789 resultados para sensibilidad química múltiple
Resumo:
The article shows how the monitoring of the water quality can be utilized in an inter-disciplinary pedagogical project involving Analytical Chemistry, Biochemistry and Microbiology making the apprenticeship more dynamic and consolidating the link between the student and the community.
Resumo:
The present paper describes the chemical composition and biological activities of artichoke cultivated in Brazil. Our studies demonstrated that glycosyl flavonoids (cynaroside and scolymoside), are the major constituents, along with cynaropicrin, a sesquiterpene lactone, and the triterpene lupeol. Cynarin, which is the main compound described for artichoke, was detected in very low concentration. Hexanic fraction exhibited considerable cytotoxicity and diuretic activities.
Resumo:
Depression is a widespread humor disturbance promoted mainly by depletion of biogenic neurotransmitter amines involved in the CNS synapses. Effective drug treatments for depression have been available for more than forty years. Despite its remarkable structural diversity, this paper discuss under the medicinal chemistry point of view, all different classes of "monoamine based" antidepressant drugs, emphasizing the rational design, structure-activity relationships (SAR), biotransformation and physico-chemical properties related with antidepressant activity and molecular mechanism of action.
Resumo:
During the last two decades there has been increasing concern within the scientific community related to the effects of indoor air quality on health. Changes in building design devised to improve energy efficiency and new synthetic building materials have contributed to increase pollutant concentrations. These factors have generated poor air quality and caused the development of a lot of symptoms known as Sick Building Syndrome (SBS). In Brazil, there are few studies in this area, collected in this review to support researches and awareness of the need to adopt preventive measures to reach a better quality for the Indoor Environment.
Resumo:
Naphthoquinones have been extensively studied due to their activity as topoisomerase inhibitors. These enzymes are critical to DNA replication in cells. In addition, naphthoquinones have been shown to induce what are known as "reactive oxygen species" that can cause damage to cells. beta-Lapachone is a very important pyranaphthoquinone obtained from the heartwood of the lapacho tree, Tabebuia avellanedae Lorentz ex. Griseb. (Bignoniaceae), and other Tabebuia trees native to Central and South America and chemically from lapachol. beta-Lapachone has a diversity of useful biological activities against various cancer cell lines such as human ovarian and prostate tumors and, at lower doses is a radiosensitizer of several human cancer cell lines. It gives rise to a variety of effects in vitro including the inhibition or activation of topoisomerase I an II in a distinct manner from that of other topoisomerase inhibitors. This review intend to discuss some details of the mechanisms of quinone-induced cell damage and death, and we also summarize results of the literature indicating that b-Lapachone may take part in quinone-elicited apoptosis despite the fact that its mechanism of action in vivo and its targets are still unknown.
Resumo:
An experiment for the synthesis of isobutylene from tert-butanol dehydratation using oxalic acid as catalyst, followed by preparations of tert-butyl benzoate and tert-butyl cinnamate is described. The synthesis are simple, requiring two periods of 4 hours and are suitable for undergraduate organic chemistry experimental courses.
Resumo:
Molecular Modeling is an important tool in drug design and it is very useful to predict biological activity from a library of compounds. A wide variety of computer programs and methods have been developed to visualize the tridimensional geometry and calculate physical properties of drugs. In this work, we describe a practical approach of molecular modeling as a powerful tool to study structure-activity relationships of drugs, including some antibacterials, hormones, cholinergic and adrenergic agents. At first, the students learn how to draw 3D structures and use them to perform conformational and molecular analysis. Thus, they compare drugs with similar pharmacological activity by superimposing one structure on the top of another and evaluate the geometry and physical properties.
Resumo:
This article describes the history of four decades of activities in the Institute of Chemistry of Araraquara, UNESP: the beginning, the evolution of undergraduate and graduate courses and the infra-structure of teaching and research.
Resumo:
Over the last five years there have been significant changes in higher education in Brazil as well as in research funding. As a contribution to the development of Science and Technology, and aiming to portray Chemistry today in Brazil, in the context of last year´s elections for President, State Governors, National Congress and Legislative Chamber, the Directors and Consulting Council of the Brazilian Chemical Society, SBQ, initiated in 2002 a series of activities to produce a document entitled Mobilizing Axes in Chemistry. This discusses undergraduate and graduate teaching in Chemistry, a new model for research funding, and the overall state of the art, and future perspectives. Six mobilizing axes have been identified and discussed to date: 1. Training of highly qualified personnel; 2. Decentralization, and discouragement of institutional in-breeding; 3. Stimulation of entrepreneurship and interdisciplinarity; 4. A guaranteed budget for Science and Technology; 5. Proactive interaction of academics with economic activity; and 6. Removal of institutional bottle-necks of all sorts. The Brazilian Chemical Society hopes that the new administration will in the near future begin the task of improving the national education system and increase funding for Science and Technology.
Resumo:
A new model for the H2 antagonists binding site is postulated based on adsorption coefficient values of sixteen antagonists, in the affinities constants of the primary and secondary binding sites, and in the chemical characterization of these sites by 3D-QSAR. All study compounds are in the extended conformation and deprotonated form. The lateral validation of the QSARs, CoMFA analysis, affinity constants and chemical similarity data suggest that the antagonists block the proton pump in the H2 receptor interacting with two tyrosines - one in the helix 5, and other in the helix 6.
Resumo:
This article presents a review of published literature concerning the use of computer simulations and modeling tools in Chemical Education. The findings about the possibilities of their application in the Chemistry curriculum, their effective implementation, the teaching methods involved, the research methodology and also the instruments of evaluation that were used and their results were described and analyzed. The need to develop adequate theory support to educators who want to start using this new technology in their Chemistry classes became evident along the research, as well as the lack of development of model perception among Chemistry educators and learners.
Resumo:
The toxic heavy metals can not be transformed in other less toxic substances as organic wastes through chemical process. Various chemistry courses at Faculty of Philosophy, Sciences and Humanities (FFCLRP/USP) use heavy metals in their experimental classes. In this context, a course were created: "Heavy Metal Wastes generated in the teaching and research laboratories: disposal or recovery" and has a specific goal to capacitate the students to define the adequate strategy for disposal or recovery of the chemical wastes, in particular heavy metals, through an interdisciplinary approaching. This course was given to 25 students during the second semester of 2000 and 2001. The environmental responsibility desired for the professional and citizen can be promoted.
Resumo:
The teaching of general chemistry involves both the choice and the organization of its concepts. Although College Teachers make their choices, frequently the text books play an important role in this selection. In the present project we intend to show what are Teachers' perceptions of conceptual organization and selection as well as their perceptions of how to teach general chemistry. This demonstration is carried out through the use of metaphors from new information technologies.
Resumo:
The graduate programs in Chemistry were evaluated and classified from the data collected for the period 1998-2000 by CAPES, the Minister of Education agency that is responsible for the regulation and support of this level of human resources formation. The next classification will be made in 2004, from the data of the period 2001-2003. The years in between, like the present year, are used for an evaluation without classification, from what comments are emitted to the programs to know how their data are improving or not, before the new ranking reporting. The progresses in the area of chemistry in Brazil are analysed from the confrontation of the present data with that of all previous evaluations, since 1983. The results confirm that the research and graduate formation in the area of Chemistry is continuously improving in Brazil, particularly during the last seven years.