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El primer microscopio electrónico que hubo en Costa Rica fue donado por el Gobierno de Japón, mediante su Agencia de Cooperación Internacional ("JICA" por sus siglas del Inglés) en 1974. Con ese equipo se consolidó la Unidad de Microscopia Electrónica (UME) de la Universidad de Costa Rica. Tres años más tarde se publicaron los primeros artículos científicos relacionados con aspectos ultraestructurales del Virus del rayado fino del maíz y rotavirus, el agente de la diarrea infantil. Subsecuentes trabajos de la UME fueron publicados en la Revista de Biología Tropical, totalizando al menos 50 artículos solo en esta revista para el año 2000. La reciente adquisición de espectrómetros de dispersión energética para el análisis de rayos X, acoplados a los microscopios electrónicos de transmisión y de rastreo, aumentan la capacidad de análisis de la UME, haciendo posible el análisis ultraestructural y químico elemental de un espécimen. Entre las aplicaciones de esta metodología está la evaluación de la contaminación ambiental con metales pesados; como estudios comparativos de residuos sobre hojas de árboles en zonas urbanas y en bosques primarios.The first electron microscope in Costa Rica was a donation from the government of Japan throught its International Cooperation Agency (JICA) in 1974. This donation made possible the consolidation of what was to hecome the University of Costa Rica's Electron Microscope Unit (UME). Within three years the first scientific papers were published, dealing with ultrastructural aspects of "Com's rayado fino virus" and rotavirus, viral agent of human diarrhea. Subsequent papers out of the UME were published for the most part in the Journal of Tropical Biology, totaling at least 50 in that journal alone by the year 2000. With the recent acquisition of Energy Dispersive Spectrometer to coupled in transmission electron microscope and scanning electron microscope to X ray analysis, the data acquisition of the UME has been greatly enhanced, making possible to analyze both structure and elemental chemical composition in a specimen. Other applications of this new technology include studies of environmental pollution with heavy metals, such as comparative analysis of residues on leaves from urban areas and those on leaves from primary forest.

In this paper, a contribution to the archaeometric characterization of colonial pottery of Mendoza province is introduced. It is carried out by microscopic analysis of paste (petrographic) and surface treatments (SEM), and by microanalysis (EDS) of the composition of glazes. It is proposed to investigate aspects of colonial local production regarding to raw materials provenance, production areas and the skills involved. The results of these analyzes would located the probable sources in the northwest and central west of Mendoza province. On the other hand, from the technological point of view, some features of the operating sequence (crushed of non plastic inclusions, handmade and wheel modeling, glaze applying and two different firings) are identified and discussed. These data, together with data provided by other archaeological studies and by historical documentation, allow proposing a revision of the “Carrascal” type as the only colonial pottery class of Mendoza, considering the variety of technical resources used in multiple production centers throughout time.

There are numerous mechanisms that can lead to deterioration of portland-cement concrete in service. The best known are corrosion of reinforcement, freezing-thawing expansion, alkali-silica reaction, acid attack, and sulfate-related problems, including delayed ettringite formation. Additionally, concrete can deteriorate as a consequence of improper processing, including curing. Often, several of the above mechanisms of deterioration are jointly responsible for the observed damage. This paper briefly reviews the light-optical and electronoptical microscopic methods available to study some of the causes of concrete deterioration, and briefly describes selected case studies. Specifically, microstructural features resulting from physical (e.g., freezing-thawing) and chemical (e.g., alkali-silica reaction, delayed ettringite formation) deterioration of concrete are highlighted. Corrosion of reinforcement is not discussed.