Trends in male contraception

Methods that are available for male contraception, namely coitus interruptus, condoms, and vasectomy, have been used since the 19th century. With the exceptions of a few improvements of these methods, no major progress has been made with respect to introducing new male contraceptives since then. It is extremely urgent to develop new, safe, effective, and reversible male contraceptive methods. Among all male contraceptive methods that are being investigated, the hormonal approach is the closest to clinical application. Hormonal contraception provides pregnancy protection by means of spermatogenic suppression. Androgen-progestin regimens currently represent the best available hormonal combination for induction of a profound suppression of spermatogenesis. Further development of new steroids is mandatory for increasing the choices of available contraceptive formulations and to optimize long-term safety of these regimens.

The mineralogy and chemistry of the German and Portuguese tiles used to face a historic building in the Amazon region and their natural susceptibility to tropical weathering

During the 19th century, the most prominent buildings of the city of Belém were faced entirely with tiles manufactured in Portugal and Germany, which now exhibit distinct degrees of degradation. The Pinho mansion is one of the most important of these buildings and was selected for the investigation of the action of the tropical Amazonian climate on the degradation of the tiles. To achieve this objective, the tiles were mapped for organic and inorganic degradation, and samples were collected for analysis. The minerals were determined by XRD, the chemical composition by classical wet methods and SEM/EDS, and the microorganisms under the microscope. The results show that the German and Portuguese tiles are quite different in their composition. While both ceramic bodies are composed of SiO2 and Al2O3, CaO was found only in the Portuguese tile. The low Na2O and K2O contents indicate the addition of materials to reduce the fusion temperature. SiO2 and PbO are the main constituents of the glaze, with CoO and FeO being added as pigment. The ceramic body of the German tiles is constituted of quartz, mullite, and cristobalite, in contrast with the Portuguese tiles, which are made of quartz, gehlenite, diopside, calcite, and feldspars. The glazes are XRD-amorphous. The chemical and mineralogical differences between the German and Portuguese tiles indicate that they were produced from different raw materials under distinct thermal processes. The most prominent weathering-related modifications are the thin layers (German tiles), oxidation stains, dark stains, the detachment of the tile (Portuguese tiles), loss of the glaze and powdering of the ceramic body (Portuguese tiles) through the establishment of Cyanophyta and Bacillariophyta.. The distinct degradation patterns of the tiles exposed to the tropical Amazon climate are a consequence of their distinct mineralogy and chemistry.

Myxomycetes collection preserved in the herbarium of the Federal University of Roraima (Brazil)

First records of myxomycetes in the North region of Brazil go back to the 19th century. Nevertheless, the myxobiota of this region is still largely unexplored, with only 42 species recorded, distributed in 20 genera and seven families. The objectives of this paper were to characterize the Myxomycetes collection of the Herbarium of the Federal University of Roraima (UFRR) and to add new records for the myxobiota of this State. The collection holds specimens collected in fragments of Open Ombrophilous Forest, Seasonal Semi-deciduous Forest, Riparian Forest, deforested areas and urban home gardens in the state of Roraima. The 157 exsiccates were analyzed and identified or redetermined based on identification keys, descriptions and illustrations. The collection is in good conditions of preservation and includes all subclasses of Myxomycetes, 83% of its orders, 50% of its families, and 20 species. Trichiales, with one family, three genera and six species, represents 62% of all exsiccates. Cribraria aff. splendens, Metatrichia vesparia, Physarella oblonga, Stemonaria longa and Stemonitis splendens are new records for Roraima and Arcyria obvelata, Comatricha pulchella, Stemonitis pallida and Stemonitopsis aequalis are referred for the first time in the Northern Region, enlarging the knowledge of the Brazilian geographic distribution of these species.

Some notes on a historical perspective of panic disorder

This article aims to describe important points in the history of panic disorder concept, as well as to highlight the importance of its diagnosis for clinical and research developments. Panic disorder has been described in several literary reports and folklore. One of the oldest examples lies in Greek mythology - the god Pan, responsible for the term panic. The first half of the 19th century witnessed the culmination of medical approach. During the second half of the 19th century came the psychological approach of anxiety. The 20th century associated panic disorder to hereditary, organic and psychological factors, dividing anxiety into simple and phobic anxious states. Therapeutic development was also observed in psychopharmacological and psychotherapeutic fields. Official classifications began to include panic disorder as a category since the third edition of the American Classification Manual (1980). Some biological theories dealing with etiology were widely discussed during the last decades of the 20th century. They were based on laboratory studies of physiological, cognitive and biochemical tests, as the false suffocation alarm theory and the fear network. Such theories were important in creating new diagnostic paradigms to modern psychiatry. That suggests the need to consider a wide range of historical variables to understand how particular features for panic disorder diagnosis have been developed and how treatment has emerged.

Natural immunoglobulins (contribution to a debate on biomedical education)

Immunology has contributed to biomedical education in many important ways since the creation of scientific medicine in the last quarter of the 19th century. Today, immunology is a major area of biomedical research. Nevertheless, there are many basic problems unresolved in immunological activities and phenomena. Solving these problems is probably necessary to devise predictable and safe ways to produce new vaccines, treat allergy and autoimmune diseases and perform safe transplants. This challenge involves not only technical developments but also changes in attitude, of which the most fundamental is to abandon the traditional stimulus-response perspective in favor of more "systemic" views. Describing immunological activities as the operation of a complex multiconnected network, raises biological and epistemological issues not usually dealt with in biomedical education. Here we point to one example of systemic approaches. A new form of immunoblot (Panama blot), by which the reaction of natural immunoglobulins with complex protein mixtures may be analyzed by a special software and multivariate statistics, has been recently used to characterize human autoimmune diseases. Our preliminary data show that Panama blots can also be used to characterize global (systemic) immunogical changes in chronic human parasitic diseases, such as malaria and schistosomiasis mansoni, that correlate with the clinical status.

Brazilian soil science: from its inception to the future, and beyond

The present essay is meant to provide some background on the evolution of the soil science community in Brazil, since its inception, to describe its current situation, and to outline a number of opportunities and challenges facing the discipline in decades to come. The origin of Brazilian agronomy dates back to the beginning of the 19th century as a subdiscipline of botany, and its association with chemistry would later establish it as a science. In the middle of the 19th century, agricultural chemistry was born as a result of this association, leading to the establishment of edaphology, a branch of Soil Science. Another branch of Soil Science, known as pedology, was established as an applied and scientific knowledge in Brazil during the middle of the 20th century. During the same period, the Brazilian Soil Science Society (SBCS) was created, merging the knowledge of both branches and gathering all scientists involved. Twenty years after the SBCS foundation, the creation of Graduate Programs made Brazilian Soil Science enter the modern era, generating crucial knowledge to reach the current levels of agricultural productivity. Part of a community composed of 25 Soil Departments, 15 Graduate Programs and a great number of institutions that promote research and technology transfer, Brazilian soil scientists are responsible for developing solutions for sustainable development, by generating, adapting and transferring technology to the benefit of the country. The knowledge produced by SBCS members has been particularly significant for Brazil to achieve the status of most competitive tropical agriculture in the world. In the future decades, Soil Science will still remain topical in discussions regarding environment care and production of food and fibers, in addition, it will be essential and strategic for certain issues, such as water quality, reducing poverty and development of renewable sources of energy.

Institutional landmarks in Brazilian research on soil erosion: a historical overview

The problem of soil erosion in Brazil has been a focus of agricultural scientific research since the 19th century. The aim of this study was to provide a historical overview of the institutional landmarks which gave rise to the first studies in soil erosion and established the foundations of agricultural research in Brazil. The 19th century and beginning of the 20th century saw the founding of a series of institutions in Brazil, such as Botanical Gardens, executive institutions, research institutes, experimental stations, educational institutions of agricultural sciences, as well as the creation and diversification of scientific journals. These entities, each in its own way, served to foster soil erosion research in Brazil. During the Imperial period (1808-1889), discussions focused on soil degradation and conserving the fertility of agricultural land. During the First Republic (1889-1930), with the founding of various educational institutions and consolidation of research on soil degradation conducted by the Agronomic Institute of Campinas in the State of São Paulo, studies focused on soil depletion, identification of the major factors causing soil erosion and the measures necessary to control it. During the New State period (1930-1945), many soil conservation practices were developed and disseminated to combat erosion and field trials were set up, mainly to measure soil and water losses induced by hydric erosion. During the Brazilian New Republic (1945-1964), experiments were conducted throughout Brazil, consolidating soil and water conservation as one of the main areas of Soil Science in Brazil. This was followed by scientific conferences on erosion and the institutionalization of post-graduate studies. During the Military Regime (1964-1985), many research and educational institutions were founded, experimental studies intensified, and coincidently, soil erosion reached alarming levels which led to the development of the no-tillage system.

Antimoniais empregados no tratamento da leishmaniose: estado da arte

Antimony preparations are the drugs of choice for the treatment of leishmaniasis over 90 years, a disease that currently affects 12 million people worldwide. Its introduction was based on 19th century concepts of therapeutic effects of metal salts as arsenicals and other metals, most of them abandoned due to toxic effects or better drugs. In the last three decades, there was a great improvement in the knowledge of cell biology and immunology of those infections, but chemotherapy has not been improved in the same strength. The structure and mechanism of action of the two pentavalent antimonial drugs of choice, meglumine antimoniate and sodium stibogluconate, are not well known and the contamination of those pharmaceutical by toxic contaminants have been verified.

A química na educação da Princesa Isabel

The private archive of the Brazilian Imperial Family holds a wealth of little known documents about the education of the daughters of Emperor D. Pedro II, especially of the eldest, Isabel, Princess Imperial. Science, particularly chemistry, for which her father had a particular fondness, occupied an important place in the girl's education. The study of these documents sheds a new light on the contrast between female education in the country in general, during most of the 19th century, and the careful upbringing envisaged by the Emperor for his future successor.

Heterociclos 1,2,3-triazólicos: histórico, métodos de preparação, aplicações e atividades farmacológicas

The 1,2,3-triazole, known since the end of 19th century, is a very widely used heterocyclic system present in many synthetic substances and commercial pharmaceutical compounds. In fact, 1,2,3-triazoles show several applications in many areas especially as medicines against many diseases like cancer, AIDS, Parkinson and Alzheimer. Nowadays there is a large variety of known methods to obtain these heterocyclic compounds comprising mainly three synthetic routes. Nevertheless, there is no article that gives an objective overview of the synthetic methods for obtaining these kinds of azoheterocycles. This paper presents a brief history of this class of compounds, and a synthetic discussion concerning the main synthetic methods for its preparation, such as cyclization through hydrazones, concerted cycloadditon [2+3] and pseudopericyclic cyclization - and some others of restricted application, but also important. Finally, this paper also provides a brief overview on pharmacological applications of some 1,2,3-triazoles.

Justus Von Liebig, 1803-1873. Parte 1: vida, personalidade, pensamento

This first of two papers allusive to the 200th birthday of Justus von Liebig (1803-1873) deals with the origins, life, education, ideas and influence of one of the great 19th century chemists. The principal characteristics of his "Giessen model of teaching research in chemistry" are presented, as well as the role played by many of his students in the evolution of chemical research in various countries. Liebig's strong personality, his controversies, his contribution to the chemical scene in Giessen and Munich are presented. Although few, the connections with Latin-American chemistry are focused.

A química orgânica na consolidação dos conceitos de átomo e molécula

The present work discusses the appearance of the concepts of valence and molecular structure, and describes the appropriation and evolution of the concept of molecule in the period following the publication of Avogadro's Hypothesis. The point of reference is the development of what became known as Organic Chemistry, which encompassed Pharmacy, Physiological Chemistry, Animal and Plant Chemistry, Chemistry of Dyestuffs, Agricultural Chemistry, and the fledgling Organic Synthesis industry in the early 19th century. The theories formulated in these areas and the quest for accurate atomic weights led to those concepts of valence and molecular structure and to a precise differentiation between atom and molecule.

Biomassa e energia

Biomass was the dominating source of energy for human activities until the middle 19th century, when coal, oil, gas and other energy sources became increasingly important but it still represents ca. 10% of the worldwide energy supply. The major part of biomass for energy is still "traditional biomass" used as wood and coal extracted from native forests and thus non-sustainable, used with low efficiency for cooking and home heating, causing pollution problems. This use is largely done in rural areas and it is usually not supported by trading activities. There is now a strong trend to the modernization of biomass use, especially making alcohol from sugar cane thus replacing gasoline, or biodiesel to replace Diesel oil, beyond the production of electricity and vegetable coal using wood from planted forests. As recently as in 2004, sustainable "modern biomass" represented 2% of worldwide energy consumption. This article discusses the perspectives of the "first" and "second" technology generations for liquid fuel production, as well as biomass gaseification to make electricity or syngas that is in turn used in the Fischer-Tropsch process.

O primeiro curso regular de química no Brasil

Chemistry gradually became a discipline in a number of institutions in Brazil after the arrival of the Portuguese court in 1808. The first of these was the Royal Military Academy in Rio de Janeiro, founded by the Prince Regent in 1810. Due to lack of local personnel for the post of Professor of Chemistry the British chemist Daniel Gardner was hired. He occupied that chair until his retirement in 1825. In this article we discuss the circumstances involving the creation of that chair, its occupant and the contents of his course.

O instituto de coimbra e a análise química de águas minerais em portugal na segunda metade do Século XIX

O Instituto, journal published by the Institute of Coimbra (IC), an academic society founded in this city in 1852, contains many articles on hydrology and chemical analysis of water for human consumption, written by well-known Portuguese chemists and physicians. Based on these papers, we analyse the evolution of hydrology in Portugal throughout the second half of the 19th century, with emphasis on the chemical studies of mineral waters by the physicians Augusto da Costa Simões, Francisco Alves and José Epifânio Marques, and by the chemists Joaquim dos Santos e Silva, António Ferreira da Silva and Charles Lepierre, all of them members of the IC.