University of Seville

About: University of Seville is a education organization based out in Seville, Andalucía, Spain. It is known for research contribution in the topics: Population & Context (language use). The organization has 20098 authors who have published 47317 publications receiving 947007 citations. The organization is also known as: Universidad de Sevilla.

Immunomodulatory role of melatonin: specific binding sites in human and rodent lymphoid cells

Abstract: This paper reviews the evidence that supports the hypothesis of the existence of specific binding sites for melatonin on immune cells. These binding sites have been described in human blood lymphocytes and granulocytes, and thymus, spleen, and bursa of Fabricius from different rodents and birds. The dissociation constant values of these binding sites are in the 0.1-1 nM range, suggesting that melatonin may play a physiological role in lymphocyte regulation. Moreover, melatonin binding sites appear to be modulated by guanine nucleotides. Therefore, in addition to other mechanisms described for the regulation of immune function by melatonin, a direct mechanism of regulation can be involved via binding of melatonin by immunocompetent cells.

Cloning and characterization of a chitinase (CHIT42) cDNA from the mycoparasitic fungus Trichoderma harzianum

Abstract: A cDNA of Trichoderma harzianum (chit42), coding for an endochitinase of 42 kDa, has been cloned using synthetic oligonucleotides corresponding to aminoacid sequences of the purified chitinase. The cDNA codes for a protein of 423 amino acids. Analysis of the N-terminal amino-acid sequence of the chitinase, and comparison with that deduced from the nucleotide sequence, revealed post-translational processing of a putative signal peptide of 22 amino acids and a second peptide of 12 amino acids. The chit42 sequence presents overall similarities with filamentous fungal and bacterial chitinases and to a lesser extent with yeast and plant chitinases. The deduced aminoacid sequence has putative catalytic, phosphorylation and glycosylation domains. Expression of chit42 mRNA is strongly induced by chitin and chitin-containing cell walls and is subjected to catabolite repression. Southern analysis shows that it is present as a single-copy gene in T. harzianum. chit42 is also detected in several tested mycoparasitic and non-mycoparasitic fungal strains.

Bifurcation Analysis of Five-Phase Induction Motor Drives With Third Harmonic Injection

Abstract: The interest in variable-speed multiphase induction- motor drives has substantially increased in recent years and novel proposals show good prospects for industrial implementation in high-power applications. The additional degrees of freedom existing in multiphase machines have allowed for new applications with high torque density by current harmonic injection in concentrated winding machines. This paper addresses, for the first time, the bifurcation analysis of a five-phase induction-motor drive when a third harmonic is injected for torque-enhancement purposes. The main focus of this paper is to present a mathematically based study of the nonlinear dynamics of the proposed drive with torque enhancement. The overall bifurcation analysis for both concentrated and distributed winding machines confirms that the harmonic injection provides not only torque enhancement but also more robust controllers. This further advantage offers improved performance of multiphase drives compared to their three-phase counterparts.

Factors Influencing Residents’ Perceptions toward Tourism Development: Differences across Rural and Urban World Heritage Sites

Abstract: This article compares the effects of factors influencing residents’ perceptions toward tourism development in urban and rural World Heritage Sites (WHSs). This study has been conducted in the rural...