In this paper we address the issue of enriching the fruition of museums and art shows for the visitors. We preliminary consider the design of an immersive audio environment by means of 3D audio ...rendering, aiming to provide each user a deeper connection with each exhibited artwork. By exploiting a real-time binaural audio system, artworks become virtual sources of the audio guide voice, making the user perceive they personally speak to her/him. As an advantage, the implementation of the proposed framework relies on basic audio and signal processing techniques, that is, no expensive or personalized equipment for the visitors is required. Furthermore, since the proposed method is independent of the recording stage, existing audio tracks or even real-time speech can be used.
5-HT4 receptors are present in human atrial cells and their stimulation has been implicated in the genesis of atrial arrhythmias including atrial fibrillation. An I(f)-like current has been recorded ...in human atrial myocytes, where it is modulated by beta-adrenergic stimulation. In the present study, we investigated the effect of serotonin (5-hydroxytryptamine, 5-HT) on I(f) electrophysiological properties, in order to get an insight into the possible contribution of I(f) to the arrhythmogenic action of 5-HT in human atria.
Human atrial myocytes were isolated by enzymatic digestion from samples of atrial appendage of patients undergoing coeffective cardiac surgery. Patch-clamped cells were superfused with a modified Tyrode's solution in order to amplify I(f) and reduce overlapping currents.
A time-dependent, cesium-sensitive increasing inward current, that we had previously described having the electrophysiological properties of the pacemaker current I(f), was elicited by negative steps (-60 to -130 mV) from a holding potential of -40 mV. Boltzmann fit of control activation curves gave a midpoint (V1/2) of -88.9 +/- 2.6 mV (n = 14). 5-HT (1 microM) consistently caused a positive shift of V1/2 of 11.0 +/- 2.0 mV (n = 8, p < 0.001) of the activation curve toward less negative potentials, thus increasing the amount of current activated by clamp steps near the physiological maximum diastolic potential of these cells. The effect was dose-dependent, the EC50 being 0.14 microM. Maximum current amplitude was not changed by 5-HT. 5-HT did not increase I(f) amplitude when the current was maximally activated by cAMP perfused into the cell. The selective 5-HT4 antagonists, DAU 6285 (10 microM) and GR 125487 (1 microM), completely prevented the effect of 5-HT on I(f). The shift of V1/2 caused by 1 microM 5-HT in the presence of DAU 6285 or GR 125487 was 0.3 +/- 1 mV (n = 6) and 1.0 +/- 0.6 mV (n = 5), respectively (p < 0.01 versus 5-HT alone). The effect of 5-HT4 receptor blockade was specific, since neither DAU 6285 nor GR 125487 prevented the effect of 1 microM isoprenaline on I(f). Thus, 5-HT4 stimulation increases I(f) in human atrial myocytes; this effect may contribute to the arrhythmogenic action of 5-HT in human atrium.
To monitor cardiac troponin I (cTnI), a newly developed biochemical index for cardiac damage, in patients during and after coronary artery bypass surgery (CABS) to determine whether the measurement ...of the serum levels of this marker could be of value in formulating an early diagnosis of Q-wave perioperative myocardial infarction (PMI).
Prospective study with sequential measurements of biological markers in a selected surgical patient group.
University research laboratory and general university hospital (Cardiac Surgery Unit and Anesthesiology and Reanimation Unit).
Forty-two patients undergoing elective CABS without concomitant valvular replacement.
There were no interventions required for this study. However, patients entered into the study had CABS, sequential arterial blood samples, ECG recordings, and echocardiograms performed.
Pre-, intra-, and postoperative (up to 48 hrs) measurements of cardiac troponin I, MB-CK, and total creatine kinase, as well as serial electrocardiograms and echocardiograms. Perioperative infarction was assessed as the development of new persistent regional wall motion abnormalities in echocardiography together with electrocardiographic alterations and MB-CK increases. Eight patients had Q-wave PMI. All PMI patients had elevated peak cTnI values (all >9.2 ng/mL), whereas the 34 nonPMI patients had peak values <9.0 ng/mL; therefore, sensitivity and specificity (with a 9.0 ng/mL cut-off value) are 100%. MB-CK measurement peak values did not demonstrate such a high specificity and sensitivity.
Because of its high specificity and sensitivity, serial measurements of cTnI provide a rapid and accurate method for confirming or excluding the diagnosis of perioperative myocardial injury. cTnI evaluation can therefore be used both as an independent prognostic marker for patients undergoing cardiac surgery and as a powerful tool for detecting smaller PMIs often missed with standard PMI diagnostic criteria.
We present additional results from our ongoing lunar occultation program. Observations are presented here for a total of seventeen sources, for the majority of which one or two new companions are ...detected. The sample comprises mostly field stars, spanning a large range of spectral types. Two infrared objects without optical counterpart are also included. The range of projected separations is $0\farcs007$ to $0\farcs162$. We report on the following binary stars: IRAS 16576-2116, IRAS 19495-1628, IRAS 18033-1955, CGCS 3964, SAO 94064, EI Tau, SAO 93950, SAO 79217, SAO 79285 and SAO 80075. We found HD 247924 and SAO 139322 to be triple systems. In the case of SAO 93950, the revised analysis of two occultation events has provided the true position angle and separation of this system. We also observed the young T Tauri star GG Tau A, where we detected a significant orbital motion with respect to the latest available measurements. In two cases, SAO 79285 and SAO 139322, a companion was already claimed on the basis of Hipparcos results, but our observations are not entirely consistent with these latter. Finally, our sample includes four stars known to be binary, namely SAO 186497, SAO 162183, SAO 96753 and SAO 161192, for which we did not detect a companion. Among these, our negative detection of the companion of SAO 162183 poses strong constraints on the parameters of this presumed binary.
We have measured the radiative lifetime of the 2s22p4 1S0 metastable level of Ne2+ (Ne iii) to be 223+/-11 ms at the 90% confidence level by observing the photons emitted at 1815 Å by a decaying ...population of 1S0 Ne2+ ions produced and stored in a radio-frequency ion trap. This is the first lifetime measurement for an excited term of a ground configuration ion in the second row of the periodic table. The transition probabilities (A-values) for the forbidden transitions in the ground configurations of these ions are required for astrophysical line-ratio diagnostics. Using calculated branching ratios, we estimate that A lambda1815 =1.94+/-0.17 and A lambda3344 =2.55+/-0.19 s-1. Because these numbers have a sum with an experimentally determined uncertainty of 5%, they will provide more accurate results than the calculated A-values for determining electron temperature and density from astrophysical Ne iii line ratios.
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