A Novel Algorithm for Movement Artifact Removal in ECG Signals Acquired from Wearable Systems Applied to Horses

This study reports on a novel method to detect and reduce the contribution of movement artifact (MA) in electrocardiogram (ECG) recordings gathered from horses in free movement conditions. We propose a model that integrates cardiovascular and movement information to estimate the MA contribution. Specifically, ECG and physical activity are continuously acquired from seven horses through a wearable system. Such a system employs completely integrated textile electrodes to monitor ECG and is also equipped with a triaxial accelerometer for movement monitoring. In the literature, the most used technique to remove movement artifacts, when noise bandwidth overlaps the primary source bandwidth, is the adaptive filter. In this study we propose a new algorithm, hereinafter called Stationary Wavelet Movement Artifact Reduction (SWMAR), where the Stationary Wavelet Transform (SWT) decomposition algorithm is employed to identify and remove movement artifacts from ECG signals in horses. A comparative analysis with the Normalized Least Mean Square Adaptive Filter technique (NLMSAF) is performed as well. Results achieved on seven hours of recordings showed a reduction greater than 40% of MA percentage (between before- and after- the application of the proposed algorithm). Moreover, the comparative analysis with the NLMSAF, applied to the same ECG recordings, showed a greater reduction of MA percentage in favour of SWMAR with a statistical significant difference (p–value < 0.0.5).     

The presence of immunoreactive vertebrate bioactive peptide substances in hemocytes of the freshwater snailViviparus ater (gastropoda,prosobranchia)

1. Using an immunocytochemical procedure a wide range of immunoreactive vertebrate bioactive peptides (BAPs) has been found in hemocytes of Viviparus ater: bombesin, calcitonin, CCK-8, CCK-39, GH, glucagon, insulin, oxytocin, neurotensin, secretin, serotonin, somatostatin, substance P, vasopressin, and VIP. 2. No immunostaining was observed for antigastrin and antithyroglobulin antibodies. 3. The presence of BAP-like molecules in hemocytes suggests a correlation between hemocyte and APUD cells and is evidence of a relationship between the neuroendocrine and the immune systems.     

Tissue distribution and levels of natural and induced serum lysozyme immunoreactive molecules in a freshwater snail

Lysozyme immunoreactive molecules (irLm) in Planorbarius corneus was demonstrated by an immunocytochemical method in oocytes, the kidney, spreading phagocytic hemocytes (SH), digestive phagocytic cells, and epithelial cells of the stomach and intestine. Three hr after the injection of a variety of bacteria or substances (S. aureus, E. coli, E. coli LPS, latex particles, PBS) a statistically significant increase in irLm serum level was detected by the microELISA method. Twenty-four hr later, this increase was detected only in specimens which had been injected with bacteria. A similar response was observed 14 days later, following a second injection of the above-mentioned substances in the same snails. The results suggest that: 1) irLm appears to be an inducible molecule responding non-specifically to foreign challenge; 2) no anamnestic response is observed for irLm; 3) a relationship exists between irLm and phagocytosis; indeed, irLm have chemotactic activity towards SH; 4) serum irLm probably originates from different sources; in fact, they are released from SH and the kidney. The increase in the serum irLm level is responsible, at least in part, for the lytic attack and death of bacteria, but it is probably also involved in unspecific inflammatory reactions.     

Acoustic structure of vocalization and stapedius muscle activity during vocal development in chickens (Gallus gallus)

The link between stapedius muscle activity and acoustic structure of vocalization was analysed in cocks of age 20–30 to 90–100 days old. The results show that stapedius muscle activation depends on the acoustic structure of vocalization and changes during vocal development. This dependence was observed in spontaneous calls and in vocalizations elicited by stimulating the mesencephalic calling area. In 30-day-old cocks stapedius muscle EMG response is never associated with vocalizations with an acoustic energy content which is always distributed at frequencies higher than 2000 Hz. The coupling between vocalization and stapedius muscle activity begins later, when birds produce vocalizations with acoustic energy shifted towards lower frequencies. Overall, stapedius muscle activity is related to a bird's production of high amplitude low frequencies. These results support the hypothesis that the primary role of the stapedius muscle during normal vocal development is to dampen the amplitude of low frequency energy that reaches the cochlea during vocalization.     

Towards MRI contrast agents of improved efficacy. NMR relaxometric investigations of the binding interaction to HSA of a novel heptadentate macrocyclic triphosphonate Gd(III)-complex

 A novel heptacoordinating ligand consisting of a thirteen-membered tetraazamacrocycle containing the pyridine ring and bearing three methylenephosphonate groups (PCTP-[13]) has been synthesized. Its Gd(III) complex displays a remarkably high longitudinal water proton relaxivity (7.7 mM^–1 s^–1 at 25  °C, 20 MHz and pH 7.5) which has been accounted for in terms of contributions arising from (1) one water molecule bound to the metal ion, (2) hydrogen-bonded water molecules in the second coordination sphere, or (3) water molecules diffusing near the paramagnetic chelate. Variable-temperature ¹⁷O-NMR transverse relaxation data indicate that the residence lifetime of the metal-bound water molecule is very short (8.0 ns at 25  °C) with respect to the Gd(III) complexes currently considered as contrast agents for magnetic resonance imaging. Furthermore, GdPCTP-[13] interacts with human serum albumin (HSA), likely through electrostatic forces. By comparing water proton relaxivity data for the GdPCTP-[13]-HSA adduct, measured as a function of temperature and magnetic field strength, with those for the analogous adduct with GdDOTP (a twelve-membered tetraaza macrocyclic tetramethylenephosphonate complex lacking a metal-bound water molecule), it has been possible to propose a general picture accounting for the main determinants of the relaxation enhancement observed when a paramagnetic Gd(III) complex is bound to HSA. Basically, the relaxation enhancement in these systems arises from (1) water molecules in the hydration shell of the macromolecule and protein exchangeable protons which lie close to the interaction site of the paramagnetic complex and (2) the metal bound water molecule(s). As far as the latter contribution is concerned, the interaction with the protein causes an elongation of the residence lifetime of the metal-bound water molecule, which limits, to some extent, the potential relaxivity enhancement expected upon the binding of the paramagnetic complex to HSA. Received: 27 January 1997 / Accepted: 12 May 1997     

Apigenin 7-glucoside diacetates in ligulate flowers of Matricaria chamomilla

From ligulate flowers of Matricaria chamomilla was isolated a mixture of apigenin 7-O-β-glucoside diacetates, which was shown to be based on (2″, 3″)- and (3″, 4″)-diacetates.