Two interacting diffusing particles on low-dimensional discrete structures

In this paper we study the motion of two particles diffusing on low-dimensional discrete structures in presence of a hard-core repulsive interaction. We show that the problem can be mapped in two decoupled problems of single particles diffusing on different graphs by a transformation we call 'diffusion graph transform'. This technique is applied to study two specific cases: the narrow comb and the ladder lattice. We focus on the determination of the long time probabilities for the contact between particles and their reciprocal crossing. We also obtain the mean square dispersion of the particles in the case of the narrow comb lattice. The case of a sticking potential and of 'vicious' particles are discussed.Comment: 9 pages, 6 postscript figures, to appear in 'Journal of Physics A',-January 200

Topology Induced Spatial Bose-Einstein Condensation for Bosons on Star-Shaped Optical Networks

New coherent states may be induced by pertinently engineering the topology of a network. As an example, we consider the properties of non-interacting bosons on a star network, which may be realized with a dilute atomic gas in a star-shaped deep optical lattice. The ground state is localized around the star center and it is macroscopically occupied below the Bose-Einstein condensation temperature T_c. We show that T_c depends only on the number of the star arms and on the Josephson energy of the bosonic Josephson junctions and that the non-condensate fraction is simply given by the reduced temperature T/T_c.Comment: 20 Pages, 5 Figure

Epidemiology of Invasive Fungal Infections in Latin America

The pathogenic role of invasive fungal infections (IFIs) has increased during the past two decades in Latin America and worldwide, and the number of patients at risk has risen dramatically. Working habits and leisure activities have also been a focus of attention by public health officials, as endemic mycoses have provoked a number of outbreaks. An extensive search of medical literature from Latin America suggests that the incidence of IFIs from both endemic and opportunistic fungi has increased. The increase in endemic mycoses is probably related to population changes (migration, tourism, and increased population growth), whereas the increase in opportunistic mycoses may be associated with the greater number of people at risk. In both cases, the early and appropriate use of diagnostic procedures has improved diagnosis and outcome

Paracoccidioidomicosis en la Provincia de Formosa, Argentina Paracoccidioidomycosis in Formosa province (Argentina)

Durante 2 años, en un estudio de corte trasversal, se estudiaron los pacientes con síntomas compatibles con paracoccidioidomicosis (PCM) que concurrieron al Hospital Central de Formosa. Se seleccionaron 335 enfermos, de los cuales 264 eran varones y 71 mujeres, con edades comprendidas entre los 25 y los 79 años. Se hizo diagnóstico de PCM en 24 pacientes, obteniéndose una prevalencia de 7,16%. Hubo un solo caso femenino. La mayoría (83%) de los pacientes había consumido tabaco por un tiempo mayor a 10 años, el 96% pertenecía al área rural y el 63% de ellos refería una ingesta elevada de alcohol. Se detectaron también un caso de PCM infanto-juvenil y uno de neuroparacoccidioidomicosis. El 100% de las muestras de lesiones muco-cutáneas de pacientes con PCM estudiadas fue positivo. El estudio serológico por inmunodifusión en gel de agar (IDGA) permitió el diagnóstico en 22/249 pacientes estudiados. La PCM es endémica en la provincia de Formosa donde coexiste con otras afecciones con manifestaciones semejantes, por lo que se debe realizar siempre el diagnóstico diferencial.Patients with paracoccidioidomycosis (PCM) compatible symptoms who attended Hospital Central de Formosa, were studied during 2 years. Three hundred and thirty five patients were selected, 264 male and 71 female, ages were between 25 and 79 years old. Twenty four patients were diagnosed, the prevalence observed was 7.16%. There was only one female positive case. Most patients (83%) had smoked for more than 10 years, 96% came from a rural area and 63% was alcoholic. Also a case of neuroparacoccidioidomycosis and a juvenile-type PCM case were detected. Specimens of mucocutaneous lesions were 100% positives. Immunodiffusion (IDGA) allowed the diagnostic in 22/249 patients. PCM and others infectious diseases with similar clinical manifestations coexist in Formosa province, for this reason differential diagnostic must be done

Characterization of some virulence factors in Malassezia spp.

Objective: The main objectives of this work was to evaluate “in vitro” the hydrophobicity levels, the adherence on a plastic surface and the biofilm formation of 51 clinical isolates of Malassezia spp. Methods: 32 M. furfur, 10 M. sympodialis, 5 M. globosa, 2 M. slooffiae, 1 M. restricta and 1 M. pachydermatis, were all clinical isolates tested. M. furfur and M. sympodialis references strains were also included. In order to examine the adherence capacity to plastic surface, the yeasts were grown for 72 h at 32◦C in Leeming-Notman modified broth, washed twice with sterile PB and then resuspended at 37◦C in RPMI 1640 modified for Malassezia plus 10% FBS at 7.5 × 102 cells/ml. After incubation for 3 h at 37◦C in six-well polystyrene plates followed by extensive washing, 1 ml of Leeming-Notman Agar medium modified was poured into each well and let solidify. After incubation for 72 h at 37◦C, colonies were counted and the results were expressed as a percentage of the inoculum size. Cellular surface hydrophobicity (CSH) levels were determined by two-phase system. The biofilm formation was determined by tetrazolium salt (XTT) reduction assay. Results: All isolates of Malassezia spp. were hydrophobic, adherent and producers of biofilm on abiotic surfaces with different capacity. In particular, hydrophobicity was variable and ranged from 24 ± 0.1% for M. pachydermatis to 69.50 ± 14.6% for M. restricta. Similar values were observed for M. furfur and M. globosa. Adherences values also display variability, with ranges between 8.4 ± 1.1% for M. pachydermatis to 85.00 ± 2.3% for M. restricta. High values of adherence were obtained for M. globosa (65.22 ± 3.5). In addition, the no lipid-dependent yeast M. pachydermatis showed low values of adherence and hydrophobicity respect to the other Malassezia species. All Malassezia spp. were able to form biofilm on surface, ranged from 0.179 ± 0.13% for M. slooffiae to 0. 574 ± 0.20% for M. furfur. Except for M. pachydermatis, similar values were reported for the other Malassezia species tested. Conclusion: Our results suggest that all clinical isolates of Malassezia spp. were hydrophobic. Since the hydrophobicity is an important factor to adherence, varying degrees of success on abiotic surface were obtained. These characteristics are also involved in the high ability to form biofilm observed in this study. These important virulence factors could be responsible of this yeast changing from a commensal to a pathogenic status. The revision of the genus Malassezia has opened up new questions about the pathogenicity of Malassezia species

Paracoccidioidomicosis asociada a otras patologías respiratorias en un hospital de Corrientes, Argentina Association of paracoccidioidomycosis with different pulmonary pathologies in a hospital in Corrientes province, Argentina

Se realizó la búsqueda sistemática de paracoccidioidomicosis (PCM) en un conjunto de pacientes que fueron atendidos en un hospital de la ciudad de Corrientes dentro de un período de dos años. El criterio de inclusión fue: pacientes con tuberculosis (TBC), pacientes con diagnóstico presuntivo o confirmado de cáncer de pulmón (CA), pacientes con enfermedad pulmonar obstructiva crónica (EPOC) y pacientes con imagen radiológica compatible con micosis pulmonar (IRXC). Se estudiaron 84 pacientes: 57 con TBC, 1 con CA, 5 con EPOC, 3 con TBC+CA, 4 con TBC+EPOC, 4 con EPOC+CA y 10 con IRXC. A todos se les realizó serología por inmunodifusión en gel de agar (IDGA) y, en los casos en que se pudo obtener una muestra clínica, también se efectuaron estudios microbiológicos. Por IDGA se diagnosticaron 10 casos de PCM: 4 asociados a TBC, 1 a TBC+CA, 3 a EPOC y 2 a IRXC; 9 de ellos se corroboraron por el hallazgo del hongo. La búsqueda sistemática de PCM en habitantes del área endémica que presentan patología pulmonar favorecería el diagnóstico precoz y, por lo tanto, las posibilidades de un tratamiento eficaz.<br>For 2 years, a systematic research of paracoccidioidomycosis (PCM) had been conducted in a hospital in the city of Corrientes. The inclusion criterium used was: tuberculosis patients (TBC), presumptive or confirmed diagnosis of pulmonary cancer (CA), chronic obstructive pulmonary disease (COPD) and/or X-ray images compatible with pulmonary mycosis (XRC). Eighty four patients were studied: 57 (TBC), 1 (CA), 5 (COPD), 3 (TBC+CA), 4 (TBC+COPD), 4 (COPD+CA) and 10 (XRC). Serology tests by agar gel immunodiffusion (IDGA) were performed on all patients, whereas microbiological studies were performed on those cases in which clinical samples could be obtained. Ten PCM were diagnosed by IDGA; 4 associated to TBC, 1 to TBC+CA, 3 to COPD and only 2 to XRC. PCM was mycologically proven in 9 of these cases. Systematic research of PCM would lead to an early diagnosis and therefore, to better chances for a successful treatment