A low-toxicity method for the separation of lanosterol and dihydrolanosterol from commercial mixtures

We describe an inexpensive, low-toxicity and high-yielding method for the production of pure lanosterol and dihydrolanosterol from the commercially available mixture. Optimum conditions are presented for the one-pot production of the intermediate 24,25 vicinal diol of lanosterol acetate (via either epoxidation or hydroxyhalogenation) which is readily separated from the unreacted dihydrolanosterol acetate. The lanosterol diol can then be converted to pure (>97%) lanosterol. Hypophosphorous acid was used for both the conversion of the epoxide to the diol, and as a catalyst for the hydroxyhalogenation by N-halosuccinimides of the olefinic bond

Efficient routes to epimerically-pure side-chain derivatives of lanosterol

A technically simple route is described to individual epimers of side-chain derivatives of lanosterol (3-hydroxy-5-lanosta-8,24-diene). Epimerically pure 24,25-epoxy-, 24,25-dihydroxy- and 24-bromo-25-hydroxy-lanosterol have been prepared in good yield from commercial (50-60%) lanosterol. Hypophosphorous acid was used as a catalyst for the cohalogenation of the 24(25) bond and also for the efficient conversion of 24,25-epoxy- and 24-bromo-25-hydroxylanosterol to epimerically pure 24(R) or 24(S)-24,25-dihydroxylanosterols

Modelling charitable donations: A latent class panel approach

We apply a latent class tobit framework to the analysis of charitable donations at the household level where the latent class aspect of the model splits households into two groups, which we subsequently interpret as "low" donators and "high" donators. Then the tobit part of the model explores the determinants of the amount donated by each household conditional on being in that class. We consider both total donations and also separately religious donations. Our findings, which are based on US panel data, suggest that price and labour income elasticities differ substantially across the two classes. The inverse price effect is most pronounced for the "low" donators group for both total and religious donations. The labour income elasticity switches direction of influence upon charitable donations across the two latent classes with a negative influence for the "high" donators group and a positive influence for the "low" donators group, for the case of total donations to charity, a pattern which is reversed in the case of solely religious donations

Modelling Charitable Donations to an Unexpected Natural Disaster: Evidence from the U.S. Panel Study of Income Dynamics

Using household-level data, we explore the relationship between donations to the victims of the 2004 Indian Ocean tsunami disaster and other charitable donations. The empirical evidence suggests that donations specifically for the victims of the tsunami are positively associated with the amount previously donated to other charitable causes, which accords with complementary rather than substitution effects. This relationship exists when we decompose overall charitable donations into different types of philanthropy, with charitable contributions to caring, needy and religious organizations having the largest positive association with donations to the victims of the tsunami. When we explore the impact of donations to the victims of the tsunami on future donations to charity, however, our findings suggest an inverse relationship with the largest inverse association with donations to needy and caring organizations

Measurement of the derivative 'ZW' for an oscillating aerofoil

This report presents the results of experimental measurements of the damping derivative coefficient zw for constant chord rigid wings of various aspect ratios having sweepback angles of zero and 450. The results for the rectangular wings Flow substantial agreement with the unsteady aerofoil theory developed by TI.P. Jones $2) The dependence of Zvi upon frequency parameter is as given by theory and is much less than for two dimensional flow, but the numerical results are approximately 10 per cent below the theoretical. This is attributed to the large trailing edge angle 22° of the N.A.C.A. 0020 section used for the model aerofoils. The effect of sweepback is to decrease the numerical value of z , but this effect is much less pronounced, for low than for high aspect ratios. For aspect ratios 5 and 3 the numerical value is greater than would be given by a factor of proportionality equal to the cosine of the angle of sweepback. The measurements were corrected for tunnel interference by a method based on the theoretical work of 7.P.Jones.(1

Modelling Charitable Donations to an Unexpected Natural Disaster: Evidence from the U.S. Panel Study of Income Dynamics

Using household-level data, we explore the relationship between donations to the victims of the 2004 Indian Ocean tsunami disaster and other charitable donations. The empirical evidence suggests that donations specifically for the victims of the tsunami are positively associated with the amount previously donated to other charitable causes, which accords with complementary rather than substitution effects. This relationship exists when we decompose overall charitable donations into different types of philanthropy, with charitable contributions to caring, needy and religious organizations having the largest positive association with donations to the victims of the tsunami. When we explore the impact of donations to the victims of the tsunami on future donations to charity, however, our findings suggest an inverse relationship with the largest inverse association with donations to needy and caring organizations

Testing goodwill: Conflict and co-operation in new product development networks

Network forms are often seen as models of organisational flexibility, promoting the building of trust and exchange of information between different business functions while offering both cost savings and reductions in the uncertainties usually associated with innovation. Both internal and external networks have been identified as key elements in the collaborative development of new products. The actual process of network building and ongoing network management is not well researched, although the existing literature highlights difficulties for organisations attempting to maintain active product development networks. This article examines the development and management of such a network in the defence industry and focuses on network building processes in terms of the interactions between the individuals involved. This network has endured and evolved over many years despite a series of conflicts. One of the key findings is that the effective functioning of the overall network is closely allied to established processes within the two participating firms

Please, Miss Central, Find My Mamma

https://digitalcommons.library.umaine.edu/mmb-vp/2926/thumbnail.jp