Aplicações de QCM, EIS e SPR na investigação de superfícies e interfaces para o desenvolvimento de (bio)sensores

The use of the quartz crystal microbalance process, electrochemical impedance spectroscopy and surface plasmon resonance for characterizing thin films and monitoring interfaces is presented. The theorical aspects of QCM, EIS and SPR are introduced and the main application areas are outlined. Future prospects of the combined applications of QCM, EIS and SPR methods in the studies of interfacial processes at surfaces are also discussed.

Métodos de obtenção e aplicações sintéticas de tiazóis, uma importante classe de compostos heterocíclicos

Thiazoles comprise an important class of heterocyclic compounds present in many potent biologically active molecules. This heterocyclic ring also shows various applications in organic synthesis to obtain new compounds. This paper presents different methodologies for the preparation of thiazole ring systems, as well as their synthetic applications.

Terras raras: aplicações industriais e biológicas

The history of the rare earths is rich in innovation and these elements have been the object of study of a number of scientists. Rare earths are used practically in almost all aspects of life and these applications are due to their outstanding properties, mainly spectroscopic and magnetic. In industry, the applications of rare earths are many, such as in catalysis, phosphors, magnetism, glass and lasers. In biological systems, rare earths are used, for example, as luminescent probes in the investigation of binding sites in proteins, labels in immunoassays and in noninvasive tests.

Sobre o desenvolvimento da análise volumétrica e algumas aplicações atuais

Classical methods of analysis played a fundamental role in the development of Chemistry and the chemical industry. They have been tools for analytical procedures since the 18th century, remaining useful until today. The technological appeal of the instrumental methods seems to dazzle the incoming generations of chemists who do not recognize the importance of titrimetry. A short description of the development of titrimetry is presented in order to call attention to historical landmarks for teaching and learning activities in Portuguese. A compilation of some current standard analytical methods that employ titrations is presented to illustrate the availability of titrimetry nowadays.

Bisfosfonatos: síntese, análises químicas e aplicações farmacológicas

Bisphosphonates are drugs that have been widely used in different bone diseases, and have recently been used successfully against many parasites. Various synthetic routes to prepare different types of bisphosphonates have been described, with distinct potency and pharmacological activity. A number of analytical techniques are currently being used to analyze these drugs; among these, the high performance liquid chromatography (HPLC), with different systems of detection, is worth highlighting. However, the development of more sensitive methods is still necessary, once they are essential for bioavailability and bioequivalence studies. This paper reports the major synthesis routes, chemical analysis methodologies and pharmacological applications of bisphosphonates.

Materiais híbridos orgânico-inorgânicos: preparação e algumas aplicações

The preparation and application of organic-inorganic hybrid materials are under fast development and constitute an interesting research topic on account of the versatility and wide range of applications offered by these materials. These properties can be achieved due to the mixture of the components at the molecular level. The present review covers the state of the art, the most useful preparation routes and the potential applications of these materials.

Lipossomas: propriedades físico-químicas e farmacológicas, aplicações na quimioterapia à base de antimônio

The use of organoantimonial complexes in the therapeutic of leishmaniasis and schistosomiasis has been limited mainly by the need for daily parenteral administration, their adverse side-effects and the appearance of drug resistance. Liposome encapsulation has been so far the most effective means to improve the efficacy of pentavalent antimonials against visceral leishmaniasis. Pharmacologically- and pharmaceutically-acceptable liposomal compositions are still being investigated through manipulation of preparation method, lipid composition and vesicle size. Recently, the encapsulation of a trivalent antimonial within "stealth" liposomes was found to reduce its acute toxicity and effectively deliver this compound to the parasite in experimental schistosomiasis.

PARAFAC: uma ferramenta quimiométrica para tratamento de dados multidimensionais. Aplicações na determinação direta de fármacos em plasma humano por espectrofluorimetria

Since the last decade, the combined use of chemometrics and molecular spectroscopic techniques has become a new alternative for direct drug determination, without the need of physical separation. Among the new methodologies developed, the application of PARAFAC in the decomposition of spectrofluorimetric data should be highlighted. The first objective of this article is to describe the theoretical basis of PARAFAC. For this purpose, a discussion about the order of chemometric methods used in multivariate calibration and the development of multi-dimensional methods is presented first. The other objective of this article is to divulge for the Brazilian chemical community the potential of the combination PARAFAC/spectrofluorimetry for the determination of drugs in complex biological matrices. For this purpose, two applications aiming at determining, respectively, doxorrubicine and salicylate in human plasma are presented.

Tiossemicarbazonas: métodos de obtenção, aplicações sintéticas e importância biológica

Thiosemicarbazones are a class of compounds known by their chemical and biological properties, such as antitumor, antibacterial, antiviral and antiprotozoal activity. Their ability to form chelates with metals has great importance in their biological activities. Their synthesis is very simple, versatile and clean, usually giving high yields. They are largely employed as intermediates, in the synthesis of others compounds. This article is a survey of some of these characteristics showing their great importance to organic and medicinal chemistry.

Polímeros biomiméticos em química analítica. Parte 1: preparo e aplicações de MIP ("Molecularly Imprinted Polymers") em técnicas de extração e separação

MIPs are synthetic polymers that are used as biomimetic materials simulating the mechanism verified in natural entities such as antibodies and enzymes. Although MIPs have been successfully used as an outstanding tool for enhancing the selectivity or different analytical approaches, such as separation science and electrochemical and optical sensors, several parameters must be optimized during their synthesis. Therefore, the state-of-the-art of MIP production as well as the different polymerization methods are discussed. The potential selectivity of MIPs in the extraction and separation techniques focusing mainly on environmental, clinical and pharmaceutical samples as applications for analytical purposes is presented.

Polímeros biomiméticos em química analítica. Parte 2: aplicações de MIP ("Molecularly Imprinted Polymers") no desenvolvimento de sensores químicos

The aim of this paper is the description of the strategies and advances in the use of MIP in the development of chemical sensors. MIP has been considered an emerging technology, which allows the synthesis of materials that can mimic some highly specific natural receptors such as antibodies and enzymes. In recent years a great number of publications have demonstrated a growth in their use as sensing phases in the construction of sensors . Thus, the MIP technology became very attractive as a promising analytical tool for the development of sensors.

Matemáticas para vivir y conocer: Un enfoque para primaria

Cuando se habla de matemática y realidad, frecuentemente se asocia con una matemática centrada en hechos y situaciones de la vida diaria. Dicha interpretación nos dirige a una determinada concepción que, aunque tiene como referente la realidad o aspectos de ésta, no siempre la forma de integrar estarealidad en la escuela o el aula resulta ser la correcta.La escuela tiene la ineludible obligación deprocurar formar personas felices, y por ello debe procurar que las personas logren integrarse y conozcan su realidad y entorno

Caracterização química de glucanas fúngicas e suas aplicações biotecnológicas

This article gives an overview of exopolysaccharides produced by fungi. The structural characterization of beta-D-(1->3) and beta-D-(1->3, 1->6)- glucans is discussed focusing on different chemical and physical procedures. The industrial applications are also considered mainly from the point of view of human health.

Lipases de látex vegetais: propriedades e aplicações industriais

Biocatalysts have innumerous advantages with respect to classical chemical processes, such as high specificity. Lipases (EC 3.1.1.3) are biocatalysts with large application in synthesis and hydrolysis reactions of triacylglycerols. The search for new sources of lipases has been intensified in the last years due to the high cost of microbial and animal lipases, wich restricts their use on an industrial scale. Lipases obtained from the latex of Carica papaya, Carica pentagona, Euphorbia characias, E. wulfenii, known for their proteolytic properties, are a good alternative source. In this review, we describe the well-known sources of vegetal lipases extracted from the latex and present some of their industrial applications.

Filmes de nanodiamantes para aplicações em sistemas eletroquímicos e tecnologia aeroespacial

The goal of this work is to show the use of undoped nanodiamond films as a new material for electrochemical and aerospace applications. Correlation between the applications and physico-chemical features of nano and conventional CVD polycrystalline diamond films are presented. An important and innovative application of these nanodiamonds is organic electrosynthesis, including pharmaceutical and water disinfection products, as well as electroanalytical applications, for example, development of biosensors for detection of glucose, glutamate and dopamine. In aeronautics and space developments, these nanodiamonds could be used as electrodes in rechargable batteries and in tribological investigations.