8,329 research outputs found

    Small heat-shock proteins: important players in regulating cellular proteostasis

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    Small heat-shock proteins (sHsps) are a diverse family of intra-cellular molecular chaperone proteins that play a critical role in mitigating and preventing protein aggregation under stress conditions such as elevated temperature, oxidation and infection. In doing so, they assist in the maintenance of protein homeostasis (proteostasis) thereby avoiding the deleterious effects that result from loss of protein function and/or protein aggregation. The chaperone properties of sHsps are therefore employed extensively in many tissues to prevent the development of diseases associated with protein aggregation. Significant progress has been made of late in understanding the structure and chaperone mechanism of sHsps. In this review, we discuss some of these advances, with a focus on mammalian sHsp hetero-oligomerisation, the mechanism by which sHsps act as molecular chaperones to prevent both amorphous and fibrillar protein aggregation, and the role of post-translational modifications in sHsp chaperone function, particularly in the context of disease.SM was supported by a Royal Society Dorothy Hodgkin Fellowship, HE is supported by an Australian Research Council Future Fellowship (FT110100586) and JC is supported by a National Health and Medical Research Council Project Grant (#1068087)

    Delay-time optimization for driving and sensing of signals on high-capacitance paths of VLSI systems

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    Minimization of the delay times associated with driving and sensing signals from large capacitance paths by optimizing the fan-out factor of the driver stages, the gain of the input sensing stages, and the path voltage swing are examined. Examples of driving signals on a high capacitance path with two driving schemes are: a push-pull depletion-load driver chain and a fixed driver; and of sensing signals with two sensing schemes: a single-ended depletion-load inverter input stage and a balanced regenerative strobed latch are presented

    Parity-Violating Interaction Effects in the np System

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    We investigate parity-violating observables in the np system, including the longitudinal asymmetry and neutron-spin rotation in np elastic scattering, the photon asymmetry in np radiative capture, and the asymmetries in deuteron photo-disintegration d(gamma,n)p in the threshold region and electro-disintegration d(e,e`)np in quasi-elastic kinematics. To have an estimate of the model dependence for the various predictions, a number of different, latest-generation strong-interaction potentials--Argonne v18, Bonn 2000, and Nijmegen I--are used in combination with a weak-interaction potential consisting of pi-, rho-, and omega-meson exchanges--the model known as DDH. The complete bound and scattering problems in the presence of parity-conserving, including electromagnetic, and parity-violating potentials is solved in both configuration and momentum space. The issue of electromagnetic current conservation is examined carefully. We find large cancellations between the asymmetries induced by the parity-violating interactions and those arising from the associated pion-exchange currents. In the np capture, the model dependence is nevertheless quite small, because of constraints arising through the Siegert evaluation of the relevant E1 matrix elements. In quasi-elastic electron scattering these processes are found to be insignificant compared to the asymmetry produced by gamma-Z interference on individual nucleons.Comment: 65 pages, 26 figures, submitted to PR

    Charge transfer in overlapping gate charge-coupled devices

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    A detailed numerical simulation of the free charge transfer in overlapped gate charge-coupled devices is presented. The transport are analyzed in terms of thermal diffusion, self-induced fields, and fringing fields under all the relevant electrodes and interelectrode regions with time-varying gate potentials. The results of the charge transfer with different clocking schemes and clocking waveforms are presented. The dependence of the stages of the charge transfer on the device parameters are discussed in detail. A lumped-circuit model of CCD that could be used to obtain the charge-transfer characteristics with various clocking waveforms is also presented

    Small heat-shock proteins and clusterin: intra- and extracellular molecular chaperones with a common mechanism of action and function

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    Small heat-shock proteins (sHsps) and clusterin are molecular chaperones that share many functional similarities despite their lack of significant sequence similarity. These functional similarities, and some differences, are discussed. sHsps are ubiquitous intracellular proteins whereas clusterin is generally found extracellularly. Both chaperones potently prevent the amorphous aggregation and precipitation of target proteins under stress conditions such as elevated temperature, reduction and oxidation. In doing so, they act on the slow off-folding protein pathway. The conformational dynamism and aggregated state of both proteins may be crucial for their chaperone function. Subunit exchange is likely to be important in regulating chaperone action; the dissociated form of the protein is probably the chaperone-active species rather than the aggregated state. They both exert their chaperone action without the need for hydrolysis of ATP and have little ability to refold target proteins. Increased expression of sHsp and clusterin accompanies a range of diseases, e.g. Alzheimer’s, Creutzfeldt-Jakob and Parkinson’s diseases, that arise from protein misfolding and deposition of highly structured protein aggregates known as amyloid fibrils. The interaction of sHsps and clusterin with fibril-forming species is discussed along with their ability to prevent fibril formation, probably via utilization of their chaperone ability

    Small heat-shock proteins: important players in regulating cellular proteostasis

    Get PDF
    Small heat-shock proteins (sHsps) are a diverse family of intra-cellular molecular chaperone proteins that play a critical role in mitigating and preventing protein aggregation under stress conditions such as elevated temperature, oxidation and infection. In doing so, they assist in the maintenance of protein homeostasis (proteostasis) thereby avoiding the deleterious effects that result from loss of protein function and/or protein aggregation. The chaperone properties of sHsps are therefore employed extensively in many tissues to prevent the development of diseases associated with protein aggregation. Significant progress has been made of late in understanding the structure and chaperone mechanism of sHsps. In this review, we discuss some of these advances, with a focus on mammalian sHsp hetero-oligomerisation, the mechanism by which sHsps act as molecular chaperones to prevent both amorphous and fibrillar protein aggregation, and the role of post-translational modifications in sHsp chaperone function, particularly in the context of disease

    An Analysis of Governed vs Different Focal Points on Vertical Jump Performance in Collegiate Males

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    Please see the pdf version of the abstract

    Voltage control of nuclear spin in ferromagnetic Schottky diodes

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    We employ optical pump-probe spectroscopy to investigate the voltage dependence of spontaneous electron and nuclear spin polarizations in hybrid MnAs/n-GaAs and Fe/n-GaAs Schottky diodes. Through the hyperfine interaction, nuclear spin polarization that is imprinted by the ferromagnet acts on conduction electron spins as an effective magnetic field. We demonstrate tuning of this nuclear field from <0.05 to 2.4 kG by varying a small bias voltage across the MnAs device. In addition, a connection is observed between the diode turn-on and the onset of imprinted nuclear polarization, while traditional dynamic nuclear polarization exhibits relatively little voltage dependence.Comment: Submitted to Physical Review B Rapid Communications. 15 pages, 3 figure

    The influence of interface states on incomplete charge transfer in overlapping gate charge-coupled devices

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    A simple and accurate model is used to estimate the incomplete charge transfer due to interface states trapping in the overlapping gate charge-coupled devices. It is concluded that trapping in the interface states under the edges of the gates parallel to the active channel limits the performance of the devices at moderate and low frequencies. The influence of the device parameters, dimensions, and clocking waveforms on the signal degradation is discussed. It is shown that increasing the clock voltages, reduces the incomplete charge transfer due to interface state trapping

    Application of a Fath-Based Integration Tool to Assess Mental and Physical Health Interventions

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    Background: To build on current research involving faith-based interventions (FBIs) for addressing mental and physical health, this study a) reviewed the extent to which relevant publications integrate faith concepts with health and b) initiated analysis of the degree of FBI integration with intervention outcomes. Methods: Derived from a systematic search of articles published between 2007 and 2017, 36 studies were assessed with a FaithBased Integration Assessment Tool (FIAT) to quantify faith-health integration. Basic statistical procedures were employed to determine the association of faith-based integration with intervention outcomes. Results: The assessed studies possessed (on average) moderate, inconsistent integration because of poor use of faith measures, and moderate, inconsistent use of faith practices. Analysis procedures for determining the effect of FBI integration on intervention outcomes were inadequate for formulating practical conclusions. Conclusions: Regardless of integration, interventions were associated with beneficial outcomes. To determine the link between FBI integration and intervention outcomes, additional analyses are needed. Key words: faith-based integration and interventions, faith and health studies, religion and spirituality, integrative healt
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