After-Eden: Narratives of Nature, Degradation, and Poverty in Amazonian Discourse

In this article, I consider the environmental narratives of an Amazonian expedition at the turn of the 21st century, called Amazon Quest, a seemingly novel program that connected a team of explorers to elementary students in the United States. Situating the program within a longer discursive history of Amazonian nature, I examine how Amazon Quest’s portrayal of contemporary Amazonia comes to be defined by degradation and poverty. Unlike many popular accounts, Amazon Quest is less a story of unspoiled nature and exotic culture and more a narrative of degraded lands and peoples. I discuss how poverty and degradation are not merely elements in Amazon Quest’s narration, but rather iconic simplifications, ways of knowing the Amazon, its landscapes, its people, and its future

From Dearth to El Dorado: Andean Nature, Plate Tectonics, and the Ontologies of Ecuadorian Resource Wealth

Since the early 1990s, the Ecuadorian government has pledged to convert the nation into a “mining country” of global standing. Contemporary claims of mineral wealth, however, stand in stark contrast to previous assessments. Indeed, through much of the 20th century, geologists described Ecuador as a country of mineral dearth. Exploring the process through which Ecuador seemingly transitioned from a nation of resource scarcity to one of mineral plenty, I demonstrate how assessments of Ecuador’s resource potential relate to ideas of Andean nature. Promoters of resource abundance have emphasized Andean uniformity and equivalence—the notion that Ecuador’s mineral wealth is inevitable by virtue of the resource richness of its Andean neighbors. Geologists who have questioned Ecuador’s mineral content, on the other hand, have emphasized Andean heterogeneity. In the recent promotion of Ecuador’s resource potential, notions of Andean uniformity have been bolstered by models of subsoil copper that emerged in the in 1970s in the context of plate-tectonic theory. In highlighting the linkage between ideas of Andean nature and appraisals of Ecuadorian resource potential since the late 19th century, I outline the dialectics between nature and natural resources that underpin processes of resource becoming

Luminescent Metal-Organic Frameworks for the Detection of Alcohols

Metal-organic frameworks (MOFs), porous materials composed of metal ions and organic linkers, have broad applications in separation, small molecule storage, and catalysis. Luminescent metal-organic frameworks (LMOFs) hold great potential in the development of sensors, and, with their relatively straightforward syntheses that produce predictable, homogeneous, extended structures, should result in good sensor-to-sensor reproducibility and uniform response. In addition, subtle differences in overall LMOF structure, metal ion coordination, pore surfaces, and host-guest interactions within pores should have significant impact on observed photoluminescence and provide numerous strategies for analyte detection, which shows promise for the detection of alcohols. Highlighted here is the development of LMOFs composed of zinc ions that incorporate luminescent osmium complex into the framework structure and the excitation and emission spectra of these materials in the presence of small molecules of varying polarity. The effect of the organic linkers within the MOF scaffold on the luminescence osmium was also studied

Relative humidity sensors based on an environment-sensitive fluorophore in hydrogel films

A fluorescence-based sensing scheme exploiting an environment-sensitive fluorophore embedded in a hydrogel has been developed for measurement of relative humidity (RH). The fluorophore, dapoxyl sulfonic acid (DSA), is incorporated into two different hydrogel films, agarose and a copolymer of acrylamide and 2-(dimethylamino)ethyl methacrylate (DMAEM) cross-linked with N,N\u27-methylenebisacrylamide. The swelling and contracting of the hydrogels in response to relative humidity alters the polarity of the environment of DSA, stimulating a shift in the emission wavelength. From 0 to 100% RH, acrylamide-DMAEM sensors exhibited a 40 and 15 nm wavelength shift in still air and flowing gas, respectively. Agarose sensors showed a 40 nm wavelength shift from 0 to 100% RH in still air and a 30 nm shift from 0 to 70% RH in flowing gas. Response times for both sensors were 15 min in still air and less than 5 min in flowing gas. The sensing approach is straightforward and cost-effective, yields sensors with characteristics suitable for commercial measurement of RH (i.e., sensitivity, response times, reproducibility), and allows ease of adaptability to specific RH measurement requirements. The results support the potential extension of the method to a wide variety of analytes in the vapor phase and aqueous solution by incorporation of functionalized smart hydrogels. © 2010 American Chemical Society

Whose Diversity Counts? The Politics and Paradoxes of Modern Diversity

sustainabilit

Water-Soluble Osmium Complexes Suitable for use in Luminescence-Based, Hydrogel-Supported Sensors

Osmium transition metal complexes are of particular interest in luminescence-based sensing applications because of their longer wavelength absorptions and emissions, relative to similar ruthenium and rhenium complexes, that allow for inexpensive excitation and minimize interferences from autofluorescence when the sensor is used in biological samples. Reported here are the photophysical properties of a series of water-soluble osmium complexes suitable for use in hydrogel-based sensors: [Os(bpy)2(sulf-dpp)]Cl2, [Os(phen)2(sulf-dpp)]Cl2, [Os(dpp)2(sulf-dpp)]Cl2, and [Os(CO)2Cl2(sulf-dpp)], where bpy is 2,2′-bipyridine, phen is 1,10-phenanthroline, dpp is 4,7-diphenyl-1,10-phenanthroline, and sulf-dpp is bathophenanthrolinedisulfonic acid disodium salt. The family of complexes showed minimal oxygen quenching, making them particularly well-suited for sensing applications in which oxygen concentration varies. Luminescence anisotropy was found to depend more significantly on net dipole moment than hydrodynamic radius of the molecule, and, as expected, excited state lifetime and luminescence anisotropy were highly dependent on the local environment of the reporter molecule. Results obtained for hydrogel-based relative humidity sensors containing [Os(CO)2Cl2(sulf-dpp)] and [Os(bpy)2(sulf-dpp)]Cl2 complexes highlight the significant potential for this class of compounds in a hydrogel-supported luminescence-based sensing approach