Assessing the stability of thematic and taxonomic preferences across explicit and implicit measures

Assessments of similarity between objects has shown to draw upon both taxonomic and thematic properties. While cross-task preferences have been demonstrated (Mirman & Graziano, 2012), the current experiment aimed to examine the reliability of such preferences across an extended range of explicit and implicit measures of similarity. In a within-subjects design, 50 participants completed three established measures assessing preferences for taxonomic or thematic relations; a free sort task, a triad task and the Visual World Paradigm, with a further implicit measure developed based upon the single category Implicit Association Task. Preferences were calculated on the basis of choices made on the sorting and triad task, competitor viewing time on the VWP, and response time on the IAT. Across all measures, consistent preferences were not found. Furthermore, no significant correlations were found between the magnitude of preferences for the four measures including no correlations between the two explicit or the two implicit measures. In contrast to previous research demonstrating reliable cross-task preferences, performance on the tasks used here argue against stable individual differences in taxonomic and thematic processing and suggest that, for most people, the use of each processing pathway is flexible and determined by both context and goals.Non peer reviewe

Redox regulation of muscle adaptations to contractile activity and aging

Jackson MJ. Redox regulation of muscle adaptations to contractile activity an

In vitro susceptibility of thioredoxins and glutathione to redox modification and aging-related changes in skeletal muscle

AbstractThioredoxins (Trx's) regulate redox signaling and are localized to various cellular compartments. Specific redox-regulated pathways for adaptation of skeletal muscle to contractions are attenuated during aging, but little is known about the roles of Trx's in regulating these pathways. This study investigated the susceptibility of Trx1 and Trx2 in skeletal muscle to oxidation and reduction in vitro and the effects of aging and contractions on Trx1, Trx2, and thioredoxin reductase (TrxR) 1 and 2 contents and nuclear and cytosolic Trx1 and mitochondrial Trx2 redox potentials in vivo. The proportions of cytosolic and nuclear Trx1 and mitochondrial Trx2 in the oxidized or reduced forms were analyzed using redox Western blotting. In myotubes, the mean redox potentials were nuclear Trx1, −251mV; cytosolic Trx1, −242mV; mitochondrial Trx2, −346mV, data supporting the occurrence of differing redox potentials between cell compartments. Exogenous treatment of myoblasts and myotubes with hydrogen peroxide or dithiothreitol modified glutathione redox status and nuclear and cytosolic Trx1, but mitochondrial Trx2 was unchanged. Tibialis anterior muscles from young and old mice were exposed to isometric muscle contractions in vivo. Aging increased muscle contents of Trx1, Trx2, and TrxR2, but neither aging nor endogenous ROS generated during contractions modified Trx redox potentials, although oxidation of glutathione and other thiols occurred. We conclude that glutathione redox couples in skeletal muscle are more susceptible to oxidation than Trx and that Trx proteins are upregulated during aging, but do not appear to modulate redox-regulated adaptations to contractions that fail during aging

Effect of aging in functional redox state of single isolated skeletal muscle fibres

[EN] Skeletal muscle constantly produces reactive oxygen species (ROS). During contractile activity ROS are generated in skeletal muscle fibres. There is considerable support for an involvement of ROS in the process of aging. Several studies indicate that adaptive responses of skeletal muscle that are activated and regulated by ROS are disrupted during aging. The aim of this study was to monitor, in real time, intracellular ROS production in single skeletal muscle fibres from old and young mice and study the effect of contractile activity in these cells. Following evaluate and correlate the potential changes in intracellular ROS production with glutathione redox state and antioxidant enzymatic activities in muscle. Single skeletal muscle fibres were isolated from the Flexor Digitorus Brevis muscle from young (2-4 monthold) and old (26-28 month-old) C57BL/6 mice. Fibres were loaded with DCFH-DA, a fluorophore probe that allows the quantification of intracellular ROS generation by fluorescence microscopy imaging. Contractile activity was induced in fibres by electrical stimulation. Glutathione redox state and activity of antioxidant enzymes were analysed in gastrocnemious muscle. Intracellular basal level of ROS was higher in fibres from old mice. Contractile activity induced increase of ROS generation in fibres from young mice. However, this response was attenuated in fibres from old mice. Glutathione redox state was significant different, in favour of oxidized glutathione, in muscles from old mice. Glutathione peroxidase and catalase activities were significantly augmented in muscles from old mice. In conclusion, the process of aging modifies the basal redox status in skeletal muscle fibres in favour of oxidation and induces adaptation mechanisms of antioxidant defences. These are not able to neutralize the increase of basal oxidation, but they might lead to the attenuation of ROS produced by contractile activity observed in fibres from old mice

Are there functional consequences of a reduction in selenium intake in UK subjects?

Dietary Se levels in the UK have fallen over the last 20 years and recent surveys indicate that average Se intakes are 30-40 microg/d, which is well below the current UK reference nutrient intake for adult men (75 microg/d) or women (60 microg/d). Functional consequences of this decline have not been recognised, although epidemiological data suggest it may contribute to increased risk of infections and incidence of some cancers. Previous data have indicated that biochemical changes in Se-dependent proteins occur in otherwise healthy UK subjects given small Se supplements. The current studies have focused on the effect of small Se supplements on the immune response since there is evidence of specific interactions between Se intake and viral replication, and since the potential anti-cancer effects of Se may be mediated by non-antioxidant effects of Se such as changes in immune function. Data indicate that subjects given small Se supplements (50 or 100 microg Se/d) have changes in the activity of Se-dependent enzymes and evidence of improved immune function and clearance of an administered live attenuated virus in the form of poliovirus vaccine. Responses of individual subjects to Se supplements are variable, and current work is evaluating potential explanations for this variability, including genetic variability and pre-existing Se status

Biogas Production Optimization from Palm Oil Mill Effluent: Experiments with Anaerobic Reactor

The research domain of this work is the implementation of waste-to-energy [WtE] strategy for achieving sustainability in renewable energy supply and environment. This paper aims to present a research conducted on biogas production performance of anaerobic digestion process of palm oil mill effluent (POME). This research attempts to address the problem relating to poor biogas production performance of anaerobic digester experienced by industries with POME. Various published papers have suggested that the performance of the currently available continuous stirred-tank reactor (CSTR) based anaerobic reactor is significantly poor and not technically and financially feasible to use. A two-stage CSTR has been used with carbon-to-nitrogen (C/N) enriched inoculum at different pH for the POME digestion. The anaerobic reactor was operated at temperature 35 ℃ with various range of inputs. The Design Expert software is used to determine the range and levels of inputs and to determine the number of experimental runs with different combinations of inputs factors. The findings of this research demonstrate that the optimum biogas production was achieved at significant (p-value<0.05) level of organic materials utilization (R2=62.26%) in digestion process at organic loading rate (OLR) of 5 g.VSS/L.d, C/N of 30.5, and pH of 6.6. This study concludes that the biogas production performance of CSTR could be improved by using optimum level of C/N and OLR based POME substrate. The findings of this research would be useful in palm oil mills for optimizing biogas production from POME as WtE. The novelty of this research is the use of C/N enriched inoculum (11<C/N<40) prepared from banana peel in the POME substrate for producing biogas

Design, Testing And Commissioning Of A Synchronous Motor-Gear-Axial Compressor.

LecturePg. 97-112This paper presents the design features involved in providing two air compressor trains at high efficiency. Testing and commissioning data are also presented, including specific electrical requirements; foundation and assembly features; grade maintained air filter designs at 0.5 in. water drop; torsional features not using soft elastomeric couplings; bearing designs for motor, gear and compressors; and test and commissioning data. The test and commissioning data include torsional data, alignment heat rise data, torsional-lateral interaction on run-up, quadrant inlet vane surge tests with flow and vibration responses, eccentricity plots of journals in bearing, transient responses through criticals, and correlations of predicted vs. actual rotor dynamics responses

Redox proteomic analysis of the gastrocnemius muscle from adult and old mice.

The data provides information in support of the research article, "Differential Cysteine Labeling and Global Label-Free Proteomics Reveals an Altered Metabolic State in Skeletal Muscle Aging", Journal of Proteome Research, 2014, 13 (11), 2008-21 [1]. Raw data is available from ProteomeXchange [2] with identifier PDX001054. The proteome of gastrocnemius muscle from adult and old mice was analyzed by global label-free proteomics and the relative quantification of specific reduced and reversibly oxidized Cysteine (Cys) residues was performed using Skyline [3]. Briefly, reduced Cysteine (Cys) containing peptides was alkylated using N-ethylmalemide (d0-NEM). Samples were desalted and reversibly oxidized Cys residues were reduced using tris(2-carboxyethyl)phosphine (TCEP) and the newly formed reduced Cys residues were labeled with heavy NEM( d5-NEM). Label-free analysis of the global proteome of adult (n=5) and old (n=4) gastrocnemius muscles was performed using Peaks7™ mass spectrometry data analysis software [4]. Relative quantification of Cys containing peptides that were identified as reduced (d(0) NEM labeled) and reversibly oxidized d(5)-NEM labeled was performed using the intensity of their precursor ions in Skyline. Results indicate that muscles from old mice show reduced redox flexibility particularly in proteins involved in the generation of precursor metabolites and energy metabolism, indicating a loss in the flexibility of the redox energy response