Publications by authors named "Robert Leon"

An asymmetric synthesis of C14-desmethylene corialactone D is described on the basis of strategic application of a metallacycle-mediated annulative cross-coupling reaction, a Still [2,3]-Wittig rearrangement, and Morken's hydroxyl-directed diboration reaction. While representing a convenient approach to access novel compositions of matter inspired by the sesquiterpenoid natural product class (including classic natural product synthesis targets including the picrotaxanes and dendrobine), these studies have led to the discovery of natural product-inspired agents that inhibit nerve growth factor (NGF)-mediated neurite outgrowth in PC-12 cells.

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A complementary process to the Pauson-Khand annulation is described that is well suited to forging densely substituted/oxygenated cyclopentenone products (including fully substituted variants). The reaction is thought to proceed through a sequence of metallacycle-mediated bond-forming events that engages an internal alkyne and a β-keto ester in an annulation process that forges two C-C bonds. A variant of this annulation process has also been established that delivers deoxygenated cyclopentenones that lack the allylic tertiary alcohol.

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A mechanistic investigation of the carbohydrate/DBU cocatalyzed enantioselective diboration of alkenes is presented. These studies provide an understanding of the origin of stereoselectivity and also reveal a strategy for enhancing reactivity and broadening the substrate scope.

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Densely substituted and highly oxygenated carbocycles are challenging targets for synthesis. In particular, those possessing numerous contiguous, fully substituted carbon atoms (i.e.

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This is the first in a series of papers describing the epidemiology of malaria in an isolated village in western Thailand. The study site was the village of Kong Mong Tha, located in Sangkhla Buri District, Kanchanaburi Province, Thailand. In this paper we present an overview of the study site and results from our adult anopheline mosquito surveillance conducted over 56 consecutive months from June 1999 until January 2004.

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The long-term strategic focus of US foreign policy has pivoted to the Pacific, but tensions in the Middle East require constant attention in the present. As our current role in Afghanistan diminishes, we must seize the opportunity to refocus on the new priority of regionally-aligned forces. The short-term reality requires first reestablishing core warfighting competencies of a smaller Army and then building the capacity of forces focused on regional alignment.

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The development and prove-out of yellow-light-emitting pyrotechnic illuminants based on recover, recycle, and reuse (R ) technology is described. Magnesium used in this investigation was recovered from four different illuminating pyrotechnic munitions by means of an environmentally friendly demilitarization process. Despite significant differences in the particle size and purity between the four lots of recovered magnesium, the performance of each lot-on evaluation in the M127A1 US Army yellow-light-emitting illuminant configuration-exceeded the military requirement and performance of the virgin magnesium-containing control.

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Anthroponotic cutaneous leishmaniasis (CL) is a common cause of ulcerative lesions and disfiguring scarring among children in Afghanistan. Most lesions occur on the face and are commonly caused by the trypanosome protozoan parasite Leishmania tropica, transmitted by the bite of an infected sandfly (Phlebotomus sergenti). This study compared the effectiveness of a single localized treatment with thermotherapy to 5 days of intralesional administration of Glucantime for the treatment of CL.

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Military entomologists function as part of medical civil-military operations and are an essential combat multiplier direction supporting COIN operations. They not only directly support US and coalition military forces by performing their traditional wartime mission of protecting personnel from vector-borne and rodent-borne diseases but also enhance the legitimacy of medical services by the host nation government such as controlling diseases promulgated by food, water, vectors, and rodents. These unique COIN missions demand a new skill set required of military entomologists that are not learned from existing training courses and programs.

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Hazards in opportunity.

J Immigr Health

April 2002

Epidemiology studies have found that immigrants who enter the United States from Mexico have prevalence rates of mental disorder similar to residents of Mexico City. These rates are much lower than rates of mental disorder found in those of Mexican decent who were born in the United States. Prevalence of depression in U.

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Two recent outbreaks of locally acquired, mosquito-transmitted malaria in Virginia in 1998 and 2002 demonstrate the continued risk of endemic mosquito-transmitted malaria in heavily populated areas of the eastern United States. Increasing immigration, growth in global travel, and the presence of competent anopheline vectors throughout the eastern United States contribute to the increasing risk of malaria importation and transmission. On August 23 and 25, 2002, Plasmodium vivax malaria was diagnosed in 2 teenagers in Loudoun County, Virginia.

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Furuncular myiasis is a parasitic infestation of human and other vertebrate tissues by fly larvae of primarily two species: Dermatobia hominis (human botfly, t6rsalo, or berne) in Mexico and South and Central America and Cordylobia anthropophaga (tumbu fly or mango fly) in Africa. Cuterebra species (rabbit and rodent botflies) are also rarely reported to cause furuncular myiasis only within the United States. Although these species inhabit different geographic regions and have different life cycles, their clinical presentations can be similar.

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