Identification des dermatophytes en cultures sur la base de leurs critères macroscopiques et microscopiques

Contexte : Les dermatophytes sont des champignons filamenteux parasites spécialisés qui dégradent les tissus kératinisés. Ils sont responsables de la plupart des mycoses de la peau, du cuir chevelu et des cheveux, et des ongles. Le choix du traitement des dermatophytoses dépend des symptômes et du dermatophyte incriminé parmi une quinzaine d'espèces possibles. L'identification des dermatophytes se fait en général sur la base des caractères macroscopiques et microscopiques des cultures. L'identification est parfois difficile ou reste incertaine car il peut y avoir des variations d'un isolat à l'autre au sein d'une même espèce. Cependant, les espèces sont facilement identifiées sur la base de séquences d'ADN. En pratique, des séquences d'ADN ribosomique suffisamment polymorphes sont le plus souvent utilisées pour discriminer les espèces de dermatophytes. Des méthodes spécialisées et sophistiquées telles que les séquences d'ADN et la spectrométrie de masse sont de plus en plus proposées dans la littérature pour identifier les dermatophytes. Toutefois, ces méthodes ne peuvent pas être utilisées directement par un médecin dans un cabinet médical. C'est pourquoi des méthodes plus simples basées sur l'observation de caractères phénotypiques des champignons en culture ne devraient pas être abandonnées. Objectif : Etablir une clé d'identification dichotomique se basant sur des caractères macroscopiques et microscopiques permettant une identification fiable du dermatophyte par la culture. Des clés d'identification des espèces seront élaborées et testées pour leur validation en parallèle avec leur identification par des méthodes de Biologie Moléculaire. Créer un outil simple qui pourra être utilisé au laboratoire par des médecins ou des biologistes non spécialisés en mycologie pour identifier les dermatophytes sans avoir recours à une technologie sophistiquée. Méthodes : Inventaire des espèces isolées de 2001 à 2012 au laboratoire de dermatologie du CHUV. Inventaire des caractères phénotypiques permettant de caractériser chaque espèce. Création d'un système dichotomique sur la base des caractères phénotypiques pour séparer et identifier les espèces (clé d'identification des espèces). Résultats attendus : Les résultats attendus sont définis au niveau des objectifs. L'outil doit être accessible pour des personnes inexpérimentées qui pourront alors identifier les dermatophytes. Plus-value : Les dermatophytoses sont fréquemment diagnostiquées. Cet outil est destiné à tous les dermatologues installés et au personnel de laboratoire qui ne sont pas nécessairement spécialisés en la matière.

Um fotômetro de fluxo para análises clínicas a base de um diodo emissor de luz bicolor

The construction and evaluation of an inexpensive flow photometer for clinical analysis, using a bicolour LED and a phototransistor adapted for tubular flow cell, are described. The instrument presents some new features such as: automatic zero, electronic calibration and peak-hold signal. When compared with a classical photometer, it is simpler and has the advantages of a flow analysis system: lower volumes of reagents and samples, lower levels of contamination, shorter time for analysis and lower analysis costs. The instrument was used in the determination of the constituents in blood samples. The results obtained agree with those obtained by a classical photometer and the precision was better.

Transdutores potenciométricos a base de polímeros condutores: aplicações analíticas

A review is given about the most relevant advances on the analytical applications of conducting polymers in potentiometric sensors. These organic polymers represent a new class of materials with conducting properties due to its doping by ions. Several polymers already were synthesized such as polypyrrole, polyaniline, polythiophene, among others. Particular attention is devoted to the main advantages supplied by ion selective electrodes and gas sensors using conducting polymers, as well as the incorporation of bioactive elements in these polymers for the construction of biosensors. The correlation between structure, stability and ability to ion exchange of some conducting polymers applied as potentiometric transducers, is discussed.

Influência da adição de defloculante, ligante e partículas de alumina no comportamento reológico de suspensões a base de frita e caulim

Enamel suspensions were characterized according to their rheological behavior. The suspensions presented a pseudoplastic behavior, yield stress and thixotropy, with or without the presence of deffloculant. Added carboxymethylcellulose increases the apparent viscosity of enamel suspensions and interacts complexly with the deffloculant, here sodium silicate. Addition of crystalline particles of two types of alumina, used to improve the wear resistance of ceramic glazes, also change strongly the rheological behavior of the suspensions. Added high specific area, irregular alumina particles produce a higher increase of the apparent viscosity of enamel suspensions compared to rounded ones.

Estudo do comportamento ácido-base da 4,4'-ditiodipiridina

Despite the importance of the 4,4'-dithiodipyridine as an electrode modifier on the protein electrochemical studies and as a remarkable bridged-ligand on conducting electronic density in binuclear mixed valence complexes, there is no data available in the literature concerning acid-base behavior of this compound. Aiming to afford such information we undertook the ionization equilibrium study of this ligand. Although two acid species, DTDPH+ and DTDPH2+ have been detected in solution, only the diacid-form was possible to be isolated as a perclorate salt DTDPH2(ClO4)2. The ionization constants for the two step equilibrium processes (pKa1=2.70 and pKa2=4.80) were determined by using the spectrophotometric technique and aqueous solutions of CF3COONa, mu=0,1 mol.L-1 .

Atividade e seletividade de catalisadores a base de caulim modificado

Studies of the use of a soil from river Pardo basin located at the Ribeirão Preto region, were realized with the aim of preparing catalysts. A clay, high purity kaolin type, was obtained after purification followed by treatment with acid and then calcined. The activity and selectivity of the catalysts were determined using cycloexene as substrate. The majority of the catalysts obtained yield a conversion higher than 70%.

Caracterização ácido-base da superfície de espécies mistas da alga Spirulina através de titulação potenciométrica e modelo de distribuição de sítios discretos

Acid base properties of mixed species of the microalgae Spirulina were studied by potentiometric titration in medium of 0.01 and 0.10 mols L-1 NaNO3 at 25.0±0.10 C using modified Gran functions or nonlinear regression techniques for data fitting. The discrete site distribution model was used, permitting the characterization of five classes of ionizable sites in both ionic media. This fact suggests that the chemical heterogeneity of the ionizable sites on the cell surface plays a major role on the acid-base properties of the suspension in comparison to electrostatic effects due to charge-charge interactions. The total of ionizable sites were 1.75±0.10 and 1.86±0.20 mmolsg-1 in ionic media of 0.01 and 0.10 mols L-1 NaNO3, respectively. A major contribution of carboxylic groups was observed with an average 34 and 22% of ionizable sites being titrated with conditional pcKa of 4.0 and 5.4, respectively. The remaining 44% of ionizable sites were divided in three classes with averaged conditional pcKa of 6.9, 8.7 and 10.12, which may be assigned respectively to imidazolic, aminic, and phenolic functionalities.

Disseny i implementació de la base de dades d'un sistema de recollida de dades d'activitat físicaprovinents de dispositius "portables"

Disseny i implementació de la base de dades d'un sistema de recollida de dades d'activitat física provinents de dispositius "portables", a més de les dades de salut dels ciutadans de la Unió Europea.

Gestió de base de dades d'un videojoc

Disseny i implementació d'una base de dades relacional per a la gestió d'un videojoc, el qual s'ha d'incorporar a un sistema per obtenir dades d'ús dels usuaris.

O ensino de aspectos históricos e filosóficos da Química e as teorias ácido-base do século XX

In this paper, an overview about philosophy of science, the concept of "theory" and some characteristics of a"good"theory (1- ordination and explanation of the facts, 2- proposal of problems, and 3- simplicity and funcionality) are initialy introduced. Following, some historical landmarks of acidity and basicity and a summary of the main acid-base theories of the XX century (Arrhenius, solvent systems, protonic, electronic, Lux, Usanovich and ionotropic) are presented. Historical and conceptual relations between these theories are discussed and the three characteristics of a "good" theory are applied. The results showed that the protonic and eletronic theories are the "best". Some discussion of the implications to chemical education are presented too.

Diseño e implementación de una base de datos para recogida y análisis de datos de actividad física provenientes de dispositivos wearables

Este proyecto consiste en diseñar e implementar un sistema de información alojado en una base de datos Oracle, con el fin de dar respuesta al proyecto Big Data, cuyo objetivo es cruzar los datos de salud y los datos de actividad física de los ciudadanos europeos.

Estudo espectroscópico de vidros a base de aluminato de cálcio contendo Nd3+

Multicomponent ( Al2O3, CaO, SiO2, MgO) calcium aluminate-based glasses containing Nd3+ were prepared in order to evaluate their possibilities as laser host materials. The refractive index, UV-visible-near IR absorption spectrum, IR and visible luminescence spectra, and fluorescence decay time were measured. Judd-Ofelt model was used to obtain experimental intensity parameters ( omega2, omega4 and omega6), emission cross-section, radiative lifetimes, emission branching ratios and quantum efficiency.

Disseny i implementació de la base de dades d'un sistema de recollida de dades d'activitat física provinents de dispositius wearables, en el marc d'un projecte big data de salut

Aquest treball de final de carrera vol donar una solució a un suposat encàrrec de la Unió Europea de construir una base de dades relacional que permeti emmagatzemar dades de l'activitat física dels ciutadans, obtingudes a partir de dispositius wearables, i dades de l'estat de salut i malalties diagnosticades, recollides pels sistemes informàtics dels diferents serveis de salut. Amb totes aquestes dades recopilades la nostra base de dades permetrà, a través d'aplicacions d'alt nivell, extreure informació útil que permeti conèixer l'estat de salut real dels ciutadans i dissenyar actuacions i campanyes que permetin la seva millora.

Substâncias húmicas: sistema de fracionamento sequencial por ultrafiltração com base no tamanho molecular

A sequential system for fractionation by ultrafiltration (SSFU) equipped with advanced membranes filters (molecular size cut-off: 5, 10, 30, 50 and 100 kDalton) of the polyethersulfone type was developed for analytical fractionation of humic substances (HS) extracted from aquatic systems or soils. The device consists of five membrane filters (Sartocon® Micro) operated by a multi-channel peristaltic pump, enabling an easy handling, working in a closed system and with simple collection of the six obtained fractions (F1>100; F2: 100-50; F3: 50-30; F4:30-10; F5: 10-5 and F6 <5 kDalton). Then, the HS sample (250 mL solution 1.0 mg/mL, pH 5.0 to 6.0) to be fractionated is pumped by pump through the series of membrane filters with a tangential flow of 85 mL/min, initial pressure 0.2 to 0.3 bar and permeation flux through the membranes of 0.8 to 1.4 mL/min. The overall time for fractionation and cleaning of the device is about 10 h and 25 mL of each fraction is obtained.

Aplicação de extratos brutos de flores de quaresmeira e azaléia e da casca de feijão preto em volumetria ácido-base. Um experimento para cursos de análise quantitativa

Crude extract of Tibouchina granulosa, Rhododendron simsii and Phaseolus vulgaris L. were prepared and used as alternative indicators in quantitative analysis teaching in standardization of NaOH solutions and in the determination of acetic acid contents in vinegar. Effect of using such natural extracts as indicators was very attractive to the students and the quantitative results were compared with conventional indicators with good agreement. Concepts of data statistics can successfully be discussed using the interest revived by the use of natural indicators.