Roger Thornton Dean

Batch-to-batch variation of chelex-100 confounds metal-catalysed oxidation. Leaching of inhibitory compounds from a batch of chelex-100 and their removal by a pre-washing procedure

Publisher: Informa UK Limited

Date: 1995

DOI: 10.3109/10715769509065274

Abstract: Removal of adventitious redox-active metals from buffers by treatment with Chelex resin is a widely used procedure in free radical research. Use of a new batch of Chelex-100 resin in our laboratory coincided with a sudden inability to oxidise low-density lipoprotein with copper. We found that copper-mediated oxidation of ascorbate in water treated with the same batch of Chelex was inhibited when compared with untreated water and water treated with a different batch of the resin. Washing the Chelex removed the inhibitory effect suggesting that material was leaching from the resin. The washing procedure for Chelex-100 described is simple and can be scaled up. Oxidation of ascorbate with low concentrations of copper can be used to test the quality of batches of the resin.

AMMRI: a computational assessment tool for music novices’ replication and improvisation tasks

Publisher: Informa UK Limited

Date: 26-10-2023

DOI: 10.1080/09298215.2023.2270973

Low density lipoprotein of synovial fluid in inflammatory joint disease is mildly oxidized

Publisher: Wiley

Date: 11-1998

DOI: 10.1007/S11745-998-0313-8

Abstract: Oxidatively modified low density lipoprotein (LDL) has many biological activities which could contribute to the pathology of the atherosclerotic lesion. Because atherosclerosis has an inflammatory component, there has been much interest in the extent to which LDL could be oxidatively modified in vivo by inflammation. The present study examined LDL present in an accessible inflammatory site, the inflamed synovial joint, for evidence of compositional change and oxidative modification. LDL was isolated from knee joint synovial fluid (SF) from subjects with inflammatory arthropathies and also from matched plasma s les. SF and plasma LDL had similar free cholesterol and alpha-tocopherol content, but SF LDL had a lower content of esterified cholesterol. On electrophoresis, SF LDL was slightly more electronegative than LDL from matched plasma s les, but the changes were much less than those resulting from Cu2+-treatment of LDL. Oxidized cholesterol was not detected in any s les, but cholesterol ester hydroperoxide levels were greater in SF than in plasma LDL. When s les from three subjects were incubated with macrophages, the SF LDL did not cause significant loading of the cells with cholesterol or cholesterol esters, in contrast to the situation with acetylated LDL. Overall, the SF LDL displayed evidence of slightly increased oxidation by comparison with matched plasma s les. Despite their isolation from an environment with active inflammation, changes were modest compared with those resulting from Cu2+ treatment. Thus, extensive LDL oxidation is not a necessary correlate of location in a chronic inflammatory site, even though it is characteristic of atherosclerotic lesions.

Memory for melodies in unfamiliar tuning systems: Investigating effects of recency and number of intervening items

Publisher: SAGE Publications

Date: 2018

DOI: 10.1177/1747021817734978

Abstract: In a continuous recognition paradigm, most stimuli elicit superior recognition performance when the item to be recognized is the most recent stimulus (a recency-in-memory effect). Furthermore, increasing the number of intervening items cumulatively disrupts memory in most domains. Memory for melodies composed in familiar tuning systems also shows superior recognition for the most recent melody, but no disruptive effects from the number of intervening melodies. A possible explanation has been offered in a novel regenerative multiple representations (RMR) conjecture. The RMR assumes that prior knowledge informs perception and perception influences memory representations. It postulates that melodies are perceived, thus also represented, simultaneously as integrated entities and also as their components (such as pitches, pitch intervals, short phrases and rhythm). Multiple representations of the melody components and melody as a whole can restore one another, thus providing resilience against disruptive effects from intervening items. The conjecture predicts that melodies in an unfamiliar tuning system are not perceived as integrated melodies and should (a) disrupt recency-in-memory advantages and (b) facilitate disruptive effects from the number of intervening items. We test these two predictions in three experiments. Experiments 1 and 2 show that no recency-in-memory effects emerge for melodies in an unfamiliar tuning system. In Experiment 3, disruptive effects occurred as the number of intervening items and unfamiliarity of the stimuli increased. Overall, results are coherent with the predictions of the RMR conjecture. Further investigation of the conjecture’s predictions may lead to greater understanding of the fundamental relationships between memory, perception and behavior.

Author index

Publisher: Wiley

Date: 08-2003

DOI: 10.1046/J.1432-1033.2003.03742.X

Abstract: Patients with diabetes mellitus suffer from an increased incidence of complications including cardiovascular disease and cataracts the mechanisms responsible for this are not fully understood. One characteristic of such complications is an accumulation of advanced glycation end-products formed by the adduction of glucose or species derived from glucose, such as low-molecular mass aldehydes, to proteins. These reactions can be nonoxidative (glycation) or oxidative (glycoxidation) and result in the conversion of low-density lipoproteins (LDL) to a form that is recognized by the scavenger receptors of macrophages. This results in the accumulation of cholesterol and cholesteryl esters within macrophages and the formation of foam cells, a hallmark of atherosclerosis. The nature of the LDL modifications required for cellular recognition and unregulated uptake are poorly understood. We have therefore examined the nature, time course, and extent of LDL modifications induced by glucose and two aldehydes, methylglyoxal and glycolaldehyde. It has been shown that these agents modify Arg, Lys and Trp residues of the apoB protein of LDL, with the extent of modification induced by the two aldehydes being more rapid than with glucose. These processes are rapid and unaffected by low concentrations of copper ions. In contrast, lipid and protein oxidation are slow processes and occur to a limited extent in the absence of added copper ions. No evidence was obtained for the stimulation of lipid or protein oxidation by glucose or methylglyoxal in the presence of copper ions, whereas glycolaldehyde stimulated such reactions to a modest extent. These results suggest that the earliest significant events in this system are metal ion-independent glycation (modification) of the protein component of LDL, whilst oxidative events (glycoxidation or direct oxidation of lipid or proteins) only occur to any significant extent at later time points. This 'carbonyl-stress' may facilitate the formation of foam cells and the vascular complications of diabetes.

Translational incorporation of L‐3,4‐dihydroxyphenylalanine into proteins

Publisher: Wiley

Date: 06-2005

DOI: 10.1111/J.1742-4658.2005.04735.X

Abstract: An Escherichia coli cell-free transcription/translation system was used to explore the high-level incorporation of L-3,4-dihydroxyphenylalanine (DOPA) into proteins by replacing tyrosine with DOPA in the reaction mixtures. ESI-MS showed specific incorporation of DOPA in place of tyrosine. More than 90% DOPA incorporation at each tyrosine site was achieved, allowing the recording of clean 15N-HSQC NMR spectra. A redox-staining method specific for DOPA was shown to provide a sensitive and generally applicable method for assessing the cell-free production of proteins. Of four proteins produced in soluble form in the presence of tyrosine, two resulted in insoluble aggregates in the presence of high levels of DOPA. DOPA has been found in human proteins, often in association with various disease states that implicate protein aggregation and/or misfolding. Our results suggest that misfolded and aggregated proteins may result, in principle, from ribosome-mediated misincorporation of intracellular DOPA accumulated due to oxidative stress. High-yield cell-free protein expression systems are uniquely suited to obtain rapid information on solubility and aggregation of nascent polypeptide chains.

Inactivation of cellular enzymes by carbonyls and protein-bound glycation/glycoxidation products

Publisher: Elsevier BV

Date: 07-2002

DOI: 10.1016/S0003-9861(02)00222-9

Abstract: Diabetic plasma contains elevated levels of glucose and various low-molecular-weight carbonyl compounds derived from the metabolism of glucose and related materials. These compounds react with protein side chains (Arg, Lys, Cys, and His) to give glycated materials and advanced glycation end products. In this study, we have examined the effect of glucose and carbonyl compounds (methylglyoxal, glyoxal, glycolaldehyde, and hydroxyacetone), and glycation products arising from reaction of these materials with model proteins, on the activity of three key cellular enzymes: glyceraldehyde-3-phosphate dehydrogenase (GAPDH), glutathione reductase, and lactate dehydrogenase, both in isolation and in cell lysates. In contrast to glucose (1M, both fresh and aged for 8 weeks), which had no effect, marked inhibition of all three enzymes was observed with methylglyoxal and glyoxal. GAPDH was also inhibited by glycolaldehyde and hydroxyacetone. Incubation of these enzymes with proteins that had been preglycated with methylglyoxal, but not glucose, also resulted in significant time- and concentration-dependent inhibition with both isolated enzymes and cell lysates. This inhibition was not metal ion, oxygen, superoxide dismutase, or catalase dependent, suggesting that inhibition is not radical mediated. These effects are suggested to be due to direct adduction of the free- or protein-bound carbonyls with the target enzyme. Such an interpretation is supported by the detection of the loss of thiol groups on GAPDH and the detection of cross-linked materials on protein gels. Though direct comparison of the extent of inhibition induced by free versus protein-bound carbonyls was not possible, the significantly higher concentrations of the latter materials over the former in diabetic plasma and cells lead us to suggest that alterations in the activity of key cellular enzymes induced by glycated proteins may play a significant role in the development of diabetic complications.

Evidence that DOPA-derivatives are generated after L-DOPA incorporation into proteins by mammalian cells

Publisher: Informa UK Limited

Date: 13-08-2009

DOI: 10.1080/00218460902996747

Apolipoprotein J (clusterin) induces cholesterol export from macrophage-foam cells: a potential anti-atherogenic function?

Publisher: Portland Press Ltd.

Date: 04-1998

DOI: 10.1042/BJ3310231

Abstract: Apolipoprotein J (apo J) is a secreted glycoprotein of which the exact function remains a matter for speculation. Apo J has been implicated in such erse processes as sperm maturation, regulation of complement activation, programmed cell death, tissue remodelling and lipid transport. In this study a possible role for apo J in lipid transport was explored. Mouse peritoneal macrophages were incubated with acetylated low-density lipoprotein (AcLDL) to produce foam cells containing cholesterol and cholesteryl esters. Incubation of the foam cells with physiological concentrations of purified apo J led to a dose-dependent export of cholesterol. The appearance of cholesterol in the medium was associated predominantly with a decline in intracellular cholesteryl esters rather than intracellular free cholesterol. The kinetics of cholesterol release to apo J were similar to apo A-I, an established promoter of cholesterol efflux. Apo J was also shown to induce phospholipid efflux from cells, whereas the cholesterol exported to the medium was associated with the apo J. Studies using foam cells from apo E-null mice showed that the cholesterol exported to the medium was independent of apo E production by the cells. These results present the first evidence that apo J can promote cholesterol efflux from foam cells and indicates that it might have a function in cellular cholesterol homoeostasis in both normal and pathological situations.

Inhibition of glyceraldehyde‐3‐phosphate dehydrogenase by peptide and protein peroxides generated by singlet oxygen attack

Publisher: Wiley

Date: 04-2002

DOI: 10.1046/J.1432-1033.2002.02845.X

Abstract: Reaction of certain peptides and proteins with singlet oxygen (generated by visible light in the presence of rose bengal dye) yields long-lived peptide and protein peroxides. Incubation of these peroxides with glyceraldehyde-3-phosphate dehydrogenase, in the absence of added metal ions, results in loss of enzymatic activity. Comparative studies with a range of peroxides have shown that this inhibition is concentration, peroxide, and time dependent, with H2O2 less efficient than some peptide peroxides. Enzyme inhibition correlates with loss of both the peroxide and enzyme thiol residues, with a stoichiometry of two thiols lost per peroxide consumed. Blocking the thiol residues prevents reaction with the peroxide. This stoichiometry, the lack of metal-ion dependence, and the absence of electron paramagnetic resonance (EPR)-detectable species, is consistent with a molecular (nonradical) reaction between the active-site thiol of the enzyme and the peroxide. A number of low-molecular-mass compounds including thiols and ascorbate, but not Trolox C, can prevent inhibition by removing the initial peroxide, or species derived from it. In contrast, glutathione reductase and lactate dehydrogenase are poorly inhibited by these peroxides in the absence of added Fe2+-EDTA. The presence of this metal-ion complex enhanced the inhibition observed with these enzymes consistent with the occurrence of radical-mediated reactions. Overall, these studies demonstrate that singlet oxygen-mediated damage to an initial target protein can result in selective subsequent damage to other proteins, as evidenced by loss of enzymatic activity, via the formation and subsequent reactions of protein peroxides. These reactions may be important in the development of cellular dysfunction as a result of photo-oxidation.

When Is Noise Speech? A Survey in Sonic Ambiguity

Publisher: MIT Press - Journals

Date: 03-2009

DOI: 10.1162/COMJ.2009.33.1.57

Modeling Perceptions of Valence in Diverse Music

Publisher: University of California Press

Date: 09-2016

DOI: 10.1525/MP.2016.34.1.104

Abstract: We investigate the roles of the acoustic parameters intensity and spectral flatness in the modeling of continuously measured perceptions of affect in nine erse musical extracts. The extract sources range from Australian Aboriginal and Balinese music, to classical music from Mozart to minimalism and Xenakis and include jazz, ambient, drum n' bass and performance text. We particularly assess whether modeling perceptions of the valence expressed by the music, generally modeled less well than the affective dimension of arousal, can be enhanced by inclusion of perceptions of change in the sound, human agency, musical segmentation, and random effects across participants, as model components. We confirm each of these expectations, and provide indications that perceived change in the music may eventually be subsumed adequately under its components such as acoustic features and agency. We find that participants vary substantially in the predictors useful for modeling their responses (judged by the random effects components of mixed effects cross-sectional time series analyses). But we also find that pieces do too, while yet sharing sufficient features that a single common model of the responses to all nine pieces has competitive precision.

Synchronising movements with the sounds of a virtual partner enhances partner likeability

Publisher: Springer Science and Business Media LLC

Date: 08-05-2014

DOI: 10.1007/S10339-014-0618-0

Abstract: Previous studies have demonstrated that synchronising movements with other people can influence affiliative behaviour towards them. While research has focused on synchronisation with visually observed movement, synchronisation with a partner who is heard may have similar effects. We replicate findings showing that synchronisation can influence ratings of likeability of a partner, but demonstrate that this is possible with virtual interaction, involving a video of a partner. Participants performed instructed synchrony in time to sounds instead of the observable actions of another person. Results show significantly higher ratings of likeability of a partner after moving at the same time as sounds attributed to that partner, compared with moving in between sounds. Objectively quantified synchrony also correlated with ratings of likeability. Belief that sounds were made by another person was manipulated in Experiment 2, and results demonstrate that when sounds are attributed to a computer, ratings of likeability are not affected by moving in or out of time. These findings demonstrate that interaction with sound can be experienced as social interaction in the absence of genuine interpersonal contact, which may help explain why people enjoy engaging with recorded music.

Radicals Derived from Histone Hydroperoxides Damage Nucleobases in RNA and DNA

Publisher: American Chemical Society (ACS)

Date: 16-06-2000

DOI: 10.1021/TX000053U

Abstract: Exposure of in idual histone proteins (H1, H2A, H2B, H3, or H4) and histone octamers (consisting of two molecules each of H2A, H2B, H3, and H4) to hydroxyl radicals, generated by gamma-irradiation, in the presence of O(2) generates protein-bound hydroperoxides in a dose-dependent fashion this is in accord with previous studies with other proteins. These histone hydroperoxides are stable in the absence of exogenous catalysts (e.g., heat, light, and transition metal ions), but in the presence of these agents decompose rapidly to give a variety of radicals which have been identified by EPR spin trapping. Histone hydroperoxide-derived radicals generated on decomposition of the hydroperoxides with Cu(+) react with both pyrimidine and purine nucleobases. Thus, with uridine the histone hydroperoxide-derived radicals undergo addition across the C(5)-C(6) double bond of the pyrimidine ring to give cross-linked adduct species which have been identified by EPR spectroscopy. HPLC analysis of the products generated on reaction of histone hydroperoxide-derived radicals with 2'-deoxyguanosine, or intact calf thymus DNA, has shown that significant levels of the mutagenic oxidized DNA base 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) are formed, with the yield dependent on the in idual histone protein, the presence of hydroperoxide functions, and the concentration of metal ion. These studies demonstrate that initial oxidative damage to in idual histone proteins or histone octamers can result in the transfer of oxidative damage to associated DNA via the formation and subsequent decomposition of protein hydroperoxides to reactive radicals, and provide a novel route for the formation of mutagenic lesions in DNA.

Relationships Between Generated Musical Structure, Performers’ Physiological Arousal and Listener Perceptions in Solo Piano Improvisation

Publisher: Informa UK Limited

Date: 17-07-2016

DOI: 10.1080/09298215.2016.1207668

Cyclodextrins differentially mobilize free and esterified cholesterol from primary human foam cell macrophages

Publisher: Elsevier BV

Date: 06-2003

DOI: 10.1194/JLR.M200464-JLR200

Emotional responses in Papua New Guinea show negligible evidence for a universal effect of major versus minor music

Publisher: Center for Open Science

Date: 12-07-2021

DOI: 10.31234/OSF.IO/X7SJF

Abstract: Music is a vital part of most cultures and has a strong impact on emotions. In Western cultures, emotive valence (happiness and sadness) is strongly influenced by major and minor melodies and harmony (chords and their progressions). Yet, how pitch and harmony affect our emotions, and to what extent these effects are culturally mediated or universal, is hotly debated. Here, we report an experiment conducted in a remote cloud forest region of Papua New Guinea, across several communities with similar traditional music but differing levels of exposure to Western-influenced tonal music. One hundred and seventy participants were presented with pairs of major and minor cadences (chord progressions) and melodies, and chose which of them made them happier. The experiment was repeated by 60 non-musicians and 19 musicians in Sydney, Australia. Bayesian analyses show that, for cadences, there is strong evidence that major induced greater reported happiness than minor in every community except one: the community with minimal exposure to Western-like music. For melodies, there is strong evidence that those with higher mean pitch (major melodies) induced greater happiness than those with lower mean pitch (minor melodies) in only one of the three PNG communities and in both Sydney groups. The results show that the emotive valence of major and minor is strongly associated with exposure to Western-influenced music and culture, and there is no evidence for universality.

Toward a Sociobiology of Music

Publisher: University of California Press

Date: 09-2006

DOI: 10.1525/MP.2006.24.1.83

Abstract: We propose a continued evaluation of Darwin’s suggestion that musical functioning is sexually selected, because of recent evidence on sexual dimorphism and its relation to potentially musical activities. We also propose specifically that music may enhance social trust, and hence social coalition, and anticipate some empirical assessments of this idea. The extended altriciality of the human species and the sexual differentiation of empathic responses may link these two propositions.

Perception of affect in unfamiliar musical chords

Publisher: Public Library of Science (PLoS)

Date: 21-06-2019

DOI: 10.1371/JOURNAL.PONE.0218570

A point-process model of tapping along to difficult rhythms

Publisher: Elsevier BV

Date: 12-2022

DOI: 10.1016/J.JMP.2022.102724

The effects of rhythmic structure on tapping accuracy

Publisher: Center for Open Science

Date: 23-01-2021

DOI: 10.31234/OSF.IO/QAEK6

Abstract: Prior investigations of simple rhythms in familiar time signatures have shown the importance of several mechanisms notably, those related to metricization and grouping. But there has been limited study of complex rhythms, including those in unfamiliar time signatures, such as are found outside mainstream Western music. Here, we investigate how the structures of 91 rhythms with non-isochronous onsets (mostly complex, several in unfamiliar time signatures) influence the accuracy, velocity, and timing of taps made by participants attempting to synchronize with these onsets. The onsets were piano-tone cues sounded at a well-formed subset of isochronous cymbal pulses the latter occurring every 234 ms. We modelled tapping at both the rhythm level and the pulse level the latter provides insight into how rhythmic structure makes some cues easier to tap and why incorrect (uncued) taps may occur. In our models, we use a wide variety of quantifications of rhythmic features, several of which are novel and many of which are indicative of underlying mechanisms, strategies, or heuristics. The results show that, for these tricky rhythms, taps are disrupted by unfamiliar period lengths and are guided by crude encodings of each rhythm: the density of rhythmic cues, their circular mean and variance, and recognizing common small patterns and the approximate positions of groups of cues. These lossy encodings are often counterproductive for discriminating between cued and uncued pulses and are quite different to mechanisms – such as metricization and emphasizing group boundaries – thought to guide tapping behaviours in learned and familiar rhythms.

Direct copper reduction by macrophages: Its role in low density lipoprotein oxidation

Publisher: Elsevier BV

Date: 03-1997

DOI: 10.1074/JBC.272.11.6927

Synchronization Can Influence Trust Following Virtual Interaction

Publisher: Hogrefe Publishing Group

Date: 10-2013

DOI: 10.1027/1618-3169/A000173

Abstract: Synchronization has recently received attention as a form of interpersonal interaction that may affect the affiliative relationships of those engaged in it. While there is evidence to suggest that synchronized movements lead to increased affiliative behavior ( Hove & Risen, 2009 Valdesolo & DeSteno, 2011 Wiltermuth & Heath, 2009 ), the influence of other interpersonal cues has yet to be fully controlled. The current study controls for these features by using computer algorithms to replace human partners. By removing genuine interpersonal interaction, it also tests whether sounds alone can influence affiliative relationships, when it appears that another human agent has triggered those sounds. Results suggest that subjective experience of synchrony had a positive effect on a measure of trust, but task success was a similarly good predictor. An objective measure of synchrony was only related to trust in conditions where participants were instructed to move at the same time as stimuli.

The Perceived Affective Expression of Computer-Manipulated Sung Sounds

Publisher: MIT Press - Journals

Date: 03-2011

DOI: 10.1162/COMJ_A_00042

Prooxidant and antioxidant activities of macrophages in metal-mediated LDL oxidation: The importance of metal sequestration

Publisher: Ovid Technologies (Wolters Kluwer Health)

Date: 04-1999

DOI: 10.1161/01.ATV.19.4.1119

Abstract: Abstract —Murine macrophages incubated in metal-supplemented RPMI could block or promote oxidation of low-density lipoprotein (LDL) depending on the degree of metal supplementation. Only at high concentrations of Cu (1 μmol/L) and Fe (30 μmol/L) were cells prooxidant, leading to an accelerated rate of LDL oxidation over that measured in comparable cell-free media. At lower concentrations of Cu and Fe in RPMI, LDL oxidation in the presence of macrophages was inhibited relative to the cell-free condition. This appeared to be dependent on a stable modification of the culture medium, because preconditioning of media by incubation with macrophages could also decrease their capacity to sustain subsequent cell-free LDL oxidation. This was due, in part, to a removal of metal from the media during preconditioning. However, resupplementation of media with metals did not fully restore oxidative capacity, indicating that other cell-dependent antioxidant modifications occurred. This did not involve significant alterations to the thiol content of the media. This study highlights the complexity of the role that cells such as macrophages have with regards to LDL oxidation in vitro and demonstrate that there are both antioxidative and prooxidative components.

Biosynthetic incorporation of oxidized amino acids into proteins and their cellular proteolysis.

Publisher: Elsevier BV

Date: 04-2002

DOI: 10.1016/S0891-5849(02)00768-2

Abstract: We demonstrate that oxidized amino acids can be incorporated into proteins by protein synthesis. The level of incorporation into protein was dependent on the concentration of oxidized amino acid supplied to the cells. At low levels of incorporation, the oxidized amino acids examined increased the degradation rate of the cell proteins. Degradation of certain proteins containing high levels of DOPA (but not ortho or meta tyrosine) was decreased to below the basal degradation rates suggesting that DOPA may contribute to proteins becoming resistant to proteolysis. Changes in the degradation rates of the oxidized amino acid-containing proteins was shown to have no impact on the degradation rates of native proteins, indicating that the activity of the degradative machinery was not affected. We demonstrate that oxidized proteins are selectively degraded by the proteasomes and provide evidence to suggest that the proteasomes and the endosomal-lysosomal systems may act in sequence as well as in parallel. The incorporation approach, unlike cell studies in which an exogenous oxidant is used, allows the degradation rates of the oxidatively modified proteins to be selectively measured, offering a greater sensitivity as well as greatly reducing toxicity to the cell and avoiding oxidative modification of other cell components.

Timbre Preferences in the Context of Mixing Music

Publisher: MDPI AG

Date: 24-04-2019

DOI: 10.3390/APP9081695

Abstract: Mixing music is a highly complex task. This is exacerbated by the fact that timbre perception is still poorly understood. As a result, few studies have been able to pinpoint listeners’ preferences in terms of timbre. In order to investigate timbre preference in a music production context, we let participants mix multiple in idual parts of musical pieces (bassline, harmony, and arpeggio parts, all sounded with a synthesizer) by adjusting four specific timbral attributes of the synthesizer (lowpass, sawtooth/square wave oscillation blend, distortion, and inharmonicity). After participants mixed all parts of a musical piece, they were asked to rate multiple mixes of the same musical piece. Listeners showed preferences for their own mixes over random, fixed sawtooth, or expert mixes. However, participants were unable to identify their own mixes. Despite not being able to accurately identify their own mixes, participants consistently preferred the mix they thought to be their own, regardless of whether or not this mix was indeed their own. Correlations and cluster analysis of the participants’ mixing settings show most participants behaving independently in their mixing approaches and one moderate sized cluster of participants who are actually rather similar. In reference to the starting-settings, participants applied the biggest changes to the sound with the inharmonicity manipulation (measured in the perceptual distance) despite often mentioning that they do not find this manipulation particularly useful. The results show that listeners have a consistent, yet in idual timbre preference and are able to reliably evoke changes in timbre towards their own preferences.

Evidence for a universal association of auditory roughness with musical dissonance

Publisher: Center for Open Science

Date: 23-04-2022

DOI: 10.31234/OSF.IO/VTX2C

Abstract: We provide evidence that the roughness of chords – a psychoacoustic property resulting from unresolved frequency components – is associated with perceived dissonance (operationalized as stability) in participants with differing levels and types of exposure to Western or Western-like music. Three groups of participants were tested in a remote cloud forest region of Papua New Guinea (PNG), and two groups in Sydney, Australia (musicians and non-musicians). We find a negative relationship between roughness and musical stability in every group including the PNG community with minimal experience of musical harmony. The effect of roughness is stronger for the Sydney participants, particularly musicians. We find an effect of harmonicity – a psychoacoustic property resulting from chords having a spectral structure resembling a single pitched tone (such as produced by human vowel sounds) – only in the Sydney musician group, which indicates this feature’s effect is medi- ated via a culture-dependent mechanism. In sum, these results underline the importance of both universal and cultural mechanisms in music cognition, and they suggest powerful implications for understanding the origin of pitch structures in Western tonal music as well as on possibilities for new musical forms that align with humans’ perceptual and cognitive biases.

Metabolism of protein-bound DOPA in mammals.

Publisher: Elsevier BV

Date: 09-2000

DOI: 10.1016/S1357-2725(00)00034-0

Abstract: Protein-bound 3,4-dihydroxyphenylalanine (DOPA) can be generated in mammalian cells by both controlled enzymatic pathways, and by uncontrolled radical reactions. Protein-bound DOPA (PB-DOPA) has reducing activity and the capacity to inflict secondary damage on other important biomolecules such as DNA. This may be mediated through replenishment of transition metals or from catechol-quinone-catechol redox cycles in the presence of cellular components such as ascorbate or cysteine, resulting in lification of radical damaging events. The generation of PB-DOPA confers on protein the ability to chelate transition metals generating protein 'oxychelates' this may be amongst the factors, which localise such damage. Tissue levels of PB-DOPA are increased in a number of age-related pathologies such as atherosclerosis and cataract formation. We discuss the detoxification, and the subsequent proteolysis and excretion of components of PB-DOPA. We contrast the fact that in marine organisms, and particularly in extracellular proteins, PB-DOPA and other DOPA-polymers can play important functional roles in adhesion and the provision of tensile properties.

A Rise–Fall Temporal Asymmetry of Intensity in Composed and Improvised Electroacoustic Music

Publisher: Cambridge University Press (CUP)

Date: 06-07-2010

DOI: 10.1017/S1355771810000142

Reactive species and their accumulation on radical-damaged proteins

Publisher: Elsevier BV

Date: 11-1993

DOI: 10.1016/0968-0004(93)90145-D

Abstract: Hydroperoxides and catechols are described as novel reactive products of radical attack on proteins. These species, like other components of oxidized and otherwise damaged proteins, may accumulate in some biological systems. We propose that the reactive species may then attack other biomolecules, and constitute both a marker and a mechanism of age-related pathologies.

The pulse of symmetry: On the possible co-evolution of rhythm in music and dance

Publisher: SAGE Publications

Date: 09-2009

DOI: 10.1177/1029864909013002151

Abstract: Darwin proposed that music and dance may be part of courtship display leading to reproduction, and hence preservation of genes. Sexual selection could act on either or both music and dance, but we argue it may act most powerfully on their synergistic rhythmic co-performance. We suggest that motoric and temporal capacities evolved for, and adapted to, essential biological functions were exapted to working drills and to dance, and in combination with auditory capacities, to music. We propose that the recently observed correlation between bodily symmetry and perceived dancing quality in Jamaican dance is in part a reflection of the rhythmic abilities of the dancers: their capacity to produce and to synchronise with an isochronic pulse, and their simultaneous capacity to elaborate polyrhythms of movement in relation to that pulse. We elaborate empirical tests of these ideas. Since an exaptation can become a secondary adaptation, music/dance may have become an adaptation that favours reproductive success through sexual selection via display, as has been argued to apply to the studied Jamaican dancers and their community. The combination of dance with music may lify such phenotypic success.

Proteolytic 'defences' and the accumulation of oxidized polypeptides in cataractogenesis and atherogenesis

Publisher: Portland Press Ltd.

Date: 09-2003

DOI: 10.1042/BSS0700135

Abstract: Over the last few years, it has been clearly established that normal plasma contains low levels of oxidized polypeptides, and that these accumulate in tissues during several age-related pathologies. In contrast, normal mammalian aging, contrary to conventional dogma, is not clearly associated with enhanced levels of oxidized proteins, except in extracellular connective tissues, whose proteins can, for ex le, be oxidized by the neutrophil oxidative burst. Since mildly oxidized proteins are susceptible to accelerated degradation in most experimental systems, the question arises as to how the accumulation of oxidized proteins can take place. Such accumulation requires an excess of production (or deposition) over removal, which might reflect alterations in capacity or rate of production or removal. This chapter discusses our presently limited knowledge of rates and control of proteolysis of oxidized proteins in two pathologies, cataractogenesis and atherogenesis. It commences with a brief summary of current understanding of the mechanisms of protein oxidation, and of the observed accumulation of oxidized proteins in several pathologies.

Oxysterols in biological systems: Sources, metabolism and pathophysiological relevance

Publisher: Informa UK Limited

Date: 12-2006

DOI: 10.1179/135100006X155003

Does free extracellular iron exist in haemochromatosis and other pathologies, and is it redox active?

Publisher: Portland Press Ltd.

Date: 03-2001

DOI: 10.1042/CS20000287

Musical Imagery and the Planning of Dynamics and Articulation During Performance

Publisher: University of California Press

Date: 12-2012

DOI: 10.1525/MP.2013.31.2.97

Abstract: Musicians anticipate the effects of their actions during performance. Online musical imagery, or the consciously accessible anticipation of desired effects, may enable expressive performance when auditory feedback is disrupted and help guide performance when it is present. This study tested the hypotheses that imagery 1) can occur concurrently with normal performance, 2) is strongest when auditory feedback is absent but motor feedback is present, and 3) improves with increasing musical expertise. Auditory and motor feedback conditions were manipulated as pianists performed melodies expressively from notation. Dynamic and articulation markings were introduced into the score during performance and pianists indicated verbally whether the markings matched their expressive intentions while continuing to play their own interpretation. Expression was similar under auditory-motor (i.e., normal feedback) and motor-only (i.e., no auditory feedback) performance conditions, and verbal task performance suggested that imagery was stronger when auditory feedback was absent. Verbal task performance also improved with increasing expertise, suggesting a strengthening of online imagery.

Radical chemistry of epigallocatechin gallate and its relevance to protein damage

Publisher: Elsevier BV

Date: 06-2003

DOI: 10.1016/S0003-9861(03)00158-9

Abstract: The radical chemistry of the plant polyphenolics epigallocatechin gallate (EGCG) and epigallocatechin (EGC) were investigated using electron paramagnetic resonance spectroscopy. Radical species formed spontaneously in aqueous solutions at low pH without external oxidant and were spin stabilized with Zn(II). The spectra were assigned to the gallyl radical and the anion gallyl radical, with only 10% of the signal assigned to a radical from the galloyl ester. Spectral simulations were used to establish a pK(a) of 4.8 for the EGCG radical and a pK(a) of 4.4 for the EGC radical. The electrochemical redox potentials of EGCG and EGC varied from 1000 mV at pH 3 to 400 mV at pH 8. The polyphenolics did not produce hydroxyl radicals unless reduced metal ions such as iron(II) were added to the system. Zinc(II)-stabilized EGCG radicals were more effective protein-precipitating agents than unoxidized EGCG and produced irreversibly complexed protein. EGCG and other naturally occurring polyphenolics are effective radical scavengers but their radical products have the potential to damage biological molecules such as proteins.

Human Atherosclerotic Plaque Contains Both Oxidized Lipids and Relatively Large Amounts of α-Tocopherol and Ascorbate

Publisher: Ovid Technologies (Wolters Kluwer Health)

Date: 10-1995

DOI: 10.1161/01.ATV.15.10.1616

Abstract: Abstract We assessed the antioxidant status and contents of unoxidized and oxidized lipids in freshly obtained, homogenized s les of both normal human iliac arteries and carotid and femoral atherosclerotic plaque. Optimal s le preparation involved homogenization of human atherosclerotic plaque for 5 minutes, which resulted in recovery of most of the unoxidized and oxidized lipids without substantial destruction of endogenous vitamins C and E and 87% and 43% recoveries of added standards of α-tocotrienol and isoascorbate, respectively. The total protein, lipid, and antioxidant levels obtained from human plaque varied among donors, although the reproducibility of replicates from a single s le was within 3%, except for ubiquinone-10 and ascorbate, which varied by 20% and 25%, respectively. Plaque s les contained significantly more ascorbate and urate than control arteries, with no discernible difference in the vitamin C redox status between plaque and control materials. The concentrations of α-tocopherol and ubiquinone-10 were comparable in plaque s les and control arteries. However, approximately 9 mol percent of plaque α-tocopherol was present as α-tocopherylquinone, whereas this oxidation product of vitamin E was not detectable in control arteries. Coenzyme Q 10 in plaque and control arteries was only detected in the oxidized form ubiquinone-10, although coenzyme Q 10 oxidation may have occurred during processing. The most abundant of all studied lipids in plaque s les was free cholesterol, followed by cholesteryl oleate and cholesteryl linoleate (Ch18:2). Approximately 30% of plaque Ch18:2 was oxidized, with 17%, 12%, and 1% present as fatty acyl hydroxides, ketones, and hydroperoxides, respectively. In comparison, 7-ketocholesterol was detected at an ≈75-fold lower concentration. Normal arteries contained similar levels of protein as atherosclerotic arteries, much less free cholesterol, and no detectable amounts of unoxidized or oxidized cholesteryl esters. Together, these results demonstrate the coexistence in human plaque of large amounts of oxidized cholesteryl esters with significant concentrations of ascorbate and vitamin E in their reduced, antioxidant-active form. We conclude that compared with healthy human arteries, advanced atherosclerotic plaques are not deficient in the antioxidant vitamins C and E, despite the occurrence of massive lipid oxidation.

‘Human understanding’ in imagining and organising sound: some implications of John Locke's Essay for ecological, cognitive and embodied approaches to composition

Publisher: Cambridge University Press (CUP)

Date: 04-2007

DOI: 10.1017/S1355771807001616

Abstract: We discuss John Locke's ideas in his essay of 1690 on sound and its cognition and relation to bodily motion. The ideas have interesting implications for the construction of organised sound. We argue that our ecological and statistical experience of sounds in our natural (and man-made) environment is in several respects critical for our choices as soundsmiths and our impressions as listeners. Sonic repetition, both sensory and imag(in)ed, contributes to that environment. Input sounds may be ‘coupled’ to output sounds and in some cases the physical processes generating sound and the cognitive processes of receiving them are joined. As music technologists we may think of the computer, our sonic vehicle, as a joined bodily sonic-prosthesis. ‘Simple’ sonic ideas may associate with each other through shared biological bases, and become tools for creation of ‘complex’ ideas, as Locke cogitates. Furthermore, we now have new routes towards such complex sounds, including our computer prostheses.

The impact of specific oxidized amino acids on protein turnover in J774 cells

Publisher: Portland Press Ltd.

Date: 29-01-2008

DOI: 10.1042/BJ20070161

Abstract: Oxidized protein deposition and accumulation have been implicated in the aetiology of a wide variety of age-related pathologies. Protein oxidation in vivo commonly results in the in situ modification of amino acid side chains, generating new oxidized amino acid residues in proteins. We have demonstrated previously that certain oxidized amino acids can be (mis)incorporated into cell proteins in vitro via protein synthesis. In the present study, we show that incorporation of o- and m-tyrosine resulted in increased protein catabolism, whereas dopa incorporation generated proteins that were inefficiently degraded by cells. Incorporation of higher levels of L-dopa into proteins resulted in an increase in the activity of lysosomal cathepsins, increased autofluorescence and the generation of high-molecular-mass SDS-stable complexes, indicative of protein aggregation. These effects were due to proteins containing incorporated L-dopa, since they were not seen with the stereoisomer D-dopa, which enters the cell and generates the same reactive species as L-dopa, but cannot be incorporated into proteins. The present study highlights how the nature of the oxidative modification to the protein can determine the efficiency of its removal from the cell by proteolysis. Protection against the generation of dopa and other species that promote resistance to proteolysis might prove to be critical in preventing toxicity from oxidative stress in pathologies associated with protein deposition, such as atherosclerosis, Alzheimer's disease and Parkinson's disease.

Protein-bound 3,4-dihydroxyphenylalanine is a major reductant formed during hydroxyl radical damage to proteins.

Publisher: American Chemical Society (ACS)

Date: 11-05-1993

DOI: 10.1021/BI00069A012

Abstract: Proteins and aromatic amino acids previously exposed to hydroxyl radicals reduced cytochrome c, free iron, and copper ions. A major product of hydroxyl radical addition to tyrosine is 3,4-dihydroxyphenylalanine (DOPA), which has these reducing properties. The reduction of nitro blue tetrazolium by radical-damaged protein was consistent with the generation of quinones in the protein. By acid hydrolysis followed by high-performance C18 reversed-phase liquid chromatography we have shown that hydroxyl radical-damaged proteins contain significant amounts of protein-bound DOPA (PB-DOPA). The authenticity of the DOPA measured was confirmed by gas chromatography-mass spectrometry. PB-DOPA was also generated enzymatically using mushroom tyrosinase, which catalyzes the hydroxylation of tyrosine residues. By comparing the levels of DOPA in radical-damaged or enzyme-treated protein with that of cytochrome c reduction, we show that PB-DOPA is a major source of the observed reducing activity. PB-DOPA may have a role in the replenishment of reduced transition metal ions involved in free radical generating systems in vivo.

Controlling Perception Thresholds for Changing Timbres in Continuous Sounds

Publisher: Cambridge University Press (CUP)

Date: 04-2019

DOI: 10.1017/S1355771819000074

Abstract: Perceptual dimensions underlying timbre and sound-source identification have received considerable scientific attention. While these scholarly insights help us in understanding the nature of sound within a multidimensional timbral space, they carry little meaning for the majority of musicians. To help address this, we conducted two experiments to establish listeners’ perceptual thresholds (PT) for changes in sound using a staircase-procedure. Unlike most timbre perception research, these changes were sonic manipulations that are common in synthesisers, audio processors and instruments familiar to musicians and producers, and occurred within continuous sounds (rather than between discrete pairs of sounds). In experiment 1, two sounds (variants of a sawtooth oscillation) both with the same fundamental frequency (F1: 80 Hz, 240 Hz or 600 Hz) were played with no intervening gap. In each trial, the two sounds’ partials differed in litudes or frequencies to produce a timbre change. The sonic manipulations were varied in size to detect thresholds for the perceived timbre change – listeners were instructed to indicate whether or not they perceived a change within the sound. In experiment 2, we modified stimulus presentation to introduce the factor of transition time (TT). Rather than occurring instantaneously (as in experiment 1), the timbre manipulations were introduced gradually over the course of a 100 ms or a 1000 ms TT. Results revealed that PTs were significantly affected by the manipulations in experiment 1, and additionally by TT in experiment 2. Importantly, the data revealed an interaction between the F1 and the timbre manipulations, such that there were differential effects of timbre changes on the perceptual system depending on pitch height. Musicians ( n =11) showed significantly smaller PTs compared to non-musicians ( n =10). However, PTs for musicians and non-musicians were highly correlated ( r =.83) across different sonic manipulations, indicating similar perceptual patterns in both. We hope that by establishing PTs for commonly used timbre manipulations, we can provide musicians with a general perceptual unit, for each manipulation, that can guide music composition and assessment.

Comparative Time Series Analysis of Perceptual Responses to Electroacoustic Music

Publisher: University of California Press

Date: 04-2012

DOI: 10.1525/MP.2012.29.4.359

Abstract: this study investigates the relationship between acoustic patterns in contemporary electroacoustic compositions, and listeners' real-time perceptions of their structure and affective content. Thirty-two participants varying in musical expertise (nonmusicians, classical musicians, expert computer musicians) continuously rated the affect (arousal and valence) and structure (change in sound) they perceived in four compositions of approximately three minutes duration. Time series analyses tested the hypotheses that sound intensity influences listener perceptions of structure and arousal, and spectral flatness influences perceptions of structure and valence. Results suggest that intensity strongly influences perceived change in sound, and to a lesser extent listener perceptions of arousal. Spectral flatness measures were only weakly related to listener perceptions, and valence was not strongly shaped by either acoustic measure. Differences in response by composition and musical expertise suggest that, particularly with respect to the perception of valence, in idual experience (familiarity and liking), and meaningful sound associations mediate perception.

The protein oxidation product 3,4-dihydroxyphenylalanine (DOPA) mediates oxidative DNA damage

Publisher: Portland Press Ltd.

Date: 15-03-1998

DOI: 10.1042/BJ3301059

Abstract: A major product of hydroxy-radical addition to tyrosine is 3,4-dihydroxyphenylalanine (DOPA) which has reducing properties. Protein-bound DOPA (PB-DOPA) has been shown to be a major component of the stable reducing species formed during protein oxidation under several conditions. The aim of the present work was to investigate whether DOPA, and especially PB-DOPA, can mediate oxidative damage to DNA. We chose to generate PB-DOPA using mushroom tyrosinase, which catalyses the hydroxylation of tyrosine residues in protein. This permitted us to study the reactions of PB-DOPA in the virtual absence of other protein-bound oxidation products. The formation of two oxidation products of DNA, 8-oxo-7,8-dihydro-2ʹ-deoxyguanosine (8oxodG) and 5-hydroxy-2ʹ-deoxycytidine (5OHdC), were studied with a novel HPLC using gradient elution and an electrochemical detection method, which allowed the detection of both DNA modifications in a single experiment. We found that exposure of calf thymus DNA to DOPA or PB-DOPA resulted in the formation of 8oxodG and 5OHdC, with the former predominating. The formation of these DNA oxidation products by either DOPA or PB-DOPA depended on the presence of oxygen, and also on the presence and on the concentration of transition metal ions, with copper being more effective than iron. The yields of 8oxodG and 5OHdC increased with DOPA concentration in proteins. Thus PB-DOPA was able to promote further radical-generating events, which then transferred damage to other biomolecules such as DNA.

Inhibition of Cholesterol Efflux by 7-Ketocholesterol:  Comparison between Cells, Plasma Membrane Vesicles, and Liposomes as Cholesterol Donors

Publisher: American Chemical Society (ACS)

Date: 10-2001

DOI: 10.1021/BI010833H

Abstract: Cholesterol removal from lipid-loaded macrophages is an important, potentially antiatherogenic process, and we have previously shown that an oxysterol, 7-ketocholesterol (7K), can impair efflux to lipid-free apoprotein A-1 (apoA-1). This publication investigates whether incorporation of 7K into membranes could account for this impairment of cholesterol efflux. Cholesterol efflux was studied from lipoprotein-loaded THP-1 cells, from plasma membrane vesicles obtained from these cells, and from artificial, protein-free liposomes. Impairment of cholesterol efflux by 7K was observed for all cholesterol donor systems whether measured as decline in cholesterol removal rates or as the percentage mass of total cellular cholesterol exported. 7-Ketocholesterol itself was not removed by apoA-1 from any of the cholesterol donor systems. Increasing membrane cholesterol content increased the rate of cholesterol removal by apoA-1 (as seen with plasma membrane vesicles), the quantity of cholesterol removed at equilibrium (liposomes), or both (whole cells). Although the minimum inhibitory 7K concentrations varied between the cholesterol donor systems, 7K inhibited cholesterol efflux in all systems. It was concluded that 7K induces alteration in membranes which decreased the efficiency of cholesterol efflux and the quantity of removed cholesterol induced by apoA-1. As cell membrane proteins are not essential for cholesterol efflux in these systems, the impairment of such by 7K suggests that its effect on membrane lipid composition and its structure are key regulatory elements in this efflux process.

Music Cognition as Mental Time Travel

Publisher: Springer Science and Business Media LLC

Date: 18-09-2013

DOI: 10.1038/SREP02690

Flexibility Conceiving Relationships between Timbres Revealed by Network Analysis

Publisher: Cambridge University Press (CUP)

Date: 19-06-2023

DOI: 10.1017/S1355771823000250

Abstract: Perceived relationships between timbres are critical in electroacoustic music. Most studies assume timbres have fixed inter-relationships, but we tested whether distinct tasks change these. Thirty short sounds were used, from five categories: acoustic instruments, impulse responses, convolutions of the preceding, environmental sounds and computer-manipulated instrumental sounds. In Task 1, 46 non-musicians formed a ‘cohesive’ sonic ordering of unlabelled icons (sounds attached). In Task 2, they categorised the icons into four boxes. In Task 3 listeners separately ordered the sounds from each of Task 2’s boxes using the approach of Task 1. Tasks 1 and 2/3 revealed distinct orderings, consistent with conceptual flexibility. To analyse the orderings, we replaced conventional distance by adjacency measures, and described each system as a network (rather than spatial positions), confirming that the two task outcomes were distinct. Network analyses also showed that the two systems were mechanistically distinct and allowed us to predict temporally changing networks, modelling the observed networks as successive perceptions. Further simulated networks generated with the temporal model readily encompassed all possible pairings between the sounds and not just those we observed. The temporal network model thus confirms conceptual flexibility even in untrained listeners, clearly suitable for a composer to use.

Mental imagery for musical changes in loudness

Publisher: Frontiers Media SA

Date: 2012

DOI: 10.3389/FPSYG.2012.00525

Human apo-lipoprotein B from normal plasma contains oxidised peptides

Publisher: Elsevier BV

Date: 12-1999

DOI: 10.1016/S1357-2725(99)00107-7

Abstract: Oxidation of low density lipoprotein (LDL) may be atherogenic, but radical-initiated oxidation of its apoprotein B-100 (apoB) has been little studied. Transition metal ions iron and copper are candidates for mediating radical oxidation of LDL in vivo. Therefore, we studied the copper-ion-induced oxidation of apoB in human LDL. Using HPLC methods developed in our recent work, we studied the destruction of native and the generation of six oxidised amino acids we also assessed the release of peptides from the LDL particle by FPLC. We observed time-dependent losses of apoB histidine, lysine and glycine. Long-lived reactive species, the reductant DOPA, and the oxidant hydroperoxides of valine and leucine (measured as hydroxides after reduction), were generated. Their relative abundance (mol/mol of parent amino acid) was DOPA > o- and m-tyrosine > dityrosine, valine-hydroxides, leucine hydroxides. Low molecular weight fragments were also released from the LDL in a time-dependent manner, contained hydroperoxides sensitive to GSH peroxidase, and generated radicals on reaction with iron-EDTA. The fragments contained peptides active in the quinone redox cycling procedure, comprising 0.25% of the supplied LDL amino acids. Characteristic peptides were present in each FPLC fraction containing the fragments, as judged by further HPLC fractionation. Some fragments were present in the unoxidised LDL preparations, and when these were largely removed by FPLC, copper oxidation could still generate fragments, suggesting that those present in the starting material might indicate prior oxidation. Concordantly, we found that fresh plasma LDL apoB contained 43% of total plasma protein-bound oxidised amino acids, and with the same relative abundance. We conclude that plasma proteins including apoB are subject to physiological oxidation, similar to that inflicted by copper ions the latter may contribute to intimal LDL oxidation, which could be the source of oxidised plasma apoB.

The iron-selective chelator desferal can reduce chelated copper

Publisher: Informa UK Limited

Date: 1996

DOI: 10.3109/10715769609087999

Abstract: It was shown that the iron-selective chelator desferal (desferrioxamine mesylate:DFO) can reduce Cu(II) as judged by measuring the formation of the complex between Cu(I) and a specific chelator for this species, neocuproine (NC), in phosphate buffer. It was found that under optimal conditions, 3 moles of Cu(II) could be reduced per mole of DFO. Studies of the kinetics of Cu(II) reduction by DFO revealed that the rate of Cu(II) reduction by DFO was considerably slower than that by ascorbate. In the case of both reductants, even in the absence of NC, Cu(I) complexes remained in aqueous solutions for at least 30 min. DFO could also reduce Cu complexed to histidine. The results presented highlight the interpretive dangers which can arise in studies involving multiple transition metals, especially in the presence of multiple chelators. Specifically, when desferal is used, it is important to be aware that any copper present may become reduced, and that any Cu(I) formed might participate in ongoing redox reactions.

The mirage of real-time algorithmic synaesthesia: Some compositional mechanisms and research agendas in computer music and sonification

Publisher: Informa UK Limited

Date: 08-2006

DOI: 10.1080/07494460600760981

Biochemistry and pathology of radical-mediated protein oxidation

Publisher: Portland Press Ltd.

Date: 15-05-1997

DOI: 10.1042/BJ3240001

Abstract: Radical-mediated damage to proteins may be initiated by electron leakage, metal-ion-dependent reactions and autoxidation of lipids and sugars. The consequent protein oxidation is O2-dependent, and involves several propagating radicals, notably alkoxyl radicals. Its products include several categories of reactive species, and a range of stable products whose chemistry is currently being elucidated. Among the reactive products, protein hydroperoxides can generate further radical fluxes on reaction with transition-metal ions protein-bound reductants (notably dopa) can reduce transition-metal ions and thereby facilitate their reaction with hydroperoxides and aldehydes may participate in Schiff-base formation and other reactions. Cells can detoxify some of the reactive species, e.g. by reducing protein hydroperoxides to unreactive hydroxides. Oxidized proteins are often functionally inactive and their unfolding is associated with enhanced susceptibility to proteinases. Thus cells can generally remove oxidized proteins by proteolysis. However, certain oxidized proteins are poorly handled by cells, and together with possible alterations in the rate of production of oxidized proteins, this may contribute to the observed accumulation and damaging actions of oxidized proteins during aging and in pathologies such as diabetes, atherosclerosis and neurodegenerative diseases. Protein oxidation may also sometimes play controlling roles in cellular remodelling and cell growth. Proteins are also key targets in defensive cytolysis and in inflammatory self-damage. The possibility of selective protection against protein oxidation (antioxidation) is raised.

Computational Creation and Morphing of Multilevel Rhythms by Control of Evenness

Publisher: MIT Press - Journals

Date: 03-2016

DOI: 10.1162/COMJ_A_00343

Abstract: We present an algorithm, instantiated in a freeware application called MeanTimes, that permits the parameterized production and transformation of a hierarchy of well-formed rhythms. Each “higher” rhythmic level fills in the gaps of all “lower” levels, and up to six such levels can be simultaneously sounded. MeanTimes has a slider enabling continuous variation of the ratios of the intervals between the beats (onsets) of the lowest level. This consequently changes—in a straightforward manner—the evenness of this level it also changes—in a more complex, but still highly patterned manner—the evennesses of all higher levels. This specific parameter, and others used in MeanTimes, are novel: We describe their mathematical formulation, demonstrate their utility for generating rhythms, and show how they differ from those typically used for pitch-based scales. Some of the compositional possibilities continue the tradition of Cowell and Nancarrow, proceeding further into metahuman performance, and have perceptual and cognitive implications that deserve further attention.

Going online: Successes and challenges in delivering group music instrument and aural learning for older adult novices during the COVID-19 pandemic

Publisher: SAGE Publications

Date: 31-05-2023

DOI: 10.1177/10298649221097953

Abstract: As a result of the COVID-19 pandemic, many cultural and artistic programs for older adults have been put on hold, despite the numerous physical, social, and emotional well-being benefits continued participation may bring. This article details a cross-section of participants ( n = 13) in the Active Minds Music Ensemble—a longitudinal Australian-based research project that provides 12 months of group music instrument lessons to healthy older adult novices—who transitioned from face-to-face (F2F) to an online format. Research questions include the benefits and challenges for older adults as they cope with the technological demands of “going online,” perceived effects on teaching and older adults’ musical learning, as well as perceived effects on group learning benefits. Qualitative data were collected from three different perspectives: i) a frequently asked questions (FAQ) report from the research team documenting technological issues, ii) in idual semi-structured interviews with the participants, and iii) a reflective report from the teacher. The findings confirm that online group music instrument lessons are viable for and valued by older adults, with appreciation of continued technical support. Teaching and learning changed as a result of the online format, primarily in the reduction of in idual feedback and less interplay between participants this was mitigated by use of various functions such as chat, whiteboards, and breakout rooms. Implications for older adult online music instrument lessons include providing continued technical support to learners and helping them maintain confidence with technology. Social opportunities for informal “side-chatter” may also help them to empathize with and encourage each other during music learning activities.

Resilient memory for melodies: The number of intervening melodies does not influence novel melody recognition

Publisher: SAGE Publications

Date: 2018

DOI: 10.1080/17470218.2017.1318932

Abstract: In many memory domains, a decrease in recognition performance between the first and second presentation of an object is observed as the number of intervening items increases. However, this effect is not universal. Within the auditory domain, this form of interference has been demonstrated in word and single-note recognition, but has yet to be substantiated using relatively complex musical material such as a melody. Indeed, it is becoming clear that music shows intriguing properties when it comes to memory. This study investigated how the number of intervening items influences memory for melodies. In Experiments 1, 2 and 3, one melody was presented per trial in a continuous recognition paradigm. After each melody, participants indicated whether they had heard the melody in the experiment before by responding “old” or “new.” In Experiment 4, participants rated perceived familiarity for every melody without being told that melodies reoccur. In four experiments using two corpora of music, two different memory tasks, transposed and untransposed melodies and up to 195 intervening melodies, no sign of a disruptive effect from the number of intervening melodies beyond the first was observed. We propose a new “regenerative multiple representations” conjecture to explain why intervening items increase interference in recognition memory for most domains but not music. This conjecture makes several testable predictions and has the potential to strengthen our understanding of domain specificity in human memory, while moving one step closer to explaining the “paradox” that is memory for melody.

Protective mechanisms against peptide and protein peroxides generated by singlet oxygen

Publisher: Elsevier BV

Date: 02-2004

DOI: 10.1016/J.FREERADBIOMED.2003.11.021

Apolipoprotein A-I-stimulated Apolipoprotein E Secretion from Human Macrophages Is Independent of Cholesterol Efflux

Publisher: Elsevier BV

Date: 06-2004

DOI: 10.1074/JBC.M401177200

Biosynthesis and turnover of DOPA-containing proteins by human cells

Publisher: Elsevier BV

Date: 12-2004

DOI: 10.1016/J.FREERADBIOMED.2004.08.009

Abstract: Protein-bound 3,4-dihydroxyphenylalanine (PB-DOPA) is a major product of hydroxyl radical attack on tyrosine residues of proteins. Levels of PB-DOPA in cells and tissues have been shown to be greatly elevated in age-related diseases. We demonstrate for the first time that l-DOPA (levodopa) can be biosynthetically incorporated into cell proteins by human cells (THP-1 monocytes and monocyte-derived macrophages). The DOPA-containing proteins generated were selectively visualized on PVDF membranes using a redox-cycling staining method. Many cell proteins contained DOPA and seemed to be synthesized as their full-length forms. The cellular removal of DOPA-containing proteins by THP-1 cells was by proteolysis involving both the proteasomal and the lysosomal systems. The rate of cellular proteolysis of DOPA-containing proteins increased at lower levels of DOPA incorporation but decreased at higher levels of DOPA incorporation. The decreased rate of degradation was accompanied by an increase in the activity of cathepsins B and L but the activity of cathepsin S increased only at lower levels of DOPA incorporation. These data raise the possibility that PB-DOPA could be generated in vivo from l-DOPA, which is the most widely used treatment for Parkinson disease.

Learning unfamiliar pitch intervals: A novel paradigm for demonstrating the learning of statistical associations between musical pitches

Publisher: Public Library of Science (PLoS)

Date: 30-08-2018

DOI: 10.1371/JOURNAL.PONE.0203026

Listener Detection of Segmentation in Computer-Generated Sound: An Exploratory Experimental Study

Publisher: Informa UK Limited

Date: 06-2007

DOI: 10.1080/09298210701755123

Acoustic Intensity Causes Perceived Changes in Arousal Levels in Music: An Experimental Investigation

Publisher: Public Library of Science (PLoS)

Date: 20-04-2011

DOI: 10.1371/JOURNAL.PONE.0018591

The hydroxyl radical in lens nuclear cataractogenesis

Publisher: Elsevier BV

Date: 11-1998

DOI: 10.1074/JBC.273.44.28603

Assessment of proteasome activity in cell lysates and tissue homogenates using peptide substrates

Publisher: Elsevier BV

Date: 05-2003

DOI: 10.1016/S1357-2725(02)00391-6

Abstract: The ubiquitin-proteasome pathway is a major route of degradation of cell proteins. It also plays an essential role in maintaining cell homeostasis by degrading many rate-limiting enzymes and critical regulatory proteins. Alterations in proteasome activity have been implicated in a number of pathologies including Parkinson's disease, Alzheimer's disease and diabetes. The eukaryotic proteasome is a multicatalytic protease characterized by three activities with distinct specificities against peptide substrates. Although substrates were identified which could selectively measure the in idual activities in the purified proteasome little data is available on how specific those substrates are for proteasomal activity when used with biological s les which may contain many other active peptidases. Here we examine the three major peptidase activities in lysates of two cell types and in a liver cytosol fraction in the presence of specific proteasome inhibitors and after fractionation by gel permeation chromatography. We demonstrate that other proteinases present in these preparations can degrade the commonly used proteasome substrates under the standard assay conditions. We develop a simple method for separating the proteasome from the lower molecular weight proteases using a 500kDa molecular weight cut-off membrane. This allows proteasome activity to be accurately measured in crude biological s les and may have quite broad applicability. We also identify low molecular weight tryptic activity in both the cell and tissue preparations which could not be inhibited by the proteasome inhibitor epoxomycin but was inhibitable by two cysteine proteinase inhibitors and by lactacystin suggesting that lactacystin may not be completely proteasome specific.

Oxidation of DNA, proteins and lipids by DOPA, protein-bound DOPA, and related catechol(amine)s

Publisher: Elsevier BV

Date: 08-2002

DOI: 10.1016/S0300-483X(02)00193-2

Abstract: Incubation of free 3,4-dihydroxyphenylalanine (DOPA), protein-bound DOPA (PB-DOPA) and related catechols with DNA, proteins and lipids has been shown to result in oxidative damage to the target molecule. This article reviews these reactions with particular emphasis on those that occur in the presence of molecular O(2) and redox-active metal ions (e.g. Fe(3+), Cu(2+), Cr(6+)), which are known to increase the rate of DOPA oxidation. The majority of oxidative damage appears to be mediated by reactive oxygen species (ROS) such as superoxide and HO(.) radicals, though other DOPA oxidation products, including semiquinone radicals, quinones, and metal ion-DOPA complexes have also been implicated in some cases. Non-radical reactions of DOPA with suitable nucleophiles (e.g. thiol groups) can also result in modification of the target, with this process being particularly prevalent with proteins. The exacerbation of damage observed on addition of H(2)O(2) is in accord with a key role for ROS in many of these reactions.

Distributional Analysis of n-Dimensional Feature Space for 7-Note Scales in 22-TET

Publisher: Springer International Publishing

Date: 2019

DOI: 10.1007/978-3-030-21392-3_16

Learning a Well-Formed Microtonal Scale: Pitch Intervals and Event Frequencies

Publisher: Informa UK Limited

Date: 15-02-2018

DOI: 10.1080/09298215.2018.1432060

Synthesis of α-Tocopherol Analogues

Publisher: CSIRO Publishing

Date: 1997

DOI: 10.1071/C97044

Abstract: A range of a-tocopherol analogues of varying side-chain length and structure has been prepared by the Wittig reaction of alkyltriphenylphosphonium bromides with either 6-benzyloxy-2,5,7,8-tetramethylchroman- 2-carbaldehyde (8) or 6-acetoxy-2,5,7,8-tetramethylchroman-2-carbaldehyde (14). These analogues include 2-hexyl-2,5,7,8-tetramethylchroman-6-ol (11), 2-heptyl-2,5,7,8-tetramethylchroman-6-ol (12) and 2,5,7,8-tetramethyl-2-(pent-1-enyl)chroman-6-ol (15). Methoxycarbonylmethyl 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylate (2) was formed by reaction of the triethylammonium salt of trolox (1) with methyl bromoacetate. Reaction of methoxycarbonylmethyltriphenylphosphonium bromide (16) with (8) did not produce the expected methyl 3-(6-benzyloxy-2,5,7,8-tetramethylchroman-2-yl)prop-2-enoate (17), but rather 4-(6-benzyloxy-2,5,7,8-tetramethylchroman-2-yl)but-3-en-2-one (22). A proposed mechanism for this unusual reaction is discussed.

3-Hydroxylysine, a potential marker for studying radical-induced protein oxidation

Publisher: American Chemical Society (ACS)

Date: 03-10-1998

DOI: 10.1021/TX980118H

What constitutes a phrase in sound-based music? A mixed-methods investigation of perception and acoustics

Publisher: Public Library of Science (PLoS)

Date: 20-12-2016

DOI: 10.1371/JOURNAL.PONE.0167643

Stable markers of oxidant damage to proteins and their application in the study of human disease

Publisher: Elsevier BV

Date: 12-1999

DOI: 10.1016/S0891-5849(99)00206-3

Abstract: The mechanisms of formation and the nature of the altered amino acid side chains formed on proteins subjected to oxidant attack are reviewed. The use of stable products of protein side chain oxidation as potential markers for assessing oxidative damage in vivo in humans is discussed. The methods developed in the authors laboratories are outlined, and the advantages and disadvantages of these techniques compared with other methodologies for assessing oxidative damage to proteins and other macromolecules. Evidence is presented to show that protein oxidation products are sensitive markers of oxidative damage, that the pattern of products detected may yield information as to the nature of the original oxidative insult, and that the levels of oxidized side-chains can, in certain circumstances, be much higher than those of other markers of oxidation such as lipid hydroperoxides.

How Different Are Our Perceptions of Equal-Tempered and Microtonal Intervals? A Behavioural and EEG Survey

Publisher: Public Library of Science (PLoS)

Date: 18-08-2015

DOI: 10.1371/JOURNAL.PONE.0135082

Evidence for L-dopa incorporation into cell proteins in patients treated with levodopa

Publisher: Wiley

Date: 19-06-2006

DOI: 10.1111/J.1471-4159.2006.03941.X

Abstract: Levodopa (L-dopa) is the most widely used agent for the symptomatic relief of Parkinson's disease. There is concern that chronic L-dopa treatment may be detrimental, with some studies suggesting that L-dopa may be neurotoxic. A potentially important mechanism whereby L-dopa may exert neurotoxic effects has been overlooked: that of the incorporation of L-dopa into proteins by protein synthesis. L-Dopa competes with tyrosine as a substrate in protein synthesis in vitro. We provide evidence that L-dopa can also be incorporated into proteins in vivo. Blood from L-dopa-treated and -non-treated patients was separated into protein, erythrocyte and lymphocyte fractions and levels of protein-incorporated dopa quantified by HPLC. Levels of protein-incorporated dopa were significantly increased in lymphocyte cell proteins from L-dopa-treated patients. This has not arisen from oxidative pathways as there was no evidence of oxidative damage to proteins. In addition, there was no increase in protein-incorporated dopa in erythrocytes, which are not actively synthesizing proteins. We suggest that protein-incorporated dopa could also be generated in the CNS. The accumulation of protein-incorporated dopa in cells is associated with oxidative stress and impaired function and could contribute to some of the problems associated with long-term L-dopa treatment.

Context effects of background babbling on memory for melodies

Publisher: SAGE Publications

Date: 11-06-2020

DOI: 10.1177/1029864918779415

Abstract: Disruptive effects of background noise on memory have been thoroughly investigated. Potential beneficial context effects of background noise on memory, however, have received far less attention. Here, we explore whether and how unintelligible multiple talker background babbling affects melody recognition. Participants continuously listened to melodies, each of which appeared twice during the experiment. After each melody participants were asked to indicate whether they had heard the melody previously in the experiment. The presence or absence of background noise during first or second melody presentation was manipulated in four conditions (Clear-Clear, Clear-Noise, Noise-Clear, Noise-Noise). We measured recognition performance as well as cumulative disruptive interference between first and second melody presentation. Mixed effects models revealed that recognition in Clear-Clear was significantly better compared to Noise-Clear and Noise-Noise, but not compared to Clear-Noise. Clear-Noise showed descriptively better recognition performance than Noise-Noise, however this comparison did not reach statistical significance. Recognition performance in Clear-Noise was significantly better than in Noise-Clear, suggesting that noise during encoding affects recognition performance more strongly than noise during retrieval. Furthermore, cumulative disruptive interference was stronger in mismatching contexts. Our results suggest that if possible, background noise should be avoided as it negatively affects memory performance. However, if encoding is likely to take place in a noisy environment, then presenting background noise during retrieval may be beneficial. This is because matching background noise during encoding and retrievals appears to reduce cumulative disruptive interference.

Comparative time-courses of copper-ion-mediated protein and lipid oxidation in low-density lipoprotein

Publisher: Elsevier BV

Date: 04-2002

DOI: 10.1016/S0003-9861(02)00018-8

Evidence for multiple strategies in off-beat tapping with anisochronous stimuli

Publisher: Springer Science and Business Media LLC

Date: 22-08-2013

DOI: 10.1007/S00426-013-0513-9

Abstract: There is a large body of evidence relating to the ways that people tap in time with sounds, and perform error correction in order to do this. However, off-beat tapping is less well investigated than on-beat tapping. The current study involves coordinating with a stimulus sequence with underlying isochrony and systematic deviations from this isochrony that increase or decrease in magnitude to look at people's capacity to error-correct when performing off-beat synchronisation with a set of sounds. Participants were instructed to 'tap between the tones' but 'try to maintain regularity'. While analysis using typical methods suggested a form of error correction was occurring, a series of more complex analyses demonstrated that participants' performance during each trial can be classified according to one of four different strategies: maintaining a regular pulse, error correction, phase resetting, and negative error correction. While maintaining a regular pulse was the preferred strategy in conditions with increasingly isochronous stimuli, the majority of trials are best explained by other strategies, suggesting that participants were generally influenced by variability in the stimuli.

Reactions of Hypochlorous Acid with Tyrosine and Peptidyl-tyrosyl Residues Give Dichlorinated and Aldehydic Products in Addition to 3-Chlorotyrosine

Publisher: Elsevier BV

Date: 04-2000

DOI: 10.1074/JBC.275.15.10851

Psychoacoustic manipulation of the sound-induced illusory flash

Publisher: Springer Berlin Heidelberg

Date: 2008

DOI: 10.1007/978-3-540-85035-9_15

Glycation of low-density lipoproteins by methylglyoxal and glycolaldehyde gives rise to the in vitro formation of lipid-laden cells

Publisher: Springer Science and Business Media LLC

Date: 20-01-2005

DOI: 10.1007/S00125-004-1648-4

Abstract: Previous studies have implicated the glycoxidative modification of low-density lipoprotein (LDL) by glucose and aldehydes (apparently comprising both glycation and oxidation), as a causative factor in the elevated levels of atherosclerosis observed in diabetic patients. Such LDL modification can result in unregulated cellular accumulation of lipids. In previous studies we have characterized the formation of glycated, but nonoxidized, LDL by glucose and aldehydes in this study we examine whether glycation of LDL, in the absence of oxidation, gives rise to lipid accumulation in arterial wall cell types. Glycated LDLs were incubated with macrophage, smooth muscle, or endothelial cells. Lipid loading was assessed by HPLC analysis of cholesterol and in idual esters. Oxidation was assessed by cholesterol ester loss and 7-ketocholesterol formation. Cell viability was assessed by lactate dehydrogenase release and cell protein levels. Glycation of LDL by glycolaldehyde and methylglyoxal, but not glucose (in either the presence or absence of copper ions), resulted in cholesterol and cholesterol ester accumulation in macrophage cells, but not smooth muscle or endothelial cells. The extent of lipid accumulation depends on the degree of glycation, with increasing aldehyde concentration or incubation time, giving rise to greater extents of particle modification and lipid accumulation. Modification of lysine residues appears to be a key determinant of cellular uptake. These results are consistent with LDL glycation, in the absence of oxidation, being sufficient for rapid lipid accumulation by macrophage cells. Aldehyde-mediated "carbonyl-stress" may therefore facilitate the formation of lipid-laden (foam) cells in the artery wall.

Shared and distinct mechanisms of individual and expertise-group perception of expressed arousal in four works

Publisher: Informa UK Limited

Date: 02-09-2014

DOI: 10.1080/17459737.2014.928753

Are reactive oxygen species involved in the pathogenesis of murine cerebral malaria?

Publisher: Oxford University Press (OUP)

Date: 1999

DOI: 10.1086/314552

Abstract: To investigate the involvement of oxidative tissue damage in the pathogenesis of murine cerebral malaria (CM), brain levels of protein carbonyls, 3,4-dihydroxyphenylalanine (DOPA), o-tyrosine, and dityrosine were measured during Plasmodium berghei ANKA (PbA) and P. berghei K173 (PbK) infections. During PbA infection in a CM model, brain levels of the substances were similar to those in uninfected mice. The role of phagocyte-derived reactive oxygen species in the pathogenesis of CM was examined in gp91phox gene knockout mice. The course of CM in these mice was the same as in their wild type counterparts. To examine whether superoxide production in the central nervous system could have occurred via increased xanthine oxidase activity, brain concentrations of urate were measured in CM mice and in mice infected with PbK (which does not cause CM). Brain urate concentration increased significantly in both groups of mice, suggesting that purine breakdown is not specific to CM. These results indicate that reactive oxygen species probably do not contribute to the pathogenesis of murine CM.

Time series analysis of real-time music perception: approaches to the assessment of individual and expertise differences in perception of expressed affect

Publisher: Informa UK Limited

Date: 02-09-2014

DOI: 10.1080/17459737.2014.928752

Using time series analysis to evaluate skin conductance during movement in piano improvisation

Publisher: SAGE Publications

Date: 04-09-2013

DOI: 10.1177/0305735613489917

Abstract: During musical improvisation, performers’ skin conductance (SC, a measure of psychological arousal) may respond to movement and to events whose timing is beyond control. SC has not been studied in these difficult conditions. Our purpose was to establish a procedure and analysis that would permit the meaningful use of continuous SC measures while pianists play. Consequently, two case studies of SC during piano performances develop an effective method. SC was measured at the left ankle and movement was monitored nearby. Two musicians performed manipulations of movement (flexing legs, hand motion), and performance content (playing scales versus improvisation) and type (actual, silent and imagined). Time series analysis modeled SC in relation to supplied improvisational referents. We could interpret SC during performance, provided that we accounted for the impact of movement. We detected genuine SC changes around moments of transition between musical segments these could reflect the mental effort of planning and generating music. In a subsequent validation study, we demonstrated the applicability of our method for SC analysis to performances by nine professional piano improvisers.

Separation and Characterization of Cholesteryl Oxo- and Hydroxy-Linoleate Isolated from Human Atherosclerotic Plaque

Publisher: Informa UK Limited

Date: 1997

DOI: 10.3109/10715769709065779

Abstract: In previous work we demonstrated that up to 30% of cholesteryl linoleate in homogenates of advanced human plaque s les is present in oxidized forms. Here we show that the material from plaque hexane extracts which co-elutes with cholesteryl hydroxy-linoleate on reversed phase HPLC (Anal Biochem 1993 :79), is composed of several isomers of cholesteryl hydroxy- and cholesteryl oxo-octadecadienoate. Enzymatic hydrolysis and measurement of liberated cholesterol and disappearance of the esters revealed that almost all of the material consisted of unoxidized cholesterol esterified to oxidized derivatives of octadecadienoate. Semi-preparative reversed-phase HPLC was used to obtain sufficient quantities of this co-eluting material to undertake normal phase HPLC separation of these components. The nature of such separated and isolated compounds was identified, by co-chromatography with authentic standards, UV spectroscopy and chemical ionization and electron impact mass spectrometry, as cholesteryl hydroxy- and cholesteryl oxo-octadecadienoate. These oxidized fatty acids have been observed previously in plaque, in agreement with our new unambiguous demonstration of their presence as cholesteryl esters. The application of the methods described for the separation of the various forms of oxidized cholesteryl octadecadienoate may aid mechanistic studies of in vitro and in vivo lipoprotein lipid oxidation.

Algorithmic Synesthesia

Publisher: Oxford University Press

Date: 22-04-2011

DOI: 10.1093/OXFORDHB/9780199792030.013.0015

STRUCTURAL IDENTIFICATION OF VALINE HYDROPEROXIDES AND HYDROXIDES ON RADICAL-DAMAGED AMINO-ACID, PEPTIDE, AND PROTEIN MOLECULES

Publisher: Elsevier BV

Date: 09-1995

DOI: 10.1016/0891-5849(95)00021-O

Abstract: We have previously demonstrated the formation of two reactive moieties on proteins during free radical attack: hydroperoxides, and 3,4-dihydroxyphenylalanine (DOPA). Here we have undertaken the structural elucidation of the hydroperoxides of valine, the amino acid which is most susceptible to peroxidation. Exposure of L-valine to free radicals generated by radiolysis in an oxygen-saturated system produced three valine hydroperoxides. Upon treatment with sodium borohydride these were reduced to their corresponding hydroxides, which can be separated and purified by high performance liquid chromatography (HPLC). Based on spectroscopic data from high resolution chemical ionization (CI) mass spectrometry (MS), electrospray (ES) MS, electron impact (EI) MS, proton (1H) nuclear magnetic resonance (NMR) and carbon-13 (13C) NMR studies, the three valine hydroxides have been identified as beta-hydroxyvaline [(2S)-2-amino-3-hydroxy-3-methyl-butanoic acid], (2S,3S)-gamma-hydroxyvaline [(2S,3S)-2-amino-3-hydroxymethyl-butanoic acid], and (2S,3R)-gamma-hydroxyvaline [(2S,3R)-2-amino-3-hydroxymethyl-butanoic acid]. HPLC analysis of O-phthaldialdehyde (OPA) derivatives of the hydroxyvalines provides a sensitive and accurate method for quantitative measurement. This method enabled hydroxyvalines to be detected in the hydrolysates of a tripeptide (glutamyl-valinyl-phenylalanine) and a protein (bovine serum albumin) that had been gamma-radiolysed and treated with sodium borohydride. Hydroxyvaline may be useful as a marker in studying protein oxidation in some biological systems under oxidative stress.

A Kinetic Model to Evaluate Cholesterol Efflux from THP-1 Macrophages to Apolipoprotein A-1

Publisher: American Chemical Society (ACS)

Date: 31-07-2001

DOI: 10.1021/BI010323N

Abstract: The kinetics (0 to 3 h) of cholesterol efflux to delipidated apolipoprotein A-1 were investigated, and the experimental data were best fitted to a mathematical model that involves two independent pathways of cholesterol efflux. The first pathway with a rate constant of 4.6 h(-1) is fast but removes only 3-5% of total cholesterol. After preconditioning apoA-1, it was found that this pathway remains, and hence it is a property of the cholesterol-loaded cells rather than due to modification on the apolipoprotein. This fast initial efflux does not seem to contribute to cholesterol efflux at later stages (>1 h) where a second pathway predominates. However, the fast initial efflux pool can be restored if apoA-1 is withdrawn. The second slower pathway (k(membrane--media) = 0.79 h(-1)) is associated with cholesterol ester hydrolysis whose rate constant could be experimentally verified (k(cal) = 0.43, k(exp) = 0.38 +/- 0.05). The model suggests that two different plasma membrane domains are involved in the two pathways. Loading of the cells with an oxysterol, 7-ketocholesterol (7K), inhibits efflux from both pathways. The model predicts that 7K decreases the initial efflux by decreasing the available cholesterol (by possibly affecting lipid packing), while all rate constants in the second pathway are decreased. In conclusion, the kinetic model suggests that cholesterol efflux to apoA-1 is a two-step process. In the first step, some of the plasma membrane cholesterol contributes to a fast initial efflux (possibly from lipid rafts) and leads to a second pathway that mobilizes intracellular cholesterol mobilization.

The effects of rhythmic structure on tapping accuracy

Publisher: Springer Science and Business Media LLC

Date: 10-10-2023

DOI: 10.3758/S13414-023-02778-2

Evidence for roles of radicals in protein oxidation in advanced human atherosclerotic plaque

Publisher: Portland Press Ltd.

Date: 08-1998

DOI: 10.1042/BJ3330519

Abstract: Oxidative damage might be important in atherogenesis. Oxidized lipids are present at significant concentrations in advanced human plaque, although tissue antioxidants are mostly present at normal concentrations. Indirect evidence of protein modification (notably derivatization of lysine) or oxidation has been obtained by immunochemical methods the specificities of these antibodies are unclear. Here we present chemical determinations of six protein-bound oxidation products: dopa, o-tyrosine, m-tyrosine, dityrosine, hydroxyleucine and hydroxyvaline, some of which reflect particularly oxy-radical-mediated reaction pathways, which seem to involve mainly the participation of transition- metal ions. We compared the relative abundance of these oxidation products in normal intima, and in human carotid plaque s les with that observed after radiolytically generated hydroxyl radical attack on BSA in vitro. The close similarities in relative abundances in the latter two circumstances indicate that hydroxyl radical damage might occur in plaque. The relatively higher level of dityrosine in plaque than that observed after radiolysis suggests the additional involvement of HOCl-mediated reactions in advanced plaque.

Listeners Discern Affective Variation in Computer-Generated Musical Sounds

Publisher: SAGE Publications

Date: 2009

DOI: 10.1068/P6063

Abstract: We carried out two experiments to test the relationship between real-time perception of structural change in stylistically unusual musical sounds, and perception of its affect (arousal and valence). Computer music was used because of its unfamiliarity and our capacity to control it in ecologically appropriate ways. In experiment 1, thirteen participants unselected for musical training participated in tasks to detect segmentation and changes in affect. Changes in affect occurred upon detection of segmentation but not all algorithmically distinct segments conveyed distinct affect. Short segments followed by long segments led to greater changes in arousal and valence at the point of segmentation than vice versa. In experiment 2, intra-segment sound transitions were introduced. Sixteen musicians performed the same affect task as in experiment 1, and a novel change in sound task. Participants were slow to respond to a continuous transition, but quick to respond to instantaneous transitions. Contrary to literature on the perception of affect in more familiar music, the musician participants in experiment 2 differed more in their ratings of arousal than of valence, in spite of a strong correlation of arousal with the composition of the stimuli. These findings are discussed in relation to the positive valence attributed to the more familiar sounds in both experiments.

Comparative antioxidant activity of tocotrienols and other natural lipid-soluble antioxidants in a homogeneous system, and in rat and human lipoproteins

Publisher: Elsevier BV

Date: 02-1993

DOI: 10.1016/0005-2760(93)90092-N

Abstract: The antioxidant activity of tocotrienols toward peroxyl radicals was compared with that of other natural lipid-soluble antioxidants in three different systems by measuring the temporal disappearance of antioxidants and the formation of lipid hydroperoxides. In homogeneous solution, the initial rates of consumption of the various antioxidants, assessed by competition experiments between pairs of antioxidants for radicals, decreased in the order: ubiquinol-10 approximately ubiquinol-9 > alpha-tocopherol approximately alpha-tocotrienol > beta-carotene approximately lycopene > gamma-tocopherol approximately gamma-tocotrienol. Following in vitro incubation of human plasma with alpha-tocotrienol, this form of vitamin E was present in all classes of lipoproteins isolated from the supplemented plasma. Dietary supplementation of rats and humans with a tocotrienol-rich preparation resulted in a dose-dependent appearance of alpha- and gamma-tocotrienols in plasma and all circulating lipoproteins, respectively. Exposure of such enriched rat plasma to aqueous peroxyl radicals resulted in simultaneous consumption of the alpha- and then gamma-isomers of vitamin E. The sequence of radical-induced consumption of antioxidants in freshly isolated, in vitro and in vivo tocotrienol-enriched low density lipoprotein (LDL) was again ubiquinol-10 > alpha-tocotrienol approximately alpha-tocopherol > carotenoids > gamma-tocopherol approximately gamma-tocotrienol. Under conditions where radicals were generated at constant rates, the rate of lipid hydroperoxide formation in LDL was not constant. It proceeded in at least three stages separated by the phase of ubiquinol-10 consumption and, subsequently, that of alpha-tocopherol/alpha-tocotrienol. Our results show that dietary tocotrienols become incorporated into circulating human lipoproteins where they react with peroxyl radicals as efficiently as the corresponding tocopherol isomers.

Protein oxidation and ageing

Publisher: Elsevier BV

Date: 09-2001

DOI: 10.1016/S0531-5565(01)00136-X

Abstract: Organisms produce reactive oxygen species (ROS) throughout their lives. The activities of a number of key antioxidant enzymes, such as catalase, superoxide dismutase and glutathione peroxidase, which protect against the damaging effects of ROS, have been reported to decrease with increasing age, though this is not unequivocal. In contrast, sacrificial antioxidants such as ascorbate, thiols and tocopherol do not appear to decrease with increasing age. It is also possible that ROS production increases with age as a result of poorer coupling of electron transport components, and an increased level of redox-active metal ions that could catalyse oxidant formation. As a result of this decrease in antioxidant defences, and increased rate of ROS formation, it is possible that the impact of ROS increases with age. ROS are known to oxidise biological macromolecules, with proteins an important target. If the argument that the impact of ROS increases with age is true, then proteins would be expected to accumulate oxidised materials with age, and the rate of such accumulation should increase with time, reflecting impaired inefficiency of homeostasis. Here we review the evidence for the accumulation of oxidised, or modified, extra- and intra-cellular proteins in vivo.

Musical Expertise and the Ability to Imagine Loudness

Publisher: Public Library of Science (PLoS)

Date: 27-02-2013

DOI: 10.1371/JOURNAL.PONE.0056052

Effects of CSF-1 on Cholesterol Accumulation and Efflux by Macrophages

Publisher: Ovid Technologies (Wolters Kluwer Health)

Date: 1997

DOI: 10.1161/01.ATV.17.1.18

Abstract: To assess whether human monocyte-specific colony-stimulating factor (CSF-1) might influence atherogenesis, CSF-1–induced macrophage responses that might contribute to enhanced clearance of low-density lipoprotein (LDL) or modified LDL were investigated. Careful account was made of cell preservation and increases in cell volume and protein (representing increased cell surface area, and thus endocytically active membrane) during culture with CSF-1. This permitted distinction between selective and nonspecific effects of CSF-1, the latter paralleling increases in cellular mass and volume. CSF-1 enhanced mouse peritoneal macrophage survival in vitro during exposure to lipoprotein-deficient serum with or without native LDL or acetylated LDL (Ac-LDL), as judged by maintenance of cellular DNA and cell numbers. In the presence of copper-oxidized LDL (Ox-LDL), such effects were very slight. In all conditions, CSF-1 increased cellular protein content. CSF-1 increased the uptake of both Ac-LDL and Ox-LDL calculated per culture, but this was entirely explicable by the increased cell protein, indicating that there was no selective enhancement of scavenger receptor or other routes for uptake of the modified LDLs. Similarly, CSF-1 also increased the accumulation of cholesterol and its esters nonspecifically. CSF-1 did have a marked and specific effect on the composition of cholesterol esters, decreasing the proportion of polyunsaturated esters relative to monounsaturated and saturated esters. Finally, cholesterol efflux induced by apolipoprotein A1 from Ac-LDL–loaded macrophages was not influenced by CSF-1. Thus, the enhanced macrophage catabolism of modified LDLs by CSF-1 is part of a nonspecific action on the cells but could contribute to a reduction in circulating cholesterol, observed in some situations of CSF-1 presentation in humans.

Continuous loudness response to acoustic intensity dynamics in melodies: Effects of melodic contour, tempo, and tonality

Publisher: Elsevier BV

Date: 06-2014

DOI: 10.1016/J.ACTPSY.2014.03.007

Abstract: The aim of this work was to investigate perceived loudness change in response to melodies that increase (up-r ) or decrease (down-r ) in acoustic intensity, and the interaction with other musical factors such as melodic contour, tempo, and tonality (tonal/atonal). A within-subjects design manipulated direction of linear intensity change (up-r , down-r ), melodic contour (ascending, descending), tempo, and tonality, using single r trials and paired r trials, where single up-r s and down-r s were assembled to create continuous up-r /down-r or down-r /up-r pairs. Twenty-nine (Exp 1) and thirty-six (Exp 2) participants rated loudness continuously in response to trials with monophonic 13-note piano melodies lasting either 6.4s or 12s. Linear correlation coefficients >.89 between loudness and time show that time-series loudness responses to dynamic up-r and down-r melodies are essentially linear across all melodies. Therefore, 'indirect' loudness change derived from the difference in loudness at the beginning and end points of the continuous response was calculated. Down-r s were perceived to change significantly more in loudness than up-r s in both tonalities and at a relatively slow tempo. Loudness change was also greater for down-r s presented with a congruent descending melodic contour, relative to an incongruent pairing (down-r and ascending melodic contour). No differential effect of intensity r /melodic contour congruency was observed for up-r s. In paired r trials assessing the possible impact of r context, loudness change in response to up-r s was significantly greater when preceded by down-r s, than when not preceded by another r . R context did not affect down-r perception. The contribution to the fields of music perception and psychoacoustics are discussed in the context of real-time perception of music, principles of music composition, and performance of musical dynamics.

Influence of a continuous affect ratings task on listening time for unfamiliar art music

Publisher: Informa UK Limited

Date: 04-01-2021

DOI: 10.1080/09298215.2020.1867588

Interference in memory for pitch-only and rhythm-only sequences

Publisher: SAGE Publications

Date: 02-2018

DOI: 10.1177/1029864917695654

Abstract: In human memory, the ability to recognize a previously encountered stimulus often undergoes cumulative interference when the number of intervening items between its first and second presentation increases. Although this is a common effect in many domains, melodies composed in tuning systems familiar to participants (e.g., Western tonal music) do not seem to suffer such cumulative decrements in recognition performance. Interestingly, melodies in unfamiliar tuning systems do show cumulative decrements. This finding has been predicted by a novel Regenerative Multiple Representations (RMR) conjecture. The present study further explores this phenomenon and the conjecture by investigating pitch-only (isochronous rhythm) and rhythm-only (monotone pitch) sequences of melodies in an unfamiliar tuning system that previously showed cumulative disruptive effects. Experiment 1 replicated previous studies reporting significant interference effects from the number of intervening items when melodies use uncommon rhythms and are composed in an unfamiliar tuning system. Furthermore, as predicted by the RMR conjecture, when rhythmic information was neutralized (Experiment 2), the cumulative interference related to the number of intervening items was retained. This was also the case when the original pitch information of each melody was neutralized, leaving variation only in the rhythmic information (Experiment 3). Results are discussed in the context of the RMR conjecture: given converse results, the conjecture would have been falsified. However, it currently remains plausible and appears to be a useful tool for precise predictions about the link between prior experience, perception, and formation of new memories.

Induction of DNA damage by oxidised amino acids and proteins

Publisher: Springer Science and Business Media LLC

Date: 2002

DOI: 10.1023/A:1015228001561

Abstract: Exposure of amino acids, peptides and proteins to radicals in the presence of O2 generates hydroperoxides in a dose-dependent manner. These hydroperoxides are stable in the absence of exogenous catalysts (e.g. heat, light, redox-active transition metal ions), but decompose rapidly in the presence of these agents to give a variety of radicals including alkoxyl (RO*), peroxyl (ROO*) and carbon-centred (R) species. These radicals are shown to react with DNA to give DNA-protein cross-links and single strand breaks.

Recent developments in the intracellular degradation of oxidized proteins.

Publisher: Elsevier BV

Date: 10-2002

DOI: 10.1016/S0891-5849(02)00958-9

Abstract: The accumulation of oxidized proteins in cells and tissues is a feature of a number of age-related diseases and may also occur as a result of the aging process itself. In this article we review recent advances in our understanding of the cellular degradation of oxidized proteins directing our attention primarily to information which directly bears on the behavior of intact eukaryotic cells. We summarize new work on the key intracellular degradative machineries, proteasomes and lysosomes and examine evidence implicating an increase in protein hydrophobicity as the primary signal to the proteasome to initiate degradation. The data identifying the proteasome as the main route of degradation of oxidized proteins is examined, as well as recent data investigating changes in proteasome function after exposure of cells to oxidants and the altered catabolism of oxidized proteins in aging cells. Evidence for the cooperation between the lysosomal and proteasomal systems in the degradation of oxidized proteins is discussed. We conclude that the cellular catabolism of oxidized proteins may be a more complex process than it first appeared and suggest key issues that need to be resolved to improve our understanding of this important process.

Empirical Studies of Computer Sound

Publisher: Oxford University Press

Date: 22-04-2011

DOI: 10.1093/OXFORDHB/9780199792030.013.0023

Discovery Projects - Grant ID: DP0212084

Start Date: 2002

End Date: 12-2004

Amount: $248,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0880512

Start Date: 03-2008

End Date: 03-2012

Amount: $198,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP200301401

Start Date: 07-2021

End Date: 06-2025

Amount: $262,130.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP0667671

Start Date: 12-2006

End Date: 07-2010

Amount: $130,110.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP120102426

Start Date: 07-2012

End Date: 12-2017

Amount: $254,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP190102012

Start Date: 06-2019

End Date: 12-2023

Amount: $408,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP150100487

Start Date: 01-2016

End Date: 12-2021

Amount: $243,727.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP180100697

Start Date: 10-2019

End Date: 10-2024

Amount: $335,250.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0668448

Start Date: 05-2006

End Date: 12-2007

Amount: $150,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0989831

Start Date: 01-2009

End Date: 01-2010

Amount: $205,000.00

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE220100057

Start Date: 04-2023

End Date: 04-2025

Amount: $751,723.00

Funder: Australian Research Council

Research Networks - Grant ID: RN0460284

Start Date: 12-2004

End Date: 12-2010

Amount: $2,000,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP0453179

Start Date: 07-2004

End Date: 12-2008

Amount: $277,000.00

Funder: Australian Research Council