369 research outputs found

    Thermal Conductivity and Related Properties of Heated Ground Pectoral Turkey Muscles

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    Thermal conductivity, in association with characteristics of the thermodynamic medium at the food surface, establishes heat flow at the food boundary and reflects the transient properties meat has undergone during temperature change. The purpose of this research was to design and build an apparatus to measure thermal conductivity and to study some of the transient properties of ground pectoral turkey muscles. Ground turkey pectoral muscles were heated in 9 increments from 77 to 185°F and held at end point temperature for 0 to 15 minutes. Thermal conductivity was calculated directly from data or indirectly by solving for diffusivity and then calculating for thermal conductivity. Water-holding capacity (expressible moisture index, total moisture, cooking loss), protein solubility (protein extractability), and change in pH were studied to determine the possible relation between thermal conductivity and protein denaturation. The thermal conductivity values were expressed in terms of cal/sec cm °F or Btu/hr ft °F. With both methods of calculation, thermal conductivity values were significantly affected (P \u3c 0.05) by end point temperature at the 0 minute but not at the 15 minute holding time even though holding times per se had no significant effect. Several approaches and modes of calculation of the thermal properties suggested that conductivity values were influenced by a number of factors. Protein denaturation was postulated as a factor contributing to inconsistencies in thermal values. Significant (P \u3c 0.01) effect of temperature upon cooking loss, total moisture, and expressible moisture suggested protein denaturation. The water-holding capacity expressed by these determinations tended to decrease with increasing temperature. These changes were greatest in the end point temperature range of 104 to 158°F. Protein solubility decreased with increase in end point temperature from 77 to 131 to 185°F. A protein fraction extracted with phosphate buffer (I = 0.05, pH 7.6) decreased in solubility 30 percent and 60 percent from an initial end point at 77 to 131 to 185°F, respectively. The pH was significantly (P \u3c 0.01) affected by temperature. With all parameters, no difference was found between holding times. It can be postulated that the denaturation phenomenon in the current experiment influenced conductivity values by the changes in structure and composition of the muscle system as well as by the energy consumption involved in conformational changes of the protein. However, specific relationships were not defined

    Coherent fluctuation relations: from the abstract to the concrete

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    Recent studies using the quantum information theoretic approach to thermodynamics show that the presence of coherence in quantum systems generates corrections to classical fluctuation theorems. To explicate the physical origins and implications of such corrections, we here convert an abstract framework of an autonomous quantum Crooks relation into quantum Crooks equalities for well-known coherent, squeezed and cat states. We further provide a proposal for a concrete experimental scenario to test these equalities. Our scheme consists of the autonomous evolution of a trapped ion and uses a position dependent AC Stark shift

    Neurophysiological markers discriminate different forms of motor imagery during action observation

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    The dual-action simulation hypothesis proposes that both an observed and an imagined action can be represented simultaneously in the observer's brain. These two sensorimotor streams would either merge or compete depending on their relative suitability for action planning. To test this hypothesis, three forms of combined action observation and motor imagery (AO + MI) instructions were used in this repeated-measures experiment. Participants observed index finger abduction-adduction movements while imagining the same action (congruent AO + MI), little finger abduction-adduction (coordinative AO + MI), or a static hand (conflicting AO + MI). Single-pulse transcranial magnetic stimulation was applied to the left primary motor cortex. The amplitude of motor evoked potential responses were recorded from both the first dorsal interosseous (FDI) and abductor digiti minimi (ADM) muscles of the right-hand while eye movements were tracked. When controlling for the influence of relevant eye movements, corticospinal excitability was facilitated relative to control conditions in the concurrently observed and imagined muscles for both congruent and coordinative AO + MI conditions. Eye-movement metrics and social validation data from post–experiment interviews provided insight into the attentional and cognitive mechanisms underlying these effects. The findings provide empirical support for the dual-action simulation hypothesis, indicating for the first time that it is possible to co-represent observed and imagined actions simultaneously

    High-fidelity dimer excitations using quantum hardware

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    Many-body entangled quantum spin systems exhibit emergent phenomena such as topological quantum spin liquids with distinct excitation spectra accessed in inelastic neutron scattering (INS) experiments. Here we simulate the dynamics of a quantum spin dimer, the basic quantum unit of emergent many-body spin systems. While canonical Trotterization methods require deep circuits precluding long time-scale simulations, we demonstrate 'direct' Resource-Efficient Fast-forwarding (REFF) measurements with short-depth circuits that can be used to capture longer time dynamics on quantum hardware. The temporal evolution of the 2-spin correlation coefficients enabled the calculation of the dynamical structure factor S(Q,ω)S(\mathbf{Q},\omega) - the key component of the neutron scattering cross-section. We simulate the triplet gap and the triplet splitting of the quantum dimer with sufficient fidelity to compare to experimental neutron data. Our results on current circuit hardware pave an important avenue to benchmark, or even predict, the outputs of the costly INS experiments.Comment: 24 pages, 3 tables, 16 figures, main text and supplementary material

    Psychological stress, cognitive decline and the development of dementia in amnestic mild cognitive impairment

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    To determine the relationship between psychological stress with cognitive outcomes in a multi-centre longitudinal study of people with amnestic mild cognitive impairment (aMCI) we assessed three parameters of psychological stress (Recent Life Changes Questionnaire (RLCQ); the Perceived Stress Scale (PSS) and salivary cortisol) and their relationship with rates of cognitive decline over an 18 month follow up period and conversion to dementia over a 5.5 year period. In 133 aMCI and 68 cognitively intact participants the PSS score was higher in the aMCI compared with control group but neither the RLCQ scores nor salivary cortisol measures were different between groups. In the aMCI group the RLCQ and the PSS showed no significant association with cognitive function at baseline, cognitive decline or with conversion rates to dementia but high salivary cortisol levels were associated with RLCQ scores and poorer cognitive function at baseline and lower rates of cognitive decline. No relationship was found between salivary cortisol levels and conversion rate to dementia. We conclude that psychological stress as measured by the RLCQ or PSS was not associated with adverse cognitive outcomes in an aMCI population and hypothesise that this may reflect diminished cortisol production to psychological stress as the disease progresses.</p

    Best-practice prevention alone or with conventional or biological caries management for 3- to 7-year-olds:the FiCTION three-arm RCT

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    Background Historically, lack of evidence for effective management of decay in primary teeth has caused uncertainty, but there is emerging evidence to support alternative strategies to conventional fillings, which are minimally invasive and prevention orientated. Objectives The objectives were (1) to assess the clinical effectiveness and cost-effectiveness of three strategies for managing caries in primary teeth and (2) to assess quality of life, dental anxiety, the acceptability and experiences of children, parents and dental professionals, and caries development and/or progression. Design This was a multicentre, three-arm parallel-group, participant-randomised controlled trial. Allocation concealment was achieved by use of a centralised web-based randomisation facility hosted by Newcastle Clinical Trials Unit. Setting This trial was set in primary dental care in Scotland, England and Wales. Participants Participants were NHS patients aged 3–7 years who were at a high risk of tooth decay and had at least one primary molar tooth with decay into dentine, but no pain/sepsis. Interventions Three interventions were employed: (1) conventional with best-practice prevention (local anaesthetic, carious tissue removal, filling placement), (2) biological with best-practice prevention (sealing-in decay, selective carious tissue removal and fissure sealants) and (3) best-practice prevention alone (dietary and toothbrushing advice, topical fluoride and fissure sealing of permanent teeth). Main outcome measures The clinical effectiveness outcomes were the proportion of children with at least one episode (incidence) and the number of episodes, for each child, of dental pain or dental sepsis or both over the follow-up period. The cost-effectiveness outcomes were the cost per incidence of, and cost per episode of, dental pain and/or dental sepsis avoided over the follow-up period. Results A total of 72 dental practices were recruited and 1144 participants were randomised (conventional arm, n = 386; biological arm, n = 381; prevention alone arm, n = 377). Of these, 1058 were included in an intention-to-treat analysis (conventional arm, n = 352; biological arm, n = 352; prevention alone arm, n = 354). The median follow-up time was 33.8 months (interquartile range 23.8–36.7 months). The proportion of children with at least one episode of pain or sepsis or both was 42% (conventional arm), 40% (biological arm) and 45% (prevention alone arm). There was no evidence of a difference in incidence or episodes of pain/sepsis between arms. When comparing the biological arm with the conventional arm, the risk difference was –0.02 (97.5% confidence interval –0.10 to 0.06), which indicates, on average, a 2% reduced risk of dental pain and/or dental sepsis in the biological arm compared with the conventional arm. Comparing the prevention alone arm with the conventional arm, the risk difference was 0.04 (97.5% confidence interval –0.04 to 0.12), which indicates, on average, a 4% increased risk of dental pain and/or dental sepsis in the prevention alone arm compared with the conventional arm. Compared with the conventional arm, there was no evidence of a difference in episodes of pain/sepsis among children in the biological arm (incident rate ratio 0.95, 97.5% confidence interval 0.75 to 1.21, which indicates that there were slightly fewer episodes, on average, in the biological arm than the conventional arm) or in the prevention alone arm (incident rate ratio 1.18, 97.5% confidence interval 0.94 to 1.48, which indicates that there were slightly more episodes in the prevention alone arm than the conventional arm). Over the willingness-to-pay values considered, the probability of the biological treatment approach being considered cost-effective was approximately no higher than 60% to avoid an incidence of dental pain and/or dental sepsis and no higher than 70% to avoid an episode of pain/sepsis. Conclusions There was no evidence of an overall difference between the three treatment approaches for experience of, or number of episodes of, dental pain or dental sepsis or both over the follow-up period
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