Agentes antineoplásicos biorredutíveis: uma nova alternativa para o tratamento de tumores sólidos

A problem often encountered in cancer therapy is the presence of tumor cell subpopulation that are resistant to treatment. Solid tumors frequently contain hypoxic cells that are resistant to killing by ionizing radiation and also by many chemotherapeutic agents. However, these hypoxic cells can be exploited for therapy by non-toxic hypoxic-activated prodrugs. Bioreductive drugs require metabolic reduction to generate cytotoxic metabolites. This process is facilitated by appropriate reductases and the lower oxygen conditions present in solid tumors. The unique presence of hypoxic cells in human tumors provides an important target for selective cancer therapy.

Análise de glicocorticosteróides por CG-EM: uma nova abordagem de derivatização para o controle de dopagem no esporte

Glucocorticosteroids (CT) show a powerful anti-inflammatory effect. In view of this, they are extensively used in sports medicine, but their misuse (systemic administration) can lead to severe injuries on athletes and has been restricted by the IOC in recent years. For GC-MS analysis, a derivatization step is necessary in order to convert them to a stable form, thus preventing thermal breakdown with the loss of the ketone side chain. Derivatization of CT is reviewed and a new approach of silylation is presented for screening of CT in urine.

SPR: Uma nova ferramenta para biossensores

This paper reviewed the development and theoretical aspects of surface plasmon ressonance (SPR) technique and discusses this powerful sensor technology in the development of biosensors, as well as for the investigation of biological interactions and clinical assays. The SPR has been proven to be a valuable tool to investigate dynamic processes, such as adsorption, degradation, determination of dieletric properties, association/dissociation kinetics, affinity constants of specific ligand-ligate interactions, allowing real-time analysis at almost any surface. The SPR as a complementary technique alongside electrochemical methods is also presented.

A extração de cafeína em bebidas estimulantes: uma nova abordagem para um experimento clássico em química orgânica

Caffeine extraction procedures from water soluble and water insoluble materials for preparing stimulating beverages are described. Water soluble materials used were instant tea and coffee and water insoluble materials were, among others, guaraná powder and maté leaves. The extraction of caffeine from water soluble materials, especially instant tea, is more suitable for an organic chemistry teaching laboratory than the classic experiment using tea leaves, due to the economy of time and a larger amount of extracted caffeine. The procedure is time-saving and requires only a four-hour period. The experiments illustrate the extraction process as used in undergraduate organic chemistry laboratories.

Quantificação do linalol no óleo essencial da Aniba duckei Korstermans utilizando uma nova coluna capilar POLYH4-MD em Cromatografia Gasosa

In the present work a polyurethane polymer derived from castor oil was used as stationary phase for capillary gas chromatography. The polymer was obtained by reaction of hydroxylated compound and isocynate (NCO), forming urethane. Columns of 7 m x 0,25 mm were then coated with this stationary phase (film thickness of 0,25 µm) using static coating method. The Grob test was also performed. Samples of essential oil of the Aniba duckei Korstermans was then analysed in POLYH4-MD capillary column in order to evaluate its chromatographic perfomance. The linalool was found to be the major component and has been used as compound of departure for many important syntheses. Results show that the experimental columns give higher resolution and can be employed for analysis of essentials oils.

Química geral experimental: uma nova abordagem didática

This essay describes a new didactic approach, in according with the national curriculum guidelines for chemistry undergraduate courses in Brazil, employed during the one-semester course "Experimental General Chemistry" for chemistry undergraduate students at the Federal University of Piauí. The new approach has positively helped student's training by improving their reading skills and their understanding of scientific reports, by developing the use of electronic tools to search and to recover the required knowledge for their learning activities, and by improving their skills of understanding published texts and dealing with digital sources. At the same time the students are strongly stimulated to enter the research program for undergraduate students available at the University.

Laboratório químico-prático do Rio de Janeiro: primeira tentativa de difusão da Química no Brasil (1812- 1819)

Until the present date, historians of science have described inaccurately the first laboratory created in Brazil for establishing and divulging Chemistry, namely the "Laboratório Químico-Prático do Rio de Janeiro". During recent research carried out in the Arquivo do Museu Imperial (Petrópolis, RJ), I localized a document entitled "Ensaio histórico analítico das operações do Laboratório Químico-Prático do Rio de Janeiro", which allowed me to gain the relevant information to correct some of the observations made in the first chronicles.

Ferro zero: uma nova abordagem para o tratamento de águas contaminadas com compostos orgânicos poluentes

Anthropogenic pollution of groundwater and surface water has become a very serious environmental problem around the world. A wide range of toxic pollutants is recalcitrant to the conventional treatment methods, thus there is much interest in the development of more efficient remediation processes. Degradation of organic pollutants by zero-valent iron is one of the most promising approaches for water treatment, mainly because it is of low cost, easy to obtain and effective. After a general introduction to water pollution and current treatments, this work highlights the advances, applications and future trends of water remediation by zero-valent iron. Special attention is given to degradation of organochloride and nitroaromatic compounds, which are commonly found in textile and paper mill effluents.

A graduação em química: um novo químico para uma nova era

The discussions sponsored by the Brazilian Chemical Society, over the past five years, intending to produce a chemistry agenda with perspectives and needs for the next decade for the country, have involved the national chemistry community and several related sectors of Brazilian society. Chemistry education has been the theme throughout these discussions. It is known that the low level of basic and secondary education and the recent increase in high school courses and institutions adversely affect the quality of undergraduate teaching. The recent national "Curriculum Guidelines" for Chemistry Courses, through their flexible approach, encourage the integral, interdisciplinary (non compartmentalized) and critical-reflexive training of professionals as citizens and as entrepreneurs. However, deficiencies are still recognized. The system of undergraduate course evaluation has identified the most fragile modalities of the courses and other indicators. Also, it has been verified that the Brazilian chemistry industry absorbs only minimally the highly qualified professionals, which is attributed to the fact that the Federal Council of Chemistry is vertically organized and does not recognize the graduate degrees as professional qualifications. In conclusion, the importance of the effective implantation of the national curriculum guidelines is apparent, among other aspects, highlighting courses whose didactical and pedagogical projects may offer a solid formation in Chemistry. However, at the same time the guidelines are comprehensive and general enough to enable the chemistry professionals to develop varied skills.

Uma nova síntese de alfa-bromo-acetofenonas e sua aplicação na obtenção de 2-benzoil-benzofuranas

alpha-Bromoacetophenones are important in organic synthesis. They have been widely used as precursors of several natural products. Several methods of bromination aiming at their synthesis have been described, however they furnish a mixture of starting material 10, mono 8 and dibromide 11 products. We developed a novel, simple and efficient synthesis of these compounds with applications in the synthesis of benzoylbenzofurans 9, compounds with important pharmacological properties, such as the ability of dilating the coronary artery and analgesic action. Such compounds have also been used as key intermediates to obtain quinone systems.

LS-SVM: uma nova ferramenta quimiométrica para regressão multivariada. Comparação de modelos de regressão LS-SVM e PLS na quantificação de adulterantes em leite em pó empregando NIR

Least-squares support vector machines (LS-SVM) were used as an alternative multivariate calibration method for the simultaneous quantification of some common adulterants found in powdered milk samples, using near-infrared spectroscopy. Excellent models were built using LS-SVM for determining R², RMSECV and RMSEP values. LS-SVMs show superior performance for quantifying starch, whey and sucrose in powdered milk samples in relation to PLSR. This study shows that it is possible to determine precisely the amount of one and two common adulterants simultaneously in powdered milk samples using LS-SVM and NIR spectra.

Impacto do acordo de cooperação do Conselho Nacional de Pesquisas (CNPq) com a National Academy of Sciences - (NAS)

In the beginning of the 1960's, the university education in chemistry, in Brasil, represented only a professional preparation, with no official post-graduate teaching and research, as yet. The name Federal University Rio de Janeiro, evolved, since January 30, 1959, from University of Brazil, RJ, to Federal University of Guanabara, which, on August 20, 1965, became the Federal University of Rio de Janeiro. With the Resolution nº 4, of the University direction, the first Institute of Chemistry was created, to include the Centers of Mathematical and Natural Sciences, and the Medical Sciences. The strictu sensu's system was established only in 1961.

A importância das revistas Química Nova e Journal of the Brazilian Chemical Society no crescimento da área de química no Brasil

Quimica Nova and the Journal of the Brazilian Chemical Society are two examples of successful initiatives taken by the Brazilian Chemical Society (SBQ - Sociedade Brasileira de Química), and may serve as models for the scientific societies of developing countries. Pillars of the SBQ, these two periodicals are undeniable demonstrations that idealism, utopia and dignity are the essential ingredients for transforming dreams into reality. Few believed that the Brazilian chemical community would one day have, as it does today, two scientific research periodicals indexed in the principal international data banks.

Planilha de validação: uma nova ferramenta para estimar figuras de mérito na validação de métodos analíticos univariados

This work presents the VALIDATION SPREADSHEET, a public domain tool that can be used to evaluate the figures of merit for univariate analytical methods. A real example of BTEX determination in environmental samples is included to illustrate its use. The spreadsheet has been developed for Excel® and Open Office®, and is available on the internet at http//lqta.iqm.unicamp.br.