Asymmetric Olefinative Conjugate Addition (AOCA): a New Tandem Transformation

openThe Asymmetric Allylic Substitutions (AAA) provide an invaluable synthetic tool in organic synthesis that is commonly employed for the synthesis of drugs and natural products, with high levels of regio- and stereoselectivity. Notwithstanding the widespread utilization of this reaction, certain drawbacks arise due either to the employment of precious metals or to intrinsic mechanistic constraints. In order to overcome these limitations, we developed a new tandem transformation named Asymmetric Olefinative Conjugate Addition (AOCA) for the generation of a stereocenter in α-position with respect to an internal, functionalized olefin. High yields and enantioselectivities are obtained by the use of an inexpensive and abundant copper catalyst, making this new methodology a valuable alternative to existing methods. The reaction has been optimized and the reaction scope has been evaluated within this thesis project work.The Asymmetric Allylic Substitutions (AAA) provide an invaluable synthetic tool in organic synthesis that is commonly employed for the synthesis of drugs and natural products, with high levels of regio- and stereoselectivity. Notwithstanding the widespread utilization of this reaction, certain drawbacks arise due either to the employment of precious metals or to intrinsic mechanistic constraints. In order to overcome these limitations, we developed a new tandem transformation named Asymmetric Olefinative Conjugate Addition (AOCA) for the generation of a stereocenter in α-position with respect to an internal, functionalized olefin. High yields and enantioselectivities are obtained by the use of an inexpensive and abundant copper catalyst, making this new methodology a valuable alternative to existing methods. The reaction has been optimized and the reaction scope has been evaluated within this thesis project work

An Asante Sculpture

"The subject of this article is a seated female figure from the Asante of Ghana, members of the Akan, a large family of closely related ethnic groups that occupy an area extending from central Ivory Coast to eastern Ghana along the Guinea Coast of West Africa. It was acquired by the museum with little information on provenance and function. In this article, I will discuss the piece under the following subheadings: form, style, iconography, and contextual information. I will attempt to identify the origin, function, and cultural significance of the sculpture through descriptive analysis, comparison with other pieces of similar type, and examination of the available literature on the Asante."--First paragraph.Includes bibliographical reference

De pulvere pro lupis occidendis: wolf poisoning in Southern Italy during the XIII century

In this study, we present some documents showing the official knowledgement of the role of luparius in Southern Italy during the XIII century. Luparii were professional wolf-killers, prevalently coming from three regions of the Kingdom of Naples: Abruzzo, Terra di Lavoro, Apulia, but active throughout the kingdom. Different techniques were adopted by luparii, but one of the most widespread was the so called pulvis, a powder probably obtained from an unknown poisonous plant. Dioscorides and Galen reported that a plant named akoniton was used in the Mediterranean world to poison wild animals, and according to the XVI century physician Pietro Andrea Mattioli, luparii used the Aconitum to kill wolves. Historical sources show that the problems related to the identification of Aconitum was harshly debated among the botanists contemporary to Mattioli, and that Doronicum pardalianches L. and Aconitum napellus L. were the species most frequently proposed. However, in Southern Italy both plants are scarcely present, whereas cognate species are diffused, as Doronicum columnae Ten. and two subspecies of Aconitum lycoctonum, A. lycoctonum L. subsp. neapolitanum (Ten.) Nyman or A. lycoctonum L. subsp. vulparia (Rchb. ex Spreng.) Nyman

Managing diabetic macular edema in clinical practice: systematic review and meta-analysis of current strategies and treatment options

Purpose: This meta-analysis aims to summarize 12-month best-corrected visual acuity (BCVA) outcomes in response to anti-vascular endothelial growth factor (VEGF) therapy and dexamethasone implant for the treatment of diabetic macular edema (DME) and to identify factors affecting treatment response using evidence generated from metaregression. Methods: A systematic review of electronic databases was conducted to identify randomized controlled trials (RCTs) and real-life/observational studies that reported 12-month changes in BCVA in patients with DME on anti-VEGF or dexamethasone implant treatment in monotherapy. Study factors that were analyzed are baseline patient characteristics, study type, drug employed, number of injections and 12-month change in BCVA. Data were pooled in a random-effects meta-analysis with BCVA change as the main outcome. Meta-regression was conducted to assess the impact of multiple covariates. Results: One-hundred-five heterogeneous study populations (45,032 eyes) were identified and included in the analysis. The use of anti-VEGFs and dexamethasone implant induced an overall increase of +8.13 ETDRS letters in BCVA at 12 months of follow-up. Metaregression provided evidence that mean BCVA change using anti-VEGFs was not statistically higher for RCTs (p=0.35) compared to observational studies. Dexamethasone implant showed a trend for better results in observational studies over RCTs. Populations following a fixed aflibercept regimen performed better than those following a reactive treatment regimen. Mean BCVA gain was higher in younger populations (p<0.001), with lower baseline BCVA (p<0.0001) and longer diabetes duration (p<0.0001), receiving a higher number of injections (p<0.0001). Conclusion: Intravitreal therapy with anti-VEGFs or dexamethasone implant produces a significant improvement in BCVA at 12 months in patients with DME. Meta-regression identified the modifiable covariates that can be targeted in order to maximize functional results

Empirical models of land conservation and land use

This dissertation concentrates on land use, both urban and rural, in United States. First, I focus on land conservation and study how state fiscal incentives can affect private land conservation on the eastern region of the country. Then, I move to urban uses of land and analyze how distance to certain amenities in a city can affect residential and non-residential uses, using spatial econometric techniques. Finally, taking advantage of the same methodology, I concentrate on conservation easements and estimate the probability of different levels of public access and how certain variables affect these probabilities. In the first chapter, I study the effect that state level incentives have on land conservation. Private decisions about land conservation are crucial for preservation of endangered species as 80% of their habitats are on private land. I study the efficacy of state tax breaks to promote private land conservation. I use the Protected Area Dataset of United States and construct a county-year level panel of the flow of undeveloped land protected per year. I use fixed effects panel estimations combined with optimal full matching to improve balance on observable covariates between treated and control counties. Results show that, on average, counties in a state with a tax break more than double the yearly flow of conservation after the incentive is in place. These findings suggest that state tax breaks are an effective incentive to promote land conservation. In the second chapter, I concentrate on land use in an urban area and how spatial econometric techniques can help explain land use decisions. I use a large geo-referenced data set and estimate the probability of residential use for individual lots in the urban area. I specifically concentrate on the difficulties that this type of data sets presents and how to overcome them. Spatial data sets pose challenges for discrete choice models because the data are unlikely to be independently and identically distributed. A conditionally parametric spatial probit model is amenable to very large data sets while imposing far less structure on the data than conventional parametric models. I illustrate the approach using data on 474,170 individual lots in the City of Chicago. The results suggest that simple functional forms are not appropriate for explaining the spatial variation in residential land use across the entire city. In the third chapter, I focus only on conservation easements in continental US. Conservation easements generally have a specified level of public access: open, restricted, or closed to the public. This chapter focuses on these particular levels of public access and how location and other variables play a role in that decision. A conditionally parametric multinomial logit model estimates how these variables affect the probability of each level of access. By allowing coefficients to vary throughout space I find effects not capture by standard or spatial logit models. Results show that effects not only differ by level of public access but also spatially. These findings provide useful information for shaping regional policies that are able to address these differences when promoting conservation for specific purposes that allow different levels of public access

Il ruolo della componente geologica e sostenibilità ambientale nei sistemi geotermici di climatizzazione : Il caso dell'impianto geotermico della scuola "G. Ungaretti" nel Comune di Costabissara (VI)

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Molluscs of the “Real Orto Botanico di Napoli”

The results of two years of research on the molluscs present in the Botanical Garden of Naples are reported and compared with the sole similar study published in 1875 and with other reports in the literature, the last of which published in 1930 by Boettger. As a general result, a noticeable decrease in the number of species present in the site was recorded. However, some species not reported before have also been observed, and namely Vallonia costata (O.F. Müller, 1774), Orcula dolium (Draparnaud, 1801) and Planorbarius corneus (Linnaeus, 1758), all recorded for the first time in Campania, and in addition Carychium minimum O.F. Müller, 1774, which appears to be well settled in the studied enclave; for this latter species the only previous indication was found in the bibliography for Campania (Bellini 1898). Finally, some limacid slugs, previously found and recorded only by Boettger (1930), have been found

The vertical and horizontal distribution of Mesocriconema xenoplax (Raski, 1952) in Trentino vineyards (Northern Italy)

Spatial distribution of Mesocriconema xenoplax (Raski, 1952) was investigated in vineyards in the Trentino region (Northern Italy). Horizontal distribution showed characteristic aggregate pattern for nematodes, correlated to the symptomatology of the localized spots of infestations. The vertical distribution, in compact texture soils, revealed maximum population levels of the nematode in the top layers depending on the root occurrence that, in such conditions, is lower at the deeper levels. Higher nematode number was found at greater depths in loose soils, where roots easier penetrate. The knowledge gained from the spatial distribution of this species is fundamental to investigate the effectiveness of different sampling patterns in order to improve efficacy of control strategies