Reassessing 1492

American Studie

America, Russia, hemp, and Napoleon: a study of trade between the United States and Russia, 1783-1814

Thesis (Ph.D.)--Boston University.Trade between the United States and Russia has never been given much attention by American historians, particularly by those American historians specializing in studies of our early national period. Therefore, he who would do research on early Russo-American commerce must pore over the manuscript consular and ministerial reports of the American State Department archives, the Massachusetts Historical Society microfilms of the diary and letters of John Quincy Adams, and the manuscript log, letter and account books of the Peabody Museum and Essex Institute of Salem, Massachusetts. In the early national period of the United States no field of economic endeavor except agriculture was of greater importance to our young republic than our overseas trade. The merchant marine was one of the most important tools in the creation of American economic viability and in the reinforcement of the political independence so recently won. Our merchant marine a.n:i our navy could not have operated without Russian imports: iron, sailcloth and -most important of all - hemp and hemp cordage. In the age of sail, hemp was as critically important as is oil today, for hemp cordage was the ligaments and nerves of the sailing ship. Some hemp was raised in the United States, but of such poor quality that when exposed to brine or to salt spray it quickly deteriorated. Most hemp used on American ships was grown in Russia. Russo-American trade was also important in the history of Russia and Europe as a whole. Russia was an ally of Napoleon when he created his Continental System by forbidding his empire and allies to trade with the British. However, Russia's best market was Britain and Britain's best source of essential naval stores was Russia. At the same time, Americans were discovering that the economic warfare between France and Britain was making the ports of all of Europe directly or nearly directly under Napoleon's control very dangerous for American shipping. Even the usually peaceful Danes, for instance, seized several hundred American merchantmen between 1807 and the outbreak of the War of 1812. It was inevitable that Russia, the continental European nation farthest from Napoleon's center of power, would become one of our most important trading partners. In 1811, for example, one tenth of all America's exports went to Russia. It was also inevitable that many Americans would engage in smuggling goods to and from Russia fer the British. And it was inevitable that Britons would disguise their own merchantmen with American flags and papers, and continue direct trade with Russia under false colors. Thus it was that from 1808 through 1812 the foreign flag most commonly seen in Russia's Baltic and White Sea ports was the Stars and Stripes. In the summer of 1811, for instance, a hundred vessels flying the American nag lay in Kronstadt harbor at one time. Napoleon sent demand after demand to Tsar Alexander I to halt all trade with American vessels. All Americans, the Corsican claimed, were either British or sailing on British account. From 1809 through the winter of 1812 Napoleon's ambassadors to Russia, Caulaincourt and Lauriston, fought America's minister to Russia, John Quincy Adams, for Alexander's favor. Adams won, because Alexander knew that the bulk of Russia's foreign trade was now being carried in American bottoms. To sever trade relations with the United States would have had a disastrous effect on Russia's already staggering economy. Probably Russia's lax enforcement of the Continental System against shipping flying the American colors was as important as any other single factor in convincing Napoleon that he must invade Russia, and therefore in bringing the French Einpire to wreck upon the white reefs of the Russian winter of 1812

Size-scaling limits of impulsive elastic energy release from a resilin-like elastomer

Elastically-driven motion has been used as a strategy to achieve high speeds in small organisms and engineered micro-robotic devices. We examine the size-scaling relations determining the limit of elastic energy release from elastomer bands with mechanical properties similar to the biological protein resilin. The maximum center-of-mass velocity of the elastomer bands was found to be size-scale independent, while smaller bands demonstrated larger accelerations and shorter durations of elastic energy release. Scaling relationships determined from these measurements are consistent with the performance of small organisms which utilize elastic elements to power motion. Engineered devices found in the literature do not follow the same size-scaling relationships, which suggests an opportunity for improved design of engineered devices.Comment: 9 pages, 4 figure

Control of Astrocyte Quiescence and Activation in a Synthetic Brain Hydrogel

Bioengineers have designed numerous instructive brain extracellular matrix (ECM) environments with tailored and tunable protein composition and biomechanical properties in vitro to study astrocyte reactivity during trauma and inflammation. However, a major limitation of both protein-based and model microenvironments is that astrocytes within fail to retain their characteristic stellate morphology and quiescent state without becoming activated under “normal” culture conditions. Here we introduce a synthetic hydrogel, that for the first time demonstrates maintenance of astrocyte quiescence and activation on demand. With this synthetic brain hydrogel, we show the brain-specific integrin-binding and matrix metalloprotease (MMP)-degradable domains of proteins control astrocyte star-shaped morphologies, and we can achieve an ECM condition that maintains astrocyte quiescence with minimal activation. In addition, we can induce activation in a dose-dependent manner via both defined cytokine cocktails and low molecular weight hyaluronic acid. We envision this synthetic brain hydrogel as a new tool to study the physiological role of astrocytes in health and disease

Periodic Patterns and Energy States of Buckled Films on Compliant Substrates

Thin stiff films on compliant elastic substrates subject to equi-biaxial compressive stress states are observed to buckle into various periodic mode patterns including checkerboard, hexagonal and herringbone. An experimental setting in which these modes are observed and evolve is described. The modes are characterized and ranked by the extent to which they reduce the elastic energy of the film–substrate system relative to that of the unbuckled state over a wide range of overstress. A new mode is identified and analyzed having nodal lines coincident with an equilateral triangular pattern. Two methods are employed to ascertain the energy in the buckled state: an analytical upper-bound method and a full numerical analysis. The upper-bound is shown to be reasonably accurate to large levels of overstress. For flat films, except at small states of overstress where the checkerboard is preferred, the herringbone mode has the lowest energy, followed by the checkerboard, with the hexagonal, triangular, and one-dimensional modes lowering the energy the least. At low overstress, the hexagonal mode is observed in the experiments not the square mode. It is proposed that a slight initial curvature of the film may play role in selecting the hexagonal pattern accompanied by a detailed analysis. An intriguing finding is that the hexagonal and triangular modes have the same energy in the buckled state and, moreover, a continuous transition between these modes exists involving a linear combination of the two modes with no change in energy. Experimental observations of various periodic modes are discussed with reference to the energy landscape. Discrepancies between observations and theory are identified and open issues are highlighted.Engineering and Applied Science

Mechanics of Intact Bone Marrow

The current knowledge of bone marrow mechanics is limited to its viscous properties, neglecting the elastic contribution of the extracellular matrix. To get a more complete view of the mechanics of marrow, we characterized intact yellow porcine bone marrow using three different, but complementary techniques: rheology, indentation, and cavitation. Our analysis shows that bone marrow is elastic, and has a large amount of intra- and inter-sample heterogeneity, with an effective Young’s modulus ranging from 0.25-24.7 kPa at physiological temperature. Each testing method was consistent across matched tissue samples, and each provided unique benefits depending on user needs. We recommend bulk rheology to capture the effects of temperature on tissue elasticity and moduli, indentation for quantifying local tissue heterogeneity, and cavitation rheology for mitigating destructive sample preparation. We anticipate the knowledge of bone marrow elastic properties for building in vitro models will elucidate mechanisms involved in disease progression and regenerative medicin

Functional Droplets that Recognize, Collect, and Transport Debris on Surfaces

We describe polymer-stabilized droplets capable of recognizing and picking up nanoparticles from substrates in experiments designed for transporting hydroxyapatite nanoparticles that represent the principal elemental composition of bone. Our experiments, which are inspired by cells that carry out materials transport in vivo, used oil-in-water droplets that traverse a nanoparticle-coated substrate driven by an imposed fluid flow. Nanoparticle capture is realized by interaction of the particles with chemical functionality embedded within the polymeric stabilizing layer on the droplets. Nanoparticle uptake efficiency is controlled by solution conditions and the extent of functionality available for contact with the nanoparticles. Moreover, in an elementary demonstration of nanoparticle transportation, particles retrieved initially from the substrate were later deposited “downstream,” illustrating a pickup and drop-off technique that represents a first step toward mimicking point-to-point transportation events conducted in living systems