1,300 research outputs found

    Part I. A Novel Synthesis of Dihydrojasmone. Part II. Polymethyleneketenedimers and Trimers.

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    Part I. A Novel Synthesis of Dihydrojasmone. — 3-Methylcyclopent-2-en-2-ol-l-one, a readily available substance of natural occurrence, was utilized in the synthesis of the well-known dihydrojasmone (2-n-aniyl-3-methylcyclopent-2-en-l-one). This was the first practical synthesis of dihydroJasmone which did not involve a condensation reaction, thus the possibility of obtaining an isomeric mixture of products was eliminated. Acetylation of 3-methylcyclopent-2-en-2-ol-l-one with acetic anhydride gave 2-acetoxy-3-methylcyclopent-2-en-l-one, which was converted by the action of propylene oxide to 2-acetoxy-3-methylcyclopent-2-en-l-one propylene ketal. Saponification of this ketal gave 3- methyl-l,2-cyclopentanedione-l,l-propylene ketal, which served as a precursor to dihydrojasmone. Upon treatment of this compound with n-amylmagnesium chloride, followed by hydrolysis with ammonium chloride solution, 2-n-amyl-3-methylcyclopentan-2-ol-l-one propylene ketal was obtained. Dehydration and deketalization of the latter compound with sulfuric acid solution yielded dihydrojasmone. Part II. Polymethyleneketene Dimers and Trimers. — An excellent method for the preparation of ketoketene dimers involves the dehydrohalogenation of an acyl chloride with triethylamine. The reaction of cyclopropanecarbonyl chloride with triethylamine gave no dimer but instead a solid product, presumably the acyl ammonium chloride, which reacted with aniline to form cyclopropanecarboxanilide. Cyclobutanecarbonyl chloride and triethylamine yielded at temperatures below 25® a similar addition compound which gave cyclobutanecarboxanilide when treated with aniline. When the latter reaction was carried out at a higher temperature, dispiro [3.1.3.1] decane-5,10-dione was obtained. Dispiro [3.1.3.1] decane-5,10-dione, trimethyleneketene dimer, underwent cleavage and decarboxylation in alkali to give dicyclobutyl ketone. The ketone was obtained without acidification of the alkaline solution, which is generally necessary for the decarboxylation of a β-keto acid in the form of its sodium salt. A mechanism was proposed for its formation. Trimethyleneketene dimer reacted with ethanol in the presence of a catalytic amount of base to give ethyl l- (cyclobutanecarbonyl)cyclobutanecarboxylate, and was reduced to the corresponding glycol, dispiro [3.1.3.1] decane-5,10-diol with lithium aluminum hydride. It is known that dimethylketene dimer, tetramethyl-l,3-cyclobutanedione, when treated with a catalytic amount of sodium methoxide, yields the cyclic trimer, hexamethyl-l,3,5-cyclohexanetrione. In the present investigation, this base-catalyzed process was utilized in the synthesis of trimethyleneketene trimer, trispiro [3.1.3.1.3.1] pentadecane-5,10,15-trione, from trimethyleneketene dimer. In this study it was found that the alkaline hydrolysis of dimethylketene trimer with barium hydroxide gave 2,4,4,6-tetramethylheptan-3,5-dione. Trimethyleneketene trimer, upon treatment with the same reagent gave l, l (dicyclobutanecarb6nyl) cyclobutane and dicyclobutyl ketone. Ethanolysis of trimethyleneketene trimer gave ethyl 1-[1-(cyclobutanecarbonyl)cyclobutanecarbonyl] cyclobutanecarboxylate. Reduction of the trimer was accomplished with lithium aluminum hydride to give trispiro [3.1.3.1.3.1] pentadecane-5,10,15- triol. Tetramethyleneketene dimer, dispiro [4.1.4.1] dodecane-6,12-dione, a known compound, was the only product isolated in an attempted synthesis of tetramethyleneketene monomer by dehydrohalogenation of cyclopentanecarbonyl chloride with triethylamine. The dimer underwent cleavage and decarboxylation when treated with alkali to give dicyclopentyl ketone. Only one polymethylene ketene, pentamethyleneketene, has been reported in the literature. It was found that hexamethyleneketene could be synthesized by dehydrohalogenation of cycloheptanecarbonyl chloride with triethylamine. This monomer reacted with aniline to give cycloheptanecarboxanilide, and gave with cyclopentadiene a cycloaddition product, hexamethylenebicyclo [3.2.0] hept-3-en-l-one. Hexamethyleneketene dimerized upon standing to give dispiro- [6.1.6.1] hexadecane-8, l6-dione which underwent reduction with lithium aluminum hydride to give the corresponding glycol, dispiro [6.1.6.1] hexadecane-8,l6- triol

    Effect of non-nicotinic moist snuff replacement and lobeline on withdrawal symptoms during 48-h smokeless tobacco deprivation

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    The present study investigated the effects of two herbal components (BACCOFFTM and DIPSTOP ™) of a commercially available smokeless tobacco treatment program for reducing subjective withdrawal symptoms during deprivation. One component, BACCOFF™, is a non-nicotinic chew. The second component, DIPSTOP™, is a liquid containing the alkaloid lobeline, which to some extent mimics peripheral nicotinic effects. All participants (N = 22 males) were placed in four conditions: BACCOFF™ + DIPSTOP™, BACCOFF™ + placebo control, DIPSTOP™ only, and placebo control only. The conditions involved 48 h of deprivation, and subjects were exposed to one condition per week for 4 weeks. Withdrawal measures were taken at baseline, 24 h, and 48 h of deprivation. Individuals were randomly assigned, and conditions were counterbalanced. Results showed that BACCOFF™, as compared with DIPSTOP™, significantly reduced withdrawal symptoms but not craving. These data suggest that behavioral/sensory substitutes’ influence on withdrawal might be routed through the product’s ability to approximate the preferred moist snuff

    Evaluation of clinical prediction models (part 1):from development to external validation

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    Evaluating the performance of a clinical prediction model is crucial to establish its predictive accuracy in the populations and settings intended for use. In this article, the first in a three part series, Collins and colleagues describe the importance of a meaningful evaluation using internal, internal-external, and external validation, as well as exploring heterogeneity, fairness, and generalisability in model performance

    Imaging in population science: cardiovascular magnetic resonance in 100,000 participants of UK Biobank - rationale, challenges and approaches

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    PMCID: PMC3668194SEP was directly funded by the National Institute for Health Research Cardiovascular Biomedical Research Unit at Barts. SN acknowledges support from the Oxford NIHR Biomedical Research Centre and from the Oxford British Heart Foundation Centre of Research Excellence. SP and PL are funded by a BHF Senior Clinical Research fellowship. RC is supported by a BHF Research Chair and acknowledges the support of the Oxford BHF Centre for Research Excellence and the MRC and Wellcome Trust. PMM gratefully acknowledges training fellowships supporting his laboratory from the Wellcome Trust, GlaxoSmithKline and the Medical Research Council

    1995 CSREES Reports

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    The 1995 edition of the CSREES Reports was prepared for the Maine Wild Blueberry Commission and the University of Maine Wild Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include: 1. Factors Affecting the Quality of IQF Blueberries 2. Preventing the Bleeding of Blueberry Fruit in Bakery Products 3. Removing Water from Blueberries Before Freezing 4. Determination of Pesticide Residue Levels in Freshly Harvested and Processed Lowbush Blueberries 5. Industrial Ingredients from Cull Blueberries 6. Application of Heat as a Method of Controlling Secondary Pest Insects on Lowbush Blueberries 7. The Phenology and Biology of Bumble Bees, Bombus, spp., that Pollinate Lowbush blueberry, Vaccinium spp., in Maine 8. Pollination Ecology of Lowbush Blueberry in Maine 9. Effects of Irrigation on Lowbush Blueberry Yield 10. Effect of Brief Warming Treatments on Late Winter Low-Temperature Tolerance of Native Lowbush Blueberry 11. Correlation of Late-winter/Early-spring Cold Hardiness with Date of Flowering 12. Evaluation of Cold Tolerance of Opening Flowers of Lowbush Blueberry 13. Influence of Flower Delaying Sprays on Seasonal Variation of Low Temperature Tolerance in Lowbush Blueberry 14. Effect of Various Levels of Disbudding on Yield of Lowbush Blueberry 15. Effect of Boron and the Polyamine Putrescine on Lowbush Blueberry Fruit Set and Yield 16. Effect of Boron and the Polyamine Putrescine on Extending the Receptivity of Lowbush Blueberry Blossoms 17. Effect of Soil pH on Nutrient Uptake 18. Correcting Boron Deficiency - missing 19. Phosphorus Uptake 20. Evaluation of Hexazinone Formulation on Soil Movement and Weed Control 21. Effect of Time of Fall Pruning on Growth and Productivity of Blueberries 22. Hexazinone Ground Water Survey 23. Effect of hexazinone formulation on movement through the soil profile 24. Evaluation of Tribenuron Methyl for Bunchberry Control 25. Evaluation of Tribenuron Methyl Commercial Applications for Bunchberry Control 26. Effectiveness of Resin-Exchange Columns to Determine Efficacy in Removing Hexazinone from Well Water 27. Effect of Clopyralid for Vetch Control 28. Evaluation of Tribenuron Methyl/Velpar® Tank Mix for Bunchberry Control 29. Blueberry Extension Education Progra

    Maine Blueberry Advisory Committee Research Report

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    The 1990 edition of the Maine Blueberry Advisory Committee Research Reports was prepared for the Maine Wild Blueberry Commission and the University of Maine Wild Blueberry Advisory Committee by researchers with the Maine Agricultural Experiment Station and Maine Cooperative Extension Service at the University of Maine, Orono. Projects in this report include: 1. Biology and action thresholds of secondary blueberry pests 2. Control of blueberry maggot 3. Control of secondary blueberry pests 4. Application of steam as a method of controlling secondary pest insects on lowbush blueberry: a feasibility study 5. Pollination of the lowbush blueberry by native bees 6. Nitrogen-phosphorus study 7. Potassium study 8. Multiple cropping of wild stands 9. Phosphorus dose/response curve 10. Improvement in the color and texture of the canned blueberry 11. The effect of fertilization and irrigation on blueberry fruit quality 12. Investigation of preprocess changes (chemical, microbiological, and/or physical) that could lead to the development of a simple and inexpensive method to measure preprocess berry spoilage 13. The effect of postharvest handling on the dietary fiber and ellagic acid content of lowbush blueberries 14. Determination of pesticide residue levels in freshly harvested and processed lowbush blueberries 15. Evaluation of Defoliating Diseases 16. Vacuum Sanitation for Disease Control 17. Evaluation and modification of commercial herbicide applications 18. Evaluation of the suitability of remote sensing to evaluate plant cover in lowbush blueberry fields 19. Evaluation of Sethoxydin (POAST) in lowbush blueberry fields 20. Seedling pruning study 21. Evaluation of norflurazon (SOLICAM) with or without hexazinone (VELPAR) for bunchberry control 22. Selective wiper and mechanical control of dogbane and bracken fern 23. Evaluation of norflurazon (SOLICAM) in fall vs spring for oatgrass control 24. Evaluation of sulfonyl urea herbicides for bunchberry control 25. Evaluation of postemergence applications of DPX-L5300 for bunchberry control 26. Effect of time of application and formulation of hexazinone (VELPAR) on blueberry and bunchberry 27. Investigations of lowbush blueberry fruit-bud cold hardiness 28. The economics of investing in irrigation for lowbush blueberries 29. Effects of irrigation on lowbush blueberry yield and quality 30. Groundwater and surface water development for blueberry irrigation 31. Design, fabrication and testing of an experimental sterilizer for blueberry field

    1994 CSRS Research Reports/1994 Blueberry Tax Reports

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    The 1994 edition of the CSRS Research Reports/Blueberry Tax Reports was prepared for the Maine Wild Blueberry Commission and the University of Maine Wild Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include: CSRS Research Reports 1. Potential Uses for Green and Red Cull Blueberries 2. Preventing the Bleeding of Blueberry Fruit in Bakery Products 3. The Effect of Fertilization and Irrigation on Blueberry Fruit Quality 4. Determination of Pesticide Residue Levels in Freshly Harvested and Processed Lowbush Blueberries 5. The Effect of Mechanical Harvesting on Blueberry Fruit Quality 6. Removing Water from Blueberries Before Freezing 7. Application of Heat as a Method of Controlling Secondary Pest Insects in Lowbush Blueberries 8. Evaluation of Effectiveness of Eumenid Wasps for Biocontrol of Blueberry Pests 9. Pollination Ecology of Lowbush Blueberry in Maine 10. Fungicide Treatment for Control of Monilinia Blight 11. Field Sanitation for Control of Monilinia Blight 12. Cold-hardiness of Native Lowbush Blueberry 13. Phosphorus Dose/Response Curve 14. Multiple Cropping of Wild Blueberry Stands 15. Effect of Soil pH on Nutrient Uptake 16. Effect of Boron and Calcium on Lowbush Blueberry Fruit Set and Yield 17. Effect of Time of Fall Pruning on Growth and Productivity of Lowbush Blueberries 18. A Reinvestigation of the Economics of Mechanical Harvesting 19. Thresholds of Mechanical and Chemical Weed Controls in Wild Blueberries 20. Evaluation of Pressurized Rope Wick Master Wiper for Treating Weeds Growing Above Lowbush Blueberries 21. Evaluation of Infrared Burner for Selective Weed Control Blueberry Tax Reports 22. Control of Blueberry Pest Insects 23. Biology and Action Thresholds of Secondary Blueberry Pest Insects 24. Pollination Ecology of Low bush Blueberry in Maine 25. Nitrogen-Phosphorus Study 26. Evaluation of Pronone 10G for Control of Weeds in Lowbush Blueberries 27. Evaluation of Tribenuron Methyl for Bunchberry Control 28. Evaluation of Pendimethalin for Control of Annual Grasses in Lowbush Blueberries 29. Evaluation of Time of Application of Clopyralid for Control of Vetch, and Effect on Flowering of Lowbush Blueberries 30. Hexazinone Ground Water survey 31. Blueberry Extension Program Base 32. Blueberry ICM Program for Hancock Count

    1992 Blueberry Research Progress Reports

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    The 1992 Blueberry Research Progress Reports pertain to and report on research conducted in 1991, and were prepared for the Maine Wild Blueberry Commission and the University of Maine Wild Blueberry Advisory Committee by researchers at the University of Maine, Orono. Projects in this report include: 1992 CSRS Progress Reports: 1. Investigation of Groundwater Resources 2. Sprinkler Irrigation 3. Investigation of Preprocess Changes Leading to Berry Spoilage 4. Effect of Fertilization and Irrigation on Blueberry Quality 5. Effects of Calcium Salts and Citric Acid on Quality of Canned Lowbush Blueberries 6. Pollination of Lowbush Blueberry by Native Bees 7. Application of Heat for Controlling Insects 8. Investigations of Lowbush Blueberry Fruit Bud Cold-Hardiness 9. Steam Sterilization in Lowbush Blueberry Fields 10. Heat-Tolerant Molds 11. Vacuum Sanitation for Disease Control 12. Evaluation of Infrared Burner for Weed Control 13. Evaluation and Modification of Commercial Herbicide Wipers 14. Evaluation of Remote Sensing to Estimate Plant Cover in Lowbush Blueberry Fields 15. Comparison of Three Mechanical Blueberry Harvesters vs. Hand Raking Advisory Committee Research Reports: 16. Biology and action thresholds of secondary blueberry insects 17. Control of secondary blueberry pests 18. Control of blueberry maggot 19. Effects of calcium salts and citric acid on the quality of canned lowbush blueberries 20. The effects of postharvest handling on the dietary fiber and ellagic acid content of lowbush blueberries 21. Investigation of preprocessing changes that could lead to development of simple and inexpensive method to measure preprocessing berry spoilage 22. Determination of pesticide residue levels in fresh and processed lowbush blueberries 23. Vacuum sanitation for disease control 24. Heat-tolerant molds 25. Seedling pruning study 26. Effect of time and rate of application of Clopyralid for control of Vetch in lowbush blueberries 27. Evaluation and modification of commercial herbicide wipers 28. Effect of time of application and formulation of Hexazinone (Velpar) on Blueberry and Bunchberry 29. Evaluation of postemergence applications of Tribenuron Methyl for Bunchberry control 30. Thresholds of Dogbane and Bracken Fern by mechanical and chemical control in lowbush blueberry fields 31. Evaluation of the suitability of remote sensing to evaluate plant cover in lowbush blueberry fields 32. Evalution of infrared burner for weed control 33. Effect of time of fall pruning on growth and productivity of blueberry and evaluation of infrared burner to prune blueberries 34. Effect of Boron on lowbush blueberry fruit set and yield 35. Winter injury protection by potassium 36. Multiple cropping of wild stands 37. Nitrogen-Phosphorus study 38. Phosphorus dose/response curve 39. Investigations of lowbush blueberry fruit bud cold-hardines
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