Search results for "Channels"
showing 10 items of 411 documents
Differential effects of potassium channel blockers on neurohypophysial release of oxytocin and vasopressin. Evidence for frequency-dependent interact…
1988
Isolated rat neurohypophyses were fixed by their stalks to a platinum wire electrode and superfused with Krebs-HEPES solution. Vasopressin and oxytocin released into the medium were determined by specific radioimmunoassays. Hormone secretion was increased by electrical stimulation of the pituitary stalk at different frequencies. The effects of several potassium channel blockers, tetraethylammonium (TEA) ions, 4-aminopyridine (4-AP) and 3,4-diaminopyridine (3,4-DAP) were tested. The release of vasopressin and oxytocin evoked by electrical stimulation with 900 pulses at 15 Hz (about 900 and 1,000 μU, respectively) was about 10 times higher than that evoked by 900 pulses at 3 Hz. Both 10 and 3…
Cardiac pacemaker function of HCN4 channels in mice is confined to embryonic development and requires cyclic AMP.
2008
Important targets for cAMP signalling in the heart are hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels that underlie the depolarizing 'pacemaker' current, I(f). We studied the role of I(f) in mice, in which binding of cAMP to HCN4 channels was abolished by a single amino-acid exchange (R669Q). Homozygous HCN4(R669Q/R669Q) mice die during embryonic development. Prior to E12, homozygous and heterozygous embryos display reduced heart rates and show no or attenuated responses to catecholaminergic stimulation. Adult heterozygous mice display normal heart rates at rest and during exercise. However, following beta-adrenergic stimulation, hearts exhibit pauses and sino-atrial…
The Role of the Amygdala in the Extinction of Conditioned Fear
2006
The amygdala has long been known to play a central role in the acquisition and expression of fear. More recently, convergent evidence has implicated the amygdala in the extinction of fear as well. In rodents, some of this evidence comes from the infusion of drugs directly into the amygdala and, in particular, into the basolateral complex of the amygdala, during or after extinction learning. In vivo electrophysiology has identified cellular correlates of extinction learning and memory in the lateral nucleus of that structure. Human imaging experiments also indicate that amygdaloid activity correlates with extinction training. In addition, some studies have directly identified changes in mole…
An Exact Solution for the Level-Crossing Rate and the Average Duration of Fades of the Envelope of Sum-of-Cisoids Processes
2012
Authors version of an article published in the journal: Procedia Technology. Also available from the publisher at: http://dx.doi.org/10.1016/j.protcy.2012.03.004 Sum-of-cisoids (SOC) processes provide a physically and numerically appealing framework for the modelling and simulation of a wide class of mobile radio channels. This paper is concerned with the problem of finding a general solution for the level-crossing rate (LCR) and the average duration of fades (ADF) of the envelope of SOC processes. Exact expressions are derived for the LCR and the ADF by taking into account that the inphase component, the quadrature component, and the time derivatives of the inphase and quadrature component…
Eight new mutations and the expanding phenotype variability in muscular dystrophy caused by ANO5.
2012
Objective: Description of 8 new ANO5 mutations and significant expansion of the clinical phenotype spectrum associated with previously known and unknown mutations to improve diagnostic accuracy. Methods: DNA samples of 101 patients in 95 kindreds at our quaternary referral center in Finland, who had undetermined limb-girdle muscular dystrophy (LGMD), calf distal myopathy, or creatine kinase (CK) elevations of more than 2,000 IU/L, were selected for ANO5 genetic evaluation, and the clinical findings of patients with mutations were retrospectively analyzed. Results: A total of 25 patients with muscular dystrophy caused by 11 different recessive mutations in the ANO5 gene were identified. The …
The pain threshold of high-threshold mechanosensitive receptors subsequent to maximal eccentric exercise is a potential marker in the prediction of D…
2017
Background Delayed-onset muscle soreness (DOMS) refers to dull pain and discomfort in people after participating in exercise, sport or recreational physical activities. The aim of this study was to detect underlying mechanical thresholds in an experimental model of DOMS. Methods Randomised study to detect mechanical pain thresholds in a randomised order following experimentally induced DOMS of the non-dominant arm in healthy participants. Main outcome was the detection of the pressure pain threshold (PPT), secondary thresholds included mechanical detection (MDT) and pain thresholds (MPT), pain intensity, pain perceptions and the maximum isometric voluntary force (MIVF). Results Twenty volun…
Linear fusion of interrupted reports in cooperative spectrum sensing for cognitive radio networks
2015
Interrupted reporting has recently been introduced as an effective method to increase the energy efficiency of cooperative spectrum sensing schemes in cognitive radio networks. In this paper, joint optimization of the reporting and fusion phases in a cooperative sensing with interrupted reporting is considered. This optimization aims at finding the best weights used at the fusion center to construct a linear fusion of the received interrupted reports, jointly with Bernoulli distributions governing the statistical behavior of the interruptions. The problem is formulated by using the deflection criterion and as a nonconvex quadratic program which is then solved for a suboptimal solution, in a…
Does the Learning Channel Really Matter? - Insights from Commercial Online ICT-training
2017
Evolving ICT has provided new options to participate to training. Online participation has been found to be cost effective, helping people to deal with the time and cost pressures they are facing on their jobs. Previous studies conducted in higher education sector indicates that student satisfaction or learning outcomes does not differ between online and classroom participants. However, little is known what is the situation in commercial ICT-training. This paper studied course feedbacks from courses having both online and classroom participants of a commercial ICT-training provider. Results revealed that the learning channel has no effect on satisfaction, perceived teacher’s substance and t…
Estimation of the Time-Variant Velocity of a Single Walking Person in Two-Dimensional Non-Stationary Indoor Environments Using Radio-Frequency Techni…
2020
Accurate estimation of the time-variant (TV) velocity of moving persons/objects in indoor spaces is of crucial importance for numerous wireless indoor applications. This article introduces a novel iterative procedure to estimate the TV velocity, i.e., TV speed and TV angle-of-motion (AOM), of a single moving person in 2D indoor environments by using radio-frequency (RF) techniques. The indoor area is equipped with a distributed 2 × 2 multiple-input multiple-output (MIMO) system. The proposed method is divided into two parts. In the first part, we estimate the path gains and the instantaneous Doppler frequencies by fitting the exact spectrograms of the complex channel gains of a 2D no…
Asymmetric effects of monetary policy shocks across US states
2019
This paper provides new empirical evidence of the asymmetric effects of monetary policy shocks across regions. Using a measure of unanticipated changes in the Fed's policy rates over the period 1969Q3–2008Q4 and a local projection method extended to account for spatial effects, we find that monetary policy tightening leads to a long-lasting decrease in states' real personal income, with asymmetric effects across states that are amplified by spatial spillovers. The paper then investigates the role played by several transmission channels finding larger contractionary effects of monetary policy tightening in states with higher manufacturing share, smaller firms, smaller banks and higher house …