My First Encounter with the Feminist Gift Economy

Dans cet article la chercheure et activiste Angela Dolmetsch rapporte son expérience vécue dans un atelier des Wise-Women en Norvège en 2001. Elle a été immédiatement inspirée par les exercices du don avec le résultat qu’elle a décidé spontanément de se débarrasser de ses possessions matérielles. Elle décrit ses efforts subséquents pour établir un cadre pour l’économie du don, en particulier dans le village écologique Nashira, en Colombie

Phosphomolybdic Acid Catalysis of Cellulose Hydrolysis

Renewable sources such as cellulose derived biofuels are sought after in order to replace fossil fuel sources that are currently used to meet energy demands. Cellulose is a biological polymer composed of a chain of glucose molecules. Hydrolysis of cellulosic materials then has potential to serve as a source of renewable energy in the form of biofuels. The crystalline structure of cellulose is very stable, and current methods of catalyzed hydrolysis are inefficient for industrial application. This project explores the use of phosphomolybdic acid (PMA) in water to catalyze hydrolysis of microcrystalline cellulose. Temperature of hydrolysis was varied from 40 °C – 100 °C. The amount of soluble hydrolysis product was determined through wet oxidative total organic carbon analysis using a Hach method kit. Total organic carbon content is compared between equimolar amounts of PMA and sulfuric acid, the current industry preference. The yield of total organic carbon in parts per thousand (ppt) is directly correlated to increasing temperatures. Across these temperatures, PMA is more efficient than sulfuric acid in hydrolysis of cellulosic materials. Work is ongoing for glucose-specific product detection as well as evaluating the recyclability of the catalyst

Second Valse Lente

https://digitalcommons.library.umaine.edu/mmb-ps/2129/thumbnail.jp

Versions of the 'Marseillaise'

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Calcium Imaging of Cortical Neurons using Fura-2 AM

Calcium imaging is a common technique that is useful for measuring calcium signals in cultured cells. Calcium imaging techniques take advantage of calcium indicator dyes, which are BAPTA-based organic molecules that change their spectral properties in response to the binding of Ca2+ ions. Calcium indicator dyes fall into two categories, ratio-metric dyes like Fura-2 and Indo-1 and single-wavelength dyes like Fluo-4. Ratio-metric dyes change either their excitation or their emission spectra in response to calcium, allowing the concentration of intracellular calcium to be determined from the ratio of fluorescence emission or excitation at distinct wavelengths. The main advantage of using ratio-metric dyes over single wavelength probes is that the ratio signal is independent of the dye concentration, illumination intensity, and optical path length allowing the concentration of intracellular calcium to be determined independently of these artifacts. One of the most common calcium indicators is Fura-2, which has an emission peak at 505 nM and changes its excitation peak from 340 nm to 380 nm in response to calcium binding. Here we describe the use of Fura-2 to measure intracellular calcium elevations in neurons and other excitable cells

A Study of Socialism in the Contemporary British Novel

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Deformation mechanisms of hierarchically structured 2D single-crystal materials revealed by real-time high-resolution in-situ nanomechanical testing

Hierarchically structured materials such as two-dimensional (2D) single-crystal transition metal dichalcogenides (TMDs) are being increasingly explored for their electronic and piezoelectric properties for applications in devices and sensors. These materials exhibit complex deformation mechanisms that can only be revealed by real-time, nanomechanical investigations. This study investigated the plastic delamination response of 2D, single-crystal TMDs with varying lattice parameters by an integrated in-situ nano scratch, visualization, and analytical modeling approach. Nanowear at systematically progressing depths from 15 – 45 nm delaminates 50 – 80 layers with an increasing lateral force of resistance from 3.5 – 8.0 mN, thereby consuming 80 – 154 nJ of energy. Based on in-situ visualizations, the evolution of lateral force over delamination distance is modeled on linear debonding and sinusoidal pile-up forces. These novel insights on the multi-scale, hierarchical mechanical and tribological responses and failure mechanisms constitute a significant advancement in the understanding of the processing-property correlations in these architecture materials