University of Perugia

About: University of Perugia is a education organization based out in Perugia, Umbria, Italy. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 13365 authors who have published 39516 publications receiving 1265601 citations. The organization is also known as: Universitá degli Studi di Perugia & Universita degli Studi di Perugia.

Th1 and Th2 cytokines in mice with invasive aspergillosis.

Abstract: With a murine model of invasive aspergillosis we investigated cytokine production by CD4+ T helper cells and the effects of cytokine administration or neutralization on the course and outcome of infection. Patterns of susceptibility and resistance to infection were obtained with different strains of mice injected with different inocula of Aspergillus fumigatus conidia. Mice surviving the primary infection also resisted a subsequent lethal infection that was associated with production of gamma interferon by CD4+ T splenocytes. Impaired neutrophil antifungal activity, observed in susceptible mice, was concomitant with a predominant production of interleukin-4 (IL-4) by CD4+ splenocytes. In these mice, exogenous administration of IL-12 failed to induce resistance to infection; in contrast, treatment with soluble IL-4 receptor cured more than 70% of the mice from primary infection and resulted in the onset of acquired resistance to a subsequent lethal infection. These findings indicate that in murine invasive aspergillosis, production of IL-4 by CD4+ T cells may be one major factor discriminating susceptibility and resistance to infection.

Three newly delimited species of Saccharomyces sensu stricto.

Abstract: Deoxyribonucleic acid reassociation studies of 24 different wine and beer-associated strains of Saccharomyces confirmed the presence of three separate species. S. cerevisiae and S. bayanus strains had only 22% of their genomes in common. S. pastorianus, with intermediate hybridization values between S. cerevisiae and S. bayanus (52 and 72%, respectively) could possibly be a natural hybrid of the two species. S. pastorianus replaces S. carlsbergensis with which it is homologous for 93% of its genome, since the former species was described first by Hansen in 1904. These data do not agree with the results of traditional physiological tests.

BER of OFDM systems impaired by carrier frequency offset in multipath fading channels

Abstract: We introduce an analytical approach to evaluate the error probability of orthogonal frequency-division-multiplexing (OFDM) systems subject to carrier frequency offset (CFO) in frequency-selective channels, characterized by Rayleigh or Rician fading. By properly exploiting the Gaussian approximation of the intercarrier interference (ICI), we show that the bit-error rate (BER) for an uncoded OFDM system with quadrature amplitude modulation (QAM) can be expressed by the sum of a few integrals, whose number depends on the constellation size. Each integral can be evaluated numerically, or, in Rayleigh fading, by using a series expansion that involves generalized hypergeometric functions. Simulation results illustrate that the theoretical analysis is quite accurate, especially for Rayleigh channels, and also with nonlinear amplifiers.

Saccharomyces Meyen ex Reess

Abstract: Publisher Summary This chapter focuses on Saccharomyces genus and its member species The cells of this genus are globose, ellipsoidal, or cylindroidal Vegetative reproduction occurs through multilateral budding, and pseudohyphae may be formed but not septate hyphae The vegetative phase is predominantly diploid (or of higher ploidy) and conjugation occurs on or soon after germination of the ascospores The ascospores are globose to short ellipsoidal, with a smooth wall and usually one to four per ascus The member species of this genus include Saccharomyces barnettii, Saccharomyces bayanus, Saccharomyces castellii, Saccharomyces cerevisiae, and Saccharomyces dairenensis The cells of Saccharomyces barnettii species, after a growth in 5% malt extract at 25° C for three days appear as globose, ovoidal, or elongate The vegetative cells of this species are transformed directly into persistent asci containing one or two, and rarely four, globose to short ellipsoidal ascospores The ascospores were observed on acetate agar usually after 20-40 days at 25° C The cells of Saccharomyces bayanus species, after growth in 5% malt extract for 3 days at 25° C, are globose, ovoidal, or elongate and are usually isolated The vegetative cells are transformed directly into persistent asci containing one to four globose to short ellipsoidal ascospores