On the energy impact of four information delivery methods in wireless sensor networks

A lot of researches are devoted to energy-save solutions in wireless sensor networks, to face their critical limited energy budget. In this paper we propose four information delivery mechanisms and we compare their relative energy impact, in order to make communications both reliable and energetic efficient. We present a parametric model to choose the best solution with respect to the great amount of factors that influence system performance, e.g., the hardware technology, the source to destination distance, the number of hops involved. For actual sensor nodes (/spl mu/AMPS-1) we are able to guarantee a whole delivery strategy with an energy gain ranging from 5% to 15% with respect to the trivial hop-to-hop decoding one.     

High dose intravenous immune globulins and plasma exchange in Guillain-Barré Syndrome

We report the effects of treatment with plasma-exchange (PE) and intravenous immune globulins (IVIg) in 36 out of 50 patients with Guillain-Barré syndrome (GBS) recruited by an incidence study in the Emilia-Romagna region of Italy. Comparison of the patients treated with PE and IVIg showed no significant differences in terms of effectiveness in improving the clinical course of GBS: at one month, respectively 11.1% and 25% had recovered, and 55.5% and 58.3% had improved by at least one grade. These results are in agreement with those of the Dutch GBS trial. No relapses were observed in either group. Moreover, our results showed no difference in clinical outcome at 1 and 3 months between the patients receiving only one therapy and those receiving two; a second cycle of therapy did not seem to improve the clinical course of the disease significantly. We conclude that PE and IVIg are both safe and effective therapies for GBS.     

Chip Pulse Shaping in Asynchronous Chaos-Based DS-CDMA

This paper extends and fully formalizes some previous results by developing an analytical method to account for the general chip pulse for DS-CDMA systems in an asynchronous environment with an integrate-and-dump receiver, applying it to commonly used pulses. Given the pulse, such a formal method allows us to define the optimum spreading code autocorrelation to be used and the relative signal-to-interference ratio performance. A chaos-based spreading code is plugged into this model to show that such an optimum performance can be very well approximated by practical sequence generators. This is shown by analyzing some typical bandlimited and substantially bandlimited pulses and determining the optimum spreading for each of them. These results prove that the gain of chaos-based spreading over conventional i.i.d.-like spreading can reach 75% when practical bandlimited pulses are considered.     

Cell proliferation and ploidy of human solid tumours: methodological experience with in vivo bromodeoxyuridine and DNA flow cytometry

The divalent cation selective ionophores A23187 and ionomycin were compared for their effects on the Ca2+ contents, nucleotide contents, and protein synthetic rates of several types of cultured cells. Both ionophores reduced amino acid incorporation by approximately 85% at low concentrations (50-300 nmol/L) in cultured mammalian cells without reducing ATP or GTP contents. At these concentrations A23187 and ionomycin each promoted substantial Ca2+ efflux, whereas at higher concentrations a large influx of the cation was observed. Ca2+ influx occurred at lower ionophore concentrations and to greater extents in C6 glioma and P3X63Ag8 myeloma than in GH3 pituitary cells. The ATP and GTP contents of the cells and their ability to adhere to growth surfaces declined sharply at ionophore concentrations producing increased Ca2+ influx. Prominent reductions of nucleotide contents occurred in EGTA-containing media that were further accentuated by extracellular Ca2+. Ionomycin produced more Ca2+ influx and nucleotide decline than comparable concentrations of A23187. The inhibition of amino acid incorporation and mobilization of cell-associated Ca2+ by ionomycin were readily reversed in GH3 cells by fatty acid-free bovine serum albumin, whereas the effects of A23187 were only partially reversed. Amino acid incorporation was further suppressed by ionophore concentrations depleting nucleotide contents. Mitochondrial uncouplers potentiated Ca2+ accumulation in response to both ionophores. At cytotoxic concentrations Lubrol PX abolished protein synthesis but did not cause Ca2+ influx. Nucleotide depletion at high ionophore concentrations is proposed to result from increased plasmalemmal Ca2+-ATPase activity and dissipation of mitochondrial proton gradients and to cause intracellular Ca2+ accumulation. Increased Ca2+ contents in response to Ca2+ ionophores are proposed as an indicator of ionophore-induced cytotoxicity.     

Photophysical properties of porphyrin planar aggregates in liposomes

This paper describes studies of some photophysical properties of non-covalent planar aggregates of hematoporphyrin and protoporphyrin. This porphyrin species has been recently discovered and can be generated in lipid bilayers such as liposomes and inner mitochondrial membranes. The relative weight of this species in different media, as compared to porphyrin monomers and stacked aggregates, has been deduced by fluorescence decay studies. In contrast with what is observed for stacked aggregates, promotion of planar suprastructures can occur both in aqueous and lipid environments. The spectroscopic properties are very similar to those of the corresponding monomers, in particular as regards the shape of the absorption and emission spectra. The fluorescence decay times are generally higher than those of the monomers, and depend on the medium in which the planar aggregates are formed. The photooxidation properties of porphyrin planar aggregates, as revealed by oxygen consumption and histidine photodegradation upon irradiation at 365 nm, were compared to those of the monomers. The extent of the photooxidation process is nearly 20-30% higher in planar aggregates than in the monomers. In contrast, it is well known that cofacial aggregates are photochemically inert and only monomeric species of porphyrin are efficient photosensitizers. The biological relevance of these findings is discussed.     

Interference minimisation by autocorrelation shaping inasynchronous DS-CDMA systems: chaos-based spreading is nearly optimal

The classical estimation of co-channel interference in asynchronous direct sequence-code division multiple access (DS-CDMA) systems, obtained for a conventional receiver under the standard Gaussian approximation (SGA), is analytically minimised with respect to the auto-correlation function of spreading sequences. The optimum auto-correlation function is found to be real, with alternating signs, and extremely closely follows an exponential trend. A family of chaotic maps is presented which is able to generate sequences with exponential auto-correlation function with alternating signs. The resulting DS-CDMA system is an extremely good approximation of the optimum achievable system     

Characterization of a deswapped triple mutant bovine odorant binding protein

The stability and functionality of GCC-bOBP, a monomeric triple mutant of bovine odorant binding protein, was investigated, in the presence of denaturant and in acidic pH conditions, by both protein and 1-aminoanthracene ligand fluorescence measurements, and compared to that of both bovine and porcine wild type homologues. Complete reversibility of unfolding was observed, though refolding was characterized by hysteresis. Molecular dynamics simulations, performed to detect possible structural changes of the monomeric scaffold related to the presence of the ligand, pointed out the stability of the β-barrel lipocalin scaffold.     

On the ultimate limits of chaos-based asynchronous DS-CDMA-I: basic definitions and results

The ultimate limits of chaos-based asynchronous direct-sequence code-division multiple access systems are investigated using the concept of capacity taken from information theory. To this aim, we model the spreading at the transmitter and the sampling of the incoming signal at the receiver with a unique linear multi-input multi-output transfer function. We then assume the existence of a coding/decoding pair that is able to transmit information through this channel with a vanishing error probability. The capacity of the system is then identified with the maximum rate at which such an errorless link may operate. The capacity is a random quantity depending on the spreading sequences and, due to the asynchronism, on the users relative delays and phases. We then compare different spreading strategies [classical m and Gold codes, independent identically distributed (i.i.d.) and chaos-based codes] in terms of expected performance as well as of the probability that one method outperforms another. To ease further analytical investigations that should cope with expectations of logarithms, we measure capacity not only in bits per use but also in codewords per use. Some formal results along with extensive numerical evidence show that this does not alter the performance ranking. Such a ranking shows that chaos-based spreading always outperforms i.i.d. spreading and those trying to mimic it. This aligns with and complements what was already known about the ability of chaos-based techniques of minimizing multiple access interference.