. It is known that paraquantitization offers alternative to the usual quantization scheme. In this framework, one can expect that it is possible to construct parasupersymmetric theories, that is, theories which are invariant under transformations between bosonic and parafermionic variables. As a matter of fact, Rubakov and Spiridonov has recently shown how the parasupersymmetric generalization of supersymmetric Quantum Mechanics proceeds. In this case, the fermionic creation and annihilation operators obey paracommutation relations. The applications of supersymmetric Quantum Mechanics are many. One might hope that its parasupersymmetric generalization will be as useful. The elaboration of parasupersymmeric Quantum Mechanics moreover has led to new mathematical constructs; indeed, the symmetry generators realize algebras involving products of degree higher than 2

Mechanism of J/PSI production: determining gluon distributions

International Nuclear Information System (INIS)

Nandi, S.; Schneider, H.R.

1978-01-01

Assuming a generalised Drell-Yan type mechanism for hadronic PSI-production, the relative importance of the different possible contributions is estimated from the data. We find that about 80% of the pp → PSI X cross-section is due to gluons. Therefore, these data give some information on the gluon distribution G(x) in the proton. Assuming xG(x) approximately (1-x)sup(n), data restrict n to 4... 6, in agreement with dimensional counting rules. The energy dependence of sigma(anti p p → PSI X)/sigma(pp → PSIX) is predicted. (orig.) [de

Production dynamics of fine roots in beech forests: possible mechanism of resource allocation between above- and below-ground production

Science.gov (United States)

Nakahata, R.; Osawa, A.; Naramoto, M.; Mizunaga, H.; Sato, M.

2017-12-01

The masting phenomenon that seed production has large annual variation with spatial synchrony appears generally in beeches. Therefore, net primary production and carbon allocation mechanism in beech forests may differ among several years in relation to annual variation of seed production. On the other hand, fine roots play key roles in carbon dynamics and nutrient and water acquisition of an ecosystem. Evaluation of fine root dynamics is essential to understand long-term dynamics of production in forest ecosystems. Moreover, the influence of mast seeding on resource allocation should be clarified in such beech forests. The aim of this study is to clarify possible relationships between the patterns of above- and below-ground production in relation to the masting events using observation data of litter fall and fine root dynamics. We applied the litter trap method and a minirhizotron method in a cool-temperate natural forest dominated by beech (Fagus crenata Blume). Ten litter traps were set from 2008 to 2016, then annual leaf and seed production were estimated. Four minirhizotron tubes were buried in Aug. 2008 and soil profiles were scanned monthly until Nov. 2016 during the periods of no snow covering. The scanned soil profiles were analyzed for calculating fine root production using the WinRHIZO Tron software. In the present study site, rich production of mast seeding occurred biennially and fine root production showed various seasonal patterns. There was no significant correlation between seed production and annual fine root production in the same year. However, seed production had a positive correlation with fine root production in autumn in the previous year and indicated a negative correlation with that in autumn in the current year. These results indicate that higher fine root production has led to increased nutrient acquisition, which resulted in rich seed production in the next year. It is also suppressed after the masting events due to shortage in

European freshwater VHSV genotype Ia isolates divide into two distinct subpopulations

DEFF Research Database (Denmark)

Kahns, Søren; Skall, Helle Frank; Kaas, Rolf Sommer

2012-01-01

Viral haemorrhagic septicaemia (VHS), caused by the novirhabdovirus VHSV, often leads to significant economic losses to European rainbow trout production. The virus isolates are divided into 4 distinct genotypes with additional subgroups including sublineage Ia, isolates of which are the main...... detected in Denmark since January 2009. Full-length G-genes of all Danish VHSV isolates that were submitted for diagnostic analyses in the period 2004−2009 were sequenced and analysed. All 58 Danish isolates from rainbow trout grouped with sublineage Ia isolates. Furthermore, VHSV isolates from infected...... Danish freshwater catchments appear to have evolved into a distinct clade within sublineage Ia, herein designated clade Ia-1, whereas trout isolates originating from other continental European countries cluster in another distinct clade, designated clade Ia-2. In addition, phylogenetic analyses indicate...

Production, microstructure and mechanical properties of two different austenitic ODS steels

Energy Technology Data Exchange (ETDEWEB)

Gräning, T., E-mail: tim.graening@kit.edu; Rieth, M.; Hoffmann, J.; Möslang, A.

2017-04-15

This article is to summarize and examine processing parameters of novel developed austenitic oxide dispersed strengthened (ODS) steels. Comparing hot-rolled and extruded conditions after the same degree of deformation after and before annealing, are just some examples to give insights into the complex processing of austenitic ODS steels. One of the major drawbacks of the material is the more sophisticated production process. Due to a ductile matrix material with an increased stickiness during milling, a two-step milling procedure with the use of ZrO{sub 2} milling balls was applied to raise the production yield and to use the abrasion of the ZrO{sub 2} as an additional element to facilitate the formation of nano-sized precipitates. To get a better understanding how the different powder particle sizes after milling affect final properties, sieving was applied and revealed a serious effect in terms of precipitate size, distribution and mechanical properties. Grain sizes in relation to the precipitate size, annealing time and processing parameters were determined and compared to the mechanical properties. Hardness and tensile test have pointed out, that the precipitate size and number are more important in respect to the ultimate tensile strength than the grain size and that in this study hot-rolled material exhibited the better properties. The investigation of the microstructure illustrated the stability of precipitates during annealing at 1100 °C for 40 h. These heat treatments also led to a consistent grain size, due to the pinning effect of the grain boundaries, caused by precipitates. - Highlights: •Comparison of the microstructure of extruded and hot-rolled ODS. •Two-step mechanical alloying with ZrO{sub 2} milling balls. •Determination of precipitate size distribution depending on chemical composition and annealing times. •Determination of the influence of sieving of mechanical alloyed powder on the near net shape products. •Tensile tests of two

Measures for Administration of the Import of Mechanical and Electronic Products

Institute of Scientific and Technical Information of China (English)

无

2008-01-01

@@ The Measures for the Administration of the Import of Mechanical and Electronic Products co-formulated by the Ministry of Commerce,the General Administration of Customs and the General Administration of Quality Supervision,Inspection and Quarantine,was hereby promul-gated,which entered into force as of May 1,2008.

Hydrogen sulfide increases nitric oxide production from endothelial cells by an Akt-dependent mechanism

Directory of Open Access Journals (Sweden)

Arturo J Cardounel

2011-12-01

Full Text Available Hydrogen sulfide (H2S and nitric oxide (NO are both gasotransmitters that can elicit synergistic vasodilatory responses in the in the cardiovascular system, but the mechanisms behind this synergy are unclear. In the current study we investigated the molecular mechanisms through which H2S regulates endothelial NO production. Initial studies were performed to establish the temporal and dose-dependent effects of H2S on NO generation using EPR spin trapping techniques. H2S stimulated a two-fold increase in NO production from endothelial nitric oxide synthase (eNOS, which was maximal 30 min after exposure to 25-150 µM H2S. Following 30 min H2S exposure, eNOS phosphorylation at Ser 1177 was significantly increased compared to control, consistent with eNOS activation. Pharmacological inhibition of Akt, the kinase responsible for Ser 1177 phosphorylation, attenuated the stimulatory effect of H2S on NO production. Taken together, these data demonstrate that H2S up-regulates NO production from eNOS through an Akt-dependent mechanism. These results implicate H2S in the regulation of NO in endothelial cells, and suggest that deficiencies in H2S signaling can directly impact processes regulated by NO.

Mass production of bulk artificial nacre with excellent mechanical properties.

Science.gov (United States)

Gao, Huai-Ling; Chen, Si-Ming; Mao, Li-Bo; Song, Zhao-Qiang; Yao, Hong-Bin; Cölfen, Helmut; Luo, Xi-Sheng; Zhang, Fu; Pan, Zhao; Meng, Yu-Feng; Ni, Yong; Yu, Shu-Hong

2017-08-18

Various methods have been exploited to replicate nacre features into artificial structural materials with impressive structural and mechanical similarity. However, it is still very challenging to produce nacre-mimetics in three-dimensional bulk form, especially for further scale-up. Herein, we demonstrate that large-sized, three-dimensional bulk artificial nacre with comprehensive mimicry of the hierarchical structures and the toughening mechanisms of natural nacre can be facilely fabricated via a bottom-up assembly process based on laminating pre-fabricated two-dimensional nacre-mimetic films. By optimizing the hierarchical architecture from molecular level to macroscopic level, the mechanical performance of the artificial nacre is superior to that of natural nacre and many engineering materials. This bottom-up strategy has no size restriction or fundamental barrier for further scale-up, and can be easily extended to other material systems, opening an avenue for mass production of high-performance bulk nacre-mimetic structural materials in an efficient and cost-effective way for practical applications.Artificial materials that replicate the mechanical properties of nacre represent important structural materials, but are difficult to produce in bulk. Here, the authors exploit the bottom-up assembly of 2D nacre-mimetic films to fabricate 3D bulk artificial nacre with an optimized architecture and excellent mechanical properties.

Research on the Governance Mechanism of Aviation Complex Product Manufacturing Supply Chain Based on Dynamic Game Theory

Directory of Open Access Journals (Sweden)

Wang Nan

2016-01-01

Full Text Available In the manufacturing process of aeronautical complex products, for the following problems: develop long production cycle, a large number of ancillary products, a plurality of participating units, etc, and the status of the frequency of quality problems, using single-phase static game model in the case of asymmetric information, study on Supplier Quality insufficient investment, which resulting in opportunistic behaviour reasons. And using KMRW dynamic game model, we quantitative analysis the mechanism and crucial role of reputation mechanisms to ensure aeronautical complex product manufacturing supply chain and effective operation.

Rolie-Poly fluid flowing through constrictions: Two distinct instabilities

KAUST Repository

Reis, T.; Wilson, H.J.

2013-01-01

Elastic instabilities of entangled polymer melts are common in industrial processes but the physics responsible is not well understood. We present a numerical linear stability study of a molecular based constitutive model which grants us physical insight into the underlying mechanics involved. Two constriction flows are considered - one shear dominated, the other extension dominated - and two distinct instabilities are found. The influence of the molecular structure and the behaviour of the polymer dynamics are investigated and in both cases chain relaxation and orientation play a crucial role. This suggests a molecular-based physical interpretation of the underlying mechanisms responsible for flow instabilities. © 2013 Elsevier B.V.

Rolie-Poly fluid flowing through constrictions: Two distinct instabilities

KAUST Repository

Reis, T.

2013-05-01

Elastic instabilities of entangled polymer melts are common in industrial processes but the physics responsible is not well understood. We present a numerical linear stability study of a molecular based constitutive model which grants us physical insight into the underlying mechanics involved. Two constriction flows are considered - one shear dominated, the other extension dominated - and two distinct instabilities are found. The influence of the molecular structure and the behaviour of the polymer dynamics are investigated and in both cases chain relaxation and orientation play a crucial role. This suggests a molecular-based physical interpretation of the underlying mechanisms responsible for flow instabilities. © 2013 Elsevier B.V.

Molecular mechanisms underlying mancozeb-induced inhibition of TNF-alpha production

International Nuclear Information System (INIS)

Corsini, Emanuela; Viviani, Barbara; Birindelli, Sarah; Gilardi, Federica; Torri, Anna; Codeca, Ilaria; Lucchi, Laura; Bartesaghi, Stefano; Galli, Corrado L.; Marinovich, Marina; Colosio, Claudio

2006-01-01

Mancozeb, a polymeric complex of manganese ethylenebisdithiocarbamate with zinc salt, is widely used in agriculture as fungicide. Literature data indicate that ethylenebisdithiocarbamates (EBDTCs) may have immunomodulatory effects in humans. We have recently found in agricultural workers occupationally exposed to the fungicide mancozeb a statistically significant decrease in lipopolysaccharide (LPS)-induced tumor necrosis factor-alpha (TNF) production in leukocytes. TNF is an essential proinflammatory cytokine whose production is normally stimulated during an infection. The purpose of this work was to establish an in vitro model reflecting in vivo data and to characterize the molecular mechanism of action of mancozeb. The human promyelocytic cell line THP-1 was used as in vitro model to study the effects of mancozeb and its main metabolite ethylenthiourea (ETU) on LPS-induced TNF release. Mancozeb, but not ETU, at non-cytotoxic concentrations (1-100 μg/ml), induced a dose- and time-dependent inhibition of LPS-induced TNF release, reflecting in vivo data. The modulatory effect observed was not limited to mancozeb but also other EBDTCs, namely zineb and ziram, showed similar inhibitory effects. Mancozeb must be added before or simultaneously to LPS in order to observe the effect, indicating that it acts on early events triggered by LPS. It is known that nuclear factor-κB (NF-κB) tightly regulates TNF transcription. We could demonstrate that mancozeb, modulating LPS-induced reactive oxygen species generation, prevented IκB degradation and NF-κB nuclear translocation, which in turn resulted in decreased TNF production. To further understand the mechanism of the effect of mancozeb on TNF transcription, THP-1 cells were transfected with NF-κB promoter-luciferase construct, and the effect of mancozeb on luciferase activity was measured. Cells transfected with promoter constructs containing κB site showed decreased LPS-induced luciferase activity relative to control

Execution of Educational Mechanical Production Programs for School Children

Science.gov (United States)

Itoh, Nobuhide; Itoh, Goroh; Shibata, Takayuki

The authors are conducting experience-based engineering educational programs for elementary and junior high school students with the aim to provide a chance for them to experience mechanical production. As part of this endeavor, we planned and conducted a program called “Fabrication of Original Magnet Plates by Casting” for elementary school students. This program included a course for leading nature laws and logical thinking method. Prior to the program, a preliminary program was applied to school teachers to get comments and to modify for the program accordingly. The children responded excellently to the production process which realizes their ideas, but it was found that the course on natural laws and logical methods need to be improved to draw their interest and attention. We will continue to plan more effective programs, deepening ties with the local community.

Strength and Aerobic Exercises Improve Spatial Memory in Aging Rats Through Stimulating Distinct Neuroplasticity Mechanisms.

Science.gov (United States)

Vilela, Thais Ceresér; Muller, Alexandre Pastoris; Damiani, Adriani Paganini; Macan, Tamires Pavei; da Silva, Sabrina; Canteiro, Paula Bortoluzzi; de Sena Casagrande, Alisson; Pedroso, Giulia Dos Santos; Nesi, Renata Tiscoski; de Andrade, Vanessa Moraes; de Pinho, Ricardo Aurino

2017-12-01

Aging is associated with impaired cognition and memory and increased susceptibility to neurodegenerative disorders. Physical exercise is neuroprotective; however, the major evidence of this effect involves studies of only aerobic training in young animals. The benefits of other exercise protocols such as strength training in aged animals remains unknown. Here, we investigated the effect of aerobic and strength training on spatial memory and hippocampal plasticity in aging rats. Aging Wistar rats performed aerobic or strength training for 50 min 3 to 4 days/week for 8 weeks. Spatial memory and neurotrophic and glutamatergic signaling in the hippocampus of aged rats were evaluated after aerobic or strength training. Both aerobic and strength training improved cognition during the performance of a spatial memory task. Remarkably, the improvement in spatial memory was accompanied by an increase in synaptic plasticity proteins within the hippocampus after exercise training, with some differences in the intracellular functions of those proteins between the two exercise protocols. Moreover, neurotrophic signaling (CREB, BDNF, and the P75 NTR receptor) increased after training for both exercise protocols, and aerobic exercise specifically increased glutamatergic proteins (NMDA receptor and PSD-95). We also observed a decrease in DNA damage after aerobic training. In contrast, strength training increased levels of PKCα and the proinflammatory factors TNF-α and IL-1β. Overall, our results show that both aerobic and strength training improved spatial memory in aging rats through inducing distinct molecular mechanisms of neuroplasticity. Our findings extend the idea that exercise protocols can be used to improve cognition during aging.

The Impact of a Mechanical Press on the Accuracy of Products and the Reliability of Tools in Cold Forging

DEFF Research Database (Denmark)

Krusic, V.; Arentoft, Mogens; Rodic, T.

2005-01-01

Cold extrusion is an economic production process for the production of elements of complex forms and accurate dimensions. The first part of the article is about the impact that mechanical press has on the accuracy of products and reliability of tools. There is a description of the mechanical pres...

Differential Mechanisms for SHP2 Binding and Activation Are Exploited by Geographically Distinct Helicobacter pylori CagA Oncoproteins

Directory of Open Access Journals (Sweden)

Takeru Hayashi

2017-09-01

Full Text Available Helicobacter pylori East Asian CagA is more closely associated with gastric cancer than Western CagA. Here we show that, upon tyrosine phosphorylation, the East Asian CagA-specific EPIYA-D segment binds to the N-SH2 domain of pro-oncogenic SHP2 phosphatase two orders of magnitude greater than Western CagA-specific EPIYA-C. This high-affinity binding is achieved via cryptic interaction between Phe at the +5 position from phosphotyrosine in EPIYA-D and a hollow on the N-SH2 phosphopeptide-binding floor. Also, duplication of EPIYA-C in Western CagA, which increases gastric cancer risk, enables divalent high-affinity binding with SHP2 via N-SH2 and C-SH2. These strong CagA bindings enforce enzymatic activation of SHP2, which endows cells with neoplastic traits. Mechanistically, N-SH2 in SHP2 is in an equilibrium between stimulatory “relaxed” and inhibitory “squeezed” states, which is fixed upon high-affinity CagA binding to the “relaxed” state that stimulates SHP2. Accordingly, East Asian CagA and Western CagA exploit distinct mechanisms for SHP2 deregulation.

Rutile nanopowders for pigment production: Formation mechanism and particle size prediction

Science.gov (United States)

Zhang, Wu; Tang, Hongxin

2018-01-01

Formation mechanism and particle size prediction of rutile nanoparticles for pigment production were investigated. Anatase nanoparticles were observed by oriented attachment with parallel lattice fringe spaces of 0.2419 nm. Upon increasing the calcination temperature, the (1 1 0) plane of rutile was gradually observed, suggesting that the anatase (1 0 3) planes undergo internal structural rearrangement of oxygen and titanium ions into rutile phase due to ionic diffusion. Backpropagation neural network was used to predict particle size of rutile nanopowders, the prediction errors were all smaller than 2%, providing an efficient method to control particle size in pigment production.

Σ--antihyperon correlations in Z0 decay and investigation of the baryon production mechanism

International Nuclear Information System (INIS)

Abbiendi, G.; Braibant, S.; Capiluppi, P.; Ciocca, C.; Cuffiani, M.; Dallavalle, M.; Fabbri, F.; Giacomelli, G.; Giacomelli, P.; Ludwig, J.; Merritt, F.S.; Rembser, C.; Ainsley, C.; Batley, R.J.; Carter, J.R.; Hill, J.C.; Tarem, S.; Verzocchi, M.; Voss, H.; Aakesson, P.F.; Barberio, E.; Burckhart, H.J.; Roeck, A. de; Wolf, E.A. de; Ferrari, P.; Frey, A.; Gruwe, M.; Hauschild, M.; Hawkings, R.; Maettig, P.; Nanjo, H.; Pater, J.R.; Pinfold, J.; Pooth, O.; Przybycien, M.; Runge, K.; Sarkisyan, E.K.G.; Schaile, O.; Scharff-Hansen, P.; Schroeder, M.; Shen, B.C.; Strom, D.; Thomson, M.A.; Vannerem, P.; Vertesi, R.; Watkins, P.M.; Watson, A.T.; Alexander, G.; Bella, G.; Etzion, E.; Grunhaus, J.; Toya, D.; Anagnostou, G.; Bell, P.J.; Charlton, D.G.; Hawkes, C.M.; Jeremie, H.; Nakamura, I.; Trigger, I.; Vossebeld, J.; Ward, C.P.; Ward, D.R.; Wermes, N.; Anderson, K.J.; Gupta, A.; McPherson, R.A.; Neal, H.A.; Pahl, C.; Smith, A.M.; Stroehmer, R.; Asai, S.; Igo-Kemenes, P.; Junk, T.R.; Karlen, D.; Kawagoe, K.; Kluth, S.; Kobel, M.; Marcellini, S.; Mes, H.; Mikenberg, G.; Mori, T.; Mutter, A.; O'Neale, S.W.; Rozen, Y.; Teuscher, R.; Trocsanyi, Z.; Wilson, J.A.; Axen, D.; Lloyd, S.L.; Martin, A.J.; Bailey, I.; Kanzaki, J.; Kawamoto, T.; Mashimo, T.; Rabbertz, K.; Sherwood, P.; Barillari, T.; Bethke, S.; Kennedy, B.W.; Oh, A.; Plane, D.E.; Schaile, A.D.; Barlow, R.J.; Duerdoth, I.P.; Ford, M.; Kupper, M.; Lillich, J.; Orito, S.; Skuja, A.; Wengler, T.; Wilson, G.W.; Bechtle, P.; Behnke, T.; Desch, K.; Hamann, M.; Heuer, R.D.; Komamiya, S.; Krogh, J. von; McKenna, J.; Menges, W.; Bell, K.W.; Brown, R.M.; Kellogg, R.G.; Bellerive, A.; Carnegie, R.K.; Jovanovic, P.; Krasznahorkay, A.; Meijers, F.; Rossi, A.M.; Benelli, G.; Campana, S.; Gary, J.W.; Giunta, M.; Hanson, G.G.; Oreglia, M.J.; Schumacher, M.; Wolf, G.; Biebel, O.; Boutemeur, M.; Dubbert, J.; Duckeck, G.; Fiedler, F.; Sachs, K.; Saeki, T.; Spano, F.; Turner-Watson, M.F.; Boeriu, O.; Fleck, I.; Herten, G.; Letts, J.; Lu, J.; Mihara, S.; Miller, D.J.; Roney, J.M.; Ueda, I.; Bock, P.; Krieger, P.; Wells, P.S.; Carter, A.A.; Levinson, L.; Mader, W.; Mohr, W.; Chang, C.Y.; Keeler, R.K.; Shears, T.G.; Vollmer, C.F.; Csilling, A.; Hajdu, C.; Horvath, D.; Dado, S.; Goldberg, J.; Harel, A.; Lafferty, G.D.; Renkel, P.; Stahl, A.; Wyatt, T.R.; Dienes, B.; Kraemer, T.; Torrence, E.; Tsur, E.; Ujvari, B.; Duchovni, E.; Gross, E.; Kuhl, T.; Lanske, D.; Lellouch, D.; Meyer, N.; Quadt, A.; Wetterling, D.; Gagnon, P.; Geich-Gimbel, C.; Kobayashi, T.; Loebinger, F.K.; Ludwig, A.; Schieck, J.; Watson, N.K.; Ishii, K.; Landsman, H.; Pilcher, J.E.; Schoerner-Sadenius, T.; Sobie, R.; Michelini, A.; Seuster, R.; Nagai, K.; Pasztor, G.; Soeldner-Rembold, S.; Tasevsky, M.

2009-01-01

Data collected around √(s)=91 GeV by the OPAL experiment at the LEP e + e - collider are used to study the mechanism of baryon formation. As the signature, the fraction of Σ - hyperons whose baryon number is compensated by the production of a anti Σ - , anti Λ or anti Ξ - antihyperon is determined. The method relies entirely on quantum number correlations of the baryons, and not rapidity correlations, making it more model independent than previous studies. Within the context of the JETSET implementation of the string hadronization model, the diquark baryon production model without the popcorn mechanism is strongly disfavored with a significance of 3.8 standard deviations including systematic uncertainties. It is shown that previous studies of the popcorn mechanism with Λanti Λ and p anti p correlations are not conclusive, if parameter uncertainties are considered. (orig.)

Load and distinctness interact in working memory for lexical manual gestures

Directory of Open Access Journals (Sweden)

Mary eRudner

2015-08-01

Full Text Available The Ease of Language Understanding model (ELU, Rönnberg et al., 2013 predicts that decreasing the distinctness of language stimuli increases working memory load; in the speech domain this notion is supported by empirical evidence. Our aim was to determine whether such an over-additive interaction can be generalized to sign processing in sign-naïve individuals and whether it is modulated by experience of computer gaming. Twenty young adults with no knowledge of sign language performed an n-back working memory task based on manual gestures lexicalized in sign language; the visual resolution of the signs and working memory load were manipulated. Performance was poorer when load was high and resolution was low. These two effects interacted over-additively, demonstrating that reducing the resolution of signed stimuli increases working memory load when there is no pre-existing semantic representation. This suggests that load and distinctness are handled by a shared amodal mechanism which can be revealed empirically when stimuli are degraded and load is high, even without pre-existing semantic representation. There was some evidence that the mechanism is influenced by computer gaming experience. Future work should explore how the shared mechanism is influenced by pre-existing semantic representation and sensory factors together with computer gaming experience.

Load and distinctness interact in working memory for lexical manual gestures.

Science.gov (United States)

Rudner, Mary; Toscano, Elena; Holmer, Emil

2015-01-01

The Ease of Language Understanding model (Rönnberg et al., 2013) predicts that decreasing the distinctness of language stimuli increases working memory load; in the speech domain this notion is supported by empirical evidence. Our aim was to determine whether such an over-additive interaction can be generalized to sign processing in sign-naïve individuals and whether it is modulated by experience of computer gaming. Twenty young adults with no knowledge of sign language performed an n-back working memory task based on manual gestures lexicalized in sign language; the visual resolution of the signs and working memory load were manipulated. Performance was poorer when load was high and resolution was low. These two effects interacted over-additively, demonstrating that reducing the resolution of signed stimuli increases working memory load when there is no pre-existing semantic representation. This suggests that load and distinctness are handled by a shared amodal mechanism which can be revealed empirically when stimuli are degraded and load is high, even without pre-existing semantic representation. There was some evidence that the mechanism is influenced by computer gaming experience. Future work should explore how the shared mechanism is influenced by pre-existing semantic representation and sensory factors together with computer gaming experience.

Universal mechanisms of sound production and control in birds and mammals

DEFF Research Database (Denmark)

Elemans, Coen; Rasmussen, Jeppe Have; Herbst, Christian T.

2015-01-01

As animals vocalize, their vocal organ transforms motor commands into vocalizations for social communication. In birds, the physical mechanisms by which vocalizations are produced and controlled remain unresolved because of the extreme difficulty in obtaining in vivo measurements. Here, we...... learning and is common to MEAD sound production across birds and mammals, including humans....

Distinct Neural Mechanisms Mediate Olfactory Memory Formation at Different Timescales

Science.gov (United States)

McNamara, Ann Marie; Magidson, Phillip D.; Linster, Christiane; Wilson, Donald A.; Cleland, Thomas A.

2008-01-01

Habituation is one of the oldest forms of learning, broadly expressed across sensory systems and taxa. Here, we demonstrate that olfactory habituation induced at different timescales (comprising different odor exposure and intertrial interval durations) is mediated by different neural mechanisms. First, the persistence of habituation memory is…

Developing hygiene protocols against mechanically transmitted pathogens in greenhouse tomato production systems

Science.gov (United States)

Greenhouse tomato propagation and production require intensive crop work that promotes the spread of mechanically transmitted pathogens (e.g. fungi, bacteria, viruses and viroids). Therefore, a clean seed program is very important to prevent any un-intentional introduction of seed-borne pathogens t...

Integrating mechanisms of visual guidance in naturalistic language production.

Science.gov (United States)

Coco, Moreno I; Keller, Frank

2015-05-01

Situated language production requires the integration of visual attention and linguistic processing. Previous work has not conclusively disentangled the role of perceptual scene information and structural sentence information in guiding visual attention. In this paper, we present an eye-tracking study that demonstrates that three types of guidance, perceptual, conceptual, and structural, interact to control visual attention. In a cued language production experiment, we manipulate perceptual (scene clutter) and conceptual guidance (cue animacy) and measure structural guidance (syntactic complexity of the utterance). Analysis of the time course of language production, before and during speech, reveals that all three forms of guidance affect the complexity of visual responses, quantified in terms of the entropy of attentional landscapes and the turbulence of scan patterns, especially during speech. We find that perceptual and conceptual guidance mediate the distribution of attention in the scene, whereas structural guidance closely relates to scan pattern complexity. Furthermore, the eye-voice span of the cued object and its perceptual competitor are similar; its latency mediated by both perceptual and structural guidance. These results rule out a strict interpretation of structural guidance as the single dominant form of visual guidance in situated language production. Rather, the phase of the task and the associated demands of cross-modal cognitive processing determine the mechanisms that guide attention.

Distinct neural mechanisms for body form and body motion discriminations

NARCIS (Netherlands)

Vangeneugden, Joris; Peelen, Marius V; Tadin, Duje; Battelli, Lorella

2014-01-01

Actions can be understood based on form cues (e.g., static body posture) as well as motion cues (e.g., gait patterns). A fundamental debate centers on the question of whether the functional and neural mechanisms processing these two types of cues are dissociable. Here, using fMRI, psychophysics, and

Mechanical design of translocating motor proteins.

Science.gov (United States)

Hwang, Wonmuk; Lang, Matthew J

2009-01-01

Translocating motors generate force and move along a biofilament track to achieve diverse functions including gene transcription, translation, intracellular cargo transport, protein degradation, and muscle contraction. Advances in single molecule manipulation experiments, structural biology, and computational analysis are making it possible to consider common mechanical design principles of these diverse families of motors. Here, we propose a mechanical parts list that include track, energy conversion machinery, and moving parts. Energy is supplied not just by burning of a fuel molecule, but there are other sources or sinks of free energy, by binding and release of a fuel or products, or similarly between the motor and the track. Dynamic conformational changes of the motor domain can be regarded as controlling the flow of free energy to and from the surrounding heat reservoir. Multiple motor domains are organized in distinct ways to achieve motility under imposed physical constraints. Transcending amino acid sequence and structure, physically and functionally similar mechanical parts may have evolved as nature's design strategy for these molecular engines.

Distinct brain mechanisms support spatial vs temporal filtering of nociceptive information.

Science.gov (United States)

Nahman-Averbuch, Hadas; Martucci, Katherine T; Granovsky, Yelena; Weissman-Fogel, Irit; Yarnitsky, David; Coghill, Robert C

2014-12-01

The role of endogenous analgesic mechanisms has largely been viewed in the context of gain modulation during nociceptive processing. However, these analgesic mechanisms may play critical roles in the extraction and subsequent utilization of information related to spatial and temporal features of nociceptive input. To date, it remains unknown if spatial and temporal filtering of nociceptive information is supported by similar analgesic mechanisms. To address this question, human volunteers were recruited to assess brain activation with functional magnetic resonance imaging during conditioned pain modulation (CPM) and offset analgesia (OA). CPM provides one paradigm for assessing spatial filtering of nociceptive information while OA provides a paradigm for assessing temporal filtering of nociceptive information. CPM and OA both produced statistically significant reductions in pain intensity. However, the magnitude of pain reduction elicited by CPM was not correlated with that elicited by OA across different individuals. Different patterns of brain activation were consistent with the psychophysical findings. CPM elicited widespread reductions in regions engaged in nociceptive processing such as the thalamus, insula, and secondary somatosensory cortex. OA produced reduced activity in the primary somatosensory cortex but was associated with greater activation in the anterior insula, dorsolateral prefrontal cortex, intraparietal sulcus, and inferior parietal lobule relative to CPM. In the brain stem, CPM consistently produced reductions in activity, while OA produced increases in activity. Conjunction analysis confirmed that CPM-related activity did not overlap with that of OA. Thus, dissociable mechanisms support inhibitory processes engaged during spatial vs temporal filtering of nociceptive information. Copyright © 2014 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Microvasular and macrovascular complications in diabetes mellitus: Distinct or continuum?

Directory of Open Access Journals (Sweden)

Aastha Chawla

2016-01-01

Full Text Available Diabetes and related complications are associated with long-term damage and failure of various organ systems. The line of demarcation between the pathogenic mechanisms of microvascular and macrovascular complications of diabetes and differing responses to therapeutic interventions is blurred. Diabetes induces changes in the microvasculature, causing extracellular matrix protein synthesis, and capillary basement membrane thickening which are the pathognomic features of diabetic microangiopathy. These changes in conjunction with advanced glycation end products, oxidative stress, low grade inflammation, and neovascularization of vasa vasorum can lead to macrovascular complications. Hyperglycemia is the principal cause of microvasculopathy but also appears to play an important role in causation of macrovasculopathy. There is thought to be an intersection between micro and macro vascular complications, but the two disorders seem to be strongly interconnected, with micro vascular diseases promoting atherosclerosis through processes such as hypoxia and changes in vasa vasorum. It is thus imperative to understand whether microvascular complications distinctly precede macrovascular complications or do both of them progress simultaneously as a continuum. This will allow re-focusing on the clinical issues with a unifying perspective which can improve type 2 diabetes mellitus outcomes.

Ibuprofen and Diclofenac Restrict Migration and Proliferation of Human Glioma Cells by Distinct Molecular Mechanisms

Science.gov (United States)

Leidgens, Verena; Seliger, Corinna; Jachnik, Birgit; Welz, Tobias; Leukel, Petra; Vollmann-Zwerenz, Arabel; Bogdahn, Ulrich; Kreutz, Marina; Grauer, Oliver M.; Hau, Peter

2015-01-01

Background Non-steroidal anti-inflammatory drugs (NSAIDs) have been associated with anti-tumorigenic effects in different tumor entities. For glioma, research has generally focused on diclofenac; however data on other NSAIDs, such as ibuprofen, is limited. Therefore, we performed a comprehensive investigation of the cellular, molecular, and metabolic effects of ibuprofen and diclofenac on human glioblastoma cells. Methods Glioma cell lines were treated with ibuprofen or diclofenac to investigate functional effects on proliferation and cell motility. Cell cycle, extracellular lactate levels, lactate dehydrogenase-A (LDH-A) expression and activity, as well as inhibition of the Signal Transducer and Activator of Transcription 3 (STAT-3) signaling pathway, were determined. Specific effects of diclofenac and ibuprofen on STAT-3 were investigated by comparing their effects with those of the specific STAT-3 inhibitor STATTIC. Results Ibuprofen treatment led to a stronger inhibition of cell growth and migration than treatment with diclofenac. Proliferation was affected by cell cycle arrest at different checkpoints by both agents. In addition, diclofenac, but not ibuprofen, decreased lactate levels in all concentrations used. Both decreased STAT-3 phosphorylation; however, diclofenac led to decreased c-myc expression and subsequent reduction in LDH-A activity, whereas treatment with ibuprofen in higher doses induced c-myc expression and less LDH-A alteration. Conclusions This study indicates that both ibuprofen and diclofenac strongly inhibit glioma cells, but the subsequent metabolic responses of both agents are distinct. We postulate that ibuprofen may inhibit tumor cells also by COX- and lactate-independent mechanisms after long-term treatment in physiological dosages, whereas diclofenac mainly acts by inhibition of STAT-3 signaling and downstream modulation of glycolysis. PMID:26485029

Keeping conceptual boundaries distinct between decision making and learning is necessary to understand social influence.

Science.gov (United States)

Le Mens, Gaël

2014-02-01

Bentley et al. make the deliberate choice to blur the distinction between learning and decision making. This obscures the social influence mechanisms that operate in the various empirical settings that their map aims to categorize. Useful policy prescriptions, however, require an accurate understanding of the social influence mechanisms that underlie the dynamics of popularity.

Algorithm of choosing type of mechanical assembly production of instrument making enterprises of Industry 4.0

Science.gov (United States)

Zakoldaev, D. A.; Shukalov, A. V.; Zharinov, I. O.; Zharinov, O. O.

2018-05-01

The task of the algorithm of choosing the type of mechanical assembly production of instrument making enterprises of Industry 4.0 is being studied. There is a comparison of two project algorithms for Industry 3.0 and Industry 4.0. The algorithm of choosing the type of mechanical assembly production of instrument making enterprises of Industry 4.0 is based on the technological route analysis of the manufacturing process in a company equipped with cyber and physical systems. This algorithm may give some project solutions selected from the primary part or the auxiliary one of the production. The algorithm decisive rules are based on the optimal criterion.

Distinction of water-soluble constituents between natural and cultured Cordyceps by capillary electrophoresis.

Science.gov (United States)

Li, S P; Song, Z H; Dong, T T X; Ji, Z N; Lo, C K; Zhu, S Q; Tsim, K W K

2004-11-01

Cordyceps is an expensive traditional Chinese medicine, which has anti-tumor activity and significant effects on the immune system. In Southeast Asia, Cordyceps is commonly sold in capsule form as a health food product. Most of these products are derived from cultured Cordyceps mycelia. Because of the price difference, some manufacturers claim their products are from natural Cordyceps. In order to distinguish among various types of Cordyceps in the market, the profiles of water-soluble constituents derived from different sources of Cordyceps were determined by capillary electrophoresis (CE). Both natural and cultured Cordyceps showed three peak clusters migrated at 5-7, 9-11 and 12-13 min, and the height and resolution of these peak clusters were rather distinct. Peak cluster at 9-11 min was identified as adenosine, guanosine and uridine, and shared a similarity between natural and cultured products. In contrast, the peak cluster at 5-7 min was characteristic of natural Cordyceps, regardless of hosts and sources. By using the peak characteristics of CE profiles of different Cordyceps samples, hierarchical clustering analysis was performed. The result shows that those samples of natural Cordyceps were grouped together distinct from the cultured and commercial products. Thus, the CE profiles could serve as fingerprints for the quality control of Cordyceps.

Moyal products-a new perspective on quasi-Hermitian quantum mechanics

International Nuclear Information System (INIS)

Scholtz, F G; Geyer, H B

2006-01-01

The rationale for introducing non-Hermitian Hamiltonians and other observables is reviewed and open issues identified. We present a new approach based on Moyal products to compute the metric for quasi-Hermitian systems. This approach is not only an efficient method of computation, but also suggests a new perspective on quasi-Hermitian quantum mechanics which invites further exploration. In particular, we present some first results which link the Berry connection and curvature to non-perturbative properties and the metric

On the neural mechanisms subserving consciousness and attention

Directory of Open Access Journals (Sweden)

Catherine eTallon-Baudry

2012-01-01

Full Text Available Consciousness, as described in the experimental literature, is a multi-faceted phenomenon, that impinges on other well-studied concepts such as attention and control. Do consciousness and attention refer to different aspects of the same core phenomenon, or do they correspond to distinct functions? One possibility to address this question is to examine the neural mechanisms underlying consciousness and attention. If consciousness and attention pertain to the same concept, they should rely on shared neural mechanisms. Conversely, if their underlying mechanisms are distinct, then consciousness and attention should be considered as distinct entities. This paper therefore reviews neurophysiological facts arguing in favor or against a tight relationship between consciousness and attention. Three neural mechanisms that have been associated with both attention and consciousness are examined (neural amplification, involvement of the fronto-parietal network, and oscillatory synchrony, to conclude that the commonalities between attention and consciousness at the neural level may have been overestimated. Last but not least, experiments in which both attention and consciousness were probed at the neural level point toward a dissociation between the two concepts. It therefore appears from this review that consciousness and attention rely on distinct neural properties, although they can interact at the behavioral level. It is proposed that a "cumulative influence model", in which attention and consciousness correspond to distinct neural mechanisms feeding a single decisional process leading to behavior, fits best with available neural and behavioral data. In this view, consciousness should not be considered as a top-level executive function but should rather be defined by its experiential properties.

A mechanism for the production of ultrafine particles from concrete fracture.

Science.gov (United States)

Jabbour, Nassib; Rohan Jayaratne, E; Johnson, Graham R; Alroe, Joel; Uhde, Erik; Salthammer, Tunga; Cravigan, Luke; Faghihi, Ehsan Majd; Kumar, Prashant; Morawska, Lidia

2017-03-01

While the crushing of concrete gives rise to large quantities of coarse dust, it is not widely recognized that this process also emits significant quantities of ultrafine particles. These particles impact not just the environments within construction activities but those in entire urban areas. The origin of these ultrafine particles is uncertain, as existing theories do not support their production by mechanical processes. We propose a hypothesis for this observation based on the volatilisation of materials at the concrete fracture interface. The results from this study confirm that mechanical methods can produce ultrafine particles (UFP) from concrete, and that the particles are volatile. The ultrafine mode was only observed during concrete fracture, producing particle size distributions with average count median diameters of 27, 39 and 49 nm for the three tested concrete samples. Further volatility measurements found that the particles were highly volatile, showing between 60 and 95% reduction in the volume fraction remaining by 125 °C. An analysis of the volatile fraction remaining found that different volatile material is responsible for the production of particles between the samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

HEAVY AND THERMAL OIL RECOVERY PRODUCTION MECHANISMS

Energy Technology Data Exchange (ETDEWEB)

Anthony R. Kovscek; Louis M. Castanier

2002-09-30

The Stanford University Petroleum Research Institute (SUPRI-A) conducts a broad spectrum of research intended to help improve the recovery efficiency from difficult to produce reservoirs including heavy oil and fractured low permeability systems. Our scope of work is relevant across near-, mid-, and long-term time frames. The primary functions of the group are to conduct direction-setting research, transfer research results to industry, and educate and train students for careers in industry. Presently, research in SUPRI-A is divided into 5 main project areas. These projects and their goals include: (1) Multiphase flow and rock properties--to develop better understanding of the physics of displacement in porous media through experiment and theory. This category includes work on imbibition, flow in fractured media, and the effect of temperature on relative permeability and capillary pressure. (2) Hot fluid injection--to improve the application of nonconventional wells for enhanced oil recovery and elucidate the mechanisms of steamdrive in low permeability, fractured porous media. (3) Mechanisms of primary heavy oil recovery--to develop a mechanistic understanding of so-called ''foamy oil'' and its associated physical chemistry. (4) In-situ combustion--to evaluate the effect of different reservoir parameters on the insitu combustion process. (5) Reservoir definition--to develop and improve techniques for evaluating formation properties from production information. What follows is a report on activities for the past year. Significant progress was made in all areas.

Rapid and reversible impairments of short- and long-term social recognition memory are caused by acute isolation of adult rats via distinct mechanisms.

Science.gov (United States)

Shahar-Gold, Hadar; Gur, Rotem; Wagner, Shlomo

2013-01-01

Mammalian social organizations require the ability to recognize and remember individual conspecifics. This social recognition memory (SRM) can be examined in rodents using their innate tendency to investigate novel conspecifics more persistently than familiar ones. Here we used the SRM paradigm to examine the influence of housing conditions on the social memory of adult rats. We found that acute social isolation caused within few days a significant impairment in acquisition of short-term SRM of male and female rats. Moreover, SRM consolidation into long-term memory was blocked following only one day of social isolation. Both impairments were reversible, but with different time courses. Furthermore, only the impairment in SRM consolidation was reversed by systemic administration of arginine-vasopressin (AVP). In contrast to SRM, object recognition memory was not affected by social isolation. We conclude that acute social isolation rapidly induces reversible changes in the brain neuronal and molecular mechanisms underlying SRM, which hamper its acquisition and completely block its consolidation. These changes occur via distinct, AVP sensitive and insensitive mechanisms. Thus, acute social isolation of rats swiftly causes changes in their brain and interferes with their normal social behavior.

Rapid and reversible impairments of short- and long-term social recognition memory are caused by acute isolation of adult rats via distinct mechanisms.

Directory of Open Access Journals (Sweden)

Hadar Shahar-Gold

Full Text Available Mammalian social organizations require the ability to recognize and remember individual conspecifics. This social recognition memory (SRM can be examined in rodents using their innate tendency to investigate novel conspecifics more persistently than familiar ones. Here we used the SRM paradigm to examine the influence of housing conditions on the social memory of adult rats. We found that acute social isolation caused within few days a significant impairment in acquisition of short-term SRM of male and female rats. Moreover, SRM consolidation into long-term memory was blocked following only one day of social isolation. Both impairments were reversible, but with different time courses. Furthermore, only the impairment in SRM consolidation was reversed by systemic administration of arginine-vasopressin (AVP. In contrast to SRM, object recognition memory was not affected by social isolation. We conclude that acute social isolation rapidly induces reversible changes in the brain neuronal and molecular mechanisms underlying SRM, which hamper its acquisition and completely block its consolidation. These changes occur via distinct, AVP sensitive and insensitive mechanisms. Thus, acute social isolation of rats swiftly causes changes in their brain and interferes with their normal social behavior.

Crystal structure of A. aeolicus LpxC with bound product suggests alternate deacetylation mechanism.

Science.gov (United States)

Miller, Matthew D; Gao, Ning; Ross, Philip L; Olivier, Nelson B

2015-09-01

UDP-3-O-acyl-N-acetylglucosamine deacetylase (LpxC) is the first committed step to form lipid A, an essential component of the outer membrane of Gram-negative bacteria. As it is essential for the survival of many pathogens, LpxC is an attractive target for antibacterial therapeutics. Herein, we report the product-bound co-crystal structure of LpxC from the acheal Aquifex aeolicus solved to 1.6 Å resolution. We identified interactions by hydroxyl and hydroxymethyl substituents of the product glucosamine ring that may enable new insights to exploit waters in the active site for structure-based design of LpxC inhibitors with novel scaffolds. By using this product structure, we have performed quantum mechanical modeling on the substrate in the active site. Based on our results and published experimental data, we propose a new mechanism that may lead to a better understanding of LpxC catalysis and inhibition. © 2015 Wiley Periodicals, Inc.

Effects of mechanical repetitive load on bone quality around implants in rat maxillae.

Directory of Open Access Journals (Sweden)

Yusuke Uto

Full Text Available Greater understanding and acceptance of the new concept "bone quality", which was proposed by the National Institutes of Health and is based on bone cells and collagen fibers, are required. The novel protein Semaphorin3A (Sema3A is associated with osteoprotection by regulating bone cells. The aims of this study were to investigate the effects of mechanical loads on Sema3A production and bone quality based on bone cells and collagen fibers around implants in rat maxillae. Grade IV-titanium threaded implants were placed at 4 weeks post-extraction in maxillary first molars. Implants received mechanical loads (10 N, 3 Hz for 1800 cycles, 2 days/week for 5 weeks from 3 weeks post-implant placement to minimize the effects of wound healing processes by implant placement. Bone structures, bone mineral density (BMD, Sema3A production and bone quality based on bone cells and collagen fibers were analyzed using microcomputed tomography, histomorphometry, immunohistomorphometry, polarized light microscopy and birefringence measurement system inside of the first and second thread (designated as thread A and B, respectively, as mechanical stresses are concentrated and differently distributed on the first two threads from the implant neck. Mechanical load significantly increased BMD, but not bone volume around implants. Inside thread B, but not thread A, mechanical load significantly accelerated Sema3A production with increased number of osteoblasts and osteocytes, and enhanced production of both type I and III collagen. Moreover, mechanical load also significantly induced preferential alignment of collagen fibers in the lower flank of thread B. These data demonstrate that mechanical load has different effects on Sema3A production and bone quality based on bone cells and collagen fibers between the inside threads of A and B. Mechanical load-induced Sema3A production may be differentially regulated by the type of bone structure or distinct stress distribution

TOPOISOMERASE1α Acts through Two Distinct Mechanisms to Regulate Stele and Columella Stem Cell Maintenance.

Science.gov (United States)

Zhang, Yonghong; Zheng, Lanlan; Hong, Jing Han; Gong, Ximing; Zhou, Chun; Pérez-Pérez, José Manuel; Xu, Jian

2016-05-01

TOPOISOMERASE1 (TOP1), which releases DNA torsional stress generated during replication through its DNA relaxation activity, plays vital roles in animal and plant development. In Arabidopsis (Arabidopsis thaliana), TOP1 is encoded by two paralogous genes (TOP1α and TOP1β), of which TOP1α displays specific developmental functions that are critical for the maintenance of shoot and floral stem cells. Here, we show that maintenance of two different populations of root stem cells is also dependent on TOP1α-specific developmental functions, which are exerted through two distinct novel mechanisms. In the proximal root meristem, the DNA relaxation activity of TOP1α is critical to ensure genome integrity and survival of stele stem cells (SSCs). Loss of TOP1α function triggers DNA double-strand breaks in S-phase SSCs and results in their death, which can be partially reversed by the replenishment of SSCs mediated by ETHYLENE RESPONSE FACTOR115 In the quiescent center and root cap meristem, TOP1α is epistatic to RETINOBLASTOMA-RELATED (RBR) in the maintenance of undifferentiated state and the number of columella stem cells (CSCs). Loss of TOP1α function in either wild-type or RBR RNAi plants leads to differentiation of CSCs, whereas overexpression of TOP1α mimics and further enhances the effect of RBR reduction that increases the number of CSCs Taken together, these findings provide important mechanistic insights into understanding stem cell maintenance in plants. © 2016 American Society of Plant Biologists. All Rights Reserved.

Fission product vapour - aerosol interactions in the containment: simulant fuel studies

International Nuclear Information System (INIS)

Beard, A.M.; Benson, C.G.; Bowsher, B.R.

1988-12-01

Experiments have been conducted in the Falcon facility to study the interaction of fission product vapours released from simulant fuel samples with control rod aerosols. The aerosols generated from both the control rod and fuel sample were chemically distinct and had different deposition characteristics. Extensive interaction was observed between the fission product vapours and the control rod aerosol. The two dominant mechanisms were condensation of the vapours onto the aerosol, and chemical reactions between the two components; sorption phenomena were believed to be only of secondary importance. The interaction of fission product vapours and reactor materials aerosols could have a major impact on the transport characteristics of the radioactive emission from a degrading core. (author)

Differential regulation of amyloid precursor protein sorting with pathological mutations results in a distinct effect on amyloid-β production.

Science.gov (United States)

Lin, Yen-Chen; Wang, Jia-Yi; Wang, Kai-Chen; Liao, Jhih-Ying; Cheng, Irene H

2014-11-01

The deposition of amyloid-β (Aβ) peptide, which is generated from amyloid precursor protein (APP), is the pathological hallmark of Alzheimer's disease (AD). Three APP familial AD mutations (D678H, D678N, and H677R) located at the sixth and seventh amino acid of Aβ have distinct effect on Aβ aggregation, but their influence on the physiological and pathological roles of APP remain unclear. We found that the D678H mutation strongly enhances amyloidogenic cleavage of APP, thus increasing the production of Aβ. This enhancement of amyloidogenic cleavage is likely because of the acceleration of APPD678H sorting into the endosomal-lysosomal pathway. In contrast, the APPD678N and APPH677R mutants do not cause the same effects. Therefore, this study indicates a regulatory role of D678H in APP sorting and processing, and provides genetic evidence for the importance of APP sorting in AD pathogenesis. The internalization of amyloid precursor protein (APP) increases its opportunity to be processed by β-secretase and to produce Amyloid-β (Aβ) that causes Alzheimer's disease (AD). We report a pathogenic APPD678H mutant that enhances APP internalization into the endosomal-lysosomal pathway and thus promotes the β-secretase cleavage and Aβ production. This study provides genetic evidence for the importance of APP sorting in AD pathogenesis. © 2014 International Society for Neurochemistry.

Citric acid production and citrate synthase genes in distinct strains of ...

African Journals Online (AJOL)

SAM

2014-05-28

May 28, 2014 ... synthase in lactic acid production by A. niger and with the ... A number of microorganisms, including both bacteria and fungi, possess the capacity ..... citric acid production by solid-state fermentation from cassava bagasse and ...

Measuring green productivity of country: A generlized metafrontier Malmquist productivity index approach

International Nuclear Information System (INIS)

Yu-Ying Lin, Eugene; Chen, Ping-Yu; Chen, Chi-Chung

2013-01-01

This paper measures environmental productivity in 70 countries over the period 1981–2007. Differences in green (environmental) productivity growth across countries under distinct country specific production frontier are measured using directional distance function model, which incorporates desirable output (GDP) and undesirable output (CO 2 emissions). The metafrontier which envelops the two country groups, developed countries and developing countries, are estimated using balanced panel data for the sample countries over the study period. A parametric method is used to compute technical efficiency change, technical change, and scale efficiency change, which aggregate to the generalized metafrontier Malmquist productivity index. The overall results indicated the two country groups operated under distinct stochastic production frontiers and therefore used different production technologies. It is found that developing countries achieved higher growth in their average environmental productivity relative to the metafrontier. Thus the results coincide with the convergence growth theory

Mechanisms of fever production and lysis: lessons from experimental LPS fever.

Science.gov (United States)

Roth, Joachim; Blatteis, Clark M

2014-10-01

Fever is a cardinal symptom of infectious or inflammatory insults, but it can also arise from noninfectious causes. The fever-inducing agent that has been used most frequently in experimental studies designed to characterize the physiological, immunological and neuroendocrine processes and to identify the neuronal circuits that underlie the manifestation of the febrile response is lipopolysaccharide (LPS). Our knowledge of the mechanisms of fever production and lysis is largely based on this model. Fever is usually initiated in the periphery of the challenged host by the immediate activation of the innate immune system by LPS, specifically of the complement (C) cascade and Toll-like receptors. The first results in the immediate generation of the C component C5a and the subsequent rapid production of prostaglandin E2 (PGE2). The second, occurring after some delay, induces the further production of PGE2 by induction of its synthesizing enzymes and transcription and translation of proinflammatory cytokines. The Kupffer cells (Kc) of the liver seem to be essential for these initial processes. The subsequent transfer of the pyrogenic message from the periphery to the brain is achieved by neuronal and humoral mechanisms. These pathways subserve the genesis of early (neuronal signals) and late (humoral signals) phases of the characteristically biphasic febrile response to LPS. During the course of fever, counterinflammatory factors, "endogenous antipyretics," are elaborated peripherally and centrally to limit fever in strength and duration. The multiple interacting pro- and antipyretic signals and their mechanistic effects that underlie endotoxic fever are the subjects of this review.

Pervaporation membrane bioreactor with permeate fractional condensation and mechanical vapor compression for energy efficient ethanol production

International Nuclear Information System (INIS)

Fan, Senqing; Xiao, Zeyi; Li, Minghai; Li, Sizhong

2016-01-01

Graphical abstract: Pervaporation membrane bioreactor with permeate partial condensation and mechanical vapor compression is developed for an energy efficient ethanol production. - Highlights: • PVMBR-MVC for energy efficient ethanol production. • Process separation factor of 20–44 for ethanol achieved by fractional condensation. • Energy production of 20.25 MJ and hourly energy production of 56.25 kJ/h achieved. • Over 50% of energy saved in PVMBR-MVC compared with PVMBR-LTC. • Integrated heat pump with COP of 7–9 for the energy recovery of the permeate. - Abstract: Improved process separation factor and heat integration are two key issues to increase the energy efficiency of ethanol production in a pervaporation membrane bioreactor (PVMBR). A PVMBR with permeate fractional condensation and mechanical vapor compression was developed for energy efficient ethanol production. A condensation model based on the mass balance and thermodynamic equilibrium in the partial vacuum condenser was developed for predicting the purification performance of the permeate vapor. Three runs of ethanol fermentation-pervaporation experiment were carried out and ethanol concentration of higher than 50 wt% could be achieved in the final condensate, with the separation factor of the process for ethanol increased to 20. Ethanol production could be enhanced in the bioreactor and 17.1 MJ of the energy could be produced in per liter of fermentation broth, owing to 27.0 MJ/kg heating value of the recovered ethanol. Compared with the traditional pervaporation process with low temperature condensation for ethanol production, 50% of the energy would be saved in the process. The energy consumption would be further reduced, if the available energy of the permeate vapor was utilized by integrating the mechanical vapor compression heat pump.

Unified thalamic model generates multiple distinct oscillations with state-dependent entrainment by stimulation.

Directory of Open Access Journals (Sweden)

Guoshi Li

2017-10-01

Full Text Available The thalamus plays a critical role in the genesis of thalamocortical oscillations, yet the underlying mechanisms remain elusive. To understand whether the isolated thalamus can generate multiple distinct oscillations, we developed a biophysical thalamic model to test the hypothesis that generation of and transition between distinct thalamic oscillations can be explained as a function of neuromodulation by acetylcholine (ACh and norepinephrine (NE and afferent synaptic excitation. Indeed, the model exhibited four distinct thalamic rhythms (delta, sleep spindle, alpha and gamma oscillations that span the physiological states corresponding to different arousal levels from deep sleep to focused attention. Our simulation results indicate that generation of these distinct thalamic oscillations is a result of both intrinsic oscillatory cellular properties and specific network connectivity patterns. We then systematically varied the ACh/NE and input levels to generate a complete map of the different oscillatory states and their transitions. Lastly, we applied periodic stimulation to the thalamic network and found that entrainment of thalamic oscillations is highly state-dependent. Our results support the hypothesis that ACh/NE modulation and afferent excitation define thalamic oscillatory states and their response to brain stimulation. Our model proposes a broader and more central role of the thalamus in the genesis of multiple distinct thalamo-cortical rhythms than previously assumed.

A Distinct Population of Microglia Supports Adult Neurogenesis in the Subventricular Zone

DEFF Research Database (Denmark)

Ribeiro Xavier, Anna L.; Kress, Benjamin T.; Goldman, Steven A.

2015-01-01

found that microglia residing in the SVZ and adjacent rostral migratory stream (RMS) comprise a morphologically and antigenically distinct phenotype of immune effectors. Whereas exhibiting characteristics of alternatively activated microglia, the SVZ/RMS microglia were clearly distinguished by their low...... STATEMENT: Microglial cells are a specialized population of macrophages in the CNS, playing key roles as immune mediators. As integral components in the CNS, the microglia stand out for using the same mechanisms, phagocytosis and cytochemokine release, to promote homeostasis, synaptic pruning, and neural...... toward olfactory bulb layers. In addition to other unique populations residing in the SVZ niche, microglia display distinct morphofunctional properties that boost neuronal progenitor survival and migration in the mammalian brain....

Hypothermia in mouse is caused by adenosine A1 and A3 receptor agonists and AMP via three distinct mechanisms.

Science.gov (United States)

Carlin, Jesse Lea; Jain, Shalini; Gizewski, Elizabeth; Wan, Tina C; Tosh, Dilip K; Xiao, Cuiying; Auchampach, John A; Jacobson, Kenneth A; Gavrilova, Oksana; Reitman, Marc L

2017-03-01

Small mammals have the ability to enter torpor, a hypothermic, hypometabolic state, allowing impressive energy conservation. Administration of adenosine or adenosine 5'-monophosphate (AMP) can trigger a hypothermic, torpor-like state. We investigated the mechanisms for hypothermia using telemetric monitoring of body temperature in wild type and receptor knock out (Adora1 -/- , Adora3 -/- ) mice. Confirming prior data, stimulation of the A 3 adenosine receptor (AR) induced hypothermia via peripheral mast cell degranulation, histamine release, and activation of central histamine H 1 receptors. In contrast, A 1 AR agonists and AMP both acted centrally to cause hypothermia. Commonly used, selective A 1 AR agonists, including N 6 -cyclopentyladenosine (CPA), N 6 -cyclohexyladenosine (CHA), and MRS5474, caused hypothermia via both A 1 AR and A 3 AR when given intraperitoneally. Intracerebroventricular dosing, low peripheral doses of Cl-ENBA [(±)-5'-chloro-5'-deoxy-N 6 -endo-norbornyladenosine], or using Adora3 -/- mice allowed selective stimulation of A 1 AR. AMP-stimulated hypothermia can occur independently of A 1 AR, A 3 AR, and mast cells. A 1 AR and A 3 AR agonists and AMP cause regulated hypothermia that was characterized by a drop in total energy expenditure, physical inactivity, and preference for cooler environmental temperatures, indicating a reduced body temperature set point. Neither A 1 AR nor A 3 AR was required for fasting-induced torpor. A 1 AR and A 3 AR agonists and AMP trigger regulated hypothermia via three distinct mechanisms. Published by Elsevier Ltd.

Potential to Improve the Competitiveness of China's Electronic and Mechanical Products Exports

Institute of Scientific and Technical Information of China (English)

Wei Hao; Wang Xi; Wang Luxi

2010-01-01

@@ Since launching the reform and opening policy,and particularly since the mid-1990s with accelerating industrialization processes and further policy changes,the electronics and mechanical industry in China has made huge strides in production and foreign trade value,now accounting for approximately half of total exports from China and becoming a pillar industry of China's foreign trade.

Mathematical analysis of the impact mechanism of information platform on agro-product supply chain and agro-product competitiveness

Directory of Open Access Journals (Sweden)

Jiang Qi-Jie

2017-04-01

Full Text Available How to optimize agro-product supply chain to promote its operating efficiency so as to enhance the competitiveness of regional agricultural products has posed a problem to academic circles, business circles and governments of various levels. One way to solve this problem is to introduce an information platform into the supply chain, which this essay focuses on. Firstly, a review of existing research findings concerning the agro-product competitiveness, agro-product supply chain (ASC and information platform was given. Secondly, we constructed a mathematical model to analyze the impact of information platform on the bullwhip effect in ASC. Thirdly, another mathematical model was constructed to help compare and analyze the impact of information platform on information acquisition of members in ASC. The research results show that the implantation of information platform can mitigate the bullwhip effect in ASC, and members can determine order amount or production more close to the actual market demand. And also the information platform can reduce the time for members in ASC to get information from other members. Besides, information platform can help ASC to alleviate information asymmetry among upstream and downstream members. Furthermore, researches about the operating mechanism and pattern, technical feature and running structure of the information platform, along with their impacts on agro-product supply chain and the competitiveness of agricultural products need to be advanced.

Mathematical analysis of the impact mechanism of information platform on agro-product supply chain and agro-product competitiveness

Science.gov (United States)

Jiang, Qi-Jie; Jin, Mao-Zhu; Ren, Pei-Yu

2017-04-01

How to optimize agro-product supply chain to promote its operating efficiency so as to enhance the competitiveness of regional agricultural products has posed a problem to academic circles, business circles and governments of various levels. One way to solve this problem is to introduce an information platform into the supply chain, which this essay focuses on. Firstly, a review of existing research findings concerning the agro-product competitiveness, agro-product supply chain (ASC) and information platform was given. Secondly, we constructed a mathematical model to analyze the impact of information platform on the bullwhip effect in ASC. Thirdly, another mathematical model was constructed to help compare and analyze the impact of information platform on information acquisition of members in ASC. The research results show that the implantation of information platform can mitigate the bullwhip effect in ASC, and members can determine order amount or production more close to the actual market demand. And also the information platform can reduce the time for members in ASC to get information from other members. Besides, information platform can help ASC to alleviate information asymmetry among upstream and downstream members. Furthermore, researches about the operating mechanism and pattern, technical feature and running structure of the information platform, along with their impacts on agro-product supply chain and the competitiveness of agricultural products need to be advanced.

The effect of the production method on the mechanical strength of an alumina porous hollow fiber

NARCIS (Netherlands)

de Wit, Patrick; van Daalen, Frederique S.; Benes, Nieck E.

2017-01-01

The mechanical strength of inorganic porous hollow fibers is an important property and is strongly affected by the production method. Three production methods for fibers are compared: non-solvent induced phase separation (NIPS), bio-ionic gelation with an internal multivalent ion source (BIG-I), and

The determination and analysis of site-specific rates of mitochondrial reactive oxygen species production

DEFF Research Database (Denmark)

Quinlan, Casey L; Perevoschikova, Irina V; Goncalves, Renata L S

2013-01-01

Mitochondrial reactive oxygen species (ROS) are widely implicated in physiological and pathological pathways. We propose that it is critical to understand the specific sites of mitochondrial ROS production and their mechanisms of action. Mitochondria possess at least eight distinct sites of ROS...... production in the electron transport chain and matrix compartment. In this chapter, we describe the nature of the mitochondrial ROS-producing machinery and the relative capacities of each site. We provide detailed methods for the measurement of H2O2 release and the conditions under which maximal rates from...

New production mechanism for keV sterile neutrino Dark Matter by decays of frozen-in scalars

International Nuclear Information System (INIS)

Merle, Alexander; Niro, Viviana; Schmidt, Daniel

2014-01-01

We propose a new production mechanism for keV sterile neutrino Dark Matter. In our setting, we assume the existence of a scalar singlet particle which never entered thermal equilibrium in the early Universe, since it only couples to the Standard Model fields by a really small Higgs portal interaction. For suitable values of this coupling, the scalar can undergo the so-called freeze-in process, and in this way be efficiently produced in the early Universe. These scalars can then decay into keV sterile neutrinos and produce the correct Dark Matter abundance. While similar settings in which the scalar does enter thermal equilibrium and then freezes out have been studied previously, the mechanism proposed here is new and represents a versatile extension of the known case. We perform a detailed numerical calculation of the DM production using a set of coupled Boltzmann equations, and we illustrate the successful regions in the parameter space. Our production mechanism notably can even work in models where active-sterile mixing is completely absent

The signaling lipid sphingosine 1-phosphate regulates mechanical pain

Science.gov (United States)

Hill, Rose Z; Hoffman, Benjamin U; Morita, Takeshi; Campos, Stephanie M; Lumpkin, Ellen A; Brem, Rachel B

2018-01-01

Somatosensory neurons mediate responses to diverse mechanical stimuli, from innocuous touch to noxious pain. While recent studies have identified distinct populations of A mechanonociceptors (AMs) that are required for mechanical pain, the molecular underpinnings of mechanonociception remain unknown. Here, we show that the bioactive lipid sphingosine 1-phosphate (S1P) and S1P Receptor 3 (S1PR3) are critical regulators of acute mechanonociception. Genetic or pharmacological ablation of S1PR3, or blockade of S1P production, significantly impaired the behavioral response to noxious mechanical stimuli, with no effect on responses to innocuous touch or thermal stimuli. These effects are mediated by fast-conducting A mechanonociceptors, which displayed a significant decrease in mechanosensitivity in S1PR3 mutant mice. We show that S1PR3 signaling tunes mechanonociceptor excitability via modulation of KCNQ2/3 channels. Our findings define a new role for S1PR3 in regulating neuronal excitability and establish the importance of S1P/S1PR3 signaling in the setting of mechanical pain thresholds. PMID:29561262

J/Ψ-production of photon-photon colliders as a probe of the color octet mechanism

International Nuclear Information System (INIS)

Ma, J.P.; McKellar, B.H.J.; Paranavitane, C.B

1997-01-01

We study J/Ψ production at photon-photon colliders, which can be realised with Compton scattering of laser photons at e + e - colliders. We find that the production rate through the color-octet channel is comparable to that through the color-singlet channel. Experimentally the two mechanisms can be studied separately because the processes have different signals. (authors)

Do mechanical strain and TNF-α interact to amplify pro-inflammatory cytokine production in human annulus fibrosus cells?

Science.gov (United States)

Likhitpanichkul, Morakot; Torre, Olivia M; Gruen, Jadry; Walter, Benjamin A; Hecht, Andrew C; Iatridis, James C

2016-05-03

During intervertebral disc (IVD) injury and degeneration, annulus fibrosus (AF) cells experience large mechanical strains in a pro-inflammatory milieu. We hypothesized that TNF-α, an initiator of IVD inflammation, modifies AF cell mechanobiology via cytoskeletal changes, and interacts with mechanical strain to enhance pro-inflammatory cytokine production. Human AF cells (N=5, Thompson grades 2-4) were stretched uniaxially on collagen-I coated chambers to 0%, 5% (physiological) or 15% (pathologic) strains at 0.5Hz for 24h under hypoxic conditions with or without TNF-α (10ng/mL). AF cells were treated with anti-TNF-α and anti-IL-6. ELISA assessed IL-1β, IL-6, and IL-8 production and immunocytochemistry measured F-actin, vinculin and α-tubulin in AF cells. TNF-α significantly increased AF cell pro-inflammatory cytokine production compared to basal conditions (IL-1β:2.0±1.4-84.0±77.3, IL-6:10.6±9.9-280.9±214.1, IL-8:23.9±26.0-5125.1±4170.8pg/ml for basal and TNF-α treatment, respectively) as expected, but mechanical strain did not. Pathologic strain in combination with TNF-α increased IL-1β, and IL-8 but not IL-6 production of AF cells. TNF-α treatment altered F-actin and α-tubulin in AF cells, suggestive of altered cytoskeletal stiffness. Anti-TNF-α (infliximab) significantly inhibited pro-inflammatory cytokine production while anti-IL-6 (atlizumab) did not. In conclusion, TNF-α altered AF cell mechanobiology with cytoskeletal remodeling that potentially sensitized AF cells to mechanical strain and increased TNF-α-induced pro-inflammatory cytokine production. Results suggest an interaction between TNF-α and mechanical strain and future mechanistic studies are required to validate these observations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Training mechanical engineering students to utilize biological inspiration during product development.

Science.gov (United States)

Bruck, Hugh A; Gershon, Alan L; Golden, Ira; Gupta, Satyandra K; Gyger, Lawrence S; Magrab, Edward B; Spranklin, Brent W

2007-12-01

The use of bio-inspiration for the development of new products and devices requires new educational tools for students consisting of appropriate design and manufacturing technologies, as well as curriculum. At the University of Maryland, new educational tools have been developed that introduce bio-inspired product realization to undergraduate mechanical engineering students. These tools include the development of a bio-inspired design repository, a concurrent fabrication and assembly manufacturing technology, a series of undergraduate curriculum modules and a new senior elective in the bio-inspired robotics area. This paper first presents an overview of the two new design and manufacturing technologies that enable students to realize bio-inspired products, and describes how these technologies are integrated into the undergraduate educational experience. Then, the undergraduate curriculum modules are presented, which provide students with the fundamental design and manufacturing principles needed to support bio-inspired product and device development. Finally, an elective bio-inspired robotics project course is present, which provides undergraduates with the opportunity to demonstrate the application of the knowledge acquired through the curriculum modules in their senior year using the new design and manufacturing technologies.

Circuit mechanisms of sensorimotor learning

Science.gov (United States)

Makino, Hiroshi; Hwang, Eun Jung; Hedrick, Nathan G.; Komiyama, Takaki

2016-01-01

SUMMARY The relationship between the brain and the environment is flexible, forming the foundation for our ability to learn. Here we review the current state of our understanding of the modifications in the sensorimotor pathway related to sensorimotor learning. We divide the process in three hierarchical levels with distinct goals: 1) sensory perceptual learning, 2) sensorimotor associative learning, and 3) motor skill learning. Perceptual learning optimizes the representations of important sensory stimuli. Associative learning and the initial phase of motor skill learning are ensured by feedback-based mechanisms that permit trial-and-error learning. The later phase of motor skill learning may primarily involve feedback-independent mechanisms operating under the classic Hebbian rule. With these changes under distinct constraints and mechanisms, sensorimotor learning establishes dedicated circuitry for the reproduction of stereotyped neural activity patterns and behavior. PMID:27883902

Corticosteroid receptors adopt distinct cyclical transcriptional signatures.

Science.gov (United States)

Le Billan, Florian; Amazit, Larbi; Bleakley, Kevin; Xue, Qiong-Yao; Pussard, Eric; Lhadj, Christophe; Kolkhof, Peter; Viengchareun, Say; Fagart, Jérôme; Lombès, Marc

2018-05-07

Mineralocorticoid receptors (MRs) and glucocorticoid receptors (GRs) are two closely related hormone-activated transcription factors that regulate major pathophysiologic functions. High homology between these receptors accounts for the crossbinding of their corresponding ligands, MR being activated by both aldosterone and cortisol and GR essentially activated by cortisol. Their coexpression and ability to bind similar DNA motifs highlight the need to investigate their respective contributions to overall corticosteroid signaling. Here, we decipher the transcriptional regulatory mechanisms that underlie selective effects of MRs and GRs on shared genomic targets in a human renal cellular model. Kinetic, serial, and sequential chromatin immunoprecipitation approaches were performed on the period circadian protein 1 ( PER1) target gene, providing evidence that both receptors dynamically and cyclically interact at the same target promoter in a specific and distinct transcriptional signature. During this process, both receptors regulate PER1 gene by binding as homo- or heterodimers to the same promoter region. Our results suggest a novel level of MR-GR target gene regulation, which should be considered for a better and integrated understanding of corticosteroid-related pathophysiology.-Le Billan, F., Amazit, L., Bleakley, K., Xue, Q.-Y., Pussard, E., Lhadj, C., Kolkhof, P., Viengchareun, S., Fagart, J., Lombès, M. Corticosteroid receptors adopt distinct cyclical transcriptional signatures.

Kinetic study on ferulic acid production from banana stem waste via mechanical extraction

Science.gov (United States)

Zainol, Norazwina; Masngut, Nasratun; Khairi Jusup, Muhamad

2018-04-01

Banana is the tropical plants associated with lots of medicinal properties. It has been reported to be a potential source of phenolic compounds such as ferulic acid (FA). FA has excellent antioxidant properties higher than vitamin C and E. FA also have a wide range of biological activities, such as antioxidant activities and anti-microbial activities. This paper presents an experimental and kinetic study on ferulic acid (FA) production from banana stem waste (BSW) via mechanical extraction. The objective of this research is to determine the kinetic parameters in the ferulic acid production. The banana stem waste was randomly collected from the local banana plantation in Felda Lepar Hilir, Pahang. The banana stem juice was mechanically extracted by using sugarcane press machine (KR3176) and further analyzed in high performance liquid chromatography. The differential and integral method was applied to determine the kinetic parameter of the extraction process and the data obtained were fitted into the 0th, 1st and 2nd order of extraction process. Based on the results, the kinetic parameter and R2 value from were 0.05 and 0.93, respectively. It was determined that the 0th kinetic order fitted the reaction processes to best represent the mechanical extraction.

Natural products as promising drug candidates for the treatment of Alzheimer's disease: molecular mechanism aspect.

Science.gov (United States)

Ansari, Niloufar; Khodagholi, Fariba

2013-07-01

Alzheimer's disease (AD) is the most common neurodegenerative disorder to date, with no curative or preventive therapy. Histopathological hallmarks of AD include deposition of β-amyloid plaques and formation of neurofibrillary tangles. Extent studies on pathology of the disease have made important discoveries regarding mechanism of disease and potential therapeutic targets. Many cellular changes including oxidative stress, disruption of Ca2+ homeostasis, inflammation, metabolic disturbances, and accumulation of unfolded/misfolded proteins can lead to programmed cell death in AD. Despite intensive research, only five approved drugs are available for the management of AD. Hence, there is a need to look at alternative therapies. Use of natural products and culinary herbs in medicine has gained popularity in recent years. Several natural substances with neuroprotective effects have been widely studied. Most of these compounds have remarkable antioxidant properties and act mainly by scavenging free radical species. Some of them increase cell survival and improve cognition by directly affecting amyloidogenesis and programmed cell death pathways. Further studies on these natural products and their mechanism of action, parallel with the use of novel pharmaceutical drug design and delivery techniques, enable us to offer an addition to conventional medicine. This review discussed some natural products with potential neuroprotective properties against Aβ with respect to their mechanism of action.

Production mechanism of negative pionlike particles in H2 gas discharge plasma

International Nuclear Information System (INIS)

Uramoto, Joshin.

1996-04-01

Negative pionlike and muonlike particles are produced by an electron bunch and a positive ion bunch which are generated controllably from an electron beam and a gas. Physical characteristics of the negative pionlike particles are the same with those of negative pionlike particles extracted from the H 2 gas discharge. Thus, the production mechanism in the H 2 gas discharge is deduced. (author)

Brittle Fracture Mechanics of Snow : In Situ Testing and Distinct Element Modeling

Science.gov (United States)

Faillettaz, J.; Daudon, D.; Louchet, F.

A snow slab avalanche release usually results from the rupture of the snow cover at the interface between an upper layer (slab) and an underlying substrate. Amazingly, the models proposed so far to predict this kind of rupture were only based on continuum mechanics, as they did not take into account the existing cracks or cohesion defects at the interface between the two layers, and their possible unstable propagation that eventually triggers the avalanche. This is why the present work, essentially devoted to human triggered avalanches, is based instead on Griffith's fracture approach, widely used in modelling brittle fracture of materials. The possible rupture scenario involves a propagation in a shear mode of a "basal crack" nucleated and gradually grown at the interface by the skier's weight, followed by a mode I opening and propagation of a "crown crack" at the top of the sheared zone. Different avalanche sizes are predicted according whether the basal crack propagation reaches or not the Griffith's instabil- ity size before crown crack opening (Louchet 2000). Accurate predictions therefore require a precise knowledge of snow toughness values in both modes. A theoretical estimation of toughness considering snow as an ice foam was proposed by Kirchner and Michot (2000), but the question of whether these results may be extended to an assembly of sintered grains is still open. A mode I toughness measurement of snow was also published for the first time by Kirchner and Michot on samples gathered in the Vosges range. In the present work, we developed an experimental set similar to Michot's, in order to measure mode I toughness: a vertical crack of increasing size is gradually machined from the top surface in an horizontal snow beam until failure takes place under its own weight. The toughness value is computed from the snow weight and the crack length at the onset of rapid crack propagation. A similar device was designed for mode II testing, but is still under

Mechanical and natural durability properties of wood treated with a novel organic preservative/consolidant product

International Nuclear Information System (INIS)

Lionetto, Francesca; Frigione, Mariaenrica

2009-01-01

An organic preservative/consolidant of new formulation was selected in order to evaluate its effect on the mechanical properties of worm-eaten walnut wood. Walnut wood is widely used for the realization of artistic handworks (e.g. statues, altars, etc.) furniture and flooring. The flexural strength and modulus of elasticity, the toughness and the hardness were determined on both treated and untreated samples. The experimental results showed that the product increased significantly the flexural strength while the other mechanical properties were not appreciably affected by the chemical treatment. The microstructure of the samples tested was observed using scanning electron microscopy. The preserving character against insects of the investigated product was assessed by both visual inspection and measurements of weight loss on the treated specimens after their exposure to living insects. The samples on which the product was applied, exposed to Oligomerus ptilinoides for one year, were more resistant to decay than the corresponding untreated samples.

The mechanism of improved pullulan production by nitrogen limitation in batch culture of Aureobasidium pullulans.

Science.gov (United States)

Wang, Dahui; Chen, Feifei; Wei, Gongyuan; Jiang, Min; Dong, Mingsheng

2015-08-20

Batch culture of Aureobasidium pullulans CCTCC M 2012259 for pullulan production at different concentrations of ammonium sulfate and yeast extract was investigated. Increased pullulan production was obtained under nitrogen-limiting conditions, as compared to that without nitrogen limitation. The mechanism of nitrogen limitation favoring to pullulan overproduction was revealed by determining the activity as well as gene expression of key enzymes, and energy supply for pullulan biosynthesis. Results indicated that nitrogen limitation increased the activities of α-phosphoglucose mutase and glucosyltransferase, up-regulated the transcriptional levels of pgm1 and fks genes, and supplied more ATP intracellularly, which were propitious to further pullulan biosynthesis. The economic analysis of batch pullulan production indicated that nitrogen limitation could reduce more than one third of the cost of raw materials when glucose was supplemented to a total concentration of 70 g/L. This study also helps to understand the mechanism of other polysaccharide overproduction by nitrogen limitation. Copyright © 2015 Elsevier Ltd. All rights reserved.

MHTGR product distinction

International Nuclear Information System (INIS)

1990-12-01

Commercial power reactor operating experience and regulatory practice in the United States is dominated by Light Water Reactor (LWR) technology. This experience base and regulatory structure is a point of departure for the development of any future nuclear option, and must be understood and utilized as appropriate. This report discusses experience with current generation plants considered relevant to MHTGR development, as well as the fundamental differences between the MHTGR and LWR technology, and quantifies avoided business risks relative to current generation plants. It does not attempt to compare the MHTGR with other advanced nuclear options, LWR or other technologies, which are also under development and must relate to the historical framework in accordance with their own unique characteristics. 14 refs., 5 figs., 5 tabs

Distinct Signaling Roles of cIMP, cCMP, and cUMP.

Science.gov (United States)

Seifert, Roland

2016-10-04

The cyclic purine nucleotide cIMP and the cyclic pyrimidine nucleotides cCMP and cUMP are emerging second messengers. These cNMPs show different biological effects, but the molecular mechanisms remain elusive. In this issue of Structure, Ng et al. (2016) provide structural evidence for distinct interactions of cIMP, cCMP, and cUMP with ion channels. Copyright © 2016 Elsevier Ltd. All rights reserved.

Distinctive Citizenship

DEFF Research Database (Denmark)

Kaur, Ravinder

2009-01-01

The refugee, in India's Partition history, appears as an enigmatic construct - part pitiful, part heroic, though mostly shorn of agency - representing the surface of the human tragedy of Partition. Yet this archetype masks the undercurrent of social distinctions that produced hierarchies of post...

Framework of product experience

NARCIS (Netherlands)

Desmet, P.; Hekkert, P.

2007-01-01

In this paper, we introduce a general framework for product experience that applies to all affective responses that can be experienced in human-product interaction. Three distinct components or levels of product experiences are discussed: aesthetic experience, experience of meaning, and emotional

Solid recovered fuel production through the mechanical-biological treatment of wastes

OpenAIRE

Velis, C. A.

2010-01-01

This thesis is concerned with the production of solid recovered fuel (SRF) from municipal solid waste using mechanical biological treatment (MBT) plants. It describes the first in-depth analysis of a UK MBT plant and addresses the fundamental research question: are MBT plants and their unit operations optimised to produce high quality SRF in the UK? A critical review of the process science and engineering of MBT provides timely insights into the quality management and standa...

Sustainable Development Mechanism of Food Culture’s Translocal Production Based on Authenticity

Directory of Open Access Journals (Sweden)

Guojun Zeng

2014-10-01

Full Text Available Food culture is a kind of non-material culture with authenticity. To achieve sustainable development of translocal heritage and food culture, we must protect its authenticity. By selecting the cases of the Dongbeiren Flavor Dumpling Restaurant and the Daozanjia Northeast Dumpling Restaurant and using the in-depth interview method, this study discusses how northeastern Cuisine in Guangzhou balances the inheritance and innovation of authenticity, how producers and customers negotiate, and how to realize sustainable development. The main conclusions are: first, there are two different paths of translocal food culture production, which are “authentic food culture production” and “differentiated food culture production”. Second, what translocal enterprises produce is not objective authenticity, but constructive authenticity, or even existential authenticity. Third, compared with differentiated food culture production, authentic food culture production is helpful for the sustainable development of local food culture production. It protects the locality while transmitting and developing the local culture. Fourth, translocal food culture production is a process in which the producers and consumers continue to interact to maintain a state of equilibrium, which informs the sustainable development mechanism with a high degree of authenticity.

Boldine enhances bile production in rats via osmotic and Farnesoid X receptor dependent mechanisms

International Nuclear Information System (INIS)

Cermanova, Jolana; Kadova, Zuzana; Zagorova, Marie; Hroch, Milos; Tomsik, Pavel; Nachtigal, Petr; Kudlackova, Zdenka; Pavek, Petr; Dubecka, Michaela; Ceckova, Martina; Staud, Frantisek; Laho, Tomas; Micuda, Stanislav

2015-01-01

Boldine, the major alkaloid from the Chilean Boldo tree, is used in traditional medicine to support bile production, but evidence to support this function is controversial. We analyzed the choleretic potential of boldine, including its molecular background. The acute- and long-term effects of boldine were evaluated in rats either during intravenous infusion or after 28-day oral treatment. Infusion of boldine instantly increased the bile flow 1.4-fold in healthy rats as well as in animals with Mrp2 deficiency or ethinylestradiol induced cholestasis. This effect was not associated with a corresponding increase in bile acid or glutathione biliary excretion, indicating that the effect is not related to stimulation of either bile acid dependent or independent mechanisms of bile formation and points to the osmotic activity of boldine itself. We subsequently analyzed bile production under conditions of changing biliary excretion of boldine after bolus intravenous administration and found strong correlations between both parameters. HPLC analysis showed that bile concentrations of boldine above 10 μM were required for induction of choleresis. Importantly, long-term pretreatment, when the bile collection study was performed 24-h after the last administration of boldine, also accelerated bile formation despite undetectable levels of the compound in bile. The effect paralleled upregulation of the Bsep transporter and increased biliary clearance of its substrates, bile acids. We consequently confirmed the ability of boldine to stimulate the Bsep transcriptional regulator, FXR receptor. In conclusion, our study clarified the mechanisms and circumstances surrounding the choleretic activity of boldine. - Highlights: • Boldine may increase bile production by direct as well as indirect mechanisms. • Biliary concentrations of boldine above 10 μM directly stimulate bile production. • Long-term oral boldine administration increases bile acid (BA) biliary secretion. • Boldine

Boldine enhances bile production in rats via osmotic and Farnesoid X receptor dependent mechanisms

Energy Technology Data Exchange (ETDEWEB)

Cermanova, Jolana [Department of Pharmacology, Charles University in Prague, Faculty of Medicine in Hradec Kralove (Czech Republic); Kadova, Zuzana [Department of Pharmacology, Charles University in Prague, Faculty of Medicine in Hradec Kralove (Czech Republic); Deparment of Pharmacology and Toxicology, Charles University in Prague, Faculty of Pharmacy in Hradec Kralove (Czech Republic); Zagorova, Marie [Department of Pharmacology, Charles University in Prague, Faculty of Medicine in Hradec Kralove (Czech Republic); Hroch, Milos [Department of Pharmacology, Charles University in Prague, Faculty of Medicine in Hradec Kralove (Czech Republic); Department of Medical Biochemistry, Charles University in Prague, Faculty of Medicine in Hradec Kralove (Czech Republic); Tomsik, Pavel [Department of Medical Biochemistry, Charles University in Prague, Faculty of Medicine in Hradec Kralove (Czech Republic); Nachtigal, Petr; Kudlackova, Zdenka [Department of Biological and Medical Sciences, Charles University in Prague, Faculty of Pharmacy in Hradec Kralove (Czech Republic); Pavek, Petr; Dubecka, Michaela; Ceckova, Martina; Staud, Frantisek [Deparment of Pharmacology and Toxicology, Charles University in Prague, Faculty of Pharmacy in Hradec Kralove (Czech Republic); Laho, Tomas [Department of Pharmacology, Charles University in Prague, Faculty of Medicine in Hradec Kralove (Czech Republic); Micuda, Stanislav, E-mail: micuda@lfhk.cuni.cz [Department of Pharmacology, Charles University in Prague, Faculty of Medicine in Hradec Kralove (Czech Republic)

2015-05-15

Boldine, the major alkaloid from the Chilean Boldo tree, is used in traditional medicine to support bile production, but evidence to support this function is controversial. We analyzed the choleretic potential of boldine, including its molecular background. The acute- and long-term effects of boldine were evaluated in rats either during intravenous infusion or after 28-day oral treatment. Infusion of boldine instantly increased the bile flow 1.4-fold in healthy rats as well as in animals with Mrp2 deficiency or ethinylestradiol induced cholestasis. This effect was not associated with a corresponding increase in bile acid or glutathione biliary excretion, indicating that the effect is not related to stimulation of either bile acid dependent or independent mechanisms of bile formation and points to the osmotic activity of boldine itself. We subsequently analyzed bile production under conditions of changing biliary excretion of boldine after bolus intravenous administration and found strong correlations between both parameters. HPLC analysis showed that bile concentrations of boldine above 10 μM were required for induction of choleresis. Importantly, long-term pretreatment, when the bile collection study was performed 24-h after the last administration of boldine, also accelerated bile formation despite undetectable levels of the compound in bile. The effect paralleled upregulation of the Bsep transporter and increased biliary clearance of its substrates, bile acids. We consequently confirmed the ability of boldine to stimulate the Bsep transcriptional regulator, FXR receptor. In conclusion, our study clarified the mechanisms and circumstances surrounding the choleretic activity of boldine. - Highlights: • Boldine may increase bile production by direct as well as indirect mechanisms. • Biliary concentrations of boldine above 10 μM directly stimulate bile production. • Long-term oral boldine administration increases bile acid (BA) biliary secretion. • Boldine

Distinct metal-exchange pathways of doped Ag25 nanoclusters

KAUST Repository

Bootharaju, Megalamane Siddaramappa

2016-09-09

Atomically precise metal nanoclusters (NCs) containing more than one type of metal atom (i.e., doped or alloyed), due to synergistic effects, open new avenues for engineering the catalytic and optical properties of NCs in a manner that homometal NCs cannot. Unfortunately, it is still a major challenge to controllably introduce multimetallic dopants in NCs, understanding the dopants\\' positions, mechanism, and synergistic effects. To overcome these challenges, we designed a metal-exchange approach involving NCs as molecular templates and metal ions as the source of the incoming dopant. In particular, two structurally similar monodoped silver-rich NCs, [MAg24(SR)(18)](2-) (M = Pd/Pt and SR: thiolate), were synthesized as templates to study their mechanistic transformation in response to the introduction of gold atoms. The controllable incorporation of Au atoms into the MAg24 framework facilitated the elucidation of distinct doping pathways through high-resolution mass spectrometry, optical spectroscopy and elemental analysis. Interestingly, gold replaced the central Pd atom of [PdAg24(SR)(18)](2-) clusters to produce predominantly bimetallic [AuAg24(SR)(18)](-) clusters along with a minor product of an [Au2Ag23(SR)(18)](-) cluster. In contrast, the central Pt atom remained intact in [PtAg24(SR)(18)](2-) clusters, and gold replaced the noncentral Ag atoms to form trimetallic [AuxPtAg24-x(SR)(18)](2-) NCs, where x = 1-2, with a portion of the starting [PtAg24(SR)(18)](2-) NCs remaining. This study reveals some of the unusual metal-exchange pathways of doped NCs and the important role played by the initial metal dopant in directing the position of a second dopant in the final product.

Role of asphalt paver productivity in direction development of road mechanical engineering

Directory of Open Access Journals (Sweden)

Karpushko Marina

2017-01-01

Full Text Available Road construction machinery is one of the largest and stable sectors of national economy. With the help of road-building machinery, construction, maintenance and repair of highways are carried out. Modern system of road and building machines is a complex of high-performance machines and mechanisms, of large and small capacity and productivity. Expansion of paved roads network of both federal and local values, use of resource-saving technologies, increasing of pace and quality of work, ensuring of reliability and durability of highways have a major impact on the development of road construction machinery. The level of foreign road and construction machinery puts forward complex requirements for compliance with world safety and environmental standards, increasing equipment mobility, expanding areas of effective use and, finally, increasing its capacity and productivity. Article contains approach to the calculation of the operational productivity of asphalt pavers that takes into account technical characteristics and conditions of works production and contributes to the reliability of decisions on organization and management of road maintenance works on urban roads.

Distribution of Disease-Associated Copy Number Variants across Distinct Disorders of Cognitive Development

Science.gov (United States)

Pescosolido, Matthew F.; Gamsiz, Ece D.; Nagpal, Shailender; Morrow, Eric M.

2013-01-01

Objective: The purpose of the present study was to discover the extent to which distinct "DSM" disorders share large, highly recurrent copy number variants (CNVs) as susceptibility factors. We also sought to identify gene mechanisms common to groups of diagnoses and/or specific to a given diagnosis based on associations with CNVs. Method:…

Retention in the Golgi apparatus and expression on the cell surface of Cfr/Esl-1/Glg-1/MG-160 are regulated by two distinct mechanisms.

Science.gov (United States)

Miyaoka, Yuichiro; Kato, Hidenori; Ebato, Kazuki; Saito, Shigeru; Miyata, Naoko; Imamura, Toru; Miyajima, Atsushi

2011-11-15

Cfr (cysteine-rich fibroblast growth factor receptor) is an Fgf (fibroblast growth factor)-binding protein without a tyrosine kinase. We have shown previously that Cfr is involved in Fgf18 signalling via Fgf receptor 3c. However, as Cfr is also known as Glg (Golgi apparatus protein)-1 or MG-160 and occurs in the Golgi apparatus, it remains unknown how the distribution of Cfr is regulated. In the present study, we performed a mutagenic analysis of Cfr to show that two distinct regions contribute to its distribution and stability. First, the C-terminal region retains Cfr in the Golgi apparatus. Secondly, the Cfr repeats in the extracellular juxtamembrane region destabilizes Cfr passed through the Golgi apparatus. This destabilization does not depend on the cleavage and secretion of the extracellular domain of Cfr. Furthermore, we found that Cfr with a GPI (glycosylphosphatidylinositol) anchor was predominantly expressed on the cell surface in Ba/F3 cells and affected Fgf18 signalling in a similar manner to the full-length Cfr, indicating that the interaction of Cfr with Fgfs on the cell surface is important for its function in Fgf signalling. These results suggest that the expression of Cfr in the Golgi apparatus and on the plasma membrane is finely tuned through two distinct mechanisms for exhibiting different functions.

Molecular polymorphism of a cell surface proteoglycan: distinct structures on simple and stratified epithelia.

Science.gov (United States)

Sanderson, R D; Bernfield, M

1988-12-01

Epithelial cells are organized into either a single layer (simple epithelia) or multiple layers (stratified epithelia). Maintenance of these cellular organizations requires distinct adhesive mechanisms involving many cell surface molecules. One such molecule is a cell surface proteoglycan, named syndecan, that contains both heparan sulfate and chondroitin sulfate chains. This proteoglycan binds cells to fibrillar collagens and fibronectin and thus acts as a receptor for interstitial matrix. The proteoglycan is restricted to the basolateral surface of simple epithelial cells, but is located over the entire surface of stratified epithelial cells, even those surfaces not contacting matrix. We now show that the distinct localization in simple and stratified epithelia correlates with a distinct proteoglycan structure. The proteoglycan from simple epithelia (modal molecular size, 160 kDa) is larger than that from stratified epithelia (modal molecular size, 92 kDa), but their core proteins are identical in size and immunoreactivity. The proteoglycan from simple epithelia has more and larger heparan sulfate and chondroitin sulfate chains than the proteoglycan from stratified epithelia. Thus, the cell surface proteoglycan shows a tissue-specific structural polymorphism due to distinct posttranslational modifications. This polymorphism likely reflects distinct proteoglycan functions in simple and stratified epithelia, potentially meeting the different adhesive requirements of the cells in these different organizations.

Mechanisms of methicillin resistance in Staphylococcus aureus and methods for laboratory detection.

Science.gov (United States)

Jorgensen, J H

1991-01-01

Three distinctly different mechanisms of methicillin resistance have been described in Staphylococcus aureus. The best-documented and probably most important mechanism is production of a unique, low affinity penicillin-binding protein, PBP 2a. Strains possessing PBP 2a are resistant to methicillin, oxacillin, and probably all other currently available beta-lactam antibiotics. Two additional mechanisms of reduced susceptibility to methicillin have been described. Borderline resistance (BORSA) to the semi-synthetic penicillins has been attributed to the hyperproduction of normal staphylococcal beta-lactamase. A third mechanism has recently been advanced that describes an intermediate level of resistance to methicillin due to production of modified, normal PBPs with reduced affinity for beta-lactams (MODSA). Little is known regarding the prevalence or clinical significance of the BORSA and MODSA strains. The most reliable in vitro susceptibility test methods for detecting MRSA (strains possessing PBP 2a) include the microdilution minimum inhibitory concentration (MIC) test (with 2% NaCl supplemented broth), the oxacillin agar screen plate test (incorporating 6 micrograms/ml oxacillin in 4% NaCl supplemented agar), and the National Committee for Clinical Laboratory Standards (NCCLS) disk diffusion test with oxacillin. All three methods use direct inoculum preparation and incubation of tests at 35 degrees C for a full 24 hours.

Studies on the mechanism of endogenous pyrogen production. II. Role of cell products in the regulation of pyrogen release from blood leukocytes.

Science.gov (United States)

Bodel, P

1974-09-01

Some characteristics of the process by which endogenous pyrogen (EP), the mediator of fever, is released from cells were examined by using human blood leukocytes incubated in vitro. Studies were designed to examine a possible role for leukocyte products, including EP, in the induction, augmentation, or suppression of pyrogen release by blood leukocytes. Products of stimulated leukocytes, including a partially purified preparation of EP, did not induce significant activation of nonstimulated cells. Also, no evidence was obtained that stimulated cell products either augment or inhibit pyrogen production by other stimulated cells. A feedback control of EP production was thus not observed. A crude preparation of EP, containing other products of activated cells, maintained its pyrogenicity when incubated at pH 7.4 but not at pH 5.0. These studies thus provide no support for hypothesized control mechanisms regulating production of EP by blood leukocytes. By contrast, local inactivation of EP at inflammatory sites may modify the amount of EP entering the blood, and hence fever.

Research on test of product based on spatial sampling criteria and variable step sampling mechanism

Science.gov (United States)

Li, Ruihong; Han, Yueping

2014-09-01

This paper presents an effective approach for online testing the assembly structures inside products using multiple views technique and X-ray digital radiography system based on spatial sampling criteria and variable step sampling mechanism. Although there are some objects inside one product to be tested, there must be a maximal rotary step for an object within which the least structural size to be tested is predictable. In offline learning process, Rotating the object by the step and imaging it and so on until a complete cycle is completed, an image sequence is obtained that includes the full structural information for recognition. The maximal rotary step is restricted by the least structural size and the inherent resolution of the imaging system. During online inspection process, the program firstly finds the optimum solutions to all different target parts in the standard sequence, i.e., finds their exact angles in one cycle. Aiming at the issue of most sizes of other targets in product are larger than that of the least structure, the paper adopts variable step-size sampling mechanism to rotate the product specific angles with different steps according to different objects inside the product and match. Experimental results show that the variable step-size method can greatly save time compared with the traditional fixed-step inspection method while the recognition accuracy is guaranteed.

Agricultural mechanization policy and strategy : the case of Thailand

NARCIS (Netherlands)

Rijk, A.G.

1989-01-01

The role of agricultural mechanization in a developing economy is examined in order to enhance the formulation of mechanization policy and strategy. As a result of the review and assessment of the mechanization process, seven distinct stages in the mechanization process are specified and

CCR-2 neutralization augments murine fresh BMC activation by Staphylococcus aureus via two distinct mechanisms: at the level of ROS production and cytokine response.

Science.gov (United States)

Nandi, Ajeya; Bishayi, Biswadev

2017-05-01

CCR-2 signaling regulates recruitment of monocytes from the bone marrow into the bloodstream and then to sites of infection. We sought to determine whether CCL-2/CCR-2 signaling is involved in the killing of Staphylococcus aureus by murine bone marrow cells (BMCs). The intermittent link of reactive oxygen species (ROS)-NF-κB/p38-MAPK-mediated CCL-2 production in CCR-2 signaling prompted us to determine whether neutralization of CCR-2 augments the response of murine fresh BMCs (FBMCs) after S. aureus infection. It was observed that anti-CCR-2 Ab-treated FBMCs released fewer ROS on encountering S. aureus infection than CCR-2 non-neutralized FBMCs, also correlating with reduced killing of S. aureus in CCR-2 neutralized FBMCs. Staphylococcal catalase and SOD were also found to play a role in protecting S. aureus from the ROS-mediated killing of FBMC. S. aureus infection of CCR-2 intact FBMCs pre-treated with either NF-κB or p-38-MAPK blocker induced less CCL-2, suggesting that NF-κB or p-38-MAPK is required for CCL-2 production by FBMCs. Moreover, blocking of CCR-2 along with NF-κB or p-38-MAPK resulted in elevated CCL-2 production and reduced CCR-2 expression. Inhibition of CCR-2 impairs the response of murine BMCs to S. aureus infection by attenuation ROS production and modulating the cytokine response.

Effects of chemical complexity on the autoxidation mechanisms of endocyclic alkene ozonolysis products

DEFF Research Database (Denmark)

Rissanen, Matti P.; Kurtén, Theo; Sipilä, Mikko

2015-01-01

(NO3-) based ionization scheme. The experiments were performed in borosilicate glass flow tube reactors at room temperature (T = 293 ± 3 K) and at ambient pressure. An ensemble of oxidized monomer and dimer products was detected, with elemental compositions obtained from the high......Formation of highly oxidized, multifunctional products in the ozonolysis of three endocyclic alkenes, 1- methylcyclohexene, 4-methylcyclohexene, and α-pinene, was investigated using a chemical ionization atmospheric pressure interface time-of-flight (CI-APi-TOF) mass spectrometer with a nitrate ion......-resolution mass spectra. The monomer product distributions have O/C ratios from 0.8 to 1.6 and can be explained with an autocatalytic oxidation mechanism (=autoxidation) where the oxygen-centered peroxy radical (RO2) intermediates internally rearrange by intramolecular hydrogen shift reactions...

A search for distinctive features of demand-led growth models

OpenAIRE

Sergio Parrinello

2014-01-01

This paper aims at a critical and constructive assessment of some extensions of Keynes’s analysis of effective demand to the long period and growth. A criticism is addressed to a single-cause interpretation of the demand-led growth models and to the notion of normal capacity utilization adopted in such models. A positive argument tries to find a distinctive characterization of those extensions in the productive and financial conditions that make effective the autonomous changes in aggregate d...

Counselor Identity: Conformity or Distinction?

Science.gov (United States)

McLaughlin, Jerry E.; Boettcher, Kathryn

2009-01-01

The authors explore 3 debates in other disciplines similar to counseling's identity debate in order to learn about common themes and outcomes. Conformity, distinction, and cohesion emerged as common themes. They conclude that counselors should retain their distinctive, humanistic approach rather than conforming to the dominant, medical approach.

Fluid mechanics as a driver of tissue-scale mechanical signaling in organogenesis.

Science.gov (United States)

Gilbert, Rachel M; Morgan, Joshua T; Marcin, Elizabeth S; Gleghorn, Jason P

2016-12-01

Organogenesis is the process during development by which cells self-assemble into complex, multi-scale tissues. Whereas significant focus and research effort has demonstrated the importance of solid mechanics in organogenesis, less attention has been given to the fluid forces that provide mechanical cues over tissue length scales. Fluid motion and pressure is capable of creating spatial gradients of forces acting on cells, thus eliciting distinct and localized signaling patterns essential for proper organ formation. Understanding the multi-scale nature of the mechanics is critically important to decipher how mechanical signals sculpt developing organs. This review outlines various mechanisms by which tissues generate, regulate, and sense fluid forces and highlights the impact of these forces and mechanisms in case studies of normal and pathological development.

Evaluation of Manufacturing Process Performance by CONWIP Hybridization of Pull Controlled Production Systems

Directory of Open Access Journals (Sweden)

Srikanth O.

2018-01-01

Full Text Available The main objective of this paper is pioneering an innovative tactic for the synchronization of multi-stage, multi-line, production system. This tactic is mainly depends on the optimization policy, by means of distinct event simulation process for modeling, analysis and distinction of the execution of two alternatives of Kanban control mechanism namely SEKCS (Simultaneous Extended Kanban Control System and IEKCS (Independent Extended Kanban Control System. At this juncture the authors putting forward the two variants of Extended Kanban control system with the hybridization of CONWIP control policy to incite HSEKCS (Hybrid Simultaneous Extended Kanban Control System and HIEKCS (Hybrid Independent Extended Kanban Control System to make use of pooled benefits of a representative production situation in addition to improve the outcome. Therefore in this study the comparison in between different systems of proposed HEKCS specifically are HSEKCS and HIEKCS compared with the Extended Kanban Control Systems variants SEKCS and IEKCS. Simulation studies were conducted for all the five control policies considered and modeled on a multi-line, multi-stage assembly production control system. The relative performance parameters like Throughput or Production rate, Average Waiting Time and Average Work-in-Process, were assessed by means of exponentially varying demands.

SPATIALLY RESOLVED SPECTROSCOPY OF EUROPA: THE DISTINCT SPECTRUM OF LARGE-SCALE CHAOS

International Nuclear Information System (INIS)

Fischer, P. D.; Brown, M. E.; Hand, K. P.

2015-01-01

We present a comprehensive analysis of spatially resolved moderate spectral resolution near-infrared spectra obtained with the adaptive optics system at the Keck Observatory. We identify three compositionally distinct end member regions: the trailing hemisphere bullseye, the leading hemisphere upper latitudes, and a third component associated with leading hemisphere chaos units. We interpret the composition of the three end member regions to be dominated by irradiation products, water ice, and evaporite deposits or salt brines, respectively. The third component is associated with geological features and distinct from the geography of irradiation, suggesting an endogenous identity. Identifying the endogenous composition is of particular interest for revealing the subsurface composition. However, its spectrum is not consistent with linear mixtures of the salt minerals previously considered relevant to Europa. The spectrum of this component is distinguished by distorted hydration features rather than distinct spectral features, indicating hydrated minerals but making unique identification difficult. In particular, it lacks features common to hydrated sulfate minerals, challenging the traditional view of an endogenous salty component dominated by Mg-sulfates. Chloride evaporite deposits are one possible alternative

SPATIALLY RESOLVED SPECTROSCOPY OF EUROPA: THE DISTINCT SPECTRUM OF LARGE-SCALE CHAOS

Energy Technology Data Exchange (ETDEWEB)

Fischer, P. D.; Brown, M. E. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Hand, K. P., E-mail: pfischer@caltech.edu [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

2015-11-15

We present a comprehensive analysis of spatially resolved moderate spectral resolution near-infrared spectra obtained with the adaptive optics system at the Keck Observatory. We identify three compositionally distinct end member regions: the trailing hemisphere bullseye, the leading hemisphere upper latitudes, and a third component associated with leading hemisphere chaos units. We interpret the composition of the three end member regions to be dominated by irradiation products, water ice, and evaporite deposits or salt brines, respectively. The third component is associated with geological features and distinct from the geography of irradiation, suggesting an endogenous identity. Identifying the endogenous composition is of particular interest for revealing the subsurface composition. However, its spectrum is not consistent with linear mixtures of the salt minerals previously considered relevant to Europa. The spectrum of this component is distinguished by distorted hydration features rather than distinct spectral features, indicating hydrated minerals but making unique identification difficult. In particular, it lacks features common to hydrated sulfate minerals, challenging the traditional view of an endogenous salty component dominated by Mg-sulfates. Chloride evaporite deposits are one possible alternative.

Mechanical properties used for the qualification of transport casks: Prototype development and extension to serial production

International Nuclear Information System (INIS)

Salzbrenner, R.; Crenshaw, T.B.; Sorenson, K.B.

1992-01-01

A thorough understanding of the mechanical behavior of material in a specific cask is required to properly analyze the structural response of the cask. An appropriate way to establish this understanding is through laboratory testing of cask material. The laboratory testing that was done to support the MOSAIK Drop Test Program is summarized as an example of how mechanical properties can be mapped for a prototype cask. The broad range of measured properties allows the critical aspects of mechanical behavior to be understood. This is necessary for the proper application of fracture mechanics, and focuses on fracture toughness as the inherent materials property which quantifies the fracture resistance of a material. The general fracture mechanics approach and its application to specific cask designs are described elsewhere (Salzbrenner et al. 1990, Sorenson et al. 1992a, Sorenson et al. 1992b). The understanding established by a thorough mapping of the mechanical properties is necessary to apply fracture mechanics to a particular prototype, but it is not sufficient for qualifying serially produced casks. The mechanical behavior of a prototype must be correctly associated with parameters which can be measured on production casks. Since the production casks cannot be destructively tested, measurements are commonly made on sub-size specimens. This may prevent direct measurement of valid design properties. An additional database may then be required to establish the correlation between sub-size specimen measurements and valid design properties. This is illustrated by outlining the additional testing which would be necessary to allow the successful verification of the MOSAIK Drop Test Program to be extended from the prototype to serially produced casks

Effect of fission product interactions on the corrosion and mechanical properties of HTGR alloys

International Nuclear Information System (INIS)

Aronson, S.; Chow, J.G.Y.; Soo, P.; Friedlander, M.

1978-01-01

Preliminary experiments have been carried out to determine how fission product interactions may influence the mechanical integrity of reference HTGR structural metals. In this work Type 304 stainless steel, Incoloy 800 and Hastelloy X were heated to 550 to 650 0 C in the presence of CsI. It was found that no corrosion of the alloys occurred unless air or oxygen was also present. A mechanism for the observed behavior is proposed. A description is also given of some long term exposures of HTGR materials to more prototypic, low concentrations of I 2 , Te 2 and CsI in the presence of low partial pressures of O 2 . These samples are scheduled for mechanical bend tests after exposure to determine the degree of embrittlement

HOW DO DIFFERENT COORDINATION MECHANISMS BETWEEN NEW PRODUCT DEVELOPMENT AND MANUFACTURING INFLUENCE FIRM PERFORMANCE?

DEFF Research Database (Denmark)

Timenes Laugen, Bjørge; Acur, Nuran; Boer, Harry

In the literature several suggestions have been put forward for tools, methods and mechanisms to coordinate new product development (NPD) and manufacturing. However, evidence of the operational performance effects of many of these approaches is at best limited. Furthermore, there is a lack...... of understanding of how various coordination mechanisms work in different contexts. Using a survey consisting of data from 677 manufacturing firms from 19 countries worldwide, we test how coordination mechanisms relate to operational performance, and how context moderates these relationships or affects performance...... between standardization and organization design, respectively, and performance are positively moderated by company size. Furthermore, innovativeness moderates the relationship between organization design and performance positively. For managers, our findings indicate that NPD-manufacturing coordination...

Identifying the causes of differences in ozone production from the CB05 and CBMIV chemical mechanisms

Directory of Open Access Journals (Sweden)

R. D. Saylor

2012-02-01

Full Text Available An investigation was conducted to identify the mechanistic differences between two versions of the carbon bond gas-phase chemical mechanism (CB05 and CBMIV which consistently lead to larger ground-level ozone concentrations being produced in the CB05 version of the National Air Quality Forecasting Capability (NAQFC modeling system even though the two parallel forecast systems utilize the same meteorology and base emissions and similar initial and boundary conditions. Box models of each of the mechanisms as they are implemented in the NAQFC were created and a set of 12 sensitivity simulations was designed. The sensitivity simulations independently probed the conceptual mechanistic differences between CB05 and CBMIV and were exercised over a 45-scenario simulation suite designed to emulate the wide range of chemical regimes encountered in a continental-scale atmospheric chemistry model. Results of the sensitivity simulations indicate that two sets of reactions that were included in the CB05 mechanism, but which were absent from the CBMIV mechanism, are the primary causes of the greater ozone production in the CB05 version of the NAQFC. One set of reactions recycles the higher organic peroxide species of CB05 (ROOH, resulting in additional photochemically reactive products that act to produce additional ozone in some chemical regimes. The other set of reactions recycles reactive nitrogen from less reactive forms back to NO₂, increasing the effective NO_x concentration of the system. In particular, the organic nitrate species (NTR, which was a terminal product for reactive nitrogen in the CBMIV mechanism, acts as a reservoir species in CB05 to redistribute NO_x from major source areas to potentially NO_x-sensitive areas where additional ozone may be produced in areas remote from direct NO_x sources.

Values and public acceptability dimensions of sustainable egg production.

Science.gov (United States)

Thompson, P B; Appleby, M; Busch, L; Kalof, L; Miele, M; Norwood, B F; Pajor, E

2011-09-01

The attributes of egg production that elicit values-based responses include the price and availability of eggs, environmental impacts, food safety or health concerns, and animal welfare. Different social groups have distinct interests regarding the sustainability of egg production that reflect these diverse values. Current scientifically based knowledge about how values and attitudes in these groups can be characterized is uneven and must be derived from studies conducted at varying times and using incomplete study methods. In general, some producer and consumer interests are translated through markets and are mediated by market mechanisms, whereas others are poorly reflected by economic behavior. An array of survey and focus group research has been performed to elicit consumer and activist beliefs about performance goals they would expect from an egg production system. These studies provide evidence that consumers' market behavior may be at odds with their ethical and political beliefs about performance goals.

Analysis of mechanical thinning productivity and cost for use at the wildland urban interface

Science.gov (United States)

Bruno S. Folegatti; Mathew F. Smidt; Edward F. Loewenstein; Emily Carter; Timothy P. McDonald

2007-01-01

Forest management in many parts of the urbanizing Southeastern U.S. is becoming more difficult due to fragmentation, alternative management objectives, and social conflicts with management activities. However, the public benefits from management of these are still high. This study compared the productivity and costs of mechanical thinning treatments using conventional...

Distinct mutational signatures characterize concurrent loss of polymerase proofreading and mismatch repair.

Science.gov (United States)

Haradhvala, N J; Kim, J; Maruvka, Y E; Polak, P; Rosebrock, D; Livitz, D; Hess, J M; Leshchiner, I; Kamburov, A; Mouw, K W; Lawrence, M S; Getz, G

2018-05-01

Fidelity of DNA replication is maintained using polymerase proofreading and the mismatch repair pathway. Tumors with loss of function of either mechanism have elevated mutation rates with characteristic mutational signatures. Here we report that tumors with concurrent loss of both polymerase proofreading and mismatch repair function have mutational patterns that are not a simple sum of the signatures of the individual alterations, but correspond to distinct, previously unexplained signatures: COSMIC database signatures 14 and 20. We then demonstrate that in all five cases in which the chronological order of events could be determined, polymerase epsilon proofreading alterations precede the defect in mismatch repair. Overall, we illustrate that multiple distinct mutational signatures can result from different combinations of a smaller number of mutational processes (of either damage or repair), which can influence the interpretation and discovery of mutational signatures.

Economic Ergonomic Approach to Design an Optimal Manpower and Mechanization in Rice Production

Science.gov (United States)

Muanah; Syuaib, M. F.; Liyantono

2018-05-01

Productivity of manpower could be improved by considering the economic and ergonomic aspect. The ergonomic aspect (human factor) is required to design an optimal manpower, while in the economic aspect, the well being of manpower could be evaluated from the amount of received income based on their work capability. This research was conducted on February 2016 to January 2017 in Gapoktan Silih Asih rice field Cigombong, Bogor. This study aims to analyze the income of manpower based on current conditions, increasement of working hours and mechanization addition. The results showed that manpower income based on the current condition and ergonomic consideration was Rp 1,174,030/person.month, by increasing the working hours with ergonomic consideration the obtained income was Rp 1,766,204/person.month. the revenues were based on the existing work system even though the increasement of working hours have not provided optimal income due to low productivity. Therefore the results of analysis with the addition of selective mechanization, showed self-ownership machinery was more profitable the obtained income have more than the Bogor minimum wage standard of Rp 2,969,325/person.month.

Evaluating four mathematical models for nitrous oxide production by autotrophic ammonia-oxidizing bacteria.

Science.gov (United States)

Ni, Bing-Jie; Yuan, Zhiguo; Chandran, Kartik; Vanrolleghem, Peter A; Murthy, Sudhir

2013-01-01

There is increasing evidence showing that ammonia-oxidizing bacteria (AOB) are major contributors to N(2)O emissions from wastewater treatment plants (WWTPs). Although the fundamental metabolic pathways for N(2)O production by AOB are now coming to light, the mechanisms responsible for N(2)O production by AOB in WWTP are not fully understood. Mathematical modeling provides a means for testing hypotheses related to mechanisms and triggers for N(2)O emissions in WWTP, and can then also become a tool to support the development of mitigation strategies. This study examined the ability of four mathematical model structures to describe two distinct mechanisms of N(2)O production by AOB. The production mechanisms evaluated are (1) N(2)O as the final product of nitrifier denitrification with NO(2)- as the terminal electron acceptor and (2) N(2)O as a byproduct of incomplete oxidation of hydroxylamine (NH(2)OH) to NO(2)-. The four models were compared based on their ability to predict N(2)O dynamics observed in three mixed culture studies. Short-term batch experimental data were employed to examine model assumptions related to the effects of (1) NH4+ concentration variations, (2) dissolved oxygen (DO) variations, (3) NO(2)- accumulations and (4) NH(2OH as an externally provided substrate. The modeling results demonstrate that all these models can generally describe the NH4+, NO(2)-, and NO(3)- data. However, none of these models were able to reproduce all measured N(2)O data. The results suggest that both the denitrification and NH(2)OH pathways may be involved in N(2)O production and could be kinetically linked by a competition for intracellular reducing equivalents. A unified model capturing both mechanisms and their potential interactions needs to be developed with consideration of physiological complexity. Copyright © 2012 Wiley Periodicals, Inc.

Unified treatment of the classical and quantum mechanics

International Nuclear Information System (INIS)

Shirokov, Yu.M.

1979-01-01

Classical and Quantum Mechanics are unified in the sense that almost all axioms of both mechanics are identical. The only distinction is the explicit form of one algebraic identity. The unified theory is applied to scattering problem. (Z.M.)

Use of Stable Isotopes and Incubation Studies to Characterize Methane Production Mechanism in Northern Wetlands

Science.gov (United States)

Chanton, J. P.; Fields, D.; Hines, M. E.; Rooney-Varga, J.

2003-12-01

Arctic and boreal ecosystems are important since they occupy greater than 1/5 of the Earth's terrestrial surface, they are sensitive to subtle climate changes, and they have significant effects on the atmosphere. Methanogenesis is dominated by two major pathways, acetotrophic (i.e., acetoclastic) methanogenesis in which acetate is the immediate precursor of CH4 (and CO2), and H2/CO2 methanogenesis in which CH4 is a product of H2 oxidation coupled with CO2 reduction. Recent studies suggest that acetotrophic methanogenesis does not occur widely in the northern wetlands and acetate can accumulate to high levels (Duddleston et al., 2002; Hines et al., 2001a). Methanogenesis at these sites is dominated by the H2/CO2 pathway and the importance of acetate as a precursor of CH4 seems to decrease with decreasing temperature and increasing oligotrophy. We surveyed a transect across Alaska from Deadhorse to Anchorage and used stable isotope distributions of DIC, CH4 and H2O to discern the relative importance of differing methane production mechanisms. These results compared favorably to incubation studies. Vegetation type was found to be a strong indicator of methane production mechanism, with Carex indicating acetotrophic methaneogenesis and sphagnum being an indicator of a lack of acetate methaneogenesis. The effects of production pathway variation on the dD of methane will also be presented.

Biaxial Stretch Improves Elastic Fiber Maturation, Collagen Arrangement, and Mechanical Properties in Engineered Arteries.

Science.gov (United States)

Huang, Angela H; Balestrini, Jenna L; Udelsman, Brooks V; Zhou, Kevin C; Zhao, Liping; Ferruzzi, Jacopo; Starcher, Barry C; Levene, Michael J; Humphrey, Jay D; Niklason, Laura E

2016-06-01

Tissue-engineered blood vessels (TEVs) are typically produced using the pulsatile, uniaxial circumferential stretch to mechanically condition and strengthen the arterial grafts. Despite improvements in the mechanical integrity of TEVs after uniaxial conditioning, these tissues fail to achieve critical properties of native arteries such as matrix content, collagen fiber orientation, and mechanical strength. As a result, uniaxially loaded TEVs can result in mechanical failure, thrombus, or stenosis on implantation. In planar tissue equivalents such as artificial skin, biaxial loading has been shown to improve matrix production and mechanical properties. To date however, multiaxial loading has not been examined as a means to improve mechanical and biochemical properties of TEVs during culture. Therefore, we developed a novel bioreactor that utilizes both circumferential and axial stretch that more closely simulates loading conditions in native arteries, and we examined the suture strength, matrix production, fiber orientation, and cell proliferation. After 3 months of biaxial loading, TEVs developed a formation of mature elastic fibers that consisted of elastin cores and microfibril sheaths. Furthermore, the distinctive features of collagen undulation and crimp in the biaxial TEVs were absent in both uniaxial and static TEVs. Relative to the uniaxially loaded TEVs, tissues that underwent biaxial loading remodeled and realigned collagen fibers toward a more physiologic, native-like organization. The biaxial TEVs also showed increased mechanical strength (suture retention load of 303 ± 14.53 g, with a wall thickness of 0.76 ± 0.028 mm) and increased compliance. The increase in compliance was due to combinatorial effects of mature elastic fibers, undulated collagen fibers, and collagen matrix orientation. In conclusion, biaxial stretching is a potential means to regenerate TEVs with improved matrix production, collagen organization, and mechanical

Hypo- and hyperactivated Notch signaling induce a glycolytic switch through distinct mechanisms

NARCIS (Netherlands)

Landor, S.; Mutvei, A.P.; Mamaeva, V.; Jin, S.; Busk, M.; Borra, R.; Grönroos, T.J.; Kronqvist, P.; Lendahl, U.; Sahlgren, C.M.

2011-01-01

A switch from oxidative phosphorylation to glycolysis is frequently observed in cancer cells and is linked to tumor growth and invasion, but the underpinning molecular mechanisms controlling the switch are poorly understood. In this report we show that Notch signaling is a key regulator of cellular

Triple Diagonal modeling: A mechanism to focus productivity improvement for business success

Energy Technology Data Exchange (ETDEWEB)

Levine, L.O. [Pacific Northwest Lab., Richland, WA (United States); Villareal, L.D. [Army Depot, Corpus Christi, TX (United States)

1993-09-01

Triple Diagonal (M) modeling is a technique to help quickly diagnose an organization`s existing production system and to identify significant improvement opportunities in executing, controlling, and planning operations. TD modeling is derived from ICAM Definition Language (IDEF 0)-also known as Structured Analysis and Design Technique. It has been used successfully at several Department of Defense remanufacturing facilities trying to accomplish significant production system modernization. TD has several advantages over other modeling techniques. First, it quickly does ``As-ls`` analysis and then moves on to identify improvements. Second, creating one large diagram makes it easier to share the TD model throughout an organization, rather than the many linked 8 1/2 {times} 11`` drawings used in traditional decomposition approaches. Third, it acts as a communication mechanism to share understanding about improvement opportunities that may cross existing functional/organizational boundaries. Finally, TD acts as a vehicle to build a consensus on a prioritized list of improvement efforts that ``hangs togethers as an agenda for systemic changes in the production system and the improved integration of support functions.

Promoting bioethanol production through clean development mechanism: Findings and lessons learnt from ASIATIC project

Energy Technology Data Exchange (ETDEWEB)

Gnansounou, Edgard; Bedniaguine, Denis; Dauriat, Arnaud

2005-12-15

Global climate change mitigation policies call for increasing use of biomass fuels as renewable substitutes to fossil energy resources. Quantified targets for biofuels introduction in to the market exist in the United States, the European Union, and a number of developing countries. In this context, mixing biologically produced ethanol with conventional gasoline represents an attractive technical option allowing for reducing emissions of greenhouse gases and lessening the dependence on non-renewable petrol in the transportation sector. This paper investigates technological and socio-economic aspects of ethanol production in developing countries, particularly in China, with special focus on determining eligibility of bioethanol projects for Clean Development Mechanism. Basing on the findings of the ASIATIC study (Agriculture and Small to Medium Scale Industries in Peri-urban Areas through Ethanol Production for Transport In China), we analyse how alcohol fuels can be produced in a sustainable way with mutual benefits between rural and urban people. The bioethanol production cost and life cycle CO2 eq. emissions were calculated for six different types of feedstock: sugarcane, sugarcane molasses, sweet sorghum juice, cassava, corn, and sorghum bagasse. Implications of the CDM rules and procedures for bioethanol industry were examined under the angles of environmental and economical additionality, and conformity with the principles of sustainable development. It is found that the starch-based (cassava) ethanol production path has the greatest potential for market penetration in China, followed by the conversion route using sugar-based feedstock (sorghum juice, sugarcane molasses). Meanwhile, the lignocelluloses biomass - to - ethanol technology may represent the highest interest for implementation as Clean Development Mechanism project. (Author)

Production, microstructure and mechanical properties of two different austenitic ODS steels

Science.gov (United States)

Gräning, T.; Rieth, M.; Hoffmann, J.; Möslang, A.

2017-04-01

This article is to summarize and examine processing parameters of novel developed austenitic oxide dispersed strengthened (ODS) steels. Comparing hot-rolled and extruded conditions after the same degree of deformation after and before annealing, are just some examples to give insights into the complex processing of austenitic ODS steels. One of the major drawbacks of the material is the more sophisticated production process. Due to a ductile matrix material with an increased stickiness during milling, a two-step milling procedure with the use of ZrO2 milling balls was applied to raise the production yield and to use the abrasion of the ZrO2 as an additional element to facilitate the formation of nano-sized precipitates. To get a better understanding how the different powder particle sizes after milling affect final properties, sieving was applied and revealed a serious effect in terms of precipitate size, distribution and mechanical properties. Grain sizes in relation to the precipitate size, annealing time and processing parameters were determined and compared to the mechanical properties. Hardness and tensile test have pointed out, that the precipitate size and number are more important in respect to the ultimate tensile strength than the grain size and that in this study hot-rolled material exhibited the better properties. The investigation of the microstructure illustrated the stability of precipitates during annealing at 1100 °C for 40 h. These heat treatments also led to a consistent grain size, due to the pinning effect of the grain boundaries, caused by precipitates.

A global RNA-seq-driven analysis of CHO host and production cell lines reveals distinct differential expression patterns of genes contributing to recombinant antibody glycosylation.

Science.gov (United States)

Könitzer, Jennifer D; Müller, Markus M; Leparc, Germán; Pauers, Martin; Bechmann, Jan; Schulz, Patrick; Schaub, Jochen; Enenkel, Barbara; Hildebrandt, Tobias; Hampel, Martin; Tolstrup, Anne B

2015-09-01

Boehringer Ingelheim uses two CHO-DG44 lines for manufacturing biotherapeutics, BI-HEX-1 and BI-HEX-2, which produce distinct cell type-specific antibody glycosylation patterns. A recently established CHO-K1 descended host, BI-HEX-K1, generates antibodies with glycosylation profiles differing from CHO-DG44. Manufacturing process development is significantly influenced by these unique profiles. To investigate the underlying glycosylation related gene expression, we leveraged our CHO host and production cell RNA-seqtranscriptomics and product quality database together with the CHO-K1 genome. We observed that each BI-HEX host and antibody producing cell line has a unique gene expression fingerprint. CHO-DG44 cells only transcribe Fut10, Gfpt2 and ST8Sia6 when expressing antibodies. BI-HEX-K1 cells express ST8Sia6 at host cell level. We detected a link between BI-HEX-1/BI-HEX-2 antibody galactosylation and mannosylation and the gene expression of the B4galt gene family and genes controlling mannose processing. Furthermore, we found major differences between the CHO-DG44 and CHO-K1 lineages in the expression of sialyl transferases and enzymes synthesizing sialic acid precursors, providing a rationale for the lack of immunogenic NeuGc/NGNA synthesis in CHO. Our study highlights the value of systems biotechnology to understand glycoprotein synthesis and product glycoprofiles. Such data improve future production clone selection and process development strategies for better steering of biotherapeutic product quality. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Suppressor of Cytokine Signaling (SOCS 5 utilises distinct domains for regulation of JAK1 and interaction with the adaptor protein Shc-1.

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Edmond M Linossi

Full Text Available Suppressor of Cytokine Signaling (SOCS5 is thought to act as a tumour suppressor through negative regulation of JAK/STAT and epidermal growth factor (EGF signaling. However, the mechanism/s by which SOCS5 acts on these two distinct pathways is unclear. We show for the first time that SOCS5 can interact directly with JAK via a unique, conserved region in its N-terminus, which we have termed the JAK interaction region (JIR. Co-expression of SOCS5 was able to specifically reduce JAK1 and JAK2 (but not JAK3 or TYK2 autophosphorylation and this function required both the conserved JIR and additional sequences within the long SOCS5 N-terminal region. We further demonstrate that SOCS5 can directly inhibit JAK1 kinase activity, although its mechanism of action appears distinct from that of SOCS1 and SOCS3. In addition, we identify phosphoTyr317 in Shc-1 as a high-affinity substrate for the SOCS5-SH2 domain and suggest that SOCS5 may negatively regulate EGF and growth factor-driven Shc-1 signaling by binding to this site. These findings suggest that different domains in SOCS5 contribute to two distinct mechanisms for regulation of cytokine and growth factor signaling.

Age influences the skin reaction pattern to mechanical stress and its repair level through skin care products.

Science.gov (United States)

Zouboulis, Christos C; Elewa, Rana; Ottaviani, Monica; Fluhr, Joachim; Picardo, Mauro; Bernois, Armand; Heusèle, Catherine; Camera, Emanuela

2018-03-01

Skin aging is associated with alterations of surface texture, sebum composition and immune response. Mechanical stress induces repair mechanisms, which may be dependent on the age and quality of the skin. The response to mechanical stress in young and aged individuals, their subjective opinion and the objective effectiveness of skin care products were evaluated by biophysical skin quality parameters (stratum corneum hydration, transepidermal water loss, skin pH, pigmentation and erythema) at baseline, 1, 6, 24h and 7days at the forearms of 2 groups of healthy volunteers, younger than 35 years (n=11) and older than 60 years (n=13). In addition, casual surface lipid composition was studied under the same conditions at the baseline and day 7 after mechanical stress induction. Evaluations were also performed in stressed skin areas treated daily with skin care products and the subjective opinion of the volunteers was additionally documented. The tested groups exhibited age-associated baseline skin functions as well as casual surface lipid composition and different reaction patterns to mechanical stress. Skin care was more effective in normalizing skin reaction to stress in the young than in the aged group. The subjective volunteer opinion correlated with the objective measurements. Copyright © 2017 Elsevier B.V. All rights reserved.

Mechanical properties used for the qualification of transport casks: Prototype development and extension to serial production

International Nuclear Information System (INIS)

Salzbrenner, R.; Crenshaw, T.B.; Sorenson, K.B.

1991-01-01

A thorough understanding of the mechanical behavior of material in a specific cask is required to properly analyze the structural response of the cask. An appropriate way to establish this understanding is through laboratory testing of cask material. The laboratory testing that was done to support the MOSAIK Drop Test Program is summarized as an example of how mechanical properties can be mapped for a prototype cask. The broad range behavior to be understood. This is necessary for the proper application of fracture mechanics, and focuses on fracture toughness as the inherent materials property which quantifies the fracture resistance of a material. The understanding established by a mechanics to a particular prototype, behavior of a prototype must be correctly associated with parameters which can be measured on production casks. Since the production casks cannot be destructively tested, measurements are commonly made on sub-size specimens. This may prevent direct measurement of valid design properties. An additional database may then be required to establish the correlation between sub-size specimen measurements and valid design properties. This is illustrated by outlining the additional testing which would be necessary to allow the successful verification of the MOSAIK Drop Test Program to be extended from the prototype to serially produced casks

New approach to the elucidation of corrosion mechanism of ceramics by the ion implantation

International Nuclear Information System (INIS)

Saito, J.; Hayashi, K.; Tachi, Y.; Kano, S.

1998-08-01

Ceramics possessing high temperature strength are promising materials for the structural application in severe environment. The development of ceramics has been carried out in order to use them in FBR environment such as liquid sodium. In particular, corrosion behavior of ceramics has been investigated to improve the corrosion resistance in liquid sodium. However, the corrosion mechanism of ceramics was not comprehended in detail even now. Because corrosion products which were deposited on the surface of test pieces during corrosion test and played an important role in corrosion behavior, were not detected distinctly after thr corrosion test. In this study, an ion implantation technique was applied to understand the corrosion mechanism of ceramics in stead of the conventional corrosion test. Sodium ions were implanted in ceramics (100 keV, 1.9 x 10 17 ions/cm 2 ) and then heat treatment was performed at either 923 K or 823 K for 36 ks in argon atmosphere. After that, products on the surface were analyzed using SEM and TEM observation and X-ray diffraction. Consequently, the corrosion products were not identified exactly, but their presence was confirmed on the surface. It was caused by the minute amount of corrosion products. In future, it is necessary to carry systematically out the implantation and heat treatment under various conditions. Therefore, it seems that the beneficial information will be obtained to understand the corrosion mechanism of ceramics. (author)

The rock mechanical stability of the VLJ repository

International Nuclear Information System (INIS)

Kuula, H.; Johansson, E.

1991-03-01

The aim of the study was to determine the rock mechanical stability around the VLJ repository based on the rock mechanical monitoring and rock mechanical modeling. Rock mechanical calculations were made in order to calculate the rock mass displacements and to analyze the stability around the VLJ repository The calculations were performed with three diiferent methods: continuum finite difference code FLAC, distinct element code UDEC and three dimensional distinct element code 3DEC. The first analyses were based on preliminary site investigations. The final modeling was based on investigations and rock mechanical monitoring done during the excavation. Some sensitive analyses were also performed. The modelled rock mass behaviour and the measured behaviour are generally close to each other. Both results show that the VLJ repository is rock mechanically stable. The modelled displacements and stresses were small enough to cause no instability around the rock caverns. The measured values do not indicate any discontinuous deformations like block movements or joint slip. The measured displacements in the extensometers during excavation indicates that the rock mass is even stiffer than anticipated

Characterization of Trichome-Expressed BAHD Acyltransferases in Petunia axillaris Reveals Distinct Acylsugar Assembly Mechanisms within the Solanaceae.

Science.gov (United States)

Nadakuduti, Satya Swathi; Uebler, Joseph B; Liu, Xiaoxiao; Jones, A Daniel; Barry, Cornelius S

2017-09-01

Acylsugars are synthesized in the glandular trichomes of the Solanaceae family and are implicated in protection against abiotic and biotic stress. Acylsugars are composed of either sucrose or glucose esterified with varying numbers of acyl chains of differing length. In tomato ( Solanum lycopersicum ), acylsugar assembly requires four acylsugar acyltransferases (ASATs) of the BAHD superfamily. Tomato ASATs catalyze the sequential esterification of acyl-coenzyme A thioesters to the R4, R3, R3', and R2 positions of sucrose, yielding a tetra-acylsucrose. Petunia spp. synthesize acylsugars that are structurally distinct from those of tomato. To explore the mechanisms underlying this chemical diversity, a Petunia axillaris transcriptome was mined for trichome preferentially expressed BAHDs. A combination of phylogenetic analyses, gene silencing, and biochemical analyses coupled with structural elucidation of metabolites revealed that acylsugar assembly is not conserved between tomato and petunia. In P. axillaris , tetra-acylsucrose assembly occurs through the action of four ASATs, which catalyze sequential addition of acyl groups to the R2, R4, R3, and R6 positions. Notably, in P. axillaris , PaxASAT1 and PaxASAT4 catalyze the acylation of the R2 and R6 positions of sucrose, respectively, and no clear orthologs exist in tomato. Similarly, petunia acylsugars lack an acyl group at the R3' position, and congruently, an ortholog of SlASAT3, which catalyzes acylation at the R3' position in tomato, is absent in P. axillaris Furthermore, where putative orthologous relationships of ASATs are predicted between tomato and petunia, these are not supported by biochemical assays. Overall, these data demonstrate the considerable evolutionary plasticity of acylsugar biosynthesis. © 2017 American Society of Plant Biologists. All Rights Reserved.

Imbalance between production and conjugation of bilirubin: a fundamental concept in the mechanism of neonatal jaundice.

Science.gov (United States)

Kaplan, Michael; Muraca, Maurizio; Hammerman, Cathy; Rubaltelli, Firmino F; Vilei, Maria T; Vreman, Hendrik J; Stevenson, David K

2002-10-01

The objective of this study was to evaluate the roles of production and conjugation of bilirubin, individually and in combination, in the mechanism of neonatal jaundice. A cohort of healthy, term male newborns was sampled on the third day of life, coincident with routine metabolic screening, for blood carboxyhemoglobin determination, a reflection of heme catabolism, and for serum unconjugated and conjugated bilirubin fractions, reflecting bilirubin conjugation. The former was determined by gas chromatography, corrected for inspired CO (COHbc), and expressed as percentage of total hemoglobin. Serum bilirubin fractions were quantified by alkaline methanolysis and reverse phase high performance liquid chromatography. The sum of all bilirubin fractions comprised serum total bilirubin (STB). Total conjugated bilirubin (TCB) was comprised of the sum of the conjugated fractions and was expressed as percentage of STB (TCB[%]). A "bilirubin production/conjugation index" (COHbc/[TCB(%)] represented the combined roles of these modalities in the mechanism of bilirubinemia. Relationships between STB concentrations on the one hand, and COHbc values, TCB(%) proportions, and the production/conjugation index on the other, were determined by applying a best-fit regression analysis methodology. Mean (+/- standard deviation) STB concentration at the time of sampling was 114 +/- 48 micro mol/L (range: 8-263 micro mol/L). Mean COHbc value was 0.77 +/- 0.19%, and median (interquartile range) TCB(%) was 0.737 (0.465-1.260)%. COHbc values correlated directly with STB concentrations (r = 0.38; s = 46.1), and TCB(%) correlated inversely with STB (r = 0.40; s = 45.8). The production/conjugation index correlated positively with STB values (r = 0.61; s = 45.8), the r value for the index being higher than that of either COHbc or TCB(%), individually. The bilirubin production/conjugation index seemed to have a biphasic relationship to STB: STB values rose steeply in concert with increasing index

Relationship between Marketing Strategies and Governance Mechanisms: A Study in Exploration Chain Beef Cattle

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Filipe Quevedo-Silva

2015-09-01

Full Text Available The relationship between actors has been unspoilt by marketing through the bias of Transaction Costs Economics. Some authors suggest that a marketing strategy can directly impact the transactional characteristics and hence the governance mechanisms chosen to coordinate transactions. Studies suggest that future work in the field of marketing include, among other factors, aspects related to the relationship between the actors. In this context, this article aims to analyze how marketing strategies can affect the choice of governance mechanisms. The study object is the chain of beef, view their representation to the national economy. To this end, we conducted a qualitative study using semi-structured interviews with various actors in the chain. It was possible to verify the existence of the relationship between marketing strategy and governance structure. In one of the cases, product differentiation, translated into more specific assets, led the producer to perform a relational contract with the fridge and to distribute your product, make an integration with retailers, through the opening of a boutique of meat. Factor that was not observed in transactions involving producers on products without distinction, for which the transactions via spot market are prevalent.  

Nfkb1 inhibits LPS-induced IFN-β and IL-12 p40 production in macrophages by distinct mechanisms.

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Xixing Zhao

Full Text Available Nfkb1-deficient murine macrophages express higher levels of IFN-β and IL-12 p40 following LPS stimulation than control macrophages, but the molecular basis for this phenomenon has not been completely defined. Nfkb1 encodes several gene products including the NF-κB subunit p50 and its precursor p105. p50 is derived from the N-terminal of 105, and p50 homodimers can exhibit suppressive activity when overexpressed. The C-terminal region of p105 is necessary for LPS-induced ERK activation and it has been suggested that ERK activity inhibits both IFN-β and IL-12 p40 following LPS stimulation. However, the contributions of p50 and the C-terminal domain of p105 in regulating endogenous IFN-β(Ifnb and IL-12 p40 (Il12b gene expression in macrophages following LPS stimulation have not been directly compared.We have used recombinant retroviruses to express p105, p50, and the C-terminal domain of p105 (p105ΔN in Nfkb1-deficient murine bone marrow-derived macrophages at near endogenous levels. We found that both p50 and p105ΔN inhibited expression of Ifnb, and that inhibition of Ifnb by p105ΔN depended on ERK activation, because a mutant of p105ΔN (p105ΔNS930A that lacks a key serine necessary to support ERK activation failed to inhibit. In contrast, only p105ΔN but not p50 inhibited Il12b expression. Surprisingly, p105ΔNS930A retained inhibitory activity for Il12b, indicating that ERK activation was not necessary for inhibition. The differential effects of p105ΔNS930A on Ifnb and Il12b expression inversely correlated with the function of one of its binding partners, c-Rel. This raised the possibility that p105ΔNS930A influences gene expression by interfering with the function of c-Rel.These results demonstrate that Nfkb1 exhibits multiple gene-specific inhibitory functions following TLR stimulation of murine macrophages.

A high-compression electron gun for C6+ production: concept, simulations and mechanical design

Science.gov (United States)

Mertzig, Robert; Breitenfeldt, M.; Mathot, S.; Pitters, J.; Shornikov, A.; Wenander, F.

2017-07-01

In this paper we report on simulations and the mechanical design of a high-compression electron gun for an Electron Beam Ion Source (EBIS) dedicated for production of high intensity and high repetition rate pulses of bare carbon ions for injection into linac-based hadron therapy facilities. The gun is presently under construction at CERN to be retrofitted into the TwinEBIS test bench for experimental studies. We describe the design constraints, show results of numeric simulations and report on the mechanical design featuring several novel ideas. The reported design makes use of combined-function units with reduced number of mechanical joints that were carefully controlled and tuned during the manufacturing phase. The simulations addressed a wide range of topics including the influence of thermal effects, focusing optics, symmetry-breaking misalignments and injection into a full 5 T field.

Distinctiveness of Saudi Arabian EFL Learners

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Manssour Habbash

2016-04-01

Full Text Available In view of the increasing concern among English language teachers dealing with students from Saudi Arabia, as it manifests in TESOL community discussions, about the uniqueness of Saudi Arabian EFL learners, this paper attempts to document the outcome of a study of their distinctiveness from the perspective of expatriate teachers working for PYPs (Preparatory Year Programs in Saudi Arabia. This study examines the distinctiveness with regard to the learning attitudes of Saudi students that are often cultivated by the culture and academic environment in their homeland. Employing an emic approach for collecting the required data an analysis was carried out in light of the other studies on ‘education’ in Saudi Arabia that have particular reference to the factors that can positively influence student motivation, student success and the academic environment. The findings were used in constructing the rationale behind such distinctiveness. Assuming that the outcome of the discussion on the findings of this exploration can be helpful for teachers in adapting their teaching methodology and improving their teacher efficacy in dealing with students both from the kingdom and in the kingdom, some recommendations are made. Keywords: China Distinctiveness, Saudi Arabian University context, Expatriate teachers’ perspective, Distinctiveness Theory

Enhancement and Optimization Mechanisms of Biogas Production for Rural Household Energy in Developing Countries: A review

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Yitayal Addis Alemayehu

2015-10-01

Full Text Available Anaerobic digestion is common but vital process used for biogas and fertilizer production as well as one method for waste treatment. The process is currently used in developing countries primarily for biogas production in the household level of rural people. The aim of this review is to indicate possible ways of including rural households who own less than four heads of cattle for the biogas programs in developing countries. The review provides different research out puts on using biogas substrates other than cow dung or its mix through different enhancement and optimization mechanisms. Many biodegradable materials have been studied for alternative methane production. Therefore, these substrates could be used for production by addressing the optimum conditions for each factor and each processes for enhanced and optimized biogas production.

DETERMINANTS OF QUALITY MANAGEMENT PRACTICES IN STIMULATING PRODUCT AND PROCESS INNOVATIONS

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Boris Urban

2017-12-01

Full Text Available Research highlights Quality Management System (QMS has now become a recognizable guarantee of trust in certified business systems. A critical review of the literature reveals that empirical studies conducted to date have yielded conflicting findings on the relationship between quality management practices and innovation. This study empirically investigates how quality management principles may act as determinants of product and process innovations. The results show that customer focus and leadership explain a significant amount of product innovation, but not process innovation. Empirical support also finds that people management explains a significant amount of variance in both product innovation and process innovation. The findings highlight the importance of developing formal organisational mechanisms to measure levels of such quality determinants as they are easily overlooked or taken for granted. Moreover, firms need to recognise that innovation is a multi-faceted concept that can be controlled from a process or a product perspective, a distinction which is sometimes blurred.

Experimental acidification of two biogeochemically-distinct neotropical streams: Buffering mechanisms and macroinvertebrate drift

International Nuclear Information System (INIS)

Ardón, Marcelo; Duff, John H.; Ramírez, Alonso; Small, Gaston E.; Jackman, Alan P.; Triska, Frank J.; Pringle, Catherine M.

2013-01-01

Research into the buffering mechanisms and ecological consequences of acidification in tropical streams is lacking. We have documented seasonal and episodic acidification events in streams draining La Selva Biological Station, Costa Rica. Across this forested landscape, the severity in seasonal and episodic acidification events varies due to interbasin groundwater flow (IGF). Streams that receive IGF have higher concentrations of solutes and more stable pH (∼ 6) than streams that do not receive IGF (pH ∼ 5). To examine the buffering capacity and vulnerability of macroinvertebrates to short-term acidification events, we added hydrochloric acid to acidify a low-solute, poorly buffered (without IGF) and a high-solute, well buffered stream (with IGF). We hypothesized that: 1) protonation of bicarbonate (HCO 3 − ) would neutralize most of the acid added in the high-solute stream, while base cation release from the sediments would be the most important buffering mechanism in the low-solute stream; 2) pH declines would mobilize inorganic aluminum (Ali) from sediments in both streams; and 3) pH declines would increase macroinvertebrate drift in both streams. We found that the high-solute stream neutralized 745 μeq/L (96% of the acid added), while the solute poor stream only neutralized 27.4 μeq/L (40%). Protonation of HCO 3 − was an important buffering mechanism in both streams. Base cation, Fe 2+ , and Ali release from sediments and protonation of organic acids also provided buffering in the low-solute stream. We measured low concentrations of Ali release in both streams (2-9 μeq/L) in response to acidification, but the low-solute stream released double the amount Ali per 100 μeq of acid added than the high solute stream. Macroinvertebrate drift increased in both streams in response to acidification and was dominated by Ephemeroptera and Chironomidae. Our results elucidate the different buffering mechanisms in tropical streams and suggest that low

Visual distinctiveness can enhance recency effects.

Science.gov (United States)

Bornstein, B H; Neely, C B; LeCompte, D C

1995-05-01

Experimental efforts to meliorate the modality effect have included attempts to make the visual stimulus more distinctive. McDowd and Madigan (1991) failed to find an enhanced recency effect in serial recall when the last item was made more distinct in terms of its color. In an attempt to extend this finding, three experiments were conducted in which visual distinctiveness was manipulated in a different manner, by combining the dimensions of physical size and coloration (i.e., whether the stimuli were solid or outlined in relief). Contrary to previous findings, recency was enhanced when the size and coloration of the last item differed from the other items in the list, regardless of whether the "distinctive" item was larger or smaller than the remaining items. The findings are considered in light of other research that has failed to obtain a similar enhanced recency effect, and their implications for current theories of the modality effect are discussed.

BARE retrotransposons are translated and replicated via distinct RNA pools.

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Wei Chang

Full Text Available The replication of Long Terminal Repeat (LTR retrotransposons, which can constitute over 80% of higher plant genomes, resembles that of retroviruses. A major question for retrotransposons and retroviruses is how the two conflicting roles of their transcripts, in translation and reverse transcription, are balanced. Here, we show that the BARE retrotransposon, despite its organization into just one open reading frame, produces three distinct classes of transcripts. One is capped, polyadenylated, and translated, but cannot be copied into cDNA. The second is not capped or polyadenylated, but is destined for packaging and ultimate reverse transcription. The third class is capped, polyadenylated, and spliced to favor production of a subgenomic RNA encoding only Gag, the protein forming virus-like particles. Moreover, the BARE2 subfamily, which cannot synthesize Gag and is parasitic on BARE1, does not produce the spliced sub-genomic RNA for translation but does make the replication competent transcripts, which are packaged into BARE1 particles. To our knowledge, this is first demonstration of distinct RNA pools for translation and transcription for any retrotransposon.

Various Determinant Factors of Production Technology Adoption in Creative Souvenir Micro Enterprise

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Dumasari Dumasari

2017-10-01

Full Text Available This study aims to examine the existence of several factors that determine the power of the adoption of production technology on micro souvenirs creative enterprise. The location of the research was determined purposely in Purbalingga Wetan Subdistrict, Purbalingga District, Central Java Province, Indonesia. Research respondents numbered 28 people. The results showed that the various determinants of the adoption of production technology have economic, social and environmental motives. The power of influence of each factor is also distinct. The adoption of different craftsmen resulted in the quality of souvenir products from coconut waste being unequal. Some have a motif design according to market trend. Product price level is feasible. However, some products are only produced semi-finished. The price of this product is relatively lower. The economic feasibility of craftsmen is closely related to the rate of adoption of production technology. There are small number (<25 percent of craftsmen use mechanical technology. The rest is still aided on the traditional manual techniques in processing waste coconut into souvenirs or creative handicraft.

Enhancing the production effect in memory.

Science.gov (United States)

Quinlan, Chelsea K; Taylor, Tracy L

2013-01-01

The production effect is the finding that subsequent memory is better for words that are produced than for words that are not produced. Whereas the current literature demonstrates that reading aloud is the most effective form of production, the distinctiveness account used to explain the production effect predicts that there is nothing special about reading aloud per se: Other forms of vocal production that include an additional distinct element should produce even greater subsequent memory benefits than reading aloud. To test this, we presented participants with study words that they were instructed to read aloud loudly, read aloud, or read silently (Experiment 1); sing, read aloud, or read silently (Experiment 2); and sing, read aloud loudly, read aloud, or read silently (Experiment 3). We observed that both reading items aloud loudly (Experiments 1 and 3) and singing items (Experiments 2 and 3) at study resulted in greater subsequent recognition than reading items aloud in a normal voice; singing had a larger memory benefit than reading aloud loudly (Experiment 3). Our findings support the distinctiveness hypothesis by demonstrating that there are other forms of production, such as singing and reading aloud loudly that have a more pronounced effect on memory than reading aloud.

Additive Manufacturing and Casting Technology Comparison: Mechanical Properties, Productivity and Cost Benchmark

Science.gov (United States)

Vevers, A.; Kromanis, A.; Gerins, E.; Ozolins, J.

2018-04-01

The casting technology is one of the oldest production technologies in the world but in the recent years metal additive manufacturing also known as metal 3D printing has been evolving with huge steps. Both technologies have capabilities to produce parts with internal holes and at first glance surface roughness is similar for both technologies, which means that for precise dimensions parts have to be machined in places where precise fit is necessary. Benchmark tests have been made to find out if parts which are produced with metal additive manufacturing can be used to replace parts which are produced with casting technology. Most of the comparative tests have been made with GJS-400-15 grade which is one of the most popular cast iron grades. To compare mechanical properties samples have been produced using additive manufacturing and tested for tensile strength, hardness, surface roughness and microstructure and then the results have been compared with the samples produced with casting technology. In addition, both technologies have been compared in terms of the production time and production costs to see if additive manufacturing is competitive with the casting technology. The original paper has been written in the Latvian language as part of the Master Thesis within the framework of the production technology study programme at Riga Technical University.

On Hobbes’s distinction of accidents

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Lupoli Agostino

2012-06-01

Full Text Available An interpolation introduced by K. Schuhmann in his critical edition of "De corpore" (chap. VI, § 13 diametrically overturns the meaning of Hobbes’s doctrine of distinction of accidents in comparison with all previous editions. The article focuses on the complexity of this crucial juncture in "De corpore" argument on which depends the interpretation of Hobbes’s whole conception of science. It discusses the reasons pro and contra Schuhmann’s interpolation and concludes against it, because it is not compatible with the rationale underlying the complex architecture of "De corpore", which involves a symmetry between the ‘logical’ distinction of accidents and the ‘metaphysical’ distinction of phantasms.

EGL-13/SoxD Specifies Distinct O2 and CO2 Sensory Neuron Fates in Caenorhabditis elegans

DEFF Research Database (Denmark)

Gramstrup Petersen, Jakob; Rojo Romanos, Teresa; Juozaityte, Vaida

2013-01-01

that EGL-13 is sufficient to induce O2- and CO2-sensing cell fates in some cellular contexts. Thus, the same core regulatory factor, egl-13, is required and sufficient to specify the distinct fates of O2- and CO2-sensing neurons in C. elegans. These findings extend our understanding of mechanisms......Animals harbor specialized neuronal systems that are used for sensing and coordinating responses to changes in oxygen (O2) and carbon dioxide (CO2). In Caenorhabditis elegans, the O2/CO2 sensory system comprises functionally and morphologically distinct sensory neurons that mediate rapid behavioral...

Production, characterisation and flocculation mechanism of ...

African Journals Online (AJOL)

Sidney Tsolanku ST. Maliehe

2016-09-30

Sep 30, 2016 ... of TMT-1 implied that it has a promise in industrial applications. Key words: ... biotechnological applications due to their cost ... Optimisation of culture conditions for bioflocculant production ..... industrial by-product of economic insignificant (Smith, ... absorption of the nutrients and enzymatic activity of. 0. 0.1.

Quantum and classical mechanics in the phase space representation

International Nuclear Information System (INIS)

Shirokov, Yu.M.

1979-01-01

The theory of the hamiltonian mechanical systems has been formulated in terms of only such physical and mathematical concepts which are meaningful in both mechanics. For instance the observables in both mechanics are represented as c-number functions of coordinates and momenta. The operations of the usual multiplication of observables as well as Poisson bracket (also treated as a sort of multiplication) are singled out as separate objects which can possess their own structure including h-dependence. This leads to the conclusion that the only primary distinction between classical and quantum mechanics is reduced to the distinction in the form of the algebraic identity for the multiplication operations. All other distinctions are proved to be of the secondary origin. The formalism developed in the paper is especially useful for quantizations and for the transitions (including partial ones) to the classical limits. The transitions in both directions are transparent and accessible for analysis for any quantity at any step of calculations. The unified quantum-classical scattering theory is constructed. The integral quantum Lippman-Schwinder type equation is derived where the free solution term is replaced by the solution of the corresponding classical problem. The iteration of this equation gives the quantum corrections to the classical solution

How space-number associations may be created in preliterate children: six distinct mechanisms

Directory of Open Access Journals (Sweden)

Hans-Christoph eNuerk

2015-03-01

Full Text Available The directionality of space-number association (SNA is shaped by cultural experiences. It usually follows the culturally dominant reading direction. Smaller numbers are generally associated with the starting side for reading (left side in Western cultures, while larger numbers are associated with the right endpoint side. However, SNAs consistent with cultural reading directions are present before children can actually read and write. Therefore, these SNAs cannot only be shaped by the direction of children’s own reading/writing behavior. We propose six distinct processes - one biological and five cultural/educational - underlying directional space-number associations before formal reading acquisition: (i Brain lateralization (ii Monitoring adult reading behavior, (iii Pretend reading and writing, and rudimentary reading and writing skills, (iv Dominant attentional directional preferences in a society, not directly related to reading direction, (v Direct spatial-numerical learning, (vi Other spatial-directional processes independent of reading direction. In this mini-review, we will differentiate between these processes, elaborate when in development they might emerge, discuss how they may create the space-number associations observed in preliterate children and propose how they can be studied in the future.

Experimental acidification of two biogeochemically-distinct neotropical streams: Buffering mechanisms and macroinvertebrate drift

Energy Technology Data Exchange (ETDEWEB)

Ardón, Marcelo, E-mail: ardonsayaom@ecu.edu [Department of Biology and North Carolina Center for Biodiversity, East Carolina University, Greenville, NC 27858 (United States); Duff, John H. [U.S. Geological Survey, Menlo Park, CA 94025 (United States); Ramírez, Alonso [Department of Environmental Sciences, University of Puerto Rico, San Juan, PR 00931 (Puerto Rico); Small, Gaston E. [Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN 55108 (United States); Jackman, Alan P. [University of California, Davis, CA 95616 (United States); Triska, Frank J. [U.S. Geological Survey, Menlo Park, CA 94025 (United States); Pringle, Catherine M. [Odum School of Ecology, University of Georgia, Athens, GA 30602 (United States)

2013-01-15

Research into the buffering mechanisms and ecological consequences of acidification in tropical streams is lacking. We have documented seasonal and episodic acidification events in streams draining La Selva Biological Station, Costa Rica. Across this forested landscape, the severity in seasonal and episodic acidification events varies due to interbasin groundwater flow (IGF). Streams that receive IGF have higher concentrations of solutes and more stable pH (∼ 6) than streams that do not receive IGF (pH ∼ 5). To examine the buffering capacity and vulnerability of macroinvertebrates to short-term acidification events, we added hydrochloric acid to acidify a low-solute, poorly buffered (without IGF) and a high-solute, well buffered stream (with IGF). We hypothesized that: 1) protonation of bicarbonate (HCO{sub 3}{sup −}) would neutralize most of the acid added in the high-solute stream, while base cation release from the sediments would be the most important buffering mechanism in the low-solute stream; 2) pH declines would mobilize inorganic aluminum (Ali) from sediments in both streams; and 3) pH declines would increase macroinvertebrate drift in both streams. We found that the high-solute stream neutralized 745 μeq/L (96% of the acid added), while the solute poor stream only neutralized 27.4 μeq/L (40%). Protonation of HCO{sub 3}{sup −} was an important buffering mechanism in both streams. Base cation, Fe{sup 2+}, and Ali release from sediments and protonation of organic acids also provided buffering in the low-solute stream. We measured low concentrations of Ali release in both streams (2-9 μeq/L) in response to acidification, but the low-solute stream released double the amount Ali per 100 μeq of acid added than the high solute stream. Macroinvertebrate drift increased in both streams in response to acidification and was dominated by Ephemeroptera and Chironomidae. Our results elucidate the different buffering mechanisms in tropical streams and

Mechanisms Design

DEFF Research Database (Denmark)

Restrepo-Giraldo, John Dairo

2006-01-01

Most products and machines involve some kind of controlled movement. From window casements to DVD players, from harbor cranes to the shears to prune your garden, all these machines require mechanisms to move. This course intends to provide the analytical and conceptual tools to design such mechan......Most products and machines involve some kind of controlled movement. From window casements to DVD players, from harbor cranes to the shears to prune your garden, all these machines require mechanisms to move. This course intends to provide the analytical and conceptual tools to design...... using criteria such as size, performance parameters, operation environment, etc. Content: Understanding Mechanisms Design (2 weeks) Definitions, mechanisms representations, kinematic diagrams, the four bar linkage, mobility, applications of mechanisms, types of mechanisms, special mechanisms, the design......: equations for various mechanisms. At the end of this module you will be able to analyze existing mechanisms and to describe their movement. Designing mechanisms (7 weeks) Type synthesis and dimensional synthesis, function generation, path generation, three precision points in multi-loop mechanisms...

Early and long-standing rheumatoid arthritis: distinct molecular signatures identified by gene-expression profiling in synovia

Science.gov (United States)

Lequerré, Thierry; Bansard, Carine; Vittecoq, Olivier; Derambure, Céline; Hiron, Martine; Daveau, Maryvonne; Tron, François; Ayral, Xavier; Biga, Norman; Auquit-Auckbur, Isabelle; Chiocchia, Gilles; Le Loët, Xavier; Salier, Jean-Philippe

2009-01-01

Introduction Rheumatoid arthritis (RA) is a heterogeneous disease and its underlying molecular mechanisms are still poorly understood. Because previous microarray studies have only focused on long-standing (LS) RA compared to osteoarthritis, we aimed to compare the molecular profiles of early and LS RA versus control synovia. Methods Synovial biopsies were obtained by arthroscopy from 15 patients (4 early untreated RA, 4 treated LS RA and 7 controls, who had traumatic or mechanical lesions). Extracted mRNAs were used for large-scale gene-expression profiling. The different gene-expression combinations identified by comparison of profiles of early, LS RA and healthy synovia were linked to the biological processes involved in each situation. Results Three combinations of 719, 116 and 52 transcripts discriminated, respectively, early from LS RA, and early or LS RA from healthy synovia. We identified several gene clusters and distinct molecular signatures specifically expressed during early or LS RA, thereby suggesting the involvement of different pathophysiological mechanisms during the course of RA. Conclusions Early and LS RA have distinct molecular signatures with different biological processes participating at different times during the course of the disease. These results suggest that better knowledge of the main biological processes involved at a given RA stage might help to choose the most appropriate treatment. PMID:19563633

Structurally distinct polycyclic aromatic hydrocarbons induce differential transcriptional responses in developing zebrafish

International Nuclear Information System (INIS)

Goodale, Britton C.; Tilton, Susan C.; Corvi, Margaret M.; Wilson, Glenn R.; Janszen, Derek B.; Anderson, Kim A.; Waters, Katrina M.; Tanguay, Robert L.

2013-01-01

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment as components of fossil fuels and by-products of combustion. These multi-ring chemicals differentially activate the aryl hydrocarbon receptor (AHR) in a structurally dependent manner, and induce toxicity via both AHR-dependent and -independent mechanisms. PAH exposure is known to induce developmental malformations in zebrafish embryos, and recent studies have shown cardiac toxicity induced by compounds with low AHR affinity. Unraveling the potentially diverse molecular mechanisms of PAH toxicity is essential for understanding the hazard posed by complex PAH mixtures present in the environment. We analyzed transcriptional responses to PAH exposure in zebrafish embryos exposed to benz(a)anthracene (BAA), dibenzothiophene (DBT) and pyrene (PYR) at concentrations that induced developmental malformations by 120 h post-fertilization (hpf). Whole genome microarray analysis of mRNA expression at 24 and 48 hpf identified genes that were differentially regulated over time and in response to the three PAH structures. PAH body burdens were analyzed at both time points using GC–MS, and demonstrated differences in PAH uptake into the embryos. This was important for discerning dose-related differences from those that represented unique molecular mechanisms. While BAA misregulated the least number of transcripts, it caused strong induction of cyp1a and other genes known to be downstream of the AHR, which were not induced by the other two PAHs. Analysis of functional roles of misregulated genes and their predicted regulatory transcription factors also distinguished the BAA response from regulatory networks disrupted by DBT and PYR exposure. These results indicate that systems approaches can be used to classify the toxicity of PAHs based on the networks perturbed following exposure, and may provide a path for unraveling the toxicity of complex PAH mixtures. - Highlights: • Defined global mRNA expression

The Dirac equation in classical statistical mechanics

International Nuclear Information System (INIS)

Ord, G.N.

2002-01-01

The Dirac equation, usually obtained by 'quantizing' a classical stochastic model is here obtained directly within classical statistical mechanics. The special underlying space-time geometry of the random walk replaces the missing analytic continuation, making the model 'self-quantizing'. This provides a new context for the Dirac equation, distinct from its usual context in relativistic quantum mechanics

Facets of contextual realism in quantum mechanics

International Nuclear Information System (INIS)

Pan, Alok Kumar; Home, Dipankar

2011-01-01

In recent times, there is an upsurge of interest in demonstrating the quantum contextuality. In this proceedings, we explore the two different forms of arguments that have been used for showing the contextual character of quantum mechanics. First line of study concerns the violations of the noncontextual realist models by quantum mechanics, where second line of study that is qualitatively distinct from the earlier one, demonstrates the contextuality within the formalism of quantum mechanics.

Vaccine and Wild-Type Strains of Yellow Fever Virus Engage Distinct Entry Mechanisms and Differentially Stimulate Antiviral Immune Responses

Directory of Open Access Journals (Sweden)

Maria Dolores Fernandez-Garcia

2016-02-01

Full Text Available The live attenuated yellow fever virus (YFV vaccine 17D stands as a “gold standard” for a successful vaccine. 17D was developed empirically by passaging the wild-type Asibi strain in mouse and chicken embryo tissues. Despite its immense success, the molecular determinants for virulence attenuation and immunogenicity of the 17D vaccine are poorly understood. 17D evolved several mutations in its genome, most of which lie within the envelope (E protein. Given the major role played by the YFV E protein during virus entry, it has been hypothesized that the residues that diverge between the Asibi and 17D E proteins may be key determinants of attenuation. In this study, we define the process of YFV entry into target cells and investigate its implication in the activation of the antiviral cytokine response. We found that Asibi infects host cells exclusively via the classical clathrin-mediated endocytosis, while 17D exploits a clathrin-independent pathway for infectious entry. We demonstrate that the mutations in the 17D E protein acquired during the attenuation process are sufficient to explain the differential entry of Asibi versus 17D. Interestingly, we show that 17D binds to and infects host cells more efficiently than Asibi, which culminates in increased delivery of viral RNA into the cytosol and robust activation of the cytokine-mediated antiviral response. Overall, our study reveals that 17D vaccine and Asibi enter target cells through distinct mechanisms and highlights a link between 17D attenuation, virus entry, and immune activation.

Neutral Pion Production in Proton+Proton Collisions at $\\sqrt{s}=8$ TeV and Insight into Hadron Production Mechanism

CERN Document Server

Yano, Satoshi

High transverse momentum particles play an important role for investigation of Quark-Gluon Plasma (QGP) induced by nucleus-nucleus collisions. When high transverse momentum partons traverse the QGP, they lose their energy. Consequently, the yield of high transverse momentum hadron is suppressed relative to proton+proton collisions scaled by the number of binary nucleon-nucleon collisions (jet quenching). The phenomenon is expected to give us much information about properties of QGP. Thus far, almost all models consider only parton energy loss during passing through. However, the perturbative Quantum Chromo Dynamics (QCD) predicts the direct hadron production (the higher-twist effect). If hadrons produced by this mechanism exist, the hadron energy loss should be considered additionally. For checking if there is the higher-twist effect, investigation of hadron production in proton+proton collisions is suitable. The invariant differential cross sections for inclusive neutral pion at midrapidity are measured in p...

Making sense of Knowledge Productivity

NARCIS (Netherlands)

Christiaan Stam

2010-01-01

In the knowledge economy knowledge productivity is the main source of competitive advantage and thus the biggest management challenge. Based on a review of the concept from two distinct perspectives, knowledge productivity is defined as the process of knowledge-creation that leads to incremental and

Structural plasticity mediates distinct GAP-dependent GTP hydrolysis mechanisms in Rab33 and Rab5.

Science.gov (United States)

Majumdar, Soneya; Acharya, Abhishek; Prakash, Balaji

2017-12-01

The classical GTP hydrolysis mechanism, as seen in Ras, employs a catalytic glutamine provided in cis by the GTPase and an arginine supplied in trans by a GTPase activating protein (GAP). The key idea emergent from a large body of research on small GTPases is that GTPases employ a variety of different hydrolysis mechanisms; evidently, these variations permit diverse rates of GTPase inactivation, crucial for temporal regulation of different biological processes. Recently, we unified these variations and argued that a steric clash between active site residues (corresponding to positions 12 and 61 of Ras) governs whether a GTPase utilizes the cis-Gln or the trans-Gln (from the GAP) for catalysis. As the cis-Gln encounters a steric clash, the Rab GTPases employ the so-called dual finger mechanism where the interacting GAP supplies a trans-Gln for catalysis. Using experimental and computational methods, we demonstrate how the cis-Gln of Rab33 overcomes the steric clash when it is stabilized by a residue in the vicinity. In effect, this demonstrates how both cis-Gln- and trans-Gln-mediated mechanisms could operate in the same GTPase in different contexts, i.e. depending on the GAP that regulates its action. Interestingly, in the case of Rab5, which possesses a higher intrinsic GTP hydrolysis rate, a similar stabilization of the cis-Gln appears to overcome the steric clash. Taken together with the mechanisms seen for Rab1, it is evident that the observed variations in Rab and their GAP partners allow structural plasticity, or in other words, the choice of different catalytic mechanisms. © 2017 Federation of European Biochemical Societies.

The potential mechanism of Bursal-derived BPP-II on the antibody production and avian pre-B cell.

Science.gov (United States)

Feng, Xiuli; Cao, Ruibing; Zhou, Bin; Liu, Qingtao; Liu, Ke; Liu, Xiaodong; Zhang, Yuanpeng; Gu, Jinyan; Miao, Denian; Chen, Puyan

2013-03-01

The bursa of Fabricius is critical for the normal development of the B lymphocytes responsible for antibody production. However, the mechanism of the bursal-derived bioactive factor on B cell development is little reported. In this paper, chicks were immunized with BPP-II and AIV vaccine or AIV antigen, and antibody and IL-4 production were detected. The results showed that BPP-II played strongly inducing roles on the humoral immune responses. To investigate the gene expression at transcriptional level, avian pre-B lymphocyte DT40 cells were treated with BPP-II, and were analyzed with the gene microarray. The results proved that BPP-II treatment regulated 11 pathways, in which homologous recombination is a vital mechanism which is involved in antibody Ig gene conversion and diversification during B cell development. These results suggested Bursal-derived biological active factor BPP-II might be involved in the antibody production processes and B cell development, which is vital to the humoral central immune organ, the bursa of Fabricius. Copyright © 2012 Elsevier Ltd. All rights reserved.

Distinct ERP Signatures of Word Frequency, Phrase Frequency, and Prototypicality in Speech Production

Science.gov (United States)

Hendrix, Peter; Bolger, Patrick; Baayen, Harald

2017-01-01

Recent studies have documented frequency effects for word n-grams, independently of word unigram frequency. Further studies have revealed constructional prototype effects, both at the word level as well as for phrases. The present speech production study investigates the time course of these effects for the production of prepositional phrases in…

Distinct signaling roles of ceramide species in yeast revealed through systematic perturbation and systems biology analyses.

Science.gov (United States)

Montefusco, David J; Chen, Lujia; Matmati, Nabil; Lu, Songjian; Newcomb, Benjamin; Cooper, Gregory F; Hannun, Yusuf A; Lu, Xinghua

2013-10-29

Ceramide, the central molecule of sphingolipid metabolism, is an important bioactive molecule that participates in various cellular regulatory events and that has been implicated in disease. Deciphering ceramide signaling is challenging because multiple ceramide species exist, and many of them may have distinct functions. We applied systems biology and molecular approaches to perturb ceramide metabolism in the yeast Saccharomyces cerevisiae and inferred causal relationships between ceramide species and their potential targets by combining lipidomic, genomic, and transcriptomic analyses. We found that during heat stress, distinct metabolic mechanisms controlled the abundance of different groups of ceramide species and provided experimental support for the importance of the dihydroceramidase Ydc1 in mediating the decrease in dihydroceramides during heat stress. Additionally, distinct groups of ceramide species, with different N-acyl chains and hydroxylations, regulated different sets of functionally related genes, indicating that the structural complexity of these lipids produces functional diversity. The transcriptional modules that we identified provide a resource to begin to dissect the specific functions of ceramides.

Review of Mechanics and Applications of Auxetic Structures

Directory of Open Access Journals (Sweden)

Mariam Mir

2014-01-01

Full Text Available One of the important mechanical properties of materials is Poisson’s ratio, which is positive for most of the materials. However, certain materials exhibit “auxetic” properties; that is, they have a negative Poisson’s ratio. Thus auxetic and non-auxetic materials exhibit different deformation mechanisms. A specific microscopic structure in the auxetic materials is important for maintaining a negative Poisson’s ratio. Based on their distinct nature auxetic materials execute certain unique properties in contrast to other materials, which are reviewed in this paper. Thus auxetic materials have important applications in the biomedical field which are also a part of this review article. Many auxetic materials have been discovered, fabricated, and synthesized which differ on the basis of structure, scale and deformation mechanism. The different types of auxetic materials such as auxetic cellular solids, microscopic auxetic polymers, molecular auxetic materials, and auxetic composites have been reviewed comprehensively in this paper. Modeling of auxetic structures is of considerable importance and needs appropriate stress strain configurations; thus different aspects of auxetic modeling have also been reviewed. Packing parameters and relative densities are of prime importance in this regard. This review would thus help the researchers in determining and deciding the various aspects of auxetic nature for their products.

Photochemically induced carbon dioxide production as a mechanism for carbon loss from plant litter in arid ecosystems

Science.gov (United States)

Brandt, L. A.; Bohnet, C.; King, J. Y.

2009-06-01

We investigated the potential for abiotic mineralization to carbon dioxide (CO2) via photodegradation to account for carbon (C) loss from plant litter under conditions typical of arid ecosystems. We exposed five species of grass and oak litter collected from arid and mesic sites to a factorial design of ultraviolet (UV) radiation (UV pass, UV block), and sterilization under dry conditions in the laboratory. UV pass treatments produced 10 times the amount of CO2 produced in UV block treatments. CO2 production rates were unaffected by litter chemistry or sterilization. We also exposed litter to natural solar radiation outdoors on clear, sunny days close to the summer solstice at midlatitudes and found that UV radiation (280-400 nm) accounted for 55% of photochemically induced CO2 production, while shortwave visible radiation (400-500 nm) accounted for 45% of CO2 production. Rates of photochemically induced CO2 production on a per-unit-mass basis decreased with litter density, indicating that rates depend on litter surface area. We found no evidence for leaching, methane production, or facilitation of microbial decomposition as alternative mechanisms for significant photochemically induced C loss from litter. We conclude that abiotic mineralization to CO2 is the primary mechanism by which C is lost from litter during photodegradation. We estimate that CO2 production via photodegradation could be between 1 and 4 g C m-2 a-1 in arid ecosystems in the southwestern United States. Taken together with low levels of litter production in arid systems, photochemical mineralization to CO2 could account for a significant proportion of annual carbon loss from litter in arid ecosystems.

RIPK1 and PGAM5 Control Leishmania Replication through Distinct Mechanisms.

Science.gov (United States)

Farias Luz, Nivea; Balaji, Sakthi; Okuda, Kendi; Barreto, Aline Silva; Bertin, John; Gough, Peter J; Gazzinelli, Ricardo; Almeida, Roque P; Bozza, Marcelo T; Borges, Valeria M; Chan, Francis Ka-Ming

2016-06-15

Leishmaniasis is an important parasitic disease found in the tropics and subtropics. Cutaneous and visceral leishmaniasis affect an estimated 1.5 million people worldwide. Despite its human health relevance, relatively little is known about the cell death pathways that control Leishmania replication in the host. Necroptosis is a recently identified form of cell death with potent antiviral effects. Receptor interacting protein kinase 1 (RIPK1) is a critical kinase that mediates necroptosis downstream of death receptors and TLRs. Heme, a product of hemoglobin catabolism during certain intracellular pathogen infections, is also a potent inducer of macrophage necroptosis. We found that human visceral leishmaniasis patients exhibit elevated serum levels of heme. Therefore, we examined the impact of heme and necroptosis on Leishmania replication. Indeed, heme potently inhibited Leishmania replication in bone marrow-derived macrophages. Moreover, we found that inhibition of RIPK1 kinase activity also enhanced parasite replication in the absence of heme. We further found that the mitochondrial phosphatase phosphoglycerate mutase family member 5 (PGAM5), a putative downstream effector of RIPK1, was also required for inhibition of Leishmania replication. In mouse infection, both PGAM5 and RIPK1 kinase activity are required for IL-1β expression in response to Leishmania However, PGAM5, but not RIPK1 kinase activity, was directly responsible for Leishmania-induced IL-1β secretion and NO production in bone marrow-derived macrophages. Collectively, these results revealed that RIPK1 and PGAM5 function independently to exert optimal control of Leishmania replication in the host. Copyright © 2016 by The American Association of Immunologists, Inc.

The effect of stimulated fission products on the structure and the mechanical properties of zircaloy

International Nuclear Information System (INIS)

Holub, F.

1982-01-01

The objective of investigation was to study the long-term effects of individual simulated fission products on the mechanical properties and the structure of Zircaloy. Tensile Test specimens of Zircaloy were annealed with important simulated fission products at 350 0 C up to 10,000 hours and at higher temperatures (500, 700 0 C) up to 2,000 hours. The principal methods of investigation on annealed Zircaloy specimens were tension tests at room temperature and at 400 0 C, scanning electron microscopy and microprobe technique, X-ray diffraction, X-ray fluorescence, optical metallography. The action of fission products at normal temperatures of reactor operation will give rise to a small enhancement of strength and a small drop of ductility of the fuel cladding material only. At high fuel pin temperatures which may be realized under abnormal operation conditions, some of the fission products potentially will produce detrimental consequences on the integrity of fuel pins. The most effective fission products will be: lanthanum oxide, followed by the earth alkaline oxides and the other rare earth oxides, molybdenum, iodine and cadmium

Multi-stakeholder taskforces in Bangladesh--a distinctive approach to build sustainable tobacco control implementation.

Science.gov (United States)

Jackson-Morris, Angela M; Chowdhury, Ishrat; Warner, Valerie; Bleymann, Kayleigh

2015-01-07

The MPOWER policy package enables countries to implement effective, evidence-based strategies to address the threat posed to their population by tobacco. All countries have challenges to overcome when implementing tobacco control policy. Some are generic such as tobacco industry efforts to undermine and circumvent legislation; others are specific to national or local context. Various factors influence how successfully challenges are addressed, including the legal-political framework for enforcement, public and administrative attitudes towards the law, and whether policy implementation measures are undertaken. This paper examines District Tobacco Control Taskforces, a flexible policy mechanism developed in Bangladesh to support the implementation of the Smoking and Tobacco Products Usage (Control) Act 2005 and its 2013 Amendment. At the time of this study published research and/or data was not available and understanding about these structures, their role, contribution, limitations and potential, was limited. We consider Taskforce characteristics and suggest that the "package" comprises a distinctive tobacco control implementation model. Qualitative data is presented from interviews with key informants in ten districts with activated taskforces (n = 70) to provide insight from the perspectives of taskforce members and non-members. In all ten districts taskforces were seen as a crucial tool for tobacco control implementation. Where taskforces were perceived to be functioning well, current positive impacts were perceived, including reduced smoking in public places and tobacco advertising, and increased public awareness and political profile. In districts with less well established taskforces, interviewees believed in their taskforce's 'potential' to deliver similar benefits once their functioning was improved. Recommendations to improve functioning and enhance impact were made. The distinctive taskforce concept and lessons from their development may provide other

Dynamic mechanical oscillations during metamorphosis of the monarch butterfly

Science.gov (United States)

Pelling, Andrew E; Wilkinson, Paul R; Stringer, Richard; Gimzewski, James K

2008-01-01

The mechanical oscillation of the heart is fundamental during insect metamorphosis, but it is unclear how morphological changes affect its mechanical dynamics. Here, the micromechanical heartbeat with the monarch chrysalis (Danaus plexippus) during metamorphosis is compared with the structural changes observed through in vivo magnetic resonance imaging (MRI). We employ a novel ultra-sensitive detection approach, optical beam deflection, in order to measure the microscale motions of the pupae during the course of metamorphosis. We observed very distinct mechanical contractions occurring at regular intervals, which we ascribe to the mechanical function of the heart organ. Motion was observed to occur in approximately 15 min bursts of activity with frequencies in the 0.4–1.0 Hz range separated by periods of quiescence during the first 83 per cent of development. In the final stages, the beating was found to be uninterrupted until the adult monarch butterfly emerged. Distinct stages of development were characterized by changes in frequency, amplitude, mechanical quality factor and de/repolarization times of the mechanical pulsing. The MRI revealed that the heart organ remains functionally intact throughout metamorphosis but undergoes morphological changes that are reflected in the mechanical oscillation. PMID:18682363

Mechanism of the Quorum-Quenching Lactonase (AiiA) from Bacillus thuringiensis. 1. Product-Bound Structures

Energy Technology Data Exchange (ETDEWEB)

Liu, Dali; Momb, Jessica; Thomas, Pei W.; Moulin, Aaron; Petsko, Gregory A.; Fast, Walter; Ringe, Dagmar (Brandeis); (Texas)

2008-08-06

Enzymes capable of hydrolyzing N-acyl-l-homoserine lactones (AHLs) used in some bacterial quorum-sensing pathways are of considerable interest for their ability to block undesirable phenotypes. Most known AHL hydrolases that catalyze ring opening (AHL lactonases) are members of the metallo-{beta}-lactamase enzyme superfamily and rely on a dinuclear zinc site for catalysis and stability. Here we report the three-dimensional structures of three product complexes formed with the AHL lactonase from Bacillus thuringiensis. Structures of the lactonase bound with two different concentrations of the ring-opened product of N-hexanoyl-l-homoserine lactone are determined at 0.95 and 1.4 {angstrom} resolution and exhibit different product configurations. A structure of the ring-opened product of the non-natural N-hexanoyl-l-homocysteine thiolactone at 1.3 {angstrom} resolution is also determined. On the basis of these product-bound structures, a substrate-binding model is presented that differs from previous proposals. Additionally, the proximity of the product to active-site residues and observed changes in protein conformation and metal coordination provide insight into the catalytic mechanism of this quorum-quenching metalloenzyme.

Anatomical coupling between distinct metacognitive systems for memory and visual perception.

Science.gov (United States)

McCurdy, Li Yan; Maniscalco, Brian; Metcalfe, Janet; Liu, Ka Yuet; de Lange, Floris P; Lau, Hakwan

2013-01-30

A recent study found that, across individuals, gray matter volume in the frontal polar region was correlated with visual metacognition capacity (i.e., how well one's confidence ratings distinguish between correct and incorrect judgments). A question arises as to whether the putative metacognitive mechanisms in this region are also used in other metacognitive tasks involving, for example, memory. A novel psychophysical measure allowed us to assess metacognitive efficiency separately in a visual and a memory task, while taking variations in basic task performance capacity into account. We found that, across individuals, metacognitive efficiencies positively correlated between the two tasks. However, voxel-based morphometry analysis revealed distinct brain structures for the two kinds of metacognition. Replicating a previous finding, variation in visual metacognitive efficiency was correlated with volume of frontal polar regions. However, variation in memory metacognitive efficiency was correlated with volume of the precuneus. There was also a weak correlation between visual metacognitive efficiency and precuneus volume, which may account for the behavioral correlation between visual and memory metacognition (i.e., the precuneus may contain common mechanisms for both types of metacognition). However, we also found that gray matter volumes of the frontal polar and precuneus regions themselves correlated across individuals, and a formal model comparison analysis suggested that this structural covariation was sufficient to account for the behavioral correlation of metacognition in the two tasks. These results highlight the importance of the precuneus in higher-order memory processing and suggest that there may be functionally distinct metacognitive systems in the human brain.

Study on the production mechanism of Co-60 in the primary loop of HTR-10

International Nuclear Information System (INIS)

Wang Shouang; Xie Feng; Li Hong; Cao Jianzhu; Li Fu; Wei Liqiang

2015-01-01

Co-60 is an activated metallic erosion product, which is very important for waste management and decommissioning work of pressurized water reactor (PWR) power plants. Recent measurement on the samples from the primary loop of HTR-10 indicates the existence of Co-60. In current paper, the preliminary experimental results in HTR-10 will be introduced, and the production mechanism of Co-60 in the pebble bed high temperature gas-cooled reactors will be summarized and compared with that in PWRs and Germany High Temperature Nuclear Reactor (AVR). The further experiments with decomposing the post-irradiation graphite spheres of HTR-10 are put forward, which will promote the further study to testify the production sources of Co-60 and be of great significance in the waste minimization and the decommissioning work of HTR-10. (author)

Identification of a novel splice variant form of the influenza A virus M2 ion channel with an antigenically distinct ectodomain.

Directory of Open Access Journals (Sweden)

Helen M Wise

Full Text Available Segment 7 of influenza A virus produces up to four mRNAs. Unspliced transcripts encode M1, spliced mRNA2 encodes the M2 ion channel, while protein products from spliced mRNAs 3 and 4 have not previously been identified. The M2 protein plays important roles in virus entry and assembly, and is a target for antiviral drugs and vaccination. Surprisingly, M2 is not essential for virus replication in a laboratory setting, although its loss attenuates the virus. To better understand how IAV might replicate without M2, we studied the reversion mechanism of an M2-null virus. Serial passage of a virus lacking the mRNA2 splice donor site identified a single nucleotide pseudoreverting mutation, which restored growth in cell culture and virulence in mice by upregulating mRNA4 synthesis rather than by reinstating mRNA2 production. We show that mRNA4 encodes a novel M2-related protein (designated M42 with an antigenically distinct ectodomain that can functionally replace M2 despite showing clear differences in intracellular localisation, being largely retained in the Golgi compartment. We also show that the expression of two distinct ion channel proteins is not unique to laboratory-adapted viruses but, most notably, was also a feature of the 1983 North American outbreak of H5N2 highly pathogenic avian influenza virus. In identifying a 14th influenza A polypeptide, our data reinforce the unexpectedly high coding capacity of the viral genome and have implications for virus evolution, as well as for understanding the role of M2 in the virus life cycle.

Study of gas production from shale reservoirs with multi-stage hydraulic fracturing horizontal well considering multiple transport mechanisms

Science.gov (United States)

Wei, Mingzhen; Liu, Hong

2018-01-01

Development of unconventional shale gas reservoirs (SGRs) has been boosted by the advancements in two key technologies: horizontal drilling and multi-stage hydraulic fracturing. A large number of multi-stage fractured horizontal wells (MsFHW) have been drilled to enhance reservoir production performance. Gas flow in SGRs is a multi-mechanism process, including: desorption, diffusion, and non-Darcy flow. The productivity of the SGRs with MsFHW is influenced by both reservoir conditions and hydraulic fracture properties. However, rare simulation work has been conducted for multi-stage hydraulic fractured SGRs. Most of them use well testing methods, which have too many unrealistic simplifications and assumptions. Also, no systematical work has been conducted considering all reasonable transport mechanisms. And there are very few works on sensitivity studies of uncertain parameters using real parameter ranges. Hence, a detailed and systematic study of reservoir simulation with MsFHW is still necessary. In this paper, a dual porosity model was constructed to estimate the effect of parameters on shale gas production with MsFHW. The simulation model was verified with the available field data from the Barnett Shale. The following mechanisms have been considered in this model: viscous flow, slip flow, Knudsen diffusion, and gas desorption. Langmuir isotherm was used to simulate the gas desorption process. Sensitivity analysis on SGRs’ production performance with MsFHW has been conducted. Parameters influencing shale gas production were classified into two categories: reservoir parameters including matrix permeability, matrix porosity; and hydraulic fracture parameters including hydraulic fracture spacing, and fracture half-length. Typical ranges of matrix parameters have been reviewed. Sensitivity analysis have been conducted to analyze the effect of the above factors on the production performance of SGRs. Through comparison, it can be found that hydraulic fracture

Human brain basis of musical rhythm perception: common and distinct neural substrates for meter, tempo, and pattern.

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Thaut, Michael H; Trimarchi, Pietro Davide; Parsons, Lawrence M

2014-06-17

Rhythm as the time structure of music is composed of distinct temporal components such as pattern, meter, and tempo. Each feature requires different computational processes: meter involves representing repeating cycles of strong and weak beats; pattern involves representing intervals at each local time point which vary in length across segments and are linked hierarchically; and tempo requires representing frequency rates of underlying pulse structures. We explored whether distinct rhythmic elements engage different neural mechanisms by recording brain activity of adult musicians and non-musicians with positron emission tomography (PET) as they made covert same-different discriminations of (a) pairs of rhythmic, monotonic tone sequences representing changes in pattern, tempo, and meter, and (b) pairs of isochronous melodies. Common to pattern, meter, and tempo tasks were focal activities in right, or bilateral, areas of frontal, cingulate, parietal, prefrontal, temporal, and cerebellar cortices. Meter processing alone activated areas in right prefrontal and inferior frontal cortex associated with more cognitive and abstract representations. Pattern processing alone recruited right cortical areas involved in different kinds of auditory processing. Tempo processing alone engaged mechanisms subserving somatosensory and premotor information (e.g., posterior insula, postcentral gyrus). Melody produced activity different from the rhythm conditions (e.g., right anterior insula and various cerebellar areas). These exploratory findings suggest the outlines of some distinct neural components underlying the components of rhythmic structure.

What makes health promotion research distinct?

Science.gov (United States)

Woodall, James; Warwick-Booth, Louise; South, Jane; Cross, Ruth

2018-02-01

There have been concerns about the decline of health promotion as a practice and discipline and, alongside this, calls for a clearer articulation of health promotion research and what, if anything, makes it distinct. This discussion paper, based on a review of the literature, the authors' own experiences in the field, and a workshop delivered by two of the authors at the 8th Nordic Health Promotion Conference, seeks to state the reasons why health promotion research is distinctive. While by no means exhaustive, the paper suggests four distinctive features. The paper hopes to be a catalyst to enable health promotion researchers to be explicit in their practice and to begin the process of developing an agreed set of research principles.

Mechanisms of electron transfer from structrual Fe(II) in reduced nontronite to oxygen for production of hydroxyl radicals

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Yuan, Songhu; Liu, Xixiang; Liao, Wenjuan; Zhang, Peng; Wang, Xiaoming; Tong, Man

2018-02-01

Production of hydroxyl radicals (radOH) has been recently revealed upon oxygenation of sediments in redox-dynamic subsurface environments. In particular, Fe(II)-bearing clay minerals are the major sediment components contributing to radOH production upon oxygenation, and the produced radOH can oxidize contaminants and inactivate bacteria. Whereas, the mechanisms of radOH production from oxygenation of Fe(II)-bearing clay minerals remain elusive. The objectives of this study were to identify the structural variation of Fe(II) entities during the oxidation of Fe(II)-bearing clay minerals by O2, and to unravel the mechanisms of electron transfer within the mineral structure and from mineral to O2 for radOH production. Nontronite (NAu-2, 23% Fe) which was chemically reduced to 54.5% Fe(II) in total Fe was used as a model Fe(II)-bearing clay mineral. Production of radOH and oxidation of Fe(II) were measured during the oxidation of reduced NAu-2 by O2. A wide spectrum of spectroscopic techniques, including Fourier transform infrared spectroscopy (FTIR), Fe K-edge X-ray absorption spectroscopy (XAS), Mössbauer spectra, and X-ray photoelectron spectroscopy (XPS), were employed to explore the structural variation of Fe(II) entities in NAu-2 and the electron transfer within NAu-2 and from NAu-2 to O2. For 180 min oxidation of 1 g/L reduced NAu-2, a biphasic radOH production was observed, being quick within the initial 15 min and slow afterwards. Production of radOH correlates well with oxidation of Fe(II) in the reduced NAu-2. Within the initial 15 min, trioctahedral Fe(II)-Fe(II)-Fe(II) entities and edge Fe(II) in the reduced NAu-2 were preferentially and quickly oxidized, and electrons from the interior Fe(II)-Fe(II)-Fe(II) entities were most likely ejected from the basal siloxane plane to O2. Meanwhile, trioctahedral Fe(II)-Fe(II)-Fe(II) entities were mainly transformed to dioctahedral Fe(II)-Fe(II) entities. When the time of oxygenation was longer than 15 min

An enzyme-catalyzed multistep DNA refolding mechanism in hairpin telomere formation.

Directory of Open Access Journals (Sweden)

Ke Shi

Full Text Available Hairpin telomeres of bacterial linear chromosomes are generated by a DNA cutting-rejoining enzyme protelomerase. Protelomerase resolves a concatenated dimer of chromosomes as the last step of chromosome replication, converting a palindromic DNA sequence at the junctions between chromosomes into covalently closed hairpins. The mechanism by which protelomerase transforms a duplex DNA substrate into the hairpin telomeres remains largely unknown. We report here a series of crystal structures of the protelomerase TelA bound to DNA that represent distinct stages along the reaction pathway. The structures suggest that TelA converts a linear duplex substrate into hairpin turns via a transient strand-refolding intermediate that involves DNA-base flipping and wobble base-pairs. The extremely compact di-nucleotide hairpin structure of the product is fully stabilized by TelA prior to strand ligation, which drives the reaction to completion. The enzyme-catalyzed, multistep strand refolding is a novel mechanism in DNA rearrangement reactions.

A comparative study of small RNAs in Toxoplasma gondii of distinct genotypes

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Wang Jielin

2012-09-01

Full Text Available Abstract Background Toxoplasma gondii is an intracellular parasite with a significant impact on human health. Inside the mammalian and avian hosts, the parasite can undergo rapid development or remain inactive in the cysts. The mechanism that regulates parasite proliferation has not been fully understood. Small noncoding RNAs (sncRNA such as microRNAs (miRNAs are endogenous regulatory factors that can modulate cell differentiation and development. It is anticipated that hundreds of miRNAs regulate the expression of thousands of genes in a single organism. SncRNAs have been identified in T. gondii, however the profiles of sncRNAs expression and their potential regulatory function in parasites of distinct genotypes has largely been unknown. Methods The transcription profiles of miRNAs in the two genetically distinct strains, RH and ME49, of T. gondii were investigated and compared by a high-through-put RNA sequencing technique and systematic bioinformatics analysis. The expression of some of the miRNAs was confirmed by Northern blot analysis. Results 1,083,320 unique sequences were obtained. Of which, 17 conserved miRNAs related to 2 metazoan miRNA families and 339 novel miRNAs were identified. A total of 175 miRNAs showed strain-specific expression, of which 155 miRNAs were up-regulated in RH strain and 20 miRNAs were up-regulated in ME49 strain. Strain-specific expression of miRNAs in T. gondii could be due to activation of specific genes at different genomic loci or due to arm-switching of the same pre-miRNA duplex. Conclusions Evidence for the differential expression of miRNAs in the two genetically distinct strains of T. gondii has been identified and defined. MiRNAs of T. gondii are more species-specific as compared to other organisms, which can be developed as diagnostic biomarkers for toxoplasmosis. The data also provide a framework for future studies on RNAi-dependent regulatory mechanisms in the zoonotic parasite.

Hydrogen production by hyperthermophilic and extremely thermophilic bacteria and archaea: mechanisms for reductant disposal.

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Verhaart, Marcel R A; Bielen, Abraham A M; van der Oost, John; Stams, Alfons J M; Kengen, Servé W M

2010-01-01

Hydrogen produced from biomass by bacteria and archaea is an attractive renewable energy source. However, to make its application more feasible, microorganisms are needed with high hydrogen productivities. For several reasons, hyperthermophilic and extremely thermophilic bacteria and archaea are promising is this respect. In addition to the high polysaccharide-hydrolysing capacities of many of these organisms, an important advantage is their ability to use most of the reducing equivalents (e.g. NADH, reduced ferredoxin) formed during glycolysis for the production of hydrogen, enabling H2/hexose ratios of between 3.0 and 4.0. So, despite the fact that the hydrogen-yielding reactions, especially the one from NADH, are thermodynamically unfavourable, high hydrogen yields are obtained. In this review we focus on three different mechanisms that are employed by a few model organisms, viz. Caldicellulosiruptor saccharolyticus and Thermoanaerobacter tengcongensis, Thermotoga maritima, and Pyrococcus furiosus, to efficiently produce hydrogen. In addition, recent developments to improve hydrogen production by hyperthermophilic and extremely thermophilic bacteria and archaea are discussed.

Effects of displacement damage and helium production rates on the nucleation and growth of helium bubbles - Positron annihilation spectroscopy aspects

Science.gov (United States)

Krsjak, Vladimir; Degmova, Jarmila; Sojak, Stanislav; Slugen, Vladimir

2018-02-01

Fe-12 wt% Cr model alloy samples were implanted by 250 keV He2+ ions to three different fluencies (3 × 1017, 9 × 1017 and 1.5 × 1018 cm-2) at T steel samples [1] irradiated in the frame of a two-years irradiation program of the Swiss Spallation Neutron Source. Bi-modal defect distribution represented by two defect components in positron lifetime spectrum reveals two distinct helium bubbles growth mechanisms. While at the lower helium production rate of the spallation environment, the bubbles grow primarily by migration and coalescence, at the high production rates of helium in the implanted samples, the results indicate this growth is driven by Ostwald ripening mechanism. A competitive growth process via emission of interstitial atoms (clusters) is discussed in terms of low-temperature He implantations.

KIR2DL4 differentially signals downstream functions in human NK cells through distinct structural modules.

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Miah, S M Shahjahan; Hughes, Tracey L; Campbell, Kerry S

2008-03-01

KIR2DL4 (2DL4) is a member of the killer cell Ig-like receptor (KIR) family in human NK cells. It can stimulate potent cytokine production and weak cytolytic activity in resting NK cells, but the mechanism for 2DL4-mediated signaling remains unclear. In this study we characterized the signaling pathways stimulated by 2DL4 engagement. In a human NK-like cell line, KHYG-1, cross-linking of 2DL4 activated MAPKs including JNK, ERK, and p38. Furthermore, 2DL4 cross-linking resulted in phosphorylation of IkappaB kinase beta (IKKbeta) and the phosphorylation and degradation of IkappaBalpha, which indicate activation of the classical NF-kappaB pathway. Engagement of 2DL4 was also shown to activate the transcription and translation of a variety of cytokine genes, including TNF-alpha, IFN-gamma, MIP1alpha, MIP1beta, and IL-8. Pharmacological inhibitors of JNK, MEK1/2 and p38, blocked IFN-gamma, IL-8, and MIP1alpha production, suggesting that MAPKs are regulating 2DL4-mediated cytokine production in a nonredundant manner. Activation of both p38 and ERK appear to be upstream of the stimulation of NF-kappaB. Mutation of a transmembrane arginine in 2DL4 to glycine (R/G mutant) abrogated FcepsilonRI-gamma association, as well as receptor-mediated cytolytic activity and calcium responses. Surprisingly, the R/G mutant still activated MAPKs and the NF-kappaB pathway and selectively stimulated the production of MIP1alpha, but not that of IFN-gamma or IL-8. In conclusion, we provide evidence that the activating functions of 2DL4 can be compartmentalized into two distinct structural modules: 1) through transmembrane association with FcepsilonRI-gamma; and 2) through another receptor domain independent of the transmembrane arginine.

Defect, Microstructure, and Mechanical Property of Ti-6Al-4V Alloy Fabricated by High-Power Selective Laser Melting

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Cao, Sheng; Chen, Zhuoer; Lim, Chao Voon Samuel; Yang, Kun; Jia, Qingbo; Jarvis, Tom; Tomus, Dacian; Wu, Xinhua

2017-12-01

To improve the selective laser melting (SLM) productivity, a high laser power and accordingly adjusted parameters are employed to facilitate a high build rate. Three distinct processing strategies with incremental build rate are developed for SLM Ti-6Al-4V. Various types of defects are investigated. Further studies were carried out by heat-treatment and hot isostatic pressing to evaluate the influence of microstructure and porosity on mechanical properties. The anisotropic mechanical property in horizontally and vertically build samples were observed, which was attributable to the columnar grains and spatial arrangement of defects. Regardless of anisotropy, a post-SLM heat-treatment at 800°C for 2 h produces a combined high strength and ductility.

Distinct lipid a moieties contribute to pathogen-induced site-specific vascular inflammation.

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Connie Slocum

2014-07-01

Full Text Available Several successful pathogens have evolved mechanisms to evade host defense, resulting in the establishment of persistent and chronic infections. One such pathogen, Porphyromonas gingivalis, induces chronic low-grade inflammation associated with local inflammatory bone loss and systemic inflammation manifested as atherosclerosis. P. gingivalis expresses an atypical lipopolysaccharide (LPS structure containing heterogeneous lipid A species, that exhibit Toll-like receptor-4 (TLR4 agonist or antagonist activity, or are non-activating at TLR4. In this study, we utilized a series of P. gingivalis lipid A mutants to demonstrate that antagonistic lipid A structures enable the pathogen to evade TLR4-mediated bactericidal activity in macrophages resulting in systemic inflammation. Production of antagonistic lipid A was associated with the induction of low levels of TLR4-dependent proinflammatory mediators, failed activation of the inflammasome and increased bacterial survival in macrophages. Oral infection of ApoE(-/- mice with the P. gingivalis strain expressing antagonistic lipid A resulted in vascular inflammation, macrophage accumulation and atherosclerosis progression. In contrast, a P. gingivalis strain producing exclusively agonistic lipid A augmented levels of proinflammatory mediators and activated the inflammasome in a caspase-11-dependent manner, resulting in host cell lysis and decreased bacterial survival. ApoE(-/- mice infected with this strain exhibited diminished vascular inflammation, macrophage accumulation, and atherosclerosis progression. Notably, the ability of P. gingivalis to induce local inflammatory bone loss was independent of lipid A expression, indicative of distinct mechanisms for induction of local versus systemic inflammation by this pathogen. Collectively, our results point to a pivotal role for activation of the non-canonical inflammasome in P. gingivalis infection and demonstrate that P. gingivalis evades immune

The acid-catalyzed hydrolysis of an α-pinene-derived organic nitrate: kinetics, products, reaction mechanisms, and atmospheric impact

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Rindelaub, Joel D.; Borca, Carlos H.; Hostetler, Matthew A.; Slade, Jonathan H.; Lipton, Mark A.; Slipchenko, Lyudmila V.; Shepson, Paul B.

2016-12-01

The production of atmospheric organic nitrates (RONO2) has a large impact on air quality and climate due to their contribution to secondary organic aerosol and influence on tropospheric ozone concentrations. Since organic nitrates control the fate of gas phase NOx (NO + NO2), a byproduct of anthropogenic combustion processes, their atmospheric production and reactivity is of great interest. While the atmospheric reactivity of many relevant organic nitrates is still uncertain, one significant reactive pathway, condensed phase hydrolysis, has recently been identified as a potential sink for organic nitrate species. The partitioning of gas phase organic nitrates to aerosol particles and subsequent hydrolysis likely removes the oxidized nitrogen from further atmospheric processing, due to large organic nitrate uptake to aerosols and proposed hydrolysis lifetimes, which may impact long-range transport of NOx, a tropospheric ozone precursor. Despite the atmospheric importance, the hydrolysis rates and reaction mechanisms for atmospherically derived organic nitrates are almost completely unknown, including those derived from α-pinene, a biogenic volatile organic compound (BVOC) that is one of the most significant precursors to biogenic secondary organic aerosol (BSOA). To better understand the chemistry that governs the fate of particle phase organic nitrates, the hydrolysis mechanism and rate constants were elucidated for several organic nitrates, including an α-pinene-derived organic nitrate (APN). A positive trend in hydrolysis rate constants was observed with increasing solution acidity for all organic nitrates studied, with the tertiary APN lifetime ranging from 8.3 min at acidic pH (0.25) to 8.8 h at neutral pH (6.9). Since ambient fine aerosol pH values are observed to be acidic, the reported lifetimes, which are much shorter than that of atmospheric fine aerosol, provide important insight into the fate of particle phase organic nitrates. Along with rate constant

Recent progress concerning the production of controlled highly oriented electrospun nanofibrous arrays

Science.gov (United States)

Manea, L. R.; Hristian, L.; Leon, A. L.; Popa, A.

2016-08-01

Among the foreground domains of all the research-development programs at national and international level, a special place is occupied by that concerning the nanosciences, nanotechnologies, new materials and technologies. Electrospinning found a well-deserved place in this space, offering the preparation of nanomaterials with distinctive properties and applications in medicine, environment, photonic sensors, filters, etc. These multiple applications are generated by the fact that the electrospinning technology makes available the production of nanofibers with controllable characteristics (length, porosity, density, and mechanical characteristics), complexity and architecture. The apparition of 3D printing technology favors the production of complex nanofibrous structures, controlled assembly, self-assembly of electrospun nanofibers for the production of scaffolds used in various medical applications. The architecture of fibrous deposits has a special influence on the subsequent development of the cells of the reconstructed organism. The present work proposes to study of recent progress concerning the production of controlled highly oriented electrospun nanofibrous arrays and progress in research on the production of complex 2D and 3D structures.

3D FDM production and mechanical behavior of polymeric sandwich specimens embedding classical and honeycomb cores

Science.gov (United States)

Brischetto, Salvatore; Ferro, Carlo Giovanni; Torre, Roberto; Maggiore, Paolo

2018-04-01

Desktop 3D FDM (Fused Deposition Modelling) printers are usually employed for the production of nonstructural objects. In recent years, the present authors tried to use this technology also to produce structural elements employed in the construction of small UAVs (Unmanned Aerial Vehicles). Mechanical stresses are not excessive for small multirotor UAVs. Therefore, the FDM technique combined with polymers, such as the ABS (Acrylonitrile Butadiene Styrene) and the PLA(Poly Lactic Acid), can be successfully employed to produce structural components. The present new work is devoted to the production and preliminary structural analysis of sandwich configurations. These new lamination schemes could lead to an important weight reduction without significant decreases of mechanical properties. Therefore, it could be possible, for the designed application (e.g., a multifunctional small UAV produced via FDM), to have stiffener and lighter structures easy to be manufactured with a low-cost 3D printer. The new sandwich specimens here proposed are PLA sandwich specimens embedding a PLA honeycomb core produced by means of the same extruder, multilayered specimens with ABS external layers and an internal homogeneous PLA core using different extruders for the two materials, sandwich specimens with external ABS skins and an internal PLA honeycomb core using different extruders for the two materials, and sandwich specimens where two different extruders have been employed for PLA material used for skins and for the internal honeycomb core. For all the proposed configurations, a detailed description of the production activity is given.Moreover, several preliminary results about three-point bending tests, different mechanical behaviors and relative delamination problems for each sandwich configuration will be discussed in depth.

Kinetics, Mechanism, and Secondary Organic Aerosol Yield of Aqueous Phase Photo-oxidation of α-Pinene Oxidation Products.

Science.gov (United States)

Aljawhary, Dana; Zhao, Ran; Lee, Alex K Y; Wang, Chen; Abbatt, Jonathan P D

2016-03-10

Formation of secondary organic aerosol (SOA) involves atmospheric oxidation of volatile organic compounds (VOCs), the majority of which are emitted from biogenic sources. Oxidation can occur not only in the gas-phase but also in atmospheric aqueous phases such as cloudwater and aerosol liquid water. This study explores for the first time the aqueous-phase OH oxidation chemistry of oxidation products of α-pinene, a major biogenic VOC species emitted to the atmosphere. The kinetics, reaction mechanisms, and formation of SOA compounds in the aqueous phase of two model compounds, cis-pinonic acid (PIN) and tricarballylic acid (TCA), were investigated in the laboratory; TCA was used as a surrogate for 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA), a known α-pinene oxidation product. Aerosol time-of-flight chemical ionization mass spectrometry (Aerosol-ToF-CIMS) was used to follow the kinetics and reaction mechanisms at the molecular level. Room-temperature second-order rate constants of PIN and TCA were determined to be 3.3 (± 0.5) × 10(9) and 3.1 (± 0.2) × 10(8) M(-1) s(-1), respectively, from which were estimated their condensed-phase atmospheric lifetimes. Aerosol-ToF-CIMS detected a large number of products leading to detailed reaction mechanisms for PIN and MBTCA. By monitoring the particle size distribution after drying, the amount of SOA material remaining in the particle phase was determined. An aqueous SOA yield of 40 to 60% was determined for PIN OH oxidation. Although recent laboratory studies have focused primarily on aqueous-phase processing of isoprene-related compounds, we demonstrate that aqueous formation of SOA materials also occurs from monoterpene oxidation products, thus representing an additional source of biogenically driven aerosol formation.

A study of K*(890) and K*(1420) production mechanisms in K/sup +/p. -->. K/sup +/. pi. /sup -/. delta. /sup + +/ at 13 GeV/c. [Exchange mechanisms, angular distributions

Energy Technology Data Exchange (ETDEWEB)

Estabrooks, P; Martin, A D [Durham Univ. (UK); Brandenburg, G W; Carnegie, R K; Cashmore, R J; Davier, M; Dunwoodie, W M; Lasinski, T A; Leith, D W.G.S.; Matthews, J A.J.

1976-04-05

Amplitudes for K*(890) and K*(1420) production, and their lower spin background, are determined from an analysis of the K..pi.. angular distribution observed in K/sup +/p..-->..K/sup +/..pi../sup -/..delta../sup + +/ at 13 GeV/c. The exchange mechanisms responsible for K*..delta.. production are studied, and a simple model is introduced which describes all features of the data.

Integration of a linear accelerator into a production line of mechanically deboned separated poultry meat

International Nuclear Information System (INIS)

Sadat, Theo; Volle, Christophe

2000-01-01

Linear accelerators, commonly called Linacs, are being used for different industrial processes. This kind of machine produces high power electron beams and can treat many products with a high throughput. The main application of a Linac is the sterilization of medical disposable devices, polymerization and decontamination of food products. Salmonella commonly contaminates poultry. Thanks to E-beam treatment, it eradicates the pathogen quickly and permits the use of meat that should have been thrown away because of its infection. The world's first Linac dedicated to treat mechanically deboned poultry meat is located in Brittany at the Societe des Proteines Industrielles. It is a Thomson CSF Linac product, the CIRCE II, with an energy of 10 MeV and a power of 10 kW. This Linac has been used for more than 8 years, and its technology is fully proven. (author)

Functional properties of meat by-products and mechanically separated chicken (MSC) in a high-moisture model petfood system.

Science.gov (United States)

Rivera, J A; Sebranek, J G; Rust, R E

2000-05-01

Contributions to water retention capacity (% WRC) and texture changes were determined for pork by-products (lung lobes, kidneys), chicken viscera (head, feet and viscera) and mechanically separated chicken (MSC) as affected by pH and various salts in a high-moisture model system. The % WRC for meat by-products and MSC was increased by increased pH (4.5-6.8). Pork lungs and MSC had the highest % WRC (pmeat by-products. Meat by-product % WRC was not signifcantly (p>0.05) affected by salt (2%), phosphate (0.3%) or NaOH (0.075%). Chicken viscera had the lowest (pmeat by-products and MSC. Strong negative correlations (p<0.05) were obtained for texture with total collagen, soluble collagen and high ionic strength soluble (HIS) proteins. These results should be considered for product quality changes when these by-products are used in formulation of high moisture pet food products.

21 CFR 1002.10 - Product reports.

Science.gov (United States)

2010-04-01

... Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) RADIOLOGICAL... Communication, Education, and Radiation Programs, 9200 Corporate Blvd., Rockville, MD 20850, prior to the introduction of such product into commerce. The report shall be distinctly marked “Radiation Safety Product...

Effect of temperature on synthesis and properties of aluminum-magnesium mechanical alloys

International Nuclear Information System (INIS)

Umbrajkar, Swati M.; Schoenitz, Mirko; Jones, Steven R.; Dreizin, Edward L.

2005-01-01

The synthesis of an Al 0.7 Mg 0.3 mechanical alloy was studied using a planetary mill. Several distinct temperature regimes of mechanical alloying were achieved using milling jars equipped with finned heat sinks and an external air conditioner installed to cool the entire milling chamber. Wireless temperature sensors were attached to the milling jars to monitor the process temperature. Intermediate and final products were collected and were analyzed by electron microscopy and X-ray diffraction. The temperature history of the milling jars exhibited two peaks during mechanical alloying. The first peak occurred when particles of the starting powders deformed to produce flakes. The second peak was observed when the flakes agglomerated and re-fragmented forming layered composites that served as precursors for the mechanical alloy. The temperature of milling affected the magnesium solubility of the produced Al-Mg mechanical alloys. Decreasing the milling temperature from ∼70-80 deg. C to 20-30 deg. C resulted in an increase of the dissolved Mg concentration in Al from 2-3 at.% to ∼25 at.% for the Al 0.7 Mg 0.3 composition. The formation of intermetallic phases was favored at higher milling temperatures, where high solubilities cannot be achieved

Effect of temperature on synthesis and properties of aluminum-magnesium mechanical alloys

Energy Technology Data Exchange (ETDEWEB)

Umbrajkar, Swati M. [New Jersey Institute of Technology, Department of Mechanical Engineering, Newark, NJ 07102-1982 (United States); Schoenitz, Mirko [New Jersey Institute of Technology, Department of Mechanical Engineering, Newark, NJ 07102-1982 (United States); Jones, Steven R. [New Jersey Institute of Technology, Department of Mechanical Engineering, Newark, NJ 07102-1982 (United States); Dreizin, Edward L. [New Jersey Institute of Technology, Department of Mechanical Engineering, Newark, NJ 07102-1982 (United States)]. E-mail: dreizin@njit.edu

2005-10-27

The synthesis of an Al{sub 0.7}Mg{sub 0.3} mechanical alloy was studied using a planetary mill. Several distinct temperature regimes of mechanical alloying were achieved using milling jars equipped with finned heat sinks and an external air conditioner installed to cool the entire milling chamber. Wireless temperature sensors were attached to the milling jars to monitor the process temperature. Intermediate and final products were collected and were analyzed by electron microscopy and X-ray diffraction. The temperature history of the milling jars exhibited two peaks during mechanical alloying. The first peak occurred when particles of the starting powders deformed to produce flakes. The second peak was observed when the flakes agglomerated and re-fragmented forming layered composites that served as precursors for the mechanical alloy. The temperature of milling affected the magnesium solubility of the produced Al-Mg mechanical alloys. Decreasing the milling temperature from {approx}70-80 deg. C to 20-30 deg. C resulted in an increase of the dissolved Mg concentration in Al from 2-3 at.% to {approx}25 at.% for the Al{sub 0.7}Mg{sub 0.3} composition. The formation of intermetallic phases was favored at higher milling temperatures, where high solubilities cannot be achieved.

The role of scalar product and Wigner distribution in optical and quantum mechanical measurements

International Nuclear Information System (INIS)

Wodkiewicz, K.

1984-01-01

In this paper we present a unified approach to the phase-space description of optical and quantum measurements. We find that from the operational point of view the notion of a time dependent spectrum of light and a joint measurement of position and momentum in quantum mechanics can be formulated in one common approach in which the scalar product, the Wigner function and the phase-space proximity are closely related to a realistic measuring process

Characterization of Trichome-Expressed BAHD Acyltransferases in Petunia axillaris Reveals Distinct Acylsugar Assembly Mechanisms within the Solanaceae1[OPEN

Science.gov (United States)

Uebler, Joseph B.; Liu, Xiaoxiao

2017-01-01

Acylsugars are synthesized in the glandular trichomes of the Solanaceae family and are implicated in protection against abiotic and biotic stress. Acylsugars are composed of either sucrose or glucose esterified with varying numbers of acyl chains of differing length. In tomato (Solanum lycopersicum), acylsugar assembly requires four acylsugar acyltransferases (ASATs) of the BAHD superfamily. Tomato ASATs catalyze the sequential esterification of acyl-coenzyme A thioesters to the R4, R3, R3ʹ, and R2 positions of sucrose, yielding a tetra-acylsucrose. Petunia spp. synthesize acylsugars that are structurally distinct from those of tomato. To explore the mechanisms underlying this chemical diversity, a Petunia axillaris transcriptome was mined for trichome preferentially expressed BAHDs. A combination of phylogenetic analyses, gene silencing, and biochemical analyses coupled with structural elucidation of metabolites revealed that acylsugar assembly is not conserved between tomato and petunia. In P. axillaris, tetra-acylsucrose assembly occurs through the action of four ASATs, which catalyze sequential addition of acyl groups to the R2, R4, R3, and R6 positions. Notably, in P. axillaris, PaxASAT1 and PaxASAT4 catalyze the acylation of the R2 and R6 positions of sucrose, respectively, and no clear orthologs exist in tomato. Similarly, petunia acylsugars lack an acyl group at the R3ʹ position, and congruently, an ortholog of SlASAT3, which catalyzes acylation at the R3ʹ position in tomato, is absent in P. axillaris. Furthermore, where putative orthologous relationships of ASATs are predicted between tomato and petunia, these are not supported by biochemical assays. Overall, these data demonstrate the considerable evolutionary plasticity of acylsugar biosynthesis. PMID:28701351

Enhanced biogas production from anaerobic co-digestion of pig slurry and horse manure with mechanical pre-treatment.

Science.gov (United States)

Lopes, Madalena; Baptista, Patrícia; Duarte, Elizabeth; Moreira, António L N

2018-01-02

Enhanced biogas production from anaerobic co-digestion of pig slurry and horse manure with mechanical pre-treatment. In this study, co-digestion of horse manure and pig slurry was investigated in a continuously stirred tank reactor, with a mechanical pre-treatment. Experiments were conducted at 37°C, with hydraulic retention times of 23 days and increasing shares of horse manure, corresponding to different horse manure to pig slurry ratios (HM:PS) equal to 0:100, 10:90, 13:87 and 20:80, in terms of percentage of inlet volatile solids (%VS inlet). The results show that the best synergetic effect between the microbial consortia of pig slurry and the high Carbon to Nitrogen ratio (C/N) of horse manure is obtained for the mixture of 20:80%VS inlet, yielding the highest specific methane production (SMP = 142.6 L kg TCOD -1 ) and the highest soluble chemical oxygen demand (SCOD) reduction (68.5%), due to the high volatile dissolved solids content and soluble chemical oxygen demand to total chemical oxygen demand ratio (SCOD/TCOD). Thus, co-digestion of horse manure and pig slurry is shown to be a promising approach for biogas production and as a waste treatment solution. Furthermore, the analysis provides a methodology for the pre-treatment of these substrates and to investigate into the best combination for improved biogas production.

Testing the distinctiveness of visual imagery and motor imagery in a reach paradigm.

Science.gov (United States)

Gabbard, Carl; Ammar, Diala; Cordova, Alberto

2009-01-01

We examined the distinctiveness of motor imagery (MI) and visual imagery (VI) in the context of perceived reachability. The aim was to explore the notion that the two visual modes have distinctive processing properties tied to the two-visual-system hypothesis. The experiment included an interference tactic whereby participants completed two tasks at the same time: a visual or motor-interference task combined with a MI or VI-reaching task. We expected increased error would occur when the imaged task and the interference task were matched (e.g., MI with the motor task), suggesting an association based on the assumption that the two tasks were in competition for space on the same processing pathway. Alternatively, if there were no differences, dissociation could be inferred. Significant increases in the number of errors were found when the modalities for the imaged (both MI and VI) task and the interference task were matched. Therefore, it appears that MI and VI in the context of perceived reachability recruit different processing mechanisms.

Comparative transcriptome analysis reveals distinct ethylene-independent regulation of ripening in response to low temperature in kiwifruit.

Science.gov (United States)

Asiche, William O; Mitalo, Oscar W; Kasahara, Yuka; Tosa, Yasuaki; Mworia, Eric G; Owino, Willis O; Ushijima, Koichiro; Nakano, Ryohei; Yano, Kentaro; Kubo, Yasutaka

2018-03-21

endogenous ethylene production, and coincided with increased expression of low temperature-responsive DEGs as well as the decrease in environmental temperature. These results indicate that kiwifruit possess both ethylene-dependent and low temperature-modulated ripening mechanisms that are distinct and independent of each other. The current work provides a foundation for elaborating the control of these two ripening mechanisms in kiwifruit.

Variable mechanical ventilation.

Science.gov (United States)

Fontela, Paula Caitano; Prestes, Renata Bernardy; Forgiarini, Luiz Alberto; Friedman, Gilberto

2017-01-01

To review the literature on the use of variable mechanical ventilation and the main outcomes of this technique. Search, selection, and analysis of all original articles on variable ventilation, without restriction on the period of publication and language, available in the electronic databases LILACS, MEDLINE®, and PubMed, by searching the terms "variable ventilation" OR "noisy ventilation" OR "biologically variable ventilation". A total of 36 studies were selected. Of these, 24 were original studies, including 21 experimental studies and three clinical studies. Several experimental studies reported the beneficial effects of distinct variable ventilation strategies on lung function using different models of lung injury and healthy lungs. Variable ventilation seems to be a viable strategy for improving gas exchange and respiratory mechanics and preventing lung injury associated with mechanical ventilation. However, further clinical studies are necessary to assess the potential of variable ventilation strategies for the clinical improvement of patients undergoing mechanical ventilation.

Tagging like Humans: Diverse and Distinct Image Annotation

KAUST Repository

Wu, Baoyuan

2018-03-31

In this work we propose a new automatic image annotation model, dubbed {\\\\bf diverse and distinct image annotation} (D2IA). The generative model D2IA is inspired by the ensemble of human annotations, which create semantically relevant, yet distinct and diverse tags. In D2IA, we generate a relevant and distinct tag subset, in which the tags are relevant to the image contents and semantically distinct to each other, using sequential sampling from a determinantal point process (DPP) model. Multiple such tag subsets that cover diverse semantic aspects or diverse semantic levels of the image contents are generated by randomly perturbing the DPP sampling process. We leverage a generative adversarial network (GAN) model to train D2IA. Extensive experiments including quantitative and qualitative comparisons, as well as human subject studies, on two benchmark datasets demonstrate that the proposed model can produce more diverse and distinct tags than the state-of-the-arts.

Hypocretin/Orexin Peptides Alter Spike Encoding by Serotonergic Dorsal Raphe Neurons through Two Distinct Mechanisms That Increase the Late Afterhyperpolarization.

Science.gov (United States)

Ishibashi, Masaru; Gumenchuk, Iryna; Miyazaki, Kenichi; Inoue, Takafumi; Ross, William N; Leonard, Christopher S

2016-09-28

Orexins (hypocretins) are neuropeptides that regulate multiple homeostatic processes, including reward and arousal, in part by exciting serotonergic dorsal raphe neurons, the major source of forebrain serotonin. Here, using mouse brain slices, we found that, instead of simply depolarizing these neurons, orexin-A altered the spike encoding process by increasing the postspike afterhyperpolarization (AHP) via two distinct mechanisms. This orexin-enhanced AHP (oeAHP) was mediated by both OX1 and OX2 receptors, required Ca(2+) influx, reversed near EK, and decayed with two components, the faster of which resulted from enhanced SK channel activation, whereas the slower component decayed like a slow AHP (sAHP), but was not blocked by UCL2077, an antagonist of sAHPs in some neurons. Intracellular phospholipase C inhibition (U73122) blocked the entire oeAHP, but neither component was sensitive to PKC inhibition or altered PKA signaling, unlike classical sAHPs. The enhanced SK current did not depend on IP3-mediated Ca(2+) release but resulted from A-current inhibition and the resultant spike broadening, which increased Ca(2+) influx and Ca(2+)-induced-Ca(2+) release, whereas the slower component was insensitive to these factors. Functionally, the oeAHP slowed and stabilized orexin-induced firing compared with firing produced by a virtual orexin conductance lacking the oeAHP. The oeAHP also reduced steady-state firing rate and firing fidelity in response to stimulation, without affecting the initial rate or fidelity. Collectively, these findings reveal a new orexin action in serotonergic raphe neurons and suggest that, when orexin is released during arousal and reward, it enhances the spike encoding of phasic over tonic inputs, such as those related to sensory, motor, and reward events. Orexin peptides are known to excite neurons via slow postsynaptic depolarizations. Here we elucidate a significant new orexin action that increases and prolongs the postspike

Creating fair lineups for suspects with distinctive features

OpenAIRE

Zarkadi, Theodora; Wade, Kimberley A.; Stewart, Neil

2009-01-01

In their descriptions, eyewitnesses often refer to a culprit's distinctive facial features. However, in a police lineup, selecting the only member with the described distinctive feature is unfair to the suspect and provides the police with little further information. For fair and informative lineups, the distinctive feature should be either replicated across foils or concealed on the target. In the present experiments, replication produced more correct identifications in target-present lineup...

The energy policy and sustainability of the subsidy mechanism for retail petroleum products consumed in Trinidad and Tobago

Energy Technology Data Exchange (ETDEWEB)

Baksh, Timmy

2010-09-15

In 1974 the Petroleum Production Levy and Subsidy Act gave effect to legislation which detailed a mechanism to implement a subsidy on all fuel consumed within, and in the territorial waters of, Trinidad and Tobago. This paper will analyse the underlying principles of this energy policy, follow how the mechanism has evolved over the years and propose new iterations to the existing model in order to reduce the Governments liability. The sustainability of the subsidy will be examined and as well as an in-depth analysis on the possible impact on inflation if this mechanism is removed.

The evolution of compositionally and functionally distinct actin filaments.

Science.gov (United States)

Gunning, Peter W; Ghoshdastider, Umesh; Whitaker, Shane; Popp, David; Robinson, Robert C

2015-06-01

The actin filament is astonishingly well conserved across a diverse set of eukaryotic species. It has essentially remained unchanged in the billion years that separate yeast, Arabidopsis and man. In contrast, bacterial actin-like proteins have diverged to the extreme, and many of them are not readily identified from sequence-based homology searches. Here, we present phylogenetic analyses that point to an evolutionary drive to diversify actin filament composition across kingdoms. Bacteria use a one-filament-one-function system to create distinct filament systems within a single cell. In contrast, eukaryotic actin is a universal force provider in a wide range of processes. In plants, there has been an expansion of the number of closely related actin genes, whereas in fungi and metazoa diversification in tropomyosins has increased the compositional variety in actin filament systems. Both mechanisms dictate the subset of actin-binding proteins that interact with each filament type, leading to specialization in function. In this Hypothesis, we thus propose that different mechanisms were selected in bacteria, plants and metazoa, which achieved actin filament compositional variation leading to the expansion of their functional diversity. © 2015. Published by The Company of Biologists Ltd.

Distinct molecular subtypes of uterine leiomyosarcoma respond differently to chemotherapy treatment.

Science.gov (United States)

An, Yang; Wang, Shuzhen; Li, Songlin; Zhang, Lulu; Wang, Dayong; Wang, Haojie; Zhu, Shibai; Zhu, Wan; Li, Yongqiang; Chen, Wenwu; Ji, Shaoping; Guo, Xiangqian

2017-09-11

Uterine leiomyosarcoma (ULMS) is an aggressive form of soft tissue tumors. The molecular heterogeneity and pathogenesis of ULMS are not well understood. Expression profiling data were used to determine the possibility and optimal number of ULMS molecular subtypes. Next, clinicopathological characters and molecular pathways were analyzed in each subtype to prospect the clinical applications and progression mechanisms of ULMS. Two distinct molecular subtypes of ULMS were defined based on different gene expression signatures. Subtype I ULMS recapitulated low-grade ULMS, the gene expression pattern of which resembled normal smooth muscle cells, characterized by overexpression of smooth muscle function genes such as LMOD1, SLMAP, MYLK, MYH11. In contrast, subtype II ULMS recapitulated high-grade ULMS with higher tumor weight and invasion rate, and was characterized by overexpression of genes involved in the pathway of epithelial to mesenchymal transition and tumorigenesis, such as CDK6, MAPK13 and HOXA1. We identified two distinct molecular subtypes of ULMS responding differently to chemotherapy treatment. Our findings provide a better understanding of ULMS intrinsic molecular subtypes, and will potentially facilitate the development of subtype-specific diagnosis biomarkers and therapy strategies for these tumors.

Product (RED)

DEFF Research Database (Denmark)

Ponte, Stefano

2011-01-01

) and the consumers who buy iconic brand products to help ‘distant others’. While in many other forms of causumerism, labels or certification systems ‘prove’ that a product is just, in RED, aid celebrities provide the proof. From the consumer point of view both labels and celebrities provide a similar simplification...... of complex social, economic, and environmental processes. At the same time, we argue that there are important distinctions as well—labels and certifications are ultimately about improving the conditions of production, whereas RED is about accepting existing production and trade systems and donating......(PRODUCT)RED™ (hereafter RED) is a cobranding initiative launched in 2006 by the aid celebrity Bono to raise money from product sales to support The Global Fund to Fight AIDS, Tuberculosis and Malaria. In this paper we argue that RED is shifting the boundaries of ‘causumerism’ (shopping...

Defining poverty as distinctively human

Directory of Open Access Journals (Sweden)

H.P.P. Lötter

2007-05-01

Full Text Available While it is relatively easy for most people to identify human beings suffering from poverty, it is rather more difficult to come to a proper understanding of poverty. In this article the author wants to deepen our understanding of poverty by interpreting the conventional definitions of poverty in a new light. The article starts with a defence of a claim that poverty is a concept uniquely applicable to humans. It then present a critical discussion of the distinction between absolute and relative poverty and it is then argued that a revision of this distinction can provide general standards applicable to humans everywhere.

Multi-Stakeholder Taskforces in Bangladesh — A Distinctive Approach to Build Sustainable Tobacco Control Implementation

Directory of Open Access Journals (Sweden)

Angela M. Jackson-Morris

2015-01-01

Full Text Available The MPOWER policy package enables countries to implement effective, evidence-based strategies to address the threat posed to their population by tobacco. All countries have challenges to overcome when implementing tobacco control policy. Some are generic such as tobacco industry efforts to undermine and circumvent legislation; others are specific to national or local context. Various factors influence how successfully challenges are addressed, including the legal-political framework for enforcement, public and administrative attitudes towards the law, and whether policy implementation measures are undertaken. This paper examines District Tobacco Control Taskforces, a flexible policy mechanism developed in Bangladesh to support the implementation of the Smoking and Tobacco Products Usage (Control Act 2005 and its 2013 Amendment. At the time of this study published research and/or data was not available and understanding about these structures, their role, contribution, limitations and potential, was limited. We consider Taskforce characteristics and suggest that the “package” comprises a distinctive tobacco control implementation model. Qualitative data is presented from interviews with key informants in ten districts with activated taskforces (n = 70 to provide insight from the perspectives of taskforce members and non-members. In all ten districts taskforces were seen as a crucial tool for tobacco control implementation. Where taskforces were perceived to be functioning well, current positive impacts were perceived, including reduced smoking in public places and tobacco advertising, and increased public awareness and political profile. In districts with less well established taskforces, interviewees believed in their taskforce’s ‘potential’ to deliver similar benefits once their functioning was improved. Recommendations to improve functioning and enhance impact were made. The distinctive taskforce concept and lessons from their

Lipoxin A4 stable analogs reduce allergic airway responses via mechanisms distinct from CysLT1 receptor antagonism.

Science.gov (United States)

Levy, Bruce D; Lukacs, Nicholas W; Berlin, Aaron A; Schmidt, Birgitta; Guilford, William J; Serhan, Charles N; Parkinson, John F

2007-12-01

Cellular recruitment during inflammatory/immune responses is tightly regulated. The ability to dampen inflammation is imperative for prevention of chronic immune responses, as in asthma. Here we investigated the ability of lipoxin A4 (LXA4) stable analogs to regulate airway responses in two allergen-driven models of inflammation. A 15-epi-LXA4 analog (ATLa) and a 3-oxa-15-epi-LXA4 analog (ZK-994) prevented excessive eosinophil and T lymphocyte accumulation and activation after mice were sensitized and aerosol-challenged with ovalbumin. At 50% and to a greater extent than equivalent doses of the CysLT1 receptor antagonist montelukast. Distinct from montelukast, ATLa treatment led to marked reductions in cysteinyl leukotrienes, interleukin-4 (IL-4), and IL-10, and both ATLa and ZK-994 inhibited levels of IL-13. In cockroach allergen-induced airway responses, both intraperitoneal and oral administration of ZK-994 significantly reduced parameters of airway inflammation and hyper-responsiveness in a dose-dependent manner. ZK-994 also significantly changed the balance of Th1/Th2-specific cytokine levels. Thus, the ATLa/LXA4 analog actions are distinct from CysLT1 antagonism and potently block both allergic airway inflammation and hyper-reactivity. Moreover, these results demonstrate these analogs' therapeutic potential as new agonists for the resolution of inflammation.

An unconventional mechanism of lift production during the downstroke in a hovering bird ( Zosterops japonicus)

Science.gov (United States)

Chang, Yu-Hung; Ting, Shang-Chieh; Liu, Chieh-Cheng; Yang, Jing-Tang; Soong, Chyi-Yeou

2011-11-01

An unconventional mechanism of ventral clap is exploited by hovering passerines to produce lift. Quantitative visualization of the wake flow, analysis of kinematics and evaluation of the transient lift force was conducted to dissect the biomechanical role of the ventral clap in the asymmetrical hovering flight of passerines. The ventral clap can first abate and then augment lift production during the downstroke; the net effect of the ventral clap on lift production is, however, positive because the extent of lift augmentation is greater than the extent of lift abatement. Moreover, the ventral clap is inferred to compensate for the zero lift production of the upstroke because the clapping wings induce a substantial elevation of the lift force at the end of the downstroke. Overall, our observations shed light on the aerodynamic function of the ventral clap and offer biomechanical insight into how a bird hovers without kinematically mimicking hovering hummingbirds.

New insights into the by-product fatigue mechanism of the photo-induced ring-opening in diarylethenes.

Science.gov (United States)

Mendive-Tapia, David; Perrier, Aurélie; Bearpark, Michael J; Robb, Michael A; Lasorne, Benjamin; Jacquemin, Denis

2014-09-14

The photochromic properties of diarylethenes, some of the most studied class of molecular switches, are known to be controlled by non-adiabatic decay at a conical intersection seam. Nevertheless, as their fatigue-reaction mechanism - leading to non-photochromic products - is yet to be understood, we investigate the photo-chemical formation of the so-called by-product isomer using three complementary computational methods (MMVB, CASSCF and CASPT2) on three model systems of increasing complexity. We show that for the ring-opening reaction a transition state on S1(2A) involving bond breaking of the penta-ring leads to a low energy S1(2A)/S0(1A) conical intersection seam, which lies above one of the transition states leading to the by-product isomer on the ground state. Therefore, radiationless decay and subsequent side-product formation can take place explaining the photo-degradation responsible for the by-product generation in diarylethene-type molecules. The effect of dynamic electron correlation and the possible role of inter-system crossing along the penta-ring opening coordinate are discussed as well.

Production, deformation and mechanical investigation of magnetic alginate capsules

Science.gov (United States)

Zwar, Elena; Kemna, Andre; Richter, Lena; Degen, Patrick; Rehage, Heinz

2018-02-01

In this article we investigated the deformation of alginate capsules in magnetic fields. The sensitivity to magnetic forces was realised by encapsulating an oil in water emulsion, where the oil droplets contained dispersed magnetic nanoparticles. We solved calcium ions in the aqueous emulsion phase, which act as crosslinking compounds for forming thin layers of alginate membranes. This encapsulating technique allows the production of flexible capsules with an emulsion as the capsule core. It is important to mention that the magnetic nanoparticles were stable and dispersed throughout the complete process, which is an important difference to most magnetic alginate-based materials. In a series of experiments, we used spinning drop techniques, capsule squeezing experiments and interfacial shear rheology in order to determine the surface Young moduli, the surface Poisson ratios and the surface shear moduli of the magnetically sensitive alginate capsules. In additional experiments, we analysed the capsule deformation in magnetic fields. In spinning drop and capsule squeezing experiments, water droplets were pressed out of the capsules at elevated values of the mechanical load. This phenomenon might be used for the mechanically triggered release of water-soluble ingredients. After drying the emulsion-filled capsules, we produced capsules, which only contained a homogeneous oil phase with stable suspended magnetic nanoparticles (organic ferrofluid). In the dried state, the thin alginate membranes of these particles were rather rigid. These dehydrated capsules could be stored at ambient conditions for several months without changing their properties. After exposure to water, the alginate membranes rehydrated and became flexible and deformable again. During this swelling process, water diffused back in the capsule. This long-term stability and rehydration offers a great spectrum of different applications as sensors, soft actuators, artificial muscles or drug delivery systems.

Azospirillum brasilense Chemotaxis Depends on Two Signaling Pathways Regulating Distinct Motility Parameters.

Science.gov (United States)

Mukherjee, Tanmoy; Kumar, Dhivya; Burriss, Nathan; Xie, Zhihong; Alexandre, Gladys

2016-06-15

The genomes of most motile bacteria encode two or more chemotaxis (Che) systems, but their functions have been characterized in only a few model systems. Azospirillum brasilense is a motile soil alphaproteobacterium able to colonize the rhizosphere of cereals. In response to an attractant, motile A. brasilense cells transiently increase swimming speed and suppress reversals. The Che1 chemotaxis pathway was previously shown to regulate changes in the swimming speed, but it has a minor role in chemotaxis and root surface colonization. Here, we show that a second chemotaxis system, named Che4, regulates the probability of swimming reversals and is the major signaling pathway for chemotaxis and wheat root surface colonization. Experimental evidence indicates that Che1 and Che4 are functionally linked to coordinate changes in the swimming motility pattern in response to attractants. The effect of Che1 on swimming speed is shown to enhance the aerotactic response of A. brasilense in gradients, likely providing the cells with a competitive advantage in the rhizosphere. Together, the results illustrate a novel mechanism by which motile bacteria utilize two chemotaxis pathways regulating distinct motility parameters to alter movement in gradients and enhance the chemotactic advantage. Chemotaxis provides motile bacteria with a competitive advantage in the colonization of diverse niches and is a function enriched in rhizosphere bacterial communities, with most species possessing at least two chemotaxis systems. Here, we identify the mechanism by which cells may derive a significant chemotactic advantage using two chemotaxis pathways that ultimately regulate distinct motility parameters. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Advanced glycation end products and RAGE: a common thread in aging, diabetes, neurodegeneration, and inflammation.

Science.gov (United States)

Ramasamy, Ravichandran; Vannucci, Susan J; Yan, Shirley Shi Du; Herold, Kevan; Yan, Shi Fang; Schmidt, Ann Marie

2005-07-01

The products of nonenzymatic glycation and oxidation of proteins and lipids, the advanced glycation end products (AGEs), accumulate in a wide variety of environments. AGEs may be generated rapidly or over long times stimulated by a range of distinct triggering mechanisms, thereby accounting for their roles in multiple settings and disease states. A critical property of AGEs is their ability to activate receptor for advanced glycation end products (RAGE), a signal transduction receptor of the immunoglobulin superfamily. It is our hypothesis that due to such interaction, AGEs impart a potent impact in tissues, stimulating processes linked to inflammation and its consequences. We hypothesize that AGEs cause perturbation in a diverse group of diseases, such as diabetes, inflammation, neurodegeneration, and aging. Thus, we propose that targeting this pathway may represent a logical step in the prevention/treatment of the sequelae of these disorders.

Alternative mechanisms guiding salespersons’ ambidextrous product selling

NARCIS (Netherlands)

van der Borgh, M.; de Jong, A.; Nijssen, E.J.

2017-01-01

Ambidextrous product-selling strategies, in which companies’ salespeople concurrently pursue the sale of existing and new products, are hard to implement. Previous studies have addressed this issue for relatively simple consumer settings with the manager in close proximity to the salespersons and

Anaerobic Mono- and Co-digestion of Mechanically Pretreated Meadow Grass for Biogas Production

DEFF Research Database (Denmark)

Tsapekos, Panagiotis; Kougias, Panagiotis; Angelidaki, Irini

2015-01-01

), was investigated. The grass silage was mechanically pretreated with different methods to increase its biodegradability. It was found that the early cut of non-treated meadow grass silage led to higher methane production [294 mL of CH4/g of volatile solids (VS)] compared to the corresponding non-treated meadow...... grass silage from the late cut (282 mL of CH4/g of VS). Moreover, it was found that the application of two mesh grating plates, as the pretreatment method, greatly enhanced the methane production in early and late cut silage in a range of 15 and 17%, respectively, compared to the non-treated grass...... ratios in terms of organic matter. The results showed that the optimum silage concentration in the co-digestion mixture with manure, for the highest methane yield, was strongly dependent upon the chemical composition of the manure. More specifically, the ammonia concentration of manure and the C/N ratio...

Filoviral Immune Evasion Mechanisms

Directory of Open Access Journals (Sweden)

Christopher F. Basler

2011-09-01

Full Text Available The Filoviridae family of viruses, which includes the genera Ebolavirus (EBOV and Marburgvirus (MARV, causes severe and often times lethal hemorrhagic fever in humans. Filoviral infections are associated with ineffective innate antiviral responses as a result of virally encoded immune antagonists, which render the host incapable of mounting effective innate or adaptive immune responses. The Type I interferon (IFN response is critical for establishing an antiviral state in the host cell and subsequent activation of the adaptive immune responses. Several filoviral encoded components target Type I IFN responses, and this innate immune suppression is important for viral replication and pathogenesis. For example, EBOV VP35 inhibits the phosphorylation of IRF-3/7 by the TBK-1/IKKε kinases in addition to sequestering viral RNA from detection by RIG-I like receptors. MARV VP40 inhibits STAT1/2 phosphorylation by inhibiting the JAK family kinases. EBOV VP24 inhibits nuclear translocation of activated STAT1 by karyopherin-α. The examples also represent distinct mechanisms utilized by filoviral proteins in order to counter immune responses, which results in limited IFN-α/β production and downstream signaling.

Learning-performance distinction and memory processes for motor skills: a focused review and perspective.

Science.gov (United States)

Kantak, Shailesh S; Winstein, Carolee J

2012-03-01

Behavioral research in cognitive psychology provides evidence for an important distinction between immediate performance that accompanies practice and long-term performance that reflects the relative permanence in the capability for the practiced skill (i.e. learning). This learning-performance distinction is strikingly evident when challenging practice conditions may impair practice performance, but enhance long-term retention of motor skills. A review of motor learning studies with a specific focus on comparing differences in performance between that at the end of practice and at delayed retention suggests that the delayed retention or transfer performance is a better indicator of motor learning than the performance at (or end of) practice. This provides objective evidence for the learning-performance distinction. This behavioral evidence coupled with an understanding of the motor memory processes of encoding, consolidation and retrieval may provide insight into the putative mechanism that implements the learning-performance distinction. Here, we propose a simplistic empirically-based framework--motor behavior-memory framework--that integrates the temporal evolution of motor memory processes with the time course of practice and delayed retention frequently used in behavioral motor learning paradigms. In the context of the proposed framework, recent research has used noninvasive brain stimulation to decipher the role of each motor memory process, and specific cortical brain regions engaged in motor performance and learning. Such findings provide beginning insights into the relationship between the time course of practice-induced performance changes and motor memory processes. This in turn has promising implications for future research and practical applications. Copyright © 2011 Elsevier B.V. All rights reserved.

Are children conservative, liberal, or metacognitive? Preliminary evidence for the involvement of the distinctiveness heuristic in decision making.

Science.gov (United States)

Geurten, Marie; Willems, Sylvie; Meulemans, Thierry

2015-04-01

The experiment tested whether young children are able to reduce their false recognition rate after distinctive encoding by implementing a strategic metacognitive rule. The participants, 72 children aged 4, 6, and 9 years, studied two lists of unrelated items. One of these lists was visually displayed (picture condition), whereas the other was presented auditorily (word condition). After each study phase, participants completed recognition tests. Finally, they answered questions about their explicit knowledge of the distinctive encoding effect. The results revealed that even the youngest children in our sample showed a smaller proportion of intrusions in the picture condition than in the word condition. Furthermore, the results of the signal detection analyses were consistent with the hypothesis that the lower rate of false recognitions after picture encoding results from the implementation of a conservative response criterion based on metacognitive expectations (distinctiveness heuristic). Moreover, the absence of correlation between children's explicit knowledge of the distinctiveness rule and their effective use of this metacognitive heuristic seems to indicate that its involvement in memory decisions could be mediated by implicit mechanisms. Copyright © 2015 Elsevier Inc. All rights reserved.

Extracellular Monomeric and Aggregated Tau Efficiently Enter Human Neurons through Overlapping but Distinct Pathways

Directory of Open Access Journals (Sweden)

Lewis D. Evans

2018-03-01

Full Text Available Summary: In Alzheimer’s disease, neurofibrillary tangle pathology appears to spread along neuronal connections, proposed to be mediated by the release and uptake of abnormal, disease-specific forms of microtubule-binding protein tau MAPT. It is currently unclear whether transfer of tau between neurons is a toxic gain-of-function process in dementia or reflects a constitutive biological process. We report two entry mechanisms for monomeric tau to human neurons: a rapid dynamin-dependent phase typical of endocytosis and a second, slower actin-dependent phase of macropinocytosis. Aggregated tau entry is independent of actin polymerization and largely dynamin dependent, consistent with endocytosis and distinct from macropinocytosis, the major route for aggregated tau entry reported for non-neuronal cells. Anti-tau antibodies abrogate monomeric tau entry into neurons, but less efficiently in the case of aggregated tau, where internalized tau carries antibody with it into neurons. These data suggest that tau entry to human neurons is a physiological process and not a disease-specific phenomenon. : In contrast with predictions that transfer of the microtubule-associated protein tau between neurons is a toxic gain-of-function process in dementia, Evans et al. show that healthy human neurons efficiently take up both normal and aggregated tau, by distinct but overlapping uptake mechanisms. Keywords: Alzheimer’s disease, frontotemporal dementia, Tau, MAPT, iPSC, endocytosis, human neurons, intracellular transport

Mechanics of couple-stress fluid coatings

Science.gov (United States)

Waxman, A. M.

1982-01-01

The formal development of a theory of viscoelastic surface fluids with bending resistance - their kinematics, dynamics, and rheology are discussed. It is relevant to the mechanics of fluid drops and jets coated by a thin layer of immiscible fluid with rather general rheology. This approach unifies the hydrodynamics of two-dimensional fluids with the mechanics of an elastic shell in the spirit of a Cosserat continuum. There are three distinct facets to the formulation of surface continuum mechanics. Outlined are the important ideas and results associated with each: the kinematics of evolving surface geometries, the conservation laws governing the mechanics of surface continua, and the rheological equations of state governing the surface stress and moment tensors.

Vertically distinct microbial communities in the Mariana and Kermadec trenches

Science.gov (United States)

Donaldson, Sierra; Osuntokun, Oladayo; Xia, Qing; Nelson, Alex; Blanton, Jessica; Allen, Eric E.; Church, Matthew J.; Bartlett, Douglas H.

2018-01-01

Hadal trenches, oceanic locations deeper than 6,000 m, are thought to have distinct microbial communities compared to those at shallower depths due to high hydrostatic pressures, topographical funneling of organic matter, and biogeographical isolation. Here we evaluate the hypothesis that hadal trenches contain unique microbial biodiversity through analyses of the communities present in the bottom waters of the Kermadec and Mariana trenches. Estimates of microbial protein production indicate active populations under in situ hydrostatic pressures and increasing adaptation to pressure with depth. Depth, trench of collection, and size fraction are important drivers of microbial community structure. Many putative hadal bathytypes, such as members related to the Marinimicrobia, Rhodobacteraceae, Rhodospirilliceae, and Aquibacter, are similar to members identified in other trenches. Most of the differences between the two trench microbiomes consists of taxa belonging to the Gammaproteobacteria whose distributions extend throughout the water column. Growth and survival estimates of representative isolates of these taxa under deep-sea conditions suggest that some members may descend from shallower depths and exist as a potentially inactive fraction of the hadal zone. We conclude that the distinct pelagic communities residing in these two trenches, and perhaps by extension other trenches, reflect both cosmopolitan hadal bathytypes and ubiquitous genera found throughout the water column. PMID:29621268

HTR fuel modelling with the ATLAS code. Thermal mechanical behaviour and fission product release assessment

International Nuclear Information System (INIS)

Guillermier, Pierre; Daniel, Lucile; Gauthier, Laurent

2009-01-01

To support AREVA NP in its design on HTR reactor and its HTR fuel R and D program, the Commissariat a l'Energie Atomique developed the ATLAS code (Advanced Thermal mechanicaL Analysis Software) with the objectives: - to quantify, with a statistical approach, the failed particle fraction and fission product release of a HTR fuel core under normal and accidental conditions (compact or pebble design). - to simulate irradiation tests or benchmark in order to compare measurements or others code results with ATLAS evaluation. These two objectives aim at qualifying the code in order to predict fuel behaviour and to design fuel according to core performance and safety requirements. A statistical calculation uses numerous deterministic calculations. The finite element method is used for these deterministic calculations, in order to be able to choose among three types of meshes, depending on what must be simulated: - One-dimensional calculation of one single particle, for intact particles or particles with fully debonded layers. - Two-dimensional calculations of one single particle, in the case of particles which are cracked, partially debonded or shaped in various ways. - Three-dimensional calculations of a whole compact slice, in order to simulate the interactions between the particles, the thermal gradient and the transport of fission products up to the coolant. - Some calculations of a whole pebble, using homogenization methods are being studied. The temperatures, displacements, stresses, strains and fission product concentrations are calculated on each mesh of the model. Statistical calculations are done using these results, taking into account ceramic failure mode, but also fabrication tolerances and material property uncertainties, variations of the loads (fluence, temperature, burn-up) and core data parameters. The statistical method used in ATLAS is the importance sampling. The model of migration of long-lived fission products in the coated particle and more

Mechanical design

CERN Document Server

Risitano, Antonino

2011-01-01

METHODOLOGICAL STATEMENT OF ENGINEERING DESIGNApproaches to product design and developmentMechanical design and environmental requirementsPROPERTIES OF ENGINEERING MATERIALSMaterials for mechanical designCharacterization of metalsStress conditionsFatigue of materialsOptimum material selection in mechanical designDESIGN OF MECHANICAL COMPONENTS AND SYSTEMSFailure theoriesHertz theoryLubrificationShafts and bearingsSplines and keysSpringsFlexible machine elementsSpur gearsPress and shrink fitsPressure tubesCouplingsClutchesBrakes

Distinctiveness of Initial Preform Properties in Renovation

Directory of Open Access Journals (Sweden)

V. M. Yaroslavtsev

2015-01-01

Full Text Available Technologies of renovation form a special group of resource-and energy saving technological processes as they are, by definition, already aimed either at increasing resource of the objects satisfying needs of the society life support and practical activities in different spheres, or at extension of their life cycle including a reuse of material from which they are made. Renovation is used where there is a material object, which does not meet requirements of standard or technical documentation.A characteristic feature of the renovation technologies is lack of procedure for a choice of the preform as in all cases an initial preform is the renovation object itself. Thus each object, acting as an initial preform, has the exclusively individual properties, including technological ones.Distinctiveness of renovation object properties is correlated, first of all, with the personified conditions of formation and (or change of condition of their properties in time at all stages of life cycle (production – transportation – warehousing – operation starting with a preform material when manufacturing under all types of loadings (technological and operational. As a result each object forms its "history" of loading and damages and, therefore, its information base which has to consider the phenomenon of “heredity of life cycle”. The term "heredity of life cycle" characterizes information support of object at any moment under review, including both information of technological inheritance, and data of operational heredity.As a result at every moment of time we have a product with a set of new, uncertain properties caused by the phenomena of heredity of life cycle. These properties are individual for each object to be renovated, which changed its status for the status of initial preform for different types of renovation technologies. This is one of the most important distinctions of renovation technology from the technology used to manufacture a new

LEGAL INSTRUMENT FOR PROTECTION OF GEOGRAPHICAL INDICATION PRODUCT IN INDONESIA

Directory of Open Access Journals (Sweden)

Almusawir Nansa

2013-07-01

Full Text Available As an archipelago country, Indonesia comprises of a large territory where every region is capable of producing distinctive and characterized products due to its geographical, social, and cultural factors, in addition to its higher quality compared to imported products. In the market, goods with distinct characterization as a result of various geographical locations of production regions is known as Geographical Indication Products. Geographical Indication defines as a characterization that indicates the origin of a product, which includes several influencing factors such as geographical factor, natural factor, human factor or the combination of both factors which eventually contribute to establish a certain distinction and quality upon a product. Several geographical indicated products in Indonesia are widely known to have excellent reputation on the market, namely Delinese tobacco, Temanggung tobacco, Ciancur rice, Muntok white pepper, Lampung black pepper, Kerinci cinnamon, Cilembu cassava, Bandanese nutmeg, Proboliggo sweet mango, Balinese Kintamani coffee, Kalosi coffee, Papuan matoa, etc. Those are several richness of goods from certain regions in Indonesia widely known for their characterization. Characterization of goods are resulted by variation of geographic locations of producing regions in Indonesia. These goods possess high quality and high economic value. Consequently, certain instruments are required to provide protection upon the regions producing those goods against the act of counterfeiting.

Progesterone modulates the LPS-induced nitric oxide production by a progesterone-receptor independent mechanism.

Science.gov (United States)

Wolfson, Manuel Luis; Schander, Julieta Aylen; Bariani, María Victoria; Correa, Fernando; Franchi, Ana María

2015-12-15

Genital tract infections caused by Gram-negative bacteria induce miscarriage and are one of the most common complications of human pregnancy. LPS administration to 7-day pregnant mice induces embryo resorption after 24h, with nitric oxide playing a fundamental role in this process. We have previously shown that progesterone exerts protective effects on the embryo by modulating the inflammatory reaction triggered by LPS. Here we sought to investigate whether the in vivo administration of progesterone modulated the LPS-induced nitric oxide production from peripheral blood mononuclear cells from pregnant and non-pregnant mice. We found that progesterone downregulated LPS-induced nitric oxide production by a progesterone receptor-independent mechanism. Moreover, our results suggest a possible participation of glucocorticoid receptors in at least some of the anti-inflammatory effects of progesterone. Copyright © 2015 Elsevier B.V. All rights reserved.

Assessing implementation mechanisms for an international agreement on research and development for health products.

Science.gov (United States)

Hoffman, Steven J; Røttingen, John-Arne

2012-11-01

The Member States of the World Health Organization (WHO) are currently debating the substance and form of an international agreement to improve the financing and coordination of research and development (R&D) for health products that meet the needs of developing countries. In addition to considering the content of any possible legal or political agreement, Member States may find it helpful to reflect on the full range of implementation mechanisms available to bring any agreement into effect. These include mechanisms for states to make commitments, administer activities, manage financial contributions, make subsequent decisions, monitor each other's performance and promote compliance. States can make binding or non-binding commitments through conventions, contracts, declarations or institutional reforms. States can administer activities to implement their agreements through international organizations, sub-agencies, joint ventures or self-organizing processes. Finances can be managed through specialized multilateral funds, financial institutions, membership organizations or coordinated self-management. Decisions can be made through unanimity, consensus, equal voting, modified voting or delegation. Oversight can be provided by peer review, expert review, self-reports or civil society. Together, states should select their preferred options across categories of implementation mechanisms, each of which has advantages and disadvantages. The challenge lies in choosing the most effective combinations of mechanisms for supporting an international agreement (or set of agreements) that achieves collective aspirations in a way and at a cost that are both sustainable and acceptable to those involved. In making these decisions, WHO's Member States can benefit from years of experience with these different mechanisms in health and its related sectors.

Physical and mechanical properties of high manganese non-magnetic steel and its application to various products for commercial use

International Nuclear Information System (INIS)

Sasaki, Terufumi; Watanabe, Kenji; Nohara, Kiyohiko; Ono, Yutaka; Kondo, Nobuyuki; Sato, Shuzo.

1982-01-01

In order to develop new high manganese non-magnetic steels that can be employed to extensive applications ranging from cryogenic to elevated temperature uses, the effects of C and Mn on their magnetic permeability, thermal expansion coefficient and mechanical properties are investigated. It is found that the relation between thermal expansion coefficient, β, and both C and Mn contents can be expressed by the following linear regression equation: β( x 10 -6 / 0 C) = 17.66 + 3.82 C (%) - 0.22 Mn (%). Good mechanical properties are exhibited in the wide range of Mn contents between 18 % and 30 % at room temperature, while there is a tendency that this optimum range of Mn content is narrowed at cryogenic temperature. Then, H-shapes, round bars and deformed bars are manufactured at the workshops using 5t vacuum melted ingots, aiming to establish the conditions for practical processes for final products and to study such various characteristics of the products as their physical and mechanical properties, machinability and weldability. As a result, it is shown that all of those products have excellent properties as non-magnetic steels. In addition, the manufacturing of non-magnetic pinch rolls attached to the electro-magnetic stirring equipment on the continuous casting machine is described in detail as one of the practical applications of the high Mn non-magnetic steels. (author)

Creativity, Scientific Practice, and Knowledge Production

Science.gov (United States)

Fryer, Marilyn

2010-01-01

In this interesting article, Hisham Ghassib (2010) describes the transformation of science from its craft status in a pre-modern era to the major knowledge industry it is today. He then compares the production of scientific knowledge with industrial production, but makes the important distinction between the process of developing scientific…

Single-molecule spectroscopy of LHCSR1 protein dynamics identifies two distinct states responsible for multi-timescale photosynthetic photoprotection

Science.gov (United States)

Kondo, Toru; Pinnola, Alberta; Chen, Wei Jia; Dall'Osto, Luca; Bassi, Roberto; Schlau-Cohen, Gabriela S.

2017-08-01

In oxygenic photosynthesis, light harvesting is regulated to safely dissipate excess energy and prevent the formation of harmful photoproducts. Regulation is known to be necessary for fitness, but the molecular mechanisms are not understood. One challenge has been that ensemble experiments average over active and dissipative behaviours, preventing identification of distinct states. Here, we use single-molecule spectroscopy to uncover the photoprotective states and dynamics of the light-harvesting complex stress-related 1 (LHCSR1) protein, which is responsible for dissipation in green algae and moss. We discover the existence of two dissipative states. We find that one of these states is activated by pH and the other by carotenoid composition, and that distinct protein dynamics regulate these states. Together, these two states enable the organism to respond to two types of intermittency in solar intensity—step changes (clouds and shadows) and ramp changes (sunrise), respectively. Our findings reveal key control mechanisms underlying photoprotective dissipation, with implications for increasing biomass yields and developing robust solar energy devices.

Distinctive Dynamic Capabilities for New Business Creation

DEFF Research Database (Denmark)

Rosenø, Axel; Enkel, Ellen; Mezger, Florian

2013-01-01

This study examines the distinctive dynamic capabilities for new business creation in established companies. We argue that these are very different from those for managing incremental innovation within a company's core business. We also propose that such capabilities are needed in both slow...... and fast-paced industries, and that similarities exist across industries. Hence, the study contributes to dynamic capabilities literature by: 1) identifying the distinctive dynamic capabilities for new business creation; 2) shifting focus away from dynamic capabilities in environments characterised by high...... clock-speed and uncertainty towards considering dynamic capabilities for the purpose of developing new businesses, which also implies a high degree of uncertainty. Based on interviews with 33 companies, we identify distinctive dynamic capabilities for new business creation, find that dynamic...

Allelic recombination between distinct genomic locations generates copy number diversity in human β-defensins

Science.gov (United States)

Bakar, Suhaili Abu; Hollox, Edward J.; Armour, John A. L.

2009-01-01

β-Defensins are small secreted antimicrobial and signaling peptides involved in the innate immune response of vertebrates. In humans, a cluster of at least 7 of these genes shows extensive copy number variation, with a diploid copy number commonly ranging between 2 and 7. Using a genetic mapping approach, we show that this cluster is at not 1 but 2 distinct genomic loci ≈5 Mb apart on chromosome band 8p23.1, contradicting the most recent genome assembly. We also demonstrate that the predominant mechanism of change in β-defensin copy number is simple allelic recombination occurring in the interval between the 2 distinct genomic loci for these genes. In 416 meiotic transmissions, we observe 3 events creating a haplotype copy number not found in the parent, equivalent to a germ-line rate of copy number change of ≈0.7% per gamete. This places it among the fastest-changing copy number variants currently known. PMID:19131514

Potential of fructooligosaccharide prebiotics in alternative and nonconventional poultry production systems.

Science.gov (United States)

Ricke, S C

2015-06-01

Fructooligosaccharide and inulin prebiotics are carbohydrate-based polymers derived from natural sources that can be utilized by certain gastrointestinal tract bacteria but not by the host animal. They are attractive as feed additives for nonconventional poultry production systems because they select for beneficial microorganisms that are thought to promote nutritional benefits to the bird and potentially limit foodborne pathogen establishment. There have been numerous studies conducted with prebiotic supplements to assess their impact in humans, animals, and conventionally raised poultry but only limited research has been conducted with birds grown under nonconventional production conditions. Much remains unknown about the specific mechanism(s) associated with their impact on the host as well as the gastrointestinal tract microflora. Utilization of several recently developed approaches such as microbiome and metabolomic analyses should offer more insight on how dietary prebiotic additives influence the development of the gastrointestinal tract microbiota and these subsequent changes correspond with alterations in a bird's physiology as it matures. As more detailed and precise studies are done with nonconventional poultry, it is likely that structurally distinct prebiotics will influence not only the gastrointestinal tract microbiota differently, but potentially interact directly and/or indirectly with the bird host in distinguishable patterns as well. These functions will be important to delineate if further applications are to be developed for specific prebiotics in nonconventional poultry production systems. © 2015 Poultry Science Association Inc.

Many-Objective Distinct Candidates Optimization using Differential Evolution

DEFF Research Database (Denmark)

Justesen, Peter; Ursem, Rasmus Kjær

2010-01-01

for each objective. The Many-Objective Distinct Candidates Optimization using Differential Evolution (MODCODE) algorithm takes a novel approach by focusing search using a user-defined number of subpopulations each returning a distinct optimal solution within the preferred region of interest. In this paper......, we present the novel MODCODE algorithm incorporating the ROD measure to measure and control candidate distinctiveness. MODCODE is tested against GDE3 on three real world centrifugal pump design problems supplied by Grundfos. Our algorithm outperforms GDE3 on all problems with respect to all...

«Industry 4.0» as a mechanism for forming «Smart production»

Directory of Open Access Journals (Sweden)

SERGEYEVA Olesya Yurievna

2018-04-01

Full Text Available «Smart production» is a new model of industrial development of the 21st century on the basis of digital technologies, which already to some extent operates in the form of a production system that creates products and services on non - markets, contributing to the improvement of a comfortable life of the person, the population. Active development in the 21st century of information technologies and concepts contributed to the creation and development of cyberphysical systems that integrate computing resources into physical processes. Digitalisation and its transformation in manufacturing brings new features and high technology sectors, such as construction, oil service, energy, space, health, etc. Index of Russian digitization of international research for 2016 amounted to 113 points. Little use of the potential of digital transformation of industries has become the main problem of the country. The state concept of social and economic development of the Russian Federation involves the development of competitive industry in Russia and effective technology platforms, improving the efficiency and competitiveness of the Russian economy through the development of high-tech industry on the basis of the basic concept of «industry 4.0» through its digitalization and restructuring, using innovative tools and mechanisms. The use of artificial intelligence systems in production processes will radically change the production, the basic basis of which will be additive 3D technologies Additive technologies are a process of layer-by-layer expansion and synthesis of the object using computer 3D-technologies. In modern production it is a set of different processes, including UV-irradiation, extrusion, jet spraying, fusion, lamination. Modern production technologies contribute to the development of new markets and are the driving force of the digital revolution.

Biogas production from the mechanically pretreated, liquid fraction of sorted organic municipal solid wastes.

Science.gov (United States)

Alvarado-Lassman, A; Méndez-Contreras, J M; Martínez-Sibaja, A; Rosas-Mendoza, E S; Vallejo-Cantú, N A

2017-06-01

The high liquid content in fruit and vegetable wastes makes it convenient to mechanically separate these wastes into mostly liquid and solid fractions by means of pretreatment. Then, the liquid fraction can be treated using a high-rate anaerobic biofilm reactor to produce biogas, simultaneously reducing the amount of solids that must be landfilled. In this work, the specific composition of municipal solid waste (MSW) in a public market was determined; then, the sorted organic fraction of municipal solid waste was treated mechanically to separate and characterize the mostly liquid and solid fractions. Then, the mesophilic anaerobic digestion for biogas production of the first fraction was evaluated. The anaerobic digestion resulted in a reduced hydraulic retention time of two days with high removal of chemical oxygen demand, that is, 88% on average, with the additional benefit of reducing the mass of the solids that had to be landfilled by about 80%.

Mechanism for multiplicity of steady states with distinct cell concentration in continuous culture of mammalian cells.

Science.gov (United States)

Yongky, Andrew; Lee, Jongchan; Le, Tung; Mulukutla, Bhanu Chandra; Daoutidis, Prodromos; Hu, Wei-Shou

2015-07-01

Continuous culture for the production of biopharmaceutical proteins offers the possibility of steady state operations and thus more consistent product quality and increased productivity. Under some conditions, multiplicity of steady states has been observed in continuous cultures of mammalian cells, wherein with the same dilution rate and feed nutrient composition, steady states with very different cell and product concentrations may be reached. At those different steady states, cells may exhibit a high glycolysis flux with high lactate production and low cell concentration, or a low glycolysis flux with low lactate and high cell concentration. These different steady states, with different cell concentration, also have different productivity. Developing a mechanistic understanding of the occurrence of steady state multiplicity and devising a strategy to steer the culture toward the desired steady state is critical. We establish a multi-scale kinetic model that integrates a mechanistic intracellular metabolic model and cell growth model in a continuous bioreactor. We show that steady state multiplicity exists in a range of dilution rate in continuous culture as a result of the bistable behavior in glycolysis. The insights from the model were used to devise strategies to guide the culture to the desired steady state in the multiple steady state region. The model provides a guideline principle in the design of continuous culture processes of mammalian cells. © 2015 Wiley Periodicals, Inc.

Mechanical engineering

International Nuclear Information System (INIS)

1988-01-01

The Mechanical Engineering Division provides the other NAC divisions with design and construction services. Items of special mechanical significance are discussed here. The projects which received major design attention during the past year were: a coupling capacitor for SPC2; a bending magnet and solenoid for ECR ion source; a scanner for outer orbits of the SSC; a scattering chamber for an experimental beamline; a beam swinger; a rotary target magazine for isotope production; a robot arm for isotope production; an isotope transport system and a target cooling system for isotope production. The major projects that were under construction are: a magnetic spectrometer; a second injector cyclotron (SPC2) and extensions to the high-energy beamlines. 4 figs

The balancing mechanism. How to ensure the power production-consumption balance in a market opened to competition

International Nuclear Information System (INIS)

Harmnd, Y.; Nebas-Hamoudia, C.; Larripa, B.; Neupont, B.

2005-01-01

As electricity is a non-storable product in large quantities, generation and consumption have to be balanced at all times. In France, this balancing was historically solely supplied by EDF. Recent legislative changes have opened balancing supplies, thus creating competition. RTE, the electricity transmission system operator, has developed, in consultation with the main market players, the balancing mechanism. This enables available capacities to be merged in order to guarantee this balance. It operates like a permanent bidding system open to producers, industrial consumers and foreign players. Bids submitted by players are selected by RTE depending on the system requirements, taking into account merit order criterion and technical constraints. Prices issued from the balancing mechanism are used to provide a legitimate reference price for the settlement of imbalances between supplies and consumptions of the different electricity market players. Transparency, a crucial element of this mechanism, is ensured by a comprehensive system of open data publication. Since its launch, the balancing mechanism has proven its operational strength. (author)

A novel antihuman C3d monoclonal antibody with specificity to the C3d complement split product

DEFF Research Database (Denmark)

Rasmussen, Karina Juhl; Skjødt, Mikkel-Ole; Vitved, Lars

2017-01-01

The complement component C3 and the cleavage products of C3b/iC3b, C3c and C3d are used as biomarkers in clinical diagnostics. Currently, no specific antibodies are able to differentiate C3d from other fragments, although such a distinction could be very valuable considering that they may reflect...... different pathophysiological mechanisms. We have developed a rat antihuman C3d monoclonal antibody with specificity to the end sequence of the N-terminal region of C3d. The antibody can therefore only bind to C3d when it manifests itself as the final end product of cleaved C3. We believe...

Complete sequence analysis reveals two distinct poleroviruses infecting cucurbits in China.

Science.gov (United States)

Xiang, Hai-ying; Shang, Qiao-xia; Han, Cheng-gui; Li, Da-wei; Yu, Jia-lin

2008-01-01

The complete RNA genomes of a Chinese isolate of cucurbit aphid-borne yellows virus (CABYV-CHN) and a new polerovirus tentatively referred to as melon aphid-borne yellows virus (MABYV) were determined. The entire genome of CABYV-CHN shared 89.0% nucleotide sequence identity with the French CABYV isolate. In contrast, nucleotide sequence identities between MABYV and CABYV and other poleroviruses were in the range of 50.7-74.2%, with amino acid sequence identities ranging from 24.8 to 82.9% for individual gene products. We propose that CABYV-CHN is a strain of CABYV and that MABYV is a member of a tentative distinct species within the genus Polerovirus.

Computational Identification and Analysis of Signaling Subnetworks with Distinct Functional Roles in the Regulation of TNF Production

Science.gov (United States)

2016-01-04

extract four distinct quantitative features of response timing and intensity: the trajectory peak height, the peak time, the area under the curve, and...J., 2007, 21, 325–332. 16 S. L. Werner, J. D. Kearns, V. Zadorozhnaya, C. Lynch, E. O’Dea, M. P. Boldin , A. Ma, D. Baltimore and A. Hoffmann, Genes...Werner, J. D. Kearns, V. Zadorozhnaya, C. Lynch, E. O’Dea, M. P. Boldin , A. Ma, D. Baltimore and A. Hoffmann, Genes Dev., 2008, 22, 2093–2101. 58 J

Tp53 gene mediates distinct dopaminergic neuronal damage in different dopaminergic neurotoxicant models

Directory of Open Access Journals (Sweden)

Tao Lu

2017-01-01

Full Text Available Tp53, a stress response gene, is involved in diverse cell death pathways and its activation is implicated in the pathogenesis of Parkinson's disease. However, whether the neuronal Tp53 protein plays a direct role in regulating dopaminergic (DA neuronal cell death or neuronal terminal damage in different neurotoxicant models is unknown. In our recent studies, in contrast to the global inhibition of Tp53 function by pharmacological inhibitors and in traditional Tp53 knock-out mice, we examined the effects of DA-specific Tp53 gene deletion after 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and methamphetamine exposure. Our data suggests that the Tp53 gene might be involved in both neuronal apoptosis and neuronal terminal damage caused by different neurotoxicants. Additional results from other studies also suggest that as a master regulator of many pathways that regulate apoptosis and synaptic terminal damage, it is possible that Tp53 may function as a signaling hub to integrate different signaling pathways to mediate distinctive target pathways. Tp53 protein as a signaling hub might be able to evaluate the microenvironment of neurons, assess the forms and severities of injury incurred, and determine whether apoptotic cell death or neuronal terminal degeneration occurs. Identification of the precise mechanisms activated in distinct neuronal damage caused by different forms and severities of injuries might allow for development of specific Tp53 inhibitors or ways to modulate distinct downstream target pathways involved.

[Participation of final products of lipid peroxidation in the anticancer mechanism of ionizing radiation and radiomimetic cytostatics].

Science.gov (United States)

Przybyszewski, W M

2001-01-01

This review reports the evidence for the participation of final products of lipid peroxidation in the anticancer mechanism of ionising radiation and radiomimetic cytostatics. Processes of lipid peroxidation occur endogenously in response to oxidative stress and great diversity of reactive metabolites is formed. However, direct observation of radical reaction in pathophysiology of cells, tissues and organs is limited technically. Most investigations focused on the indirect assessment of their final products, aldehydes. The peroxidative breakdown of polyunsaturated fatty acids is believed to be involved in the regulation of cell division, and antitumor effect through biochemical and genetic processes.

Computational study of hydrogen shifts and ring-opening mechanisms in α-pinene ozonolysis products

DEFF Research Database (Denmark)

Kurtén, Theo; Rissanen, Matti P.; Mackeprang, Kasper

2015-01-01

, sterically unhindered) H-shifts of all four peroxy radicals formed in the ozonolysis of α-pinene using density functional (ωB97XD) and coupled cluster [CCSD(T)-F12] theory. In contrast to the related but chemically simpler cyclohexene ozonolysis system, none of the calculated H-shifts have rate constants...... products in the α-pinene ozonolysis system, additional ring-opening reaction mechanisms breaking the cyclobutyl ring are therefore needed. We further investigate possible uni- and bimolecular pathways for opening the cyclobutyl ring in the α-pinene ozonolysis system....

Creating fair lineups for suspects with distinctive features.

Science.gov (United States)

Zarkadi, Theodora; Wade, Kimberley A; Stewart, Neil

2009-12-01

In their descriptions, eyewitnesses often refer to a culprit's distinctive facial features. However, in a police lineup, selecting the only member with the described distinctive feature is unfair to the suspect and provides the police with little further information. For fair and informative lineups, the distinctive feature should be either replicated across foils or concealed on the target. In the present experiments, replication produced more correct identifications in target-present lineups--without increasing the incorrect identification of foils in target-absent lineups--than did concealment. This pattern, and only this pattern, is predicted by the hybrid-similarity model of recognition.

η{sub c} production associated with light hadrons at the B-factories and the future Super B-factories

Energy Technology Data Exchange (ETDEWEB)

Gong, Qin-Rong [Peking University, Department of Physics and State Key Laboratory of Nuclear Physics and Technology, Beijing (China); Sun, Zhan [Guizhou Minzu University, School of Science, Guiyang (China); Zhang, Hong-Fei [Chongqing University of Posts and Telecommunications, School of Science, Chongqing (China); Mo, Xue-Mei [Third Military Medical University, Institute of Digital Medicine, School of Biomedical Engineering, Chongqing (China)

2016-09-15

We present a complete study of the associated production of the η{sub c} meson with light hadrons in e{sup +}e{sup -} collisions at the B-factory energy, which is demonstrated to be one of the best laboratories for testing the colour-octet (CO) mechanism. The colour-singlet contributions are evaluated up to O(α{sup 2}α{sub s}{sup 3}), while the CO ones are evaluated up to O(α{sup 2}α{sub s}{sup 2}). For the first time, the angular distribution of the {sup 1}S{sub 0}{sup [8]} production is studied at QCD next-to-leading order. We find that the {sup 1}S{sub 0}{sup [8]} channel dominates the total cross section, while the {sup 1}P{sub 1}{sup [8]} one exhibits its importance in the angular distribution, which turns out to be downward going with respect to cosθ. This can be considered as the most distinct signal for the CO mechanism. (orig.)

Interleukin-1β modulates smooth muscle cell phenotype to a distinct inflammatory state relative to PDGF-DD via NF-κB-dependent mechanisms.

Science.gov (United States)

Alexander, Matthew R; Murgai, Meera; Moehle, Christopher W; Owens, Gary K

2012-04-02

Smooth muscle cell (SMC) phenotypic modulation in atherosclerosis and in response to PDGF in vitro involves repression of differentiation marker genes and increases in SMC proliferation, migration, and matrix synthesis. However, SMCs within atherosclerotic plaques can also express a number of proinflammatory genes, and in cultured SMCs the inflammatory cytokine IL-1β represses SMC marker gene expression and induces inflammatory gene expression. Studies herein tested the hypothesis that IL-1β modulates SMC phenotype to a distinct inflammatory state relative to PDGF-DD. Genome-wide gene expression analysis of IL-1β- or PDGF-DD-treated SMCs revealed that although both stimuli repressed SMC differentiation marker gene expression, IL-1β distinctly induced expression of proinflammatory genes, while PDGF-DD primarily induced genes involved in cell proliferation. Promoters of inflammatory genes distinctly induced by IL-1β exhibited over-representation of NF-κB binding sites, and NF-κB inhibition in SMCs reduced IL-1β-induced upregulation of proinflammatory genes as well as repression of SMC differentiation marker genes. Interestingly, PDGF-DD-induced SMC marker gene repression was not NF-κB dependent. Finally, immunofluorescent staining of mouse atherosclerotic lesions revealed the presence of cells positive for the marker of an IL-1β-stimulated inflammatory SMC, chemokine (C-C motif) ligand 20 (CCL20), but not the PDGF-DD-induced gene, regulator of G protein signaling 17 (RGS17). Results demonstrate that IL-1β- but not PDGF-DD-induced phenotypic modulation of SMC is characterized by NF-κB-dependent activation of proinflammatory genes, suggesting the existence of a distinct inflammatory SMC phenotype. In addition, studies provide evidence for the possible utility of CCL20 and RGS17 as markers of inflammatory and proliferative state SMCs within atherosclerotic plaques in vivo.

Possibility of applying mechanized coal mining in the mine 'Soko', with the comparative advantages of production results and impact

Directory of Open Access Journals (Sweden)

Denić Miodrag

2014-01-01

Full Text Available Mining method applied in the RMU 'Soko', is repeatedly technologically modified and reached the maximum limit in terms of productivity, level of job performance and safety at work. And all the other methods, which are in the technological process of obtaining coal rely on the technology of drilling-blasting works, in terms of the mine 'Soko', can not allow mass production of coal, regarding natural and technical-technological conditions prevailing in Sokobanja coal basin. Therefore, this paper proposes a possible solution which would enable a significant increase in annual production by appling mechanized coal mining system.

Nature-Inspired Design : Strategies for Sustainable Product Development

NARCIS (Netherlands)

De Pauw, I.C.

2015-01-01

Product designers can apply different strategies, methods, and tools for sustainable product development. Nature-Inspired Design Strategies (NIDS) offer designers a distinct class of strategies that use ‘nature’ as a guiding source of knowledge and inspiration for addressing sustainability.

Relational quantum mechanics

International Nuclear Information System (INIS)

Rovelli, C.

1996-01-01

I suggest that the common unease with taking quantum mechanics as a fundamental description of nature (the open-quotes measurement problemclose quotes) could derive from the use of an incorrect notion, as the unease with the Lorentz transformations before Einstein derived from the notion of observer-independent time. I suggest that this incorrect notion that generates the unease with quantum mechanics is the notion of open-quotes observer-independent stateclose quotes of a system, or open-quotes observer-independent values of physical quantities.close quotes I reformulate the problem of the open-quotes interpretation of quantum mechanicsclose quotes as the problem of deriving the formalism from a set of simple physical postulates. I consider a reformulation of quantum mechanics in terms of information theory. All systems are assumed to be equivalent, there is no observer-observed distinction, and the theory describes only the information that systems have about each other; nevertheless, the theory is complete

‘Initiative-Decision’ Typology of New Product Launching (NPL into Local Market: Toward Interaction Mechanism

Directory of Open Access Journals (Sweden)

Firmanzah

2009-12-01

Full Text Available New product launching (NPL process in subsidiaries is very complex, expensive and risky. This process is marked by the problem of role partition between headquarter and subsidiaries. This research emphasizes the quality of relation between subsidiaries and headquarter which determines the qualities of NPL process into local market. Typology of initiative-decision during NPL process has been documented. Using cluster analysis, three clusters of ‘initiative-decision’ during NPL are found in this research: ‘headquarters domination’, ‘mix-initiative’ and ‘interaction’. Using ANOVA analysis, this research found that interaction between subsidiary and headquarter managers positively increases the effectiveness of marketing-strategy during NPL process. This finding suggests that interaction mechanism between subsidiary and headquarter is the best solution to launch a new product to the local market.

Epiphytes modulate Posidonia oceanica photosynthetic production, energetic balance, antioxidant mechanisms and oxidative damage

Directory of Open Access Journals (Sweden)

Monya Mendes Costa

2015-12-01

Full Text Available Epiphytes impose physical barriers to light penetration into seagrass leaves causing shading, which may decrease the production of oxygen reactive species (ROS, but also constitute a physical aggression that may trigger the production of ROS, leading to oxidative damage. Here we investigate the effects of epiphytes on Posidonia oceanica under both interactive perspectives, light attenuation and oxidative stress. Specifically the role of epiphytes in net photosynthesis, chlorophyll a and b, photoprotection (Violaxanthin+Anteraxanthin+Zeaxanthin cycle, soluble sugar and starch contents, enzymatic (ascorbate peroxidase (APX and dehydroascorbate reductase (DHAR and global (trolox equivalent antioxidant capacity (TEAC and oxygen radical antioxidant capacity (ORAC antioxidant responses, phenolics and oxidative damage (malondialdehyde are tested. Leaves with epiphytes showed higher chlorophyll b and lower content in VAZ cycle carotenoids. Epiphyte shading was the probable reason for the lower VAZ de-epoxidation-ratio of leaves with epiphytes. In spite of being shaded, leaves with epiphytes showed higher antioxidant levels, indicating that epiphytes trigger the production of ROS. Both ORAC and TEAC and also APX and DHAR activities were higher in leaves with epiphytes, indicating that this response was related with its presence. Malondialdehyde concentrations also suggest oxidative damage caused by epiphytes. We conclude that the epiphyte load causes oxidative stress in P. oceanica and the mechanisms to scavenge ROS were not completely effective to avoid cell damage.

Investment-innovation mechanism of ensuring competitiveness of industrial enterprises

Directory of Open Access Journals (Sweden)

Kozyk Vasyl V.

2014-01-01

Full Text Available The article considers the process of formation of the investment-innovation mechanism of ensuring competitiveness of industrial enterprises. It identifies the essence, composition, goals and means of functioning of this mechanism. It establishes sequence of the process of functioning of the investment-innovation mechanism of ensuring competitiveness of economic subjects. It marks out such particular types of this mechanism: mechanism of renovation of fixed assets of an enterprise, mechanism of formation of channels and network of sales of enterprise products, mechanism of expansion of production capacity of the enterprise on manufacture of traditional types of products, mechanism of introduction of new progressive production processes, mechanism of development and production of innovation products, and mechanism of reduction of the level of risk of investment activity of the enterprise. The article conducts modelling of the process of development and realisation of investment solutions on introduction of progressive technologies of manufacture of products at the enterprise. It offers a method of selection of the most competitive variant of technology of manufacture of products depending on the level of quality and also specific current capital outlays for their manufacture.

Mechanical knowledge does matter to tool use even when assessed with a non-production task: Evidence from left brain-damaged patients.

Science.gov (United States)

Lesourd, Mathieu; Budriesi, Carla; Osiurak, François; Nichelli, Paolo F; Bartolo, Angela

2017-12-20

In the literature on apraxia of tool use, it is now accepted that using familiar tools requires semantic and mechanical knowledge. However, mechanical knowledge is nearly always assessed with production tasks, so one may assume that mechanical knowledge and familiar tool use are associated only because of their common motor mechanisms. This notion may be challenged by demonstrating that familiar tool use depends on an alternative tool selection task assessing mechanical knowledge, where alternative uses of tools are assumed according to their physical properties but where actual use of tools is not needed. We tested 21 left brain-damaged patients and 21 matched controls with familiar tool use tasks (pantomime and single tool use), semantic tasks and an alternative tool selection task. The alternative tool selection task accounted for a large amount of variance in the single tool use task and was the best predictor among all the semantic tasks. Concerning the pantomime of tool use task, group and individual results suggested that the integrity of the semantic system and preserved mechanical knowledge are neither necessary nor sufficient to produce pantomimes. These results corroborate the idea that mechanical knowledge is essential when we use tools, even when tasks assessing mechanical knowledge do not require the production of any motor action. Our results also confirm the value of pantomime of tool use, which can be considered as a complex activity involving several cognitive abilities (e.g., communicative skills) rather than the activation of gesture engrams. © 2017 The British Psychological Society.

Stalled replication forks generate a distinct mutational signature in yeast

DEFF Research Database (Denmark)

Larsen, Nicolai B.; Liberti, Sascha E.; Vogel, Ivan

2017-01-01

Proliferating cells acquire genome alterations during the act of DNA replication. This leads to mutation accumulation and somatic cell mosaicism in multicellular organisms, and is also implicated as an underlying cause of aging and tumorigenesis. The molecular mechanisms of DNA replication...... Escherichia coli Tus/Ter complex) engineered into the yeast genome. We demonstrate that transient stalling at this barrier induces a distinct pattern of genome rearrangements in the newly replicated region behind the stalled fork, which primarily consist of localized losses and duplications of DNA sequences....... These genetic alterations arise through the aberrant repair of a single-stranded DNA gap, in a process that is dependent on Exo1- and Shu1-dependent homologous recombination repair (HRR). Furthermore, aberrant processing of HRR intermediates, and elevated HRR-associated mutagenesis, is detectable in a yeast...

Distinct transmitter release properties determine differences in short-term plasticity at functional and silent synapses.

Science.gov (United States)

Cabezas, Carolina; Buño, Washington

2006-05-01

Recent evidence suggests that functional and silent synapses are not only postsynaptically different but also presynaptically distinct. The presynaptic differences may be of functional importance in memory formation because a proposed mechanism for long-term potentiation is the conversion of silent synapses into functional ones. However, there is little direct experimentally evidence of these differences. We have investigated the transmitter release properties of functional and silent Schaffer collateral synapses and show that on the average functional synapses displayed a lower percentage of failures and higher excitatory postsynaptic current (EPSC) amplitudes than silent synapses at +60 mV. Moreover, functional but not silent synapses show paired-pulse facilitation (PPF) at +60 mV and thus presynaptic short-term plasticity will be distinct in the two types of synapse. We examined whether intraterminal endoplasmic reticulum Ca2+ stores influenced the release properties of these synapses. Ryanodine (100 microM) and thapsigargin (1 microM) increased the percentage of failures and decreased both the EPSC amplitude and PPF in functional synapses. Caffeine (10 mM) had the opposite effects. In contrast, silent synapses were insensitive to both ryanodine and caffeine. Hence we have identified differences in the release properties of functional and silent synapses, suggesting that synaptic terminals of functional synapses express regulatory molecular mechanisms that are absent in silent synapses.

Distinct Mechanisms of Pathogenic DJ-1 Mutations in Mitochondrial Quality Control

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Daniela Strobbe

2018-03-01

Full Text Available The deglycase and chaperone protein DJ-1 is pivotal for cellular oxidative stress responses and mitochondrial quality control. Mutations in PARK7, encoding DJ-1, are associated with early-onset familial Parkinson’s disease and lead to pathological oxidative stress and/or disrupted protein degradation by the proteasome. The aim of this study was to gain insights into the pathogenic mechanisms of selected DJ-1 missense mutations, by characterizing protein–protein interactions, core parameters of mitochondrial function, quality control regulation via autophagy, and cellular death following dopamine accumulation. We report that the DJ-1M26I mutant influences DJ-1 interactions with SUMO-1, in turn enhancing removal of mitochondria and conferring increased cellular susceptibility to dopamine toxicity. By contrast, the DJ-1D149A mutant does not influence mitophagy, but instead impairs Ca2+ dynamics and free radical homeostasis by disrupting DJ-1 interactions with a mitochondrial accessory protein known as DJ-1-binding protein (DJBP/EFCAB6. Thus, individual DJ-1 mutations have different effects on mitochondrial function and quality control, implying mutation-specific pathomechanisms converging on impaired mitochondrial homeostasis.

Biophysical subsets of embryonic stem cells display distinct phenotypic and morphological signatures.

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Tom Bongiorno

Full Text Available The highly proliferative and pluripotent characteristics of embryonic stem cells engender great promise for tissue engineering and regenerative medicine, but the rapid identification and isolation of target cell phenotypes remains challenging. Therefore, the objectives of this study were to characterize cell mechanics as a function of differentiation and to employ differences in cell stiffness to select population subsets with distinct mechanical, morphological, and biological properties. Biomechanical analysis with atomic force microscopy revealed that embryonic stem cells stiffened within one day of differentiation induced by leukemia inhibitory factor removal, with a lagging but pronounced change from spherical to spindle-shaped cell morphology. A microfluidic device was then employed to sort a differentially labeled mixture of pluripotent and differentiating cells based on stiffness, resulting in pluripotent cell enrichment in the soft device outlet. Furthermore, sorting an unlabeled population of partially differentiated cells produced a subset of "soft" cells that was enriched for the pluripotent phenotype, as assessed by post-sort characterization of cell mechanics, morphology, and gene expression. The results of this study indicate that intrinsic cell mechanical properties might serve as a basis for efficient, high-throughput, and label-free isolation of pluripotent stem cells, which will facilitate a greater biological understanding of pluripotency and advance the potential of pluripotent stem cell differentiated progeny as cell sources for tissue engineering and regenerative medicine.

Marburg virus evades interferon responses by a mechanism distinct from ebola virus.

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Charalampos Valmas

2010-01-01

Full Text Available Previous studies have demonstrated that Marburg viruses (MARV and Ebola viruses (EBOV inhibit interferon (IFN-alpha/beta signaling but utilize different mechanisms. EBOV inhibits IFN signaling via its VP24 protein which blocks the nuclear accumulation of tyrosine phosphorylated STAT1. In contrast, MARV infection inhibits IFNalpha/beta induced tyrosine phosphorylation of STAT1 and STAT2. MARV infection is now demonstrated to inhibit not only IFNalpha/beta but also IFNgamma-induced STAT phosphorylation and to inhibit the IFNalpha/beta and IFNgamma-induced tyrosine phosphorylation of upstream Janus (Jak family kinases. Surprisingly, the MARV matrix protein VP40, not the MARV VP24 protein, has been identified to antagonize Jak and STAT tyrosine phosphorylation, to inhibit IFNalpha/beta or IFNgamma-induced gene expression and to inhibit the induction of an antiviral state by IFNalpha/beta. Global loss of STAT and Jak tyrosine phosphorylation in response to both IFNalpha/beta and IFNgamma is reminiscent of the phenotype seen in Jak1-null cells. Consistent with this model, MARV infection and MARV VP40 expression also inhibit the Jak1-dependent, IL-6-induced tyrosine phosphorylation of STAT1 and STAT3. Finally, expression of MARV VP40 is able to prevent the tyrosine phosphorylation of Jak1, STAT1, STAT2 or STAT3 which occurs following over-expression of the Jak1 kinase. In contrast, MARV VP40 does not detectably inhibit the tyrosine phosphorylation of STAT2 or Tyk2 when Tyk2 is over-expressed. Mutation of the VP40 late domain, essential for efficient VP40 budding, has no detectable impact on inhibition of IFN signaling. This study shows that MARV inhibits IFN signaling by a mechanism different from that employed by the related EBOV. It identifies a novel function for the MARV VP40 protein and suggests that MARV may globally inhibit Jak1-dependent cytokine signaling.

Study of multiple production mechanisms of neutral and charged particles in proton-proton interactions at 69GeV/c

International Nuclear Information System (INIS)

Boratav, Murat.

1976-01-01

From a sample of 30000 pictures taken in the hydrogen bubble chamber Mirabelle, with a proton beam of 69GeV/c, at Serpukhov, the multiple particle production mechanisms are studied in proton-proton collisions. The neutral pions produced are specially studied, which means that the photons coming from the disintegration of π 0 's have to be detected and measured. From these pion spectra, their multiplicity distributions and the first order moments of these distributions (particularly the Mueller correlation coefficients) data and results are compared with the predictions of theoretical models such as: 'thermodynamic' models (Feynman gas, critical fluid model, etc.) and cluster models (with a fixed size or a size depending on incoming energy). The multiple production mechanisms seem to appear through small-sized, energy-dependent clusters (about two pions per cluster at this energy) [fr

A comparative study on Ca content and distribution in two Gesneriaceae species reveals distinctive mechanisms to cope with high rhizospheric soluble calcium

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Wenlong eLi

2014-11-01

Full Text Available Excessive Ca is toxic to plants thus significantly affects plant growth and species distribution in Ca-rich karst areas. To understand how plants survive high Ca soil, laboratory experiments were established to compare the physiological responses and internal Ca distribution in organ, tissue, cell and intracellular levels under different Ca levels for Lysionotus pauciflorus and Boea hygrometrica, two karst habitant Gesneriaceae species in Southwest China. In the controlled condition, L. pauciflorus could survive as high as 200 mM rhizospheric soluble Ca, attributed to a series of physiological responses and preferential storage that limited Ca accumulation in chloroplasts of palisade cells. In contrast, B. hygrometrica could survive only 20 mM rhizospheric soluble Ca, but accumulated a high level of internal Ca in both palisade and spongy cells without disturbance on photosynthetic activity. By phenotype screening of transgenic plants expressing high Ca-inducible genes from B. hygrometrica, the expression of BhDNAJC2 in A. thaliana was found to enhance plant growth and photosynthesis under high soluble Ca stress. BhDNAJC2 encodes a recently reported heat shock protein (HSP 40 family DnaJ-domain protein. The Ca-resistant phenotype of BhDNAJC2 highlights the important role of chaperone-mediated protein quality control in Ca tolerance in B. hygrometrica. Taken together, our results revealed that distinctive mechanisms were employed in the two Gesneriaceae karst habitants to cope with a high Ca environment.

Indicine N-oxide binds to tubulin at a distinct site and inhibits the assembly of microtubules: a mechanism for its cytotoxic activity.

Science.gov (United States)

Appadurai, Prakash; Rathinasamy, Krishnan

2014-02-10

Indicine N-oxide, a pyrrolizidine alkaloid present in the plant Heliotropium indicum had shown promising cytotoxic activity in various tumor models. The compound exhibited severe toxicity to hepatocytes and bone marrow cells. The present work was aimed to evaluate the molecular mechanism of the toxicity of indicine N-oxide. We found that indicine N-oxide inhibited the proliferation of various cancer cell lines in a concentration dependent manner with IC50 ranging from 46 to 100 μM. At the half maximal inhibitory concentration it blocked the cell cycle progression at mitosis without significantly altering the organization of the spindle and interphase microtubules. The toxicities of the compound at higher concentrations are attributed to its severe depolymerizing effect on both the interphase and spindle microtubules. Binding studies using purified goat brain tubulin indicated that indicine N-oxide binds to tubulin at a distinct site not shared by colchicine or taxol. It decreased the polymer mass of both purified tubulin and MAP-rich tubulin. It was found to induce cleavage of DNA using pUC18 plasmid. The interactions of indicine N-oxide on DNA were also confirmed by computational analysis; which predicted its binding site at the minor groove of DNA. These studies bring to light that the toxicities of indicine N-oxide were due to its DNA damaging effects and depolymerization of microtubules. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Studies of some physical-mechanical and chemical property in organic waste to use for biogas production in Cuba

International Nuclear Information System (INIS)

Martinez Hernández, Carlos M.; Oechsner, Hans; Brulé, Mathieu; Marañon Maison, Elena

2014-01-01

The work approaches the study of some physical-mechanical and chemical properties of agricultural organic residuals which can be used in the biogas production in Cuba´s plants production, using their co-fermentation. It has also been necessary to collect agricultural biomass, canteen waste, influent and effluents of a biogas plant Nina Bonita) next to Santa Clara city, Cuba, for their later analysis. the investigated biomass samples (sorghum.49V-96, sorghum-132 R, sunflower JE-94, cassava, corn, sweet potato skin, bread, potatoes and peanut skin); as well as the influent and effluents of the investigated biogas plant were analyzed in some laboratories belonging to the Central University of Las Villas. Other analyses were done in the biogas lab at Hohenheim University. The maximum value of specifies methane yield achieved was with the sunflower JE-94 (0.393 m3/kg VS), while the minimum value was reached with the peanut shell (0.095 m3/Kg VS).The main objective of the work consists on determining some of the physical-mechanical and chemical properties like carbon nitrogen ratio (C/N), specific methane production (m3/kg VS), total solid (TS), organic total solid (oTS), alkalinity (pH) and volatile solid (VS) in agricultural organic residuals and canteen waste, which can be used for the production of biogas under co-fermentation with animal manure under Cuban conditions. In order to do this, we developed some experiments to syringes, small and real scale. (author)

Distinctive Correspondence Between Separable Visual Attention Functions and Intrinsic Brain Networks.

Science.gov (United States)

Ruiz-Rizzo, Adriana L; Neitzel, Julia; Müller, Hermann J; Sorg, Christian; Finke, Kathrin

2018-01-01

Separable visual attention functions are assumed to rely on distinct but interacting neural mechanisms. Bundesen's "theory of visual attention" (TVA) allows the mathematical estimation of independent parameters that characterize individuals' visual attentional capacity (i.e., visual processing speed and visual short-term memory storage capacity) and selectivity functions (i.e., top-down control and spatial laterality). However, it is unclear whether these parameters distinctively map onto different brain networks obtained from intrinsic functional connectivity, which organizes slowly fluctuating ongoing brain activity. In our study, 31 demographically homogeneous healthy young participants performed whole- and partial-report tasks and underwent resting-state functional magnetic resonance imaging (rs-fMRI). Report accuracy was modeled using TVA to estimate, individually, the four TVA parameters. Networks encompassing cortical areas relevant for visual attention were derived from independent component analysis of rs-fMRI data: visual, executive control, right and left frontoparietal, and ventral and dorsal attention networks. Two TVA parameters were mapped on particular functional networks. First, participants with higher (vs. lower) visual processing speed showed lower functional connectivity within the ventral attention network. Second, participants with more (vs. less) efficient top-down control showed higher functional connectivity within the dorsal attention network and lower functional connectivity within the visual network. Additionally, higher performance was associated with higher functional connectivity between networks: specifically, between the ventral attention and right frontoparietal networks for visual processing speed, and between the visual and executive control networks for top-down control. The higher inter-network functional connectivity was related to lower intra-network connectivity. These results demonstrate that separable visual attention

Distinctive Correspondence Between Separable Visual Attention Functions and Intrinsic Brain Networks

Science.gov (United States)

Ruiz-Rizzo, Adriana L.; Neitzel, Julia; Müller, Hermann J.; Sorg, Christian; Finke, Kathrin

2018-01-01

Separable visual attention functions are assumed to rely on distinct but interacting neural mechanisms. Bundesen's “theory of visual attention” (TVA) allows the mathematical estimation of independent parameters that characterize individuals' visual attentional capacity (i.e., visual processing speed and visual short-term memory storage capacity) and selectivity functions (i.e., top-down control and spatial laterality). However, it is unclear whether these parameters distinctively map onto different brain networks obtained from intrinsic functional connectivity, which organizes slowly fluctuating ongoing brain activity. In our study, 31 demographically homogeneous healthy young participants performed whole- and partial-report tasks and underwent resting-state functional magnetic resonance imaging (rs-fMRI). Report accuracy was modeled using TVA to estimate, individually, the four TVA parameters. Networks encompassing cortical areas relevant for visual attention were derived from independent component analysis of rs-fMRI data: visual, executive control, right and left frontoparietal, and ventral and dorsal attention networks. Two TVA parameters were mapped on particular functional networks. First, participants with higher (vs. lower) visual processing speed showed lower functional connectivity within the ventral attention network. Second, participants with more (vs. less) efficient top-down control showed higher functional connectivity within the dorsal attention network and lower functional connectivity within the visual network. Additionally, higher performance was associated with higher functional connectivity between networks: specifically, between the ventral attention and right frontoparietal networks for visual processing speed, and between the visual and executive control networks for top-down control. The higher inter-network functional connectivity was related to lower intra-network connectivity. These results demonstrate that separable visual attention

Distinctive Correspondence Between Separable Visual Attention Functions and Intrinsic Brain Networks

Directory of Open Access Journals (Sweden)

Adriana L. Ruiz-Rizzo

2018-03-01

Full Text Available Separable visual attention functions are assumed to rely on distinct but interacting neural mechanisms. Bundesen's “theory of visual attention” (TVA allows the mathematical estimation of independent parameters that characterize individuals' visual attentional capacity (i.e., visual processing speed and visual short-term memory storage capacity and selectivity functions (i.e., top-down control and spatial laterality. However, it is unclear whether these parameters distinctively map onto different brain networks obtained from intrinsic functional connectivity, which organizes slowly fluctuating ongoing brain activity. In our study, 31 demographically homogeneous healthy young participants performed whole- and partial-report tasks and underwent resting-state functional magnetic resonance imaging (rs-fMRI. Report accuracy was modeled using TVA to estimate, individually, the four TVA parameters. Networks encompassing cortical areas relevant for visual attention were derived from independent component analysis of rs-fMRI data: visual, executive control, right and left frontoparietal, and ventral and dorsal attention networks. Two TVA parameters were mapped on particular functional networks. First, participants with higher (vs. lower visual processing speed showed lower functional connectivity within the ventral attention network. Second, participants with more (vs. less efficient top-down control showed higher functional connectivity within the dorsal attention network and lower functional connectivity within the visual network. Additionally, higher performance was associated with higher functional connectivity between networks: specifically, between the ventral attention and right frontoparietal networks for visual processing speed, and between the visual and executive control networks for top-down control. The higher inter-network functional connectivity was related to lower intra-network connectivity. These results demonstrate that separable

New Mechanisms of Mercury Binding to Peat

Science.gov (United States)

Nagy, K. L.; Manceau, A.; Gasper, J. D.; Ryan, J. N.; Aiken, G. R.

2007-12-01

Mercury can be immobilized in the aquatic environment by binding to peat, a solid form of natural organic matter. Binding mechanisms can vary in strength and reversibility, and therefore will control concentrations of bioreactive mercury, may explain rates of mercury methylation, and are important for designing approaches to improve water quality using natural wetlands or engineered phytoremediation schemes. In addition, strong binding between mercury and peat is likely to result in the fixation of mercury that ultimately resides in coal. The mechanisms by which aqueous mercury at low concentrations reacts with both dissolved and solid natural organic matter remain incompletely understood, despite recent efforts. We have identified three distinct binding mechanisms of divalent cationic mercury to solid peats from the Florida Everglades using EXAFS spectroscopic data (FAME beamline, European Synchrotron Radiation Facility (ESRF)) obtained on experimental samples as compared to relevant references including mercury-bearing solids and mercury bound to various organic molecules. The proportions of the three molecular configurations vary with Hg concentration, and two new configurations that involve sulfur ligands occur at Hg concentrations up to about 4000 ppm. The binding mechanism at the lowest experimental Hg concentration (60-80 ppm) elucidates published reports on the inhibition of metacinnabar formation in the presence of Hg-bearing solutions and dissolved natural organic matter, and also, the differences in extent of mercury methylation in distinct areas of the Florida Everglades.

Evolution of Enzymatic Activities in the Enolase Superfamily: Stereochemically Distinct Mechanisms in Two Families of cis,cis-Muconate Lactonizing Enzymes

Energy Technology Data Exchange (ETDEWEB)

Sakai, A.; Fedorov, A; Fedorov, E; Schnoes, A; Glasner, M; Burley, S; Babbitt, P; Almo, S; Gerlt, J

2009-01-01

The mechanistically diverse enolase superfamily is a paradigm for elucidating Nature's strategies for divergent evolution of enzyme function. Each of the different reactions catalyzed by members of the superfamily is initiated by abstraction of the a-proton of a carboxylate substrate that is coordinated to an essential Mg2+. The muconate lactonizing enzyme (MLE) from Pseudomonas putida, a member of a family that catalyzes the syn-cycloisomerization of cis,cis-muconate to (4S)-muconolactone in the e-ketoadipate pathway, has provided critical insights into the structural bases for evolution of function within the superfamily. A second, divergent family of homologous MLEs that catalyzes anti-cycloisomerization has been identified. Structures of members of both families liganded with the common (4S)-muconolactone product (syn, Pseudomonas fluorescens, gi 70731221; anti, Mycobacterium smegmatis, gi 118470554) document that the conserved Lys at the end of the second e-strand in the (e/a)7e-barrel domain serves as the acid catalyst in both reactions. The different stereochemical courses (syn and anti) result from different structural strategies for determining substrate specificity: although the distal carboxylate group of the cis,cis-muconate substrate attacks the same face of the proximal double bond, opposite faces of the resulting enolate anion intermediate are presented to the conserved Lys acid catalyst. The discovery of two families of homologous, but stereochemically distinct, MLEs likely provides an example of 'pseudoconvergent' evolution of the same function from different homologous progenitors within the enolase superfamily, in which different spatial arrangements of active site functional groups and substrate specificity determinants support catalysis of the same reaction.

Evolution of Enzymatic Activities in the Enolase Superfamily: Stereochemically Distinct Mechanisms in Two Families of cis,cis-Muconate Lactonizing Enzymes†

Science.gov (United States)

Sakai, Ayano; Fedorov, Alexander A.; Fedorov, Elena V.; Schnoes, Alexandra M.; Glasner, Margaret E.; Brown, Shoshana; Rutter, Marc E.; Bain, Kevin; Chang, Shawn; Gheyi, Tarun; Sauder, J. Michael; Burley, Stephen K.; Babbitt, Patricia C.; Almo, Steven C.; Gerlt, John A.

2009-01-01

The mechanistically diverse enolase superfamily is a paradigm for elucidating Nature’s strategies for divergent evolution of enzyme function. Each of the different reactions catalyzed by members of the superfamily is initiated by abstraction of the α-proton of a carboxylate substrate that is coordinated to an essential Mg2+. The muconate lactonizing enzyme (MLE) from Pseudomonas putida, a member of a family that catalyzes the syn-cycloisomerization of cis,cis-muconate to (4S)-muconolactone in the β-ketoadipate pathway, has provided critical insights into the structural bases for evolution of function within the superfamily. A second, divergent family of homologues MLEs that catalyzes anti-cycloisomerization has been identified. Structures of members of both families liganded with the common (4S)-muconolactone product (syn, Pseudomonas fluorescens, GI:70731221; anti, Mycobacterium smegmatis, GI:118470554) document that the conserved Lys at the end of the second β-strand in the (β/α)7β-barrel domain serves as the acid catalyst in both reactions. The different stereochemical courses (syn and anti) result from different structural strategies for determining substrate specificity: although the distal carboxylate group of the cis,cis-muconate substrate attacks the same face of the proximal double bond, opposite faces of the resulting enolate anion intermediate are presented to the conserved Lys acid catalyst. The discovery of two families of homologous, but stereochemically distinct, MLEs likely provides an example of “pseudoconvergent” evolution of the same function from different homologous progenitors within the enolase superfamily, in which different spatial arrangements of active site functional groups and substrate specificity determinants support catalysis of the same reaction. PMID:19220063

Mechanisms of proton relay and product release by Class A β-lactamase at ultrahigh resolution

Energy Technology Data Exchange (ETDEWEB)

Lewandowski, Eric M. [Department of Molecular Medicine, University of South Florida College of Medicine, Tampa FL USA; Lethbridge, Kathryn G. [Department of Molecular Medicine, University of South Florida College of Medicine, Tampa FL USA; Sanishvili, Ruslan [GMCA@APS, X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, IL USA; Skiba, Joanna [Department of Organic Chemistry, Faculty of Chemistry, University of Lodz, Poland; Kowalski, Konrad [Department of Organic Chemistry, Faculty of Chemistry, University of Lodz, Poland; Chen, Yu [Department of Molecular Medicine, University of South Florida College of Medicine, Tampa FL USA

2017-11-20

The beta-lactam antibiotics inhibit penicillin-binding proteins (PBPs) by forming a stable, covalent, acyl-enzyme complex. During the evolution from PBPs to Class A beta-lactamases, the beta-lactamases acquired Glu166 to activate a catalytic water and cleave the acyl-enzyme bond. Here we present three product complex crystal structures of CTX-M-14 Class A beta-lactamase with a ruthenocene-conjugated penicillin-a 0.85 angstrom resolution structure of E166A mutant complexed with the penilloate product, a 1.30 angstrom resolution complex structure of the same mutant with the penicilloate product, and a 1.18 angstrom resolution complex structure of S70G mutant with a penicilloate product epimer-shedding light on the catalytic mechanisms and product inhibition of PBPs and Class A beta-lactamases. The E166A-penilloate complex captured the hydrogen bonding network following the protonation of the leaving group and, for the first time, unambiguously show that the ring nitrogen donates a proton to Ser130, which in turn donates a proton to Lys73. These observations indicate that in the absence of Glu166, the equivalent lysine would be neutral in PBPs and therefore capable of serving as the general base to activate the catalytic serine. Together with previous results, this structure suggests a common proton relay network shared by Class A beta-lactamases and PBPs, from the catalytic serine to the lysine, and ultimately to the ring nitrogen. Additionally, the E166A-penicilloate complex reveals previously unseen conformational changes of key catalytic residues during the release of the product, and is the first structure to capture the hydrolyzed product in the presence of an unmutated catalytic serine.

Experimental Study and Computational Simulations of Key Pebble Bed Thermo-mechanics Issues for Design and Safety

Energy Technology Data Exchange (ETDEWEB)

Tokuhiro, Akira; Potirniche, Gabriel; Cogliati, Joshua; Ougouag, Abderrafi

2014-07-08

An experimental and computational study, consisting of modeling and simulation (M&S), of key thermal-mechanical issues affecting the design and safety of pebble-bed (PB) reactors was conducted. The objective was to broaden understanding and experimentally validate thermal-mechanic phenomena of nuclear grade graphite, specifically, spheres in frictional contact as anticipated in the bed under reactor relevant pressures and temperatures. The contact generates graphite dust particulates that can subsequently be transported into the flowing gaseous coolent. Under postulated depressurization transients and with the potential for leaked fission products to be adsorbed onto graphite 'dust', there is the potential for fission products to escape from the primary volume. This is a design safety concern. Furthermore, earlier safety assessment identified the distinct possibility for the dispersed dust to combust in contact with air if sufficient conditions are met. Both of these phenomena were noted as important to design review and containing uncertainty to warrant study. The team designed and conducted two separate effects tests to study and benchmark the potential dust-generation rate, as well as study the conditions under which a dust explosion may occure in a standardized, instrumented explosion chamber.

Distinct Grammars and their Role in Interlanguage Development

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Aparecida de Araújo Oliveira

2016-07-01

Full Text Available The expression of temporality encompasses the concepts of tense and aspect, typically conveyed by lexical and inflectional morphemes that usually vary from language to language. This kind of cross-linguistic distinctions often affects L2 learning. In this paper I discuss the role of the Portuguese grammar in the acquisition of the English present perfect tense by eighteen Brazilian EFL learners. I compared patterns found in interlanguage data to L2 patterns, and, as expected, L1 phonology affected learners’ production of regular past tenses, especially in early interlanguage. As for form-function mappings, besides L2 patterns, learners created two major meaning categories of current relevance, based on persisting / non-persisting situations, which were systematically conveyed by forms that resembled their L1 grammar. Durative events and states (imperfective situations persisting into the present were expressed by present tenses, while all aspectual categories of concluded (perfective situations were encoded by past tenses. Specific adverbials were used in each category

Backward resonance production of pi minus plus proton goes to neutron pi plus pi minus at 8 GeV/c. [Production mechanisms

Energy Technology Data Exchange (ETDEWEB)

Wagner, R.G.

1974-01-01

A study of the interaction ..pi../sup -/p ..-->.. n..pi../sup +/..pi../sup -/ is reported where the neutron was produced fast and forward in the laboratory. The data were obtained using an 8 GeV/c ..pi../sup -/ beam that was focused on a liquid hydrogen target located inside the University of Illinois--Argonne National laboratory streamer chamber. The chamber was triggered on the interaction of a fast, forward neutral hadron in thick plate optical spark chambers. A total of 866 events had an acceptable 3-constraint fit to ..pi../sup -/p ..-->.. n..pi../sup +/..pi../sup -/ and satisfied other selection criteria. The data were characterized by backward production of the final states n rho/sup 0/, nf/sup 0/, and ..delta../sup -/(1232)..pi../sup +/. Differential cross sections and decay angular distributions for these resonant states are presented and the implications for the production mechanisms discussed. 20 references.

FTIR characterization ans chemo-mechanical distinction of reted kenaf fibres

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Emannuel Omenna

2017-12-01

Full Text Available Inadequate information on the binding characteristics of kenaf biomass at the molecular level has adversely affected the modifications of its cellulose-hemicellulose-lignin structure. This study was undertaken to assess the characteristic features and chemo-mechanical properties of kenaf fibres retted under three different media namely: tank, stream and ribbon. Fourier transform infra-red (FTIR spectra analysis as well as the ASTM standard for tensile tests were applied. The results showed that the broad bands occurred at the range of 3312- 3420 cm−1 for all the retted fibres were due to the presence of hydroxyl (–OH group while the peaks were obtained at 1635.76, 1635.34, and 1730.69 cm−1 for stream, tank and ribbon retted fibres respectively. However, tank retted fibres had the most broad band intensity at 3419.78cm-1 while ribbon fibres had the highest absorption peak of 1730.69cm-1 corresponding to C=O stretching of the acetyl group in hemi-cellulose. Stream retted Kenaf fibres had the highest tensile strength followed by the tank retted fibres while ribbon fibres had the least. Furthermore, there was no significant difference between stream and tank retted Kenaf fibres in terms of tensile modulus and this was significantly higher than that of ribbon fibre. The α-cellulose content of stream retted fibres was slightly higher than that of ribbon fibres while tank retted fibres had the least. From the results, tank retted Kenaf fibre was ranked as ‘the best fibre’ with the most intensive broad bands and least in lignin and hemi-cellulose content which were regarded as the impurities, gummy and waxy materials, responsible for an easy deformation of the fibre cellular networks.

A study on measures to reduce production cost of long-running collieries and coal mining mechanization

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-12-01

The reducing coal market has been enforcing the coal industry to make exceptional rationalization and restructuring efforts since the end of the eighties. To the competition from crude oil and natural gas has been added the growing pressure from rising wages and rising production cost as the working get deeper. To improve the competitive position of the remaining 11 coal mines after the rationalization of the industry, studies to improve mining system have been carried out. This report consists of 3 subjects. 1) Designing of the bord and pillar mining method to extract gently inclined seams of the Dogye coal mine. 2) Mechanization of coal cutting by plough. 3) Achievement of the mechanization of coal mining compared to the previous year. (author). 27 refs.

Water deprivation induces appetite and alters metabolic strategy in Notomys alexis: unique mechanisms for water production in the desert.

Science.gov (United States)

Takei, Yoshio; Bartolo, Ray C; Fujihara, Hiroaki; Ueta, Yoichi; Donald, John A

2012-07-07

Like many desert animals, the spinifex hopping mouse, Notomys alexis, can maintain water balance without drinking water. The role of the kidney in producing a small volume of highly concentrated urine has been well-documented, but little is known about the physiological mechanisms underpinning the metabolic production of water to offset obligatory water loss. In Notomys, we found that water deprivation (WD) induced a sustained high food intake that exceeded the pre-deprivation level, which was driven by parallel changes in plasma leptin and ghrelin and the expression of orexigenic and anorectic neuropeptide genes in the hypothalamus; these changed in a direction that would stimulate appetite. As the period of WD was prolonged, body fat disappeared but body mass increased gradually, which was attributed to hepatic glycogen storage. Switching metabolic strategy from lipids to carbohydrates would enhance metabolic water production per oxygen molecule, thus providing a mechanism to minimize respiratory water loss. The changes observed in appetite control and metabolic strategy in Notomys were absent or less prominent in laboratory mice. This study reveals novel mechanisms for appetite regulation and energy metabolism that could be essential for desert rodents to survive in xeric environments.

An Ultrasensitive Mechanism Regulates Influenza Virus-Induced Inflammation.

Directory of Open Access Journals (Sweden)

Jason E Shoemaker

2015-06-01

Full Text Available Influenza viruses present major challenges to public health, evident by the 2009 influenza pandemic. Highly pathogenic influenza virus infections generally coincide with early, high levels of inflammatory cytokines that some studies have suggested may be regulated in a strain-dependent manner. However, a comprehensive characterization of the complex dynamics of the inflammatory response induced by virulent influenza strains is lacking. Here, we applied gene co-expression and nonlinear regression analysis to time-course, microarray data developed from influenza-infected mouse lung to create mathematical models of the host inflammatory response. We found that the dynamics of inflammation-associated gene expression are regulated by an ultrasensitive-like mechanism in which low levels of virus induce minimal gene expression but expression is strongly induced once a threshold virus titer is exceeded. Cytokine assays confirmed that the production of several key inflammatory cytokines, such as interleukin 6 and monocyte chemotactic protein 1, exhibit ultrasensitive behavior. A systematic exploration of the pathways regulating the inflammatory-associated gene response suggests that the molecular origins of this ultrasensitive response mechanism lie within the branch of the Toll-like receptor pathway that regulates STAT1 phosphorylation. This study provides the first evidence of an ultrasensitive mechanism regulating influenza virus-induced inflammation in whole lungs and provides insight into how different virus strains can induce distinct temporal inflammation response profiles. The approach developed here should facilitate the construction of gene regulatory models of other infectious diseases.

Soil nitrate reducing processes drivers, mechanisms for spatial variation, and significance for nitrous oxide production

OpenAIRE

Giles, M.; Morley, N.; Baggs, E.M.; Daniell, T.J.

2012-01-01

The microbial processes of denitrification and dissimilatory nitrate reduction to ammonium\\ud (DNRA) are two important nitrate reducing mechanisms in soil, which are responsible for\\ud the loss of nitrate (NO−\\ud 3 ) and production of the potent greenhouse gas, nitrous oxide (N2O).\\ud A number of factors are known to control these processes, including O2 concentrations and\\ud moisture content, N, C, pH, and the size and community structure of nitrate reducing organisms\\ud responsible for the ...

Coordiantion by using Product Specifications in Product Development

DEFF Research Database (Denmark)

Terkelsen, Søren Bendix

1997-01-01

This paper is based on a case study. It treats the coordination by generating product specifications in product development. This paper contains three very important aspects, which cause a need for coordination, and call attention to the coordination mechanisms. The three aspects are task...... uncertainty, task complexity, and dependencies between activities. If one want to select coordination mechanisms, which improve the performance in product development, it is very important to have a knowledge about these three aspects. In the following the aspects are identified in the literature...

Distinctiveness of Encoding and Memory for Learning Tasks.

Science.gov (United States)

Glover, John A.; And Others

1982-01-01

A distinctiveness of encoding hypothesis, as applied to the facilitative effects that higher order objectives have on readers' prose recall, was evaluated in three experiments. Results suggest that distinctiveness of encoding may offer a theoretical basis for the effects of adjunct aids as well as a guide to their construction. (Author/GK)

Distinct mechanisms underlie adaptation of proximal tubule Na+/H+ exchanger isoform 3 in response to chronic metabolic and respiratory acidosis.

Science.gov (United States)

Silva, Pedro Henrique Imenez; Girardi, Adriana Castello Costa; Neri, Elida Adalgisa; Rebouças, Nancy Amaral

2012-04-01

The Na(+/)H(+) exchanger isoform 3 (NHE3) is essential for HCO(3)(-) reabsorption in renal proximal tubules. The expression and function of NHE3 must adapt to acid-base conditions. The goal of this study was to elucidate the mechanisms responsible for higher proton secretion in proximal tubules during acidosis and to evaluate whether there are differences between metabolic and respiratory acidosis with regard to NHE3 modulation and, if so, to identify the relevant parameters that may trigger these distinct adaptive responses. We achieved metabolic acidosis by lowering HCO(3)(-) concentration in the cell culture medium and respiratory acidosis by increasing CO(2) tension in the incubator chamber. We found that cell-surface NHE3 expression was increased in response to both forms of acidosis. Mild (pH 7.21 ± 0.02) and severe (6.95 ± 0.07) metabolic acidosis increased mRNA levels, at least in part due to up-regulation of transcription, whilst mild (7.11 ± 0.03) and severe (6.86 ± 0.01) respiratory acidosis did not up-regulate NHE3 expression. Analyses of the Nhe3 promoter region suggested that the regulatory elements sensitive to metabolic acidosis are located between -466 and -153 bp, where two consensus binding sites for SP1, a transcription factor up-regulated in metabolic acidosis, were localised. We conclude that metabolic acidosis induces Nhe3 promoter activation, which results in higher mRNA and total protein level. At the plasma membrane surface, NHE3 expression was increased in metabolic and respiratory acidosis alike, suggesting that low pH is responsible for NHE3 displacement to the cell surface.

Staying green postharvest: how three mutations in the Arabidopsis chlorophyll b reductase gene NYC1 delay degreening by distinct mechanisms.

Science.gov (United States)

Jibran, Rubina; Sullivan, Kerry L; Crowhurst, Ross; Erridge, Zoe A; Chagné, David; McLachlan, Andrew R G; Brummell, David A; Dijkwel, Paul P; Hunter, Donald A

2015-11-01

Stresses such as energy deprivation, wounding and water-supply disruption often contribute to rapid deterioration of harvested tissues. To uncover the genetic regulation behind such stresses, a simple assessment system was used to detect senescence mutants in conjunction with two rapid mapping techniques to identify the causal mutations. To demonstrate the power of this approach, immature inflorescences of Arabidopsis plants that contained ethyl methanesulfonate-induced lesions were detached and screened for altered timing of dark-induced senescence. Numerous mutant lines displaying accelerated or delayed timing of senescence relative to wild type were discovered. The underlying mutations in three of these were identified using High Resolution Melting analysis to map to a chromosomal arm followed by a whole-genome sequencing-based mapping method, termed 'Needle in the K-Stack', to identify the causal lesions. All three mutations were single base pair changes and occurred in the same gene, NON-YELLOW COLORING1 (NYC1), a chlorophyll b reductase of the short-chain dehydrogenase/reductase (SDR) superfamily. This was consistent with the mutants preferentially retaining chlorophyll b, although substantial amounts of chlorophyll b were still lost. The single base pair mutations disrupted NYC1 function by three distinct mechanisms, one by producing a termination codon, the second by interfering with correct intron splicing and the third by replacing a highly conserved proline with a non-equivalent serine residue. This non-synonymous amino acid change, which occurred in the NADPH binding domain of NYC1, is the first example of such a mutation in an SDR protein inhibiting a physiological response in plants. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Distinct cardiac transcriptional profiles defining pregnancy and exercise.

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Eunhee Chung

Full Text Available BACKGROUND: Although the hypertrophic responses of the heart to pregnancy and exercise are both considered to be physiological processes, they occur in quite different hormonal and temporal settings. In this study, we have compared the global transcriptional profiles of left ventricular tissues at various time points during the progression of hypertrophy in exercise and pregnancy. METHODOLOGY/PRINCIPAL FINDINGS: The following groups of female mice were analyzed: non-pregnant diestrus cycle sedentary control, mid-pregnant, late-pregnant, and immediate-postpartum, and animals subjected to 7 and 21 days of voluntary wheel running. Hierarchical clustering analysis shows that while mid-pregnancy and both exercise groups share the closest relationship and similar gene ontology categories, late pregnancy and immediate post-partum are quite different with high representation of secreted/extracellular matrix-related genes. Moreover, pathway-oriented ontological analysis shows that metabolism regulated by cytochrome P450 and chemokine pathways are the most significant signaling pathways regulated in late pregnancy and immediate-postpartum, respectively. Finally, increases in expression of components of the proteasome observed in both mid-pregnancy and immediate-postpartum also result in enhanced proteasome activity. Interestingly, the gene expression profiles did not correlate with the degree of cardiac hypertrophy observed in the animal groups, suggesting that distinct pathways are employed to achieve similar amounts of cardiac hypertrophy. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that cardiac adaptation to the later stages of pregnancy is quite distinct from both mid-pregnancy and exercise. Furthermore, it is very dynamic since, by 12 hours post-partum, the heart has already initiated regression of cardiac growth, and 50 genes have changed expression significantly in the immediate-postpartum compared to late-pregnancy. Thus, pregnancy

Intergroup Leadership Across Distinct Subgroups and Identities.

Science.gov (United States)

Rast, David E; Hogg, Michael A; van Knippenberg, Daan

2018-03-01

Resolving intergroup conflict is a significant and often arduous leadership challenge, yet existing theory and research rarely, if ever, discuss or examine this situation. Leaders confront a significant challenge when they provide leadership across deep divisions between distinct subgroups defined by self-contained identities-The challenge is to avoid provoking subgroup identity distinctiveness threat. Drawing on intergroup leadership theory, three studies were conducted to test the core hypothesis that, where identity threat exists, leaders promoting an intergroup relational identity will be better evaluated and are more effective than leaders promoting a collective identity; in the absence of threat, leaders promoting a collective identity will prevail. Studies 1 and 2 ( N = 170; N = 120) supported this general proposition. Study 3 ( N = 136) extended these findings, showing that leaders promoting an intergroup relational identity, but not a collective identity, improved intergroup attitudes when participants experienced an identity distinctiveness threat.

Boldine enhances bile production in rats via osmotic and farnesoid X receptor dependent mechanisms.

Science.gov (United States)

Cermanova, Jolana; Kadova, Zuzana; Zagorova, Marie; Hroch, Milos; Tomsik, Pavel; Nachtigal, Petr; Kudlackova, Zdenka; Pavek, Petr; Dubecka, Michaela; Ceckova, Martina; Staud, Frantisek; Laho, Tomas; Micuda, Stanislav

2015-05-15

Boldine, the major alkaloid from the Chilean Boldo tree, is used in traditional medicine to support bile production, but evidence to support this function is controversial. We analyzed the choleretic potential of boldine, including its molecular background. The acute- and long-term effects of boldine were evaluated in rats either during intravenous infusion or after 28-day oral treatment. Infusion of boldine instantly increased the bile flow 1.4-fold in healthy rats as well as in animals with Mrp2 deficiency or ethinylestradiol induced cholestasis. This effect was not associated with a corresponding increase in bile acid or glutathione biliary excretion, indicating that the effect is not related to stimulation of either bile acid dependent or independent mechanisms of bile formation and points to the osmotic activity of boldine itself. We subsequently analyzed bile production under conditions of changing biliary excretion of boldine after bolus intravenous administration and found strong correlations between both parameters. HPLC analysis showed that bile concentrations of boldine above 10 μM were required for induction of choleresis. Importantly, long-term pretreatment, when the bile collection study was performed 24-h after the last administration of boldine, also accelerated bile formation despite undetectable levels of the compound in bile. The effect paralleled upregulation of the Bsep transporter and increased biliary clearance of its substrates, bile acids. We consequently confirmed the ability of boldine to stimulate the Bsep transcriptional regulator, FXR receptor. In conclusion, our study clarified the mechanisms and circumstances surrounding the choleretic activity of boldine. Copyright © 2015 Elsevier Inc. All rights reserved.

Product architecture development enabling integrated re-design of mechanical products

NARCIS (Netherlands)

Begelinger, R.E.; Post, E.; van Houten, F.J.A.M.; Kals, H.J.J.

1999-01-01

Global competition forces companies to increase their competitive advantage. The design process represents an interesting area to improve the overall business performance. There are two topics involved in improving the design process. The first one is the integration of constraints from the product

The effects of distinctiveness on memory and metamemory for face-name associations.

Science.gov (United States)

Watier, Nicholas; Collin, Charles

2012-01-01

We examined the influence of face and name distinctiveness on memory and metamemory for face-name associations. Four types of monitoring judgements were solicited during encoding and retrieval of face-name pairs that contained distinct or typical faces (Experiment 1) or names (Experiment 2). The beneficial effects of distinctiveness on associative memory were symmetrical between faces and names, such that relative to their typical counterparts, distinct faces enhanced memory for names, and distinct names enhanced memory for faces. These effects were also apparent in metamemory. Estimates of prospective and retrospective memory performance were greater for face-name associations that contained a distinct face or name compared with a typical face or name, regardless of whether the distinct item was a cue or target. Moreover, the predictive validity of prospective monitoring improved with name distinctiveness, whereas the predictive validity of retrospective monitoring improved with facial distinctiveness. Our results indicate that distinctiveness affects not only the strength of the association between a face and a name, but also the ability to monitor that association.

Network analysis reveals distinct clinical syndromes underlying acute mountain sickness.

Directory of Open Access Journals (Sweden)

David P Hall

Full Text Available Acute mountain sickness (AMS is a common problem among visitors at high altitude, and may progress to life-threatening pulmonary and cerebral oedema in a minority of cases. International consensus defines AMS as a constellation of subjective, non-specific symptoms. Specifically, headache, sleep disturbance, fatigue and dizziness are given equal diagnostic weighting. Different pathophysiological mechanisms are now thought to underlie headache and sleep disturbance during acute exposure to high altitude. Hence, these symptoms may not belong together as a single syndrome. Using a novel visual analogue scale (VAS, we sought to undertake a systematic exploration of the symptomatology of AMS using an unbiased, data-driven approach originally designed for analysis of gene expression. Symptom scores were collected from 292 subjects during 1110 subject-days at altitudes between 3650 m and 5200 m on Apex expeditions to Bolivia and Kilimanjaro. Three distinct patterns of symptoms were consistently identified. Although fatigue is a ubiquitous finding, sleep disturbance and headache are each commonly reported without the other. The commonest pattern of symptoms was sleep disturbance and fatigue, with little or no headache. In subjects reporting severe headache, 40% did not report sleep disturbance. Sleep disturbance correlates poorly with other symptoms of AMS (Mean Spearman correlation 0.25. These results challenge the accepted paradigm that AMS is a single disease process and describe at least two distinct syndromes following acute ascent to high altitude. This approach to analysing symptom patterns has potential utility in other clinical syndromes.

Distinct Neural Substrates for Maintaining Locations and Spatial Relations in Working Memory

Directory of Open Access Journals (Sweden)

Kara J Blacker

2016-11-01

Full Text Available Previous work has demonstrated a distinction between maintenance of two types of spatial information in working memory (WM: spatial locations and spatial relations. While a body of work has investigated the neural mechanisms of sensory-based information like spatial locations, little is known about how spatial relations are maintained in WM. In two experiments, we used fMRI to investigate the involvement of early visual cortex in the maintenance of spatial relations in WM. In both experiments, we found less quadrant-specific BOLD activity in visual cortex when a single spatial relation, compared to a single spatial location, was held in WM. Also across both experiments, we found a consistent set of brain regions that were differentially activated during maintenance of locations versus relations. Maintaining a location, compared to a relation, was associated with greater activity in typical spatial WM regions like posterior parietal cortex and prefrontal regions. Whereas maintaining a relation, compared to a location, was associated with greater activity in the parahippocampal gyrus and precuneus/retrosplenial cortex. Further, in Experiment 2 we manipulated WM load and included trials where participants had to maintain three spatial locations or relations. Under this high load condition, the regions sensitive to locations versus relations were somewhat different than under low load. We also identified regions that were sensitive to load specifically for location or relation maintenance, as well as overlapping regions sensitive to load more generally. These results suggest that the neural substrates underlying WM maintenance of spatial locations and relations are distinct from one another and that the neural representations of these distinct types of spatial information change with load.

Formation of a Tunneling Product in the Photorearrangement of o-Nitrobenzaldehyde.

Science.gov (United States)

Gerbig, Dennis; Schreiner, Peter R

2017-08-01

The photochemical rearrangement of o-nitrobenzaldehyde to o-nitrosobenzoic acid, first reported in 1901, has been shown to proceed via a distinct ketene intermediate. In the course of matrix isolation experiments in various host materials at temperatures as low as 3 K, the ketene was re-investigated in its electronic and vibrational ground states. It was shown that hitherto unreported H-tunneling dominates its reactivity, with half-lives of a few minutes. Unexpectedly, the tunneling product is different from o-nitrosobenzoic acid formed in the photoprocess: Once prepared by irradiation, the ketene spontaneously rearranges to an isoxazolone via an intriguing mechanism initiated by H-tunneling. CCSD(T)/cc-pVTZ computations reveal that this isoxazolone is neither thermodynamically nor kinetically favored under the experimental conditions, and that formation of this unique tunneling product constitutes a remarkable and new example of tunneling control. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mechanical Devices Readiness FY04.0402.1

Energy Technology Data Exchange (ETDEWEB)

Bender, Thomas R.

2008-10-10

This Advanced Design and Production Technologies (ADAPT) project funded production process and tooling improvements to meet and sustain rate production for the program mechanism assemblies. Techniques were developed to allow evaluation and rework of sealed mechanisms that will result in prevention of the scrapping of future mechanisms. Future system mechanisms will likely be smaller with tighter tolerance parts that will require improved inspection equipment and techniques. During the latter phase of this project, the ISL (Intent Stronglink) PRT (Product Realization Team) developed designs and manufacturing processes at Sandia and at multiple KCP (Kansas City Plant) vendors, to produce glass ceramic headers to replace the brazed ceramic headers in the ISL. This achievement will result in significant production costs savings (unit cost and product scrap due to leaking headers).

Product Knowledge Modelling and Management

DEFF Research Database (Denmark)

Zhang, Y.; MacCallum, K. J.; Duffy, Alex

1996-01-01

function-oriented design. Both Specific Product Knowledge and Product Domain Knowledge are modelled at two levels, a meta-model and an information-level.Following that, a computer-based scheme to manage the proposed product lknowledge models within a dynamically changing environment is presented.......The term, Product Knowledge is used to refer to two related but distinct concepts; the knowledge of a specific product (Specific Product Knowledge) and the knowledge of a product domain (Product Domain Knowledge). Modelling and managing Product Knowlege is an essential part of carrying out design.......A scheme is presented in this paper to model, i.e. classify, structure and formalise the product knowledge for the purpose of supporting function-oriented design. The product design specification and four types of required attributes of a specific product have been identified to form the Specific Product...

Lung-Derived Mediators Induce Cytokine Production in Downstream Organs via an NF-κB-Dependent Mechanism

Directory of Open Access Journals (Sweden)

E. K. Patterson

2013-01-01

Full Text Available In the setting of acute lung injury, levels of circulating inflammatory mediators have been correlated with adverse outcomes. Previous studies have demonstrated that injured, mechanically ventilated lungs represent the origin of the host inflammatory response; however, mechanisms which perpetuate systemic inflammation remain uncharacterized. We hypothesized that lung-derived mediators generated by mechanical ventilation (MV are amplified by peripheral organs in a “feed forward” mechanism of systemic inflammation. Herein, lung-derived mediators were collected from 129X1/SVJ mice after 2 hours of MV while connected to the isolated perfused mouse lung model setup. Exposure of liver endothelial cells to lung-derived mediators resulted in a significant increase in G-CSF, IL-6, CXCL-1, CXCL-2, and MCP-1 production compared to noncirculated control perfusate media (P<0.05. Furthermore, inhibition of the NF-κB pathway significantly mitigated this response. Changes in gene transcription were confirmed using qPCR for IL-6, CXCL-1, and CXCL-2. Additionally, liver tissue obtained from mice subjected to 2 hours of in vivo MV demonstrated significant increases in hepatic gene transcription of IL-6, CXCL-1, and CXCL-2 compared to nonventilated controls. Collectively, this data demonstrates that lung-derived mediators, generated in the setting of MV, are amplified by downstream organs in a feed forward mechanism of systemic inflammation.

PDB-NMA of a protein homodimer reproduces distinct experimental motility asymmetry

Science.gov (United States)

Tirion, Monique M.; ben-Avraham, Daniel

2018-03-01

We have extended our analytically derived PDB-NMA formulation, Atomic Torsional Modal Analysis or ATMAN (Tirion and ben-Avraham 2015 Phys. Rev. E 91 032712), to include protein dimers using mixed internal and Cartesian coordinates. A test case on a 1.3 {\\mathringA} resolution model of a small homodimer, ActVA-ORF6, consisting of two 112-residue subunits identically folded in a compact 50 {\\mathringA} sphere, reproduces the distinct experimental Debye-Waller motility asymmetry for the two chains, demonstrating that structure sensitively selects vibrational signatures. The vibrational analysis of this PDB entry, together with biochemical and crystallographic data, demonstrates the cooperative nature of the dimeric interaction of the two subunits and suggests a mechanical model for subunit interconversion during the catalytic cycle.

Mechanical properties and structure of Zircaloy attached by UO2+x and fission products

International Nuclear Information System (INIS)

Holub, F.

1987-08-01

The aim of this project was to determine the combined long-term effect of simulated fission products and hyperstoichiometric uranium dioxide on the mechanical properties and structure of Zircaloy. Three groups of fission product elements or compounds were defined: The rare earth oxides CeO 2 , La 2 O 3 , Nd 2 O 3 , Y 2 O 3 ; The metals No, Ru, Ag; The low melting elements Te, Sb and Cd. Each of these groups of fission products was mixed with UO 2+x in proportion related for burnups of 5, 10 and 30%. The simulated fuel mixtures were filled into tubular Zircaloy casings, plugged and welded. These specimens were annealed at 350, 500 and 700 deg. C up to 17,500 hours. The test results indicate different kinds of action of the simulated fuel constituents. Mixtures of rare earth oxides and UO 2+x embrittle Zircaloy drastically at higher temperatures. There exists a mutual intensifying effect of rare earth oxides and UO 2+x . UO 2+x and (Mo + Ru + Ag) and their mixtures act very similar on Zircaloy. The low melting fission products (Te + Sb + Cd) influence the ductility of Zircaloy in an advantageous manner, compared to pure UO 2+x fuel. The layer of zirconium tellurides seems to protect the Zircaloy metal against the embrittling attack of oxygen from UO 2+x . The most important events of tensile tests at 400 deg. C are the high values of the elongation of specimens which are brittled at room temperature. It should guarantee the integrity of fuel elements, which have been attacked chemically by fission products at temperatures of 400 deg. C and higher

Resistive thrust production can be as crucial as added mass mechanisms for inertial undulatory swimmers

Science.gov (United States)

Piñeirua, M.; Godoy-Diana, R.; Thiria, B.

2015-08-01

In this Rapid Communication, we address a crucial point regarding the description of moderate to high Reynolds numbers aquatic swimmers. For decades, swimming animals have been classified in two different families of propulsive mechanisms based on the Reynolds number: the resistive swimmers, using local friction to produce the necessary thrust force for locomotion at low Reynolds number, and the reactive swimmers, lying in the high Reynolds range, and using added mass acceleration (described by perfect fluid theory). However, inertial swimmers are also systems that dissipate energy, due to their finite size, therefore involving strong resistive contributions, even for high Reynolds numbers. Using a complete model for the hydrodynamic forces, involving both reactive and resistive contributions, we revisit here the physical mechanisms responsible for the thrust production of such swimmers. We show, for instance, that the resistive part of the force balance is as crucial as added mass effects in the modeling of the thrust force, especially for elongated species. The conclusions brought by this work may have significant contributions to the understanding of complex swimming mechanisms, especially for the future design of artificial swimmers.

Endogenous ovarian hormones affect mitochondrial efficiency in cerebral endothelium via distinct regulation of PGC-1 isoforms.

Science.gov (United States)

Kemper, Martin F; Zhao, Yuanzi; Duckles, Sue P; Krause, Diana N

2013-01-01

Mitochondria support the energy-intensive functions of brain endothelium but also produce damaging-free radicals that lead to disease. Previously, we found that estrogen treatment protects cerebrovascular mitochondria, increasing capacity for ATP production while decreasing reactive oxygen species (ROS). To determine whether these effects occur specifically in endothelium in vivo and also explore underlying transcriptional mechanisms, we studied freshly isolated brain endothelial preparations from intact and ovariectomized female mice. This preparation reflects physiologic influences of circulating hormones, hemodynamic forces, and cell-cell interactions of the neurovascular unit. Loss of ovarian hormones affected endothelial expression of the key mitochondrial regulator family, peroxisome proliferator-activated receptor γ coactivator 1 (PGC-1), but in a unique way. Ovariectomy increased endothelial PGC-1α mRNA but decreased PGC-1β mRNA. The change in PGC-1β correlated with decreased mRNA for crucial downstream mitochondrial regulators, nuclear respiratory factor 1 and mitochondrial transcription factor A, as well as for ATP synthase and ROS protection enzymes, glutamate-cysteine ligase and manganese superoxide dismutase. Ovariectomy also decreased mitochondrial biogenesis (mitochondrial/nuclear DNA ratio). These results indicate ovarian hormones normally act through a distinctive regulatory pathway involving PGC-1β to support cerebral endothelial mitochondrial content and guide mitochondrial function to favor ATP coupling and ROS protection.

Heavy water: a distinctive and essential component of CANDU

International Nuclear Information System (INIS)

Miller, A.I.; van Alstyne, H.M.

1994-06-01

The exceptional properties of heavy water as a neutron moderator provide one of the distinctive features of CANDU reactors. Although most of the chemical and physical properties of deuterium and protium (mass 1 hydrogen) are appreciably different, the low terrestrial abundance of deuterium makes the separation of heavy water a relatively costly process, and so of considerable importance to the CANDU system. World heavy-water supplies are currently provided by the Girdler-Sulphide process or processes based on ammonia-hydrogen exchange. Due to cost and hazard considerations, new processes will be required for the production of heavy water in and beyond the next decade. Through AECL's development and refinement of wetproofed catalysts for the exchange of hydrogen isotopes between water and hydrogen, a family of new processes is expected to be deployed. Two monothermal processes, CECE (Combined Electrolysis and Catalytic Exchange, using water-to-hydrogen conversion by electrolysis) and CIRCE (Combined Industrially Reformed hydrogen and Catalytic Exchange, based on steam reforming of hydrocarbons), are furthest advanced. Besides its use for heavy-water production, the CECE process is a highly effective technology for heavy-water upgrading and for tritium separation from heavy (or light) water. (author). 10 refs., 1 tab., 7 figs

Distinct effects of rotenone, 1-methyl-4-phenylpyridinium and 6-hydroxydopamine on cellular bioenergetics and cell death.

Directory of Open Access Journals (Sweden)

Samantha Giordano

Full Text Available Parkinson's disease is characterized by dopaminergic neurodegeneration and is associated with mitochondrial dysfunction. The bioenergetic susceptibility of dopaminergic neurons to toxins which induce Parkinson's like syndromes in animal models is then of particular interest. For example, rotenone, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP and its active metabolite 1-methyl-4-phenylpyridinium (MPP(+, and 6-hydroxydopamine (6-OHDA, have been shown to induce dopaminergic cell death in vivo and in vitro. Exposure of animals to these compounds induce a range of responses characteristics of Parkinson's disease, including dopaminergic cell death, and Reactive Oxygen Species (ROS production. Here we test the hypothesis that cellular bioenergetic dysfunction caused by these compounds correlates with induction of cell death in differentiated dopaminergic neuroblastoma SH-SY5Y cells. At increasing doses, rotenone induced significant cell death accompanied with caspase 3 activation. At these concentrations, rotenone had an immediate inhibition of mitochondrial basal oxygen consumption rate (OCR concomitant with a decrease of ATP-linked OCR and reserve capacity, as well as a stimulation of glycolysis. MPP(+ exhibited a different behavior with less pronounced cell death at doses that nearly eliminated basal and ATP-linked OCR. Interestingly, MPP(+, unlike rotenone, stimulated bioenergetic reserve capacity. The effects of 6-OHDA on bioenergetic function was markedly less than the effects of rotenone or MPP(+ at cytotoxic doses, suggesting a mechanism largely independent of bioenergetic dysfunction. These studies suggest that these dopaminergic neurotoxins induce cell death through distinct mechanisms and differential effects on cellular bioenergetics.

Cognitive, cultural, and linguistic sources of a handshape distinction expressing agentivity.

Science.gov (United States)

Brentari, Diane; Di Renzo, Alessio; Keane, Jonathan; Volterra, Virginia

2015-01-01

In this paper the cognitive, cultural, and linguistic bases for a pattern of conventionalization of two types of iconic handshapes are described. Work on sign languages has shown that handling handshapes (H-HSs: those that represent how objects are handled or manipulated) and object handshapes (O-HSs: those that represent the class, size, or shape of objects) express an agentive/non-agentive semantic distinction in many sign languages. H-HSs are used in agentive event descriptions and O-HSs are used in non-agentive event descriptions. In this work, American Sign Language (ASL) and Italian Sign Language (LIS) productions are compared (adults and children) as well as the corresponding groups of gesturers in each country using "silent gesture." While the gesture groups, in general, did not employ an H-HS/O-HS distinction, all participants (signers and gesturers) used iconic handshapes (H-HSs and O-HSs together) more often in agentive than in no-agent event descriptions; moreover, none of the subjects produced an opposite pattern than the expected one (i.e., H-HSs associated with no-agent descriptions and O-HSs associated with agentive ones). These effects are argued to be grounded in cognition. In addition, some individual gesturers were observed to produce the H-HS/O-HS opposition for agentive and non-agentive event descriptions-that is, more Italian than American adult gesturers. This effect is argued to be grounded in culture. Finally, the agentive/non-agentive handshape opposition is confirmed for signers of ASL and LIS, but previously unreported cross-linguistic differences were also found across both adult and child sign groups. It is, therefore, concluded that cognitive, cultural, and linguistic factors contribute to the conventionalization of this distinction of handshape type. Copyright © 2014 Cognitive Science Society, Inc.

The Development of Productivity Practical Management Model at Automotive Mechanical Technology Skill Program in Semarang Vocational Schools, Indonesia

Science.gov (United States)

Hadromi; Rachman, Maman; Soesanto; Kartana, Tri Jaka

2015-01-01

The purpose of this research is to develop automotive Mechanical Technology Skill Program (TMO) in Vocational School. The Research and Development (R&D) object was done in SMK 1, 4 and 7 Semarang, Indonesia. The result was achieved productivity Practical Management Final Model at TMO skill Program in Vocational school named momanticproter.…

Mechanisms of proton relay and product release by Class A β-lactamase at ultrahigh resolution.

Science.gov (United States)

Lewandowski, Eric M; Lethbridge, Kathryn G; Sanishvili, Ruslan; Skiba, Joanna; Kowalski, Konrad; Chen, Yu

2018-01-01

The β-lactam antibiotics inhibit penicillin-binding proteins (PBPs) by forming a stable, covalent, acyl-enzyme complex. During the evolution from PBPs to Class A β-lactamases, the β-lactamases acquired Glu166 to activate a catalytic water and cleave the acyl-enzyme bond. Here we present three product complex crystal structures of CTX-M-14 Class A β-lactamase with a ruthenocene-conjugated penicillin-a 0.85 Å resolution structure of E166A mutant complexed with the penilloate product, a 1.30 Å resolution complex structure of the same mutant with the penicilloate product, and a 1.18 Å resolution complex structure of S70G mutant with a penicilloate product epimer-shedding light on the catalytic mechanisms and product inhibition of PBPs and Class A β-lactamases. The E166A-penilloate complex captured the hydrogen bonding network following the protonation of the leaving group and, for the first time, unambiguously show that the ring nitrogen donates a proton to Ser130, which in turn donates a proton to Lys73. These observations indicate that in the absence of Glu166, the equivalent lysine would be neutral in PBPs and therefore capable of serving as the general base to activate the catalytic serine. Together with previous results, this structure suggests a common proton relay network shared by Class A β-lactamases and PBPs, from the catalytic serine to the lysine, and ultimately to the ring nitrogen. Additionally, the E166A-penicilloate complex reveals previously unseen conformational changes of key catalytic residues during the release of the product, and is the first structure to capture the hydrolyzed product in the presence of an unmutated catalytic serine. Structural data are available in the PDB database under the accession numbers 5TOP, 5TOY, and 5VLE. © 2017 Federation of European Biochemical Societies.

The Hippo pathway controls border cell migration through distinct mechanisms in outer border cells and polar cells of the Drosophila ovary.

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Lin, Tzu-Huai; Yeh, Tsung-Han; Wang, Tsu-Wei; Yu, Jenn-Yah

2014-11-01

The Hippo pathway is a key signaling cascade in controlling organ size. The core components of this pathway are two kinases, Hippo (Hpo) and Warts (Wts), and a transcriptional coactivator, Yorkie (Yki). Yes-associated protein (YAP, a Yki homolog in mammals) promotes epithelial-mesenchymal transition and cell migration in vitro. Here, we use border cells in the Drosophila ovary as a model to study Hippo pathway functions in cell migration in vivo. During oogenesis, polar cells secrete Unpaired (Upd), which activates JAK/STAT signaling of neighboring cells and specifies them into outer border cells. The outer border cells form a cluster with polar cells and undergo migration. We find that hpo and wts are required for migration of the border cell cluster. In outer border cells, overexpression of hpo disrupts polarization of the actin cytoskeleton and attenuates migration. In polar cells, knockdown of hpo and wts or overexpression of yki impairs border cell induction and disrupts migration. These manipulations in polar cells reduce JAK/STAT activity in outer border cells. Expression of upd-lacZ is increased and decreased in yki and hpo mutant polar cells, respectively. Furthermore, forced expression of upd in polar cells rescues defects of border cell induction and migration caused by wts knockdown. These results suggest that Yki negatively regulates border cell induction by inhibiting JAK/STAT signaling. Together, our data elucidate two distinct mechanisms of the Hippo pathway in controlling border cell migration: (1) in outer border cells, it regulates polarized distribution of the actin cytoskeleton; (2) in polar cells, it regulates upd expression to control border cell induction and migration. Copyright © 2014 by the Genetics Society of America.

‘It’s Something Posh People Do’: Digital Distinction in Young People’s Cross-Media News Engagement

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Jannie Møller Hartley

2018-05-01

Full Text Available In this article, I analyse digital distinction mechanisms in young people’s cross media engagement with news. Using a combination of open online diaries and qualitative interviews with young Danes aged 15 to 18 who differ in social background and education, and with Bourdieu’s field theory as an analytical framework, the article investigates how cultural capital (CC operates in specific tastes and distastes for news genres, platforms and providers. The article argues that distinction mechanism not only works on the level of news providers and news genres but also on the level of engagement practices—the ways in which people enact and describe their own news engagement practices. Among those rich in CC, physical, analogue objects in the form of newspapers and physical conversations about news are seen as ‘better’ that digital ones, resulting in a feeling of guilt when they mostly engage with news on social media. Secondly, young people with lower CC discard legacy news, which they see as elitist and irrelevant. Thirdly, those rich in CC are media and news genre savvy in the sense that it makes them able to critically evaluate the news they engage with across platforms and sites.

Dynamic Changes in Amygdala Psychophysiological Connectivity Reveal Distinct Neural Networks for Facial Expressions of Basic Emotions.

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Diano, Matteo; Tamietto, Marco; Celeghin, Alessia; Weiskrantz, Lawrence; Tatu, Mona-Karina; Bagnis, Arianna; Duca, Sergio; Geminiani, Giuliano; Cauda, Franco; Costa, Tommaso

2017-03-27

The quest to characterize the neural signature distinctive of different basic emotions has recently come under renewed scrutiny. Here we investigated whether facial expressions of different basic emotions modulate the functional connectivity of the amygdala with the rest of the brain. To this end, we presented seventeen healthy participants (8 females) with facial expressions of anger, disgust, fear, happiness, sadness and emotional neutrality and analyzed amygdala's psychophysiological interaction (PPI). In fact, PPI can reveal how inter-regional amygdala communications change dynamically depending on perception of various emotional expressions to recruit different brain networks, compared to the functional interactions it entertains during perception of neutral expressions. We found that for each emotion the amygdala recruited a distinctive and spatially distributed set of structures to interact with. These changes in amygdala connectional patters characterize the dynamic signature prototypical of individual emotion processing, and seemingly represent a neural mechanism that serves to implement the distinctive influence that each emotion exerts on perceptual, cognitive, and motor responses. Besides these differences, all emotions enhanced amygdala functional integration with premotor cortices compared to neutral faces. The present findings thus concur to reconceptualise the structure-function relation between brain-emotion from the traditional one-to-one mapping toward a network-based and dynamic perspective.

Regulation of Caenorhabditis elegans vitellogenesis by DAF-2/IIS through separable transcriptional and posttranscriptional mechanisms.

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DePina, Ana S; Iser, Wendy B; Park, Sung-Soo; Maudsley, Stuart; Wilson, Mark A; Wolkow, Catherine A

2011-07-12

Evolutionary theories of aging propose that longevity evolves as a competition between reproduction and somatic maintenance for a finite pool of resources. Reproduction is thought to shorten lifespan by depleting resources from processes promoting somatic maintenance. Maternal yolk production, vitellogenesis, represents a significant maternal cost for reproduction and is suppressed under genetic and environmental conditions that extend lifespan. However, little is known about the pathways regulating vitellogenesis in response to prolongevity cues. In order to identify mechanisms that suppress vitellogenesis under prolongevity conditions, we studied factors regulating vitellogenesis in C. elegans nematodes. In C. elegans, vitellogenesis is depressed in the absence of insulin-like signaling (IIS). We found that the C. elegans daf-2/IIS pathway regulates vitellogenesis through two mechanisms. vit-2 transcript levels in daf-2 mutants were indirectly regulated through a germline-dependent signal, and could be rescued by introduction of daf-2(+) sperm. However, yolk protein (YP) levels in daf-2 mutants were also regulated by germline-independent posttranscriptional mechanisms. C. elegans vitellogenesis is regulated transcriptionally and posttranscriptionally in response to environmental and reproductive cues. The daf-2 pathway suppressed vitellogenesis through transcriptional mechanisms reflecting reproductive phenotypes, as well as distinct posttranscriptional mechanisms. This study reveals that pleiotropic effects of IIS pathway mutations can converge on a common downstream target, vitellogenesis, as a mechanism to modulate longevity.

Regulation of Caenorhabditis elegans vitellogenesis by DAF-2/IIS through separable transcriptional and posttranscriptional mechanisms

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Wilson Mark A

2011-07-01

Full Text Available Abstract Background Evolutionary theories of aging propose that longevity evolves as a competition between reproduction and somatic maintenance for a finite pool of resources. Reproduction is thought to shorten lifespan by depleting resources from processes promoting somatic maintenance. Maternal yolk production, vitellogenesis, represents a significant maternal cost for reproduction and is suppressed under genetic and environmental conditions that extend lifespan. However, little is known about the pathways regulating vitellogenesis in response to prolongevity cues. Results In order to identify mechanisms that suppress vitellogenesis under prolongevity conditions, we studied factors regulating vitellogenesis in C. elegans nematodes. In C. elegans, vitellogenesis is depressed in the absence of insulin-like signaling (IIS. We found that the C. elegans daf-2/IIS pathway regulates vitellogenesis through two mechanisms. vit-2 transcript levels in daf-2 mutants were indirectly regulated through a germline-dependent signal, and could be rescued by introduction of daf-2(+ sperm. However, yolk protein (YP levels in daf-2 mutants were also regulated by germline-independent posttranscriptional mechanisms. Conclusions C. elegans vitellogenesis is regulated transcriptionally and posttranscriptionally in response to environmental and reproductive cues. The daf-2 pathway suppressed vitellogenesis through transcriptional mechanisms reflecting reproductive phenotypes, as well as distinct posttranscriptional mechanisms. This study reveals that pleiotropic effects of IIS pathway mutations can converge on a common downstream target, vitellogenesis, as a mechanism to modulate longevity.

Fracture Mechanics Analyses of Reinforced Carbon-Carbon Wing-Leading-Edge Panels

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Raju, Ivatury S.; Phillips, Dawn R.; Knight, Norman F., Jr.; Song, Kyongchan

2010-01-01

Fracture mechanics analyses of subsurface defects within the joggle regions of the Space Shuttle wing-leading-edge RCC panels are performed. A 2D plane strain idealized joggle finite element model is developed to study the fracture behavior of the panels for three distinct loading conditions - lift-off and ascent, on-orbit, and entry. For lift-off and ascent, an estimated bounding aerodynamic pressure load is used for the analyses, while for on-orbit and entry, thermo-mechanical analyses are performed using the extreme cold and hot temperatures experienced by the panels. In addition, a best estimate for the material stress-free temperature is used in the thermo-mechanical analyses. In the finite element models, the substrate and coating are modeled separately as two distinct materials. Subsurface defects are introduced at the coating-substrate interface and within the substrate. The objective of the fracture mechanics analyses is to evaluate the defect driving forces, which are characterized by the strain energy release rates, and determine if defects can become unstable for each of the loading conditions.

Mechanical rebar splicing

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Milosavljević Branko

2014-01-01

Full Text Available Different mechanical rebar splicing systems are presented, and design situations where mechanical splicing has advantage over reinforcement splicing by overlapping and welding are defined in this paper. New international standards for testing and proof of systems for mechanical rebar splicing quality are considered. Mechanical splicing system for rebar and bolt connection, usable in steel and reinforced concrete structural elements connections, is presented in this paper. There are only few examples of mechanical rebar splicing in our country. The most significant one - the pylon and beam connection at Ada Bridge in Belgrade is presented in the paper. Intensive development of production and use of mechanical rebar splicing systems, research in this area, as well as the publication of international standards prescribing requirements for quality and procedures for proof of quality, represent very good base for development of the corresponding technical norms in Serbia. The legislation in this area would quicken proof of quality procedures, attest and approval issuing for individual products, leading to wider use of this system in all situations where it is in advantage over the classical reinforcement splicing.

Steroidal androgens and nonsteroidal, tissue-selective androgen receptor modulator, S-22, regulate androgen receptor function through distinct genomic and nongenomic signaling pathways.

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Narayanan, Ramesh; Coss, Christopher C; Yepuru, Muralimohan; Kearbey, Jeffrey D; Miller, Duane D; Dalton, James T

2008-11-01

Androgen receptor (AR) ligands are important for the development and function of several tissues and organs. However, the poor oral bioavailability, pharmacokinetic properties, and receptor cross-reactivity of testosterone, coupled with side effects, place limits on its clinical use. Selective AR modulators (SARMs) elicit anabolic effects in muscle and bone, sparing reproductive organs like the prostate. However, molecular mechanisms underlying the tissue selectivity remain ambiguous. We performed a variety of in vitro studies to compare and define the molecular mechanisms of an aryl propionamide SARM, S-22, as compared with dihydrotestosterone (DHT). Studies indicated that S-22 increased levator ani muscle weight but decreased the size of prostate in rats. Analysis of the upstream intracellular signaling events indicated that S-22 and DHT mediated their actions through distinct pathways. Modulation of these pathways altered the recruitment of AR and its cofactors to the PSA enhancer in a ligand-dependent fashion. In addition, S-22 induced Xenopus laevis oocyte maturation and rapid phosphorylation of several kinases, through pathways distinct from steroids. These studies reveal novel differences in the molecular mechanisms by which S-22, a nonsteroidal SARM, and DHT mediate their pharmacological effects.

Early Flowering as a Drought Escape Mechanism in Plants: How Can It Aid Wheat Production?

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Yuri Shavrukov

2017-11-01

Full Text Available Drought escape (DE is a classical adaptive mechanism which involves rapid plant development to enable the completion of the full life-cycle prior to a coming drought event. This strategy is widely used in populations of native plants, and is also applicable to cereal crops such as wheat. Early flowering time and a shorter vegetative phase can be very important for wheat production in conditions of terminal drought since this can minimize exposure to dehydration during the sensitive flowering and post-anthesis grain filling periods. A gradual shift toward early flowering has been observed over the last century of wheat breeding in countries with a Mediterranean-type climate and frequent terminal drought. This trend is predicted to continue for wheat production in the coming years in response to global climate warming. The advantage of early flowering wheat is apparent under conditions of impending terminal drought, and modern varieties are significantly more productive due to minimization of the risk associated with drought stress. Under favorable conditions, a short vegetative phase can result in reduced plant biomass due to the reduction in time available for photosynthetic production and seed nutrient accumulation. However, high yield potential has been reported for the development of both shallow and deep roots, representing plasticity in response to drought in combination with the early flowering trait. Wheat productivity can be high both in well-watered and drought-affected field trials, where an efficient strategy of DE was associated with quick growth, yield potential and water use efficiency. Therefore, early flowering provides a promising strategy for the production of advanced drought-adapted wheat cultivars.