1,063 research outputs found

    Toward the total synthesis of spirastrellolide A. Part 3: Intelligence gathering and preparation of a ring-expanded analogue

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    Different methods for the formation of the C.25–C.26 bond of spirastrellolide A (1) are evaluated that might qualify for the end game of the projected total synthesis, with emphasis on metathetic ways to forge the macrocyclic frame

    Effects of No-tillage Fallow as Compared to Conventional Tillage in a Wheat-fallow System

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    The benefits of reducing tillage by use of herbicides for weed control emphasizes why research was started to study a fallow system where all tillage was replaced by herbicides. Wheat planting was then the only soil disturbing operation. Objectives of the research were to compare the effects of no-tillage (chemical), stubble-mulch and plow (bare fallow) systems of fallow on: 1. Grain yield. 2. Grain protein. 3. Residue retention. 4. Soil nitrate-nitrogen accumulation. 5. Soil water accumulations during fallow. Data presented are in the form of a progress report. These experiments will continue

    Reducing Brutality Through Improved Police-Community Relations

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    This paper responds to negative public perceptions of United States law enforcement agencies. The research in this paper addresses six areas of policing reforms that have the potential to positively impact police-community relations: (1) building trust and legitimacy, (2) policy and oversight, (3) technology and social media, (4) community policing and crime reduction, (5) officer training and education, and (6) police-media relations. This paper reviews the existing literature in each topic area. The purpose of each literature review is to more accurately understand possible solutions to the widespread distrust of police and the issue of police brutality. This paper makes its own recommendations for how United States law enforcement agencies can successfully improve police-community relations and reduce occurrences of brutality. The recommendations made at the end of this research are applicable to all federal, state, and local law enforcement agencies across the country. Ultimately, it is the thesis of this research that improvements to police-community relations will lessen the necessity of police force and effectively reduce brutality

    Measurements of Aerosol Size Distributions and Vertical Fluxes of Aerosols on Land Subject to Wind Erosion

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    To assess wind erosion as a source of atmospheric soil particles, vertical aerosol fluxes near the ground in an eroding field were computed by assuming a vertical transport mechanism similar to that for momentum. Aerosol gradients were measured by jet impactors located 1.5 and 6 m above the ground, and wind velocity gradients were measured by totalizing-three anemometers located 1.5, 3 and 6 m above the ground. Information on the aerosol size distributions and quantity in the size range 0.

    Measurements of Aerosol Size Distributions and Vertical Fluxes of Aerosols on Land Subject to Wind Erosion

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    To assess wind erosion as a source of atmospheric soil particles, vertical aerosol fluxes near the ground in an eroding field were computed by assuming a vertical transport mechanism similar to that for momentum. Aerosol gradients were measured by jet impactors located 1.5 and 6 m above the ground, and wind velocity gradients were measured by totalizing-three anemometers located 1.5, 3 and 6 m above the ground. Information on the aerosol size distributions and quantity in the size range 0.

    Toward the Total Synthesis of Spirastrellolide A. Part 2: Conquest of the Northern Hemisphere

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    North and South: The unique biological activity of the natural product spirastrellolide A renders it an attractive lead for anticancer agents. The southern hemisphere (C1–C25) and the northern hemisphere (including the chlorinated [5,6,6]-bis-spiroacetal entity and the lateral C42–C47 chain) are prepared by concise and efficient routes. Consequently, the entire carbon framework of this potent phosphatase inhibitor, which contains 21 chiral centers, is prepared in an optically active form, and an important step toward structure determination by total synthesis is achieved

    Palladium-catalyzed substitution of (coumarinyl)methyl acetates with C-, N-, and S-nucleophiles

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    The palladium-catalyzed nucleophilic substitution of (coumarinyl)methyl acetates is described. The reaction proceeds though a palladium π-benzyl-like complex and allows for many different types of C-, N-, and S-nucleophiles to be regioselectively added to the biologically active coumarin motif. This new method was utilized to prepare a 128-membered library of aminated coumarins for biological screening.We thank the National Institutes of Health KU Chemical Methodologies and Library Development Center of Excellence (P50 GM069663) for funding. We are indebted to Dr. Conrad Santini and Ben Neuenswander for help in library production and purification

    Toward the Total Synthesis of Spirastrellolide A. Part 1: Strategic Considerations and Preparation of the Southern Domain

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    North and South: The unique biological activity of the natural product spirastrellolide A renders it an attractive lead for anticancer agents. The southern hemisphere (C1–C25) and the northern hemisphere (including the chlorinated [5,6,6]-bis-spiroacetal entity and the lateral C42–C47 chain) are prepared by concise and efficient routes. Consequently, the entire carbon framework of this potent phosphatase inhibitor, which contains 21 chiral centers, is prepared in an optically active form, and an important step toward structure determination by total synthesis is achieved

    Development of Highly Variable Microsatellite Markers for the Tetraploid Silene stellata (Caryophyllaceae)

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    Premise of the study:We designed and tested microsatellite markers for the North American native species Silene stellata (Caryophyllaceae) to investigate its population genetic structure and identify selection on floral design through male reproductive success. Methods and Results: A total of 153 candidate microsatellite loci were isolated based on next-generation sequencing. We identified 18 polymorphic microsatellite loci in three populations of S. stellata, with di- or trinucleotide repeats. Genotyping results showed the number of alleles per locus ranged from six to 45 and expected heterozygosity ranged from 0.511 to 0.951. Five of these loci were successfully amplified in S. virginica and S. caroliniana and were also polymorphic. Conclusions: The microsatellite markers reported here provide a valuable tool for paternity analysis in S. stellata. They will also be useful for investigating the population genetic structures of S. stellata and related species

    Carotid ultrasound phenotypes in vulnerable populations

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    BACKGROUND: Biomarkers of carotid atherosclerosis range from those that are widely available and relatively simple to measure such as serum cholesterol levels, and B-mode Ultrasound measurement of intima media thickness (IMT) to those that are more complex and technologically demanding but perhaps potentially more sensitive and specific to disease such as total plaque volume and total plaque area measured from 3-dimensional ultrasound images. In this study we measured and compared intima media thickness (IMT), total plaque volume (TPV) and total plaque area (TPA) in two separate populations, both vulnerable to carotid atherosclerosis. METHODS: In total, 88 subjects (mean age 72.8) with carotid stenosis of at least 60%, based on a peak Doppler flow, and 82 subjects (mean age 60.9) with diabetic nephropathy were assessed in a cross-sectional study. Conventional atherosclerotic risk factors were examined and the associations and correlations between these and carotid ultrasound phenotypes measured from B-mode and 3-dimensional ultrasound images were assessed. RESULTS: IMT and TPV were only modestly correlated in the two separate populations (r = .6, p < .01). ANOVA analyses indicated that both IMT and TPV were significantly associated with age (p < .001) and Framingham score (p < .05), but only TPV was associated with diabetes (p < .001) and presence of plaque ulcerations (p < .01) CONCLUSION: IMT and TPV were modestly correlated in a diabetic patient population and only TPV was associated with diabetes and the presence of plaque ulcerations in a diabetic population and carotid stenosis group. The 3-dimensional information provided by TPV can be critically important in unmasking association with risk factors not observed with less complex single-dimension assessments of carotid atherosclerosis such as those provided by IMT
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