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The design, synthesis, and antibacterial activity of 4-alkyliden-azetidin-2-ones as new antimicrobial agents against multidrug-resistant pathogens is reported. 4-Alkyliden-azetidin-2-ones were easily obtained using an original protocol starting from 4-acetoxy-azetidinones and diazoesters. Parent compounds were further elaborated to obtain a small library of 4-alkylidene derivatives. A molecular modeling approach using GRID descriptors based on the concept of VRS identified attractive drug candidates and contributed to the rationalization of functional group effects in QSARs. The in vitro antibacterial activity of the new agents was evaluated against 43 recent clinical isolates of antibiotic-susceptible and -resistant Gram-positive and Gram-negative pathogens by determining their minimum inhibitory concentrations (MICs). The most active compound showed MIC values ranging from 0.25 to 32 mg/L against some of the bacterial species tested. Interestingly, some compounds demonstrated similar activity against methicillin-susceptible and -resistant strains of Staphylococcus aureus suggesting possible alternative mechanisms of action of these agents, supported by citotoxicity and preliminary scanning electron microscopy studies.

Recent developments in the new international trade theory stressed the relationship between firm heterogeneity and internationalization performance. The key prediction of these models is that firms with different levels of productivity - the main source of firm heterogeneity - will generally engage in different modes of internationalization depending on the level of sunk costs incurred in acquiring information on foreign markets, establishing distribution channels, and so on. However, in these theoretical models the sources of productivity are generally unexplained, considering firm heterogeneity as exogenous. A few papers try to open the 'black box' of firm heterogeneity and to show that internationalized firms are generally more innovative, use more knowledge-intensive workers, and are characterized by superior organizational and managerial practices. Using a large sample of over 3000 Italian manufacturing firms for the period 2001-2003, we contribute to this debate employing, and extending the basic Crépon, Duguet and Mairesse (CDM) model. We estimate a five-equation model which identifies the links (correlations) between innovation investment, innovation output, firm productivity and export performance.

Psoriasis is a T-lymphocyte mediated autoimmune disease. The response to therapies targeting T-lymphocytes suggest that the latter is a key cell in the pathogenesis of the disease. Cyclosporine (CsA) inhibits the proliferation and the IL-2 dependent expansion of T-lymphocytes. Ultraviolet radiation is an effective treatment for psoriasis. Several studies have demonstrated a significant improvement of the therapeutic response when narrow-band radiation is issued by TL-01 fluorescent lamp compared to broadband UVB issued by other fluorescent sources. The effects of UVB on the immune system appear to be limited to the cell-mediated compartment of the immune response. In order to reduce the cumulative dose of UVB and limit the toxicity of drugs in the therapy of psoriasis, phototherapy with UVB has been used as treatment in association with other standard therapies. The purpose of the study is to evaluate, in patients with moderate to severe psoriasis a combined therapy with Cyclosporine A and 311 nm UVB phototherapy.

The aim of this paper is two-fold: to analyse the extent of corporate grouping in the main industrial districts of Emilia Romagna and the reasons for their formation and development; and to show how their evolution in recent years requires rethinking the very concept of industrial district in favour of a unit of analysis capable of grasping the role taken by ownership linkages among firms. In this respect, we suggest a taxonomy of business groups that brings out the key role played by ‘district groups’. The choice of Emilia Romagna as our field of investigation is motivated by the fact that in a number of ways the region’s industrial system epresents a paradigmatic model of local capitalism, combining the large-scale presence of industrial districts with a marked entrepreneurial spirit, strong social cohesion, and an exceptionally efficient system of local institutions and intermediate organisations. In this sense, even though we start from the empirical study of a case (albeit a significant one like that of Emilia Romagna), our paper has the more general purpose of depicting the forms and ways through which a special form of local capitalism characterised by the massive presence of industrial districts has evolved, while at the same time signalling the need to reconsider the theoretical concepts and methods of empirical inquiry used to analyse and interpret the new forms taken on by the Italian local capitalism.

This paper aims at investigating the presence and the main features of business groups in Emilia Romagna. The research is based on a sample comprising about 48 thousand firms and about 540 thousand employees from Emilia Romagna, the latter representing more than 42 per cent of the total regional employment. First, we find that the presence of corporate grouping in Emilia Romagna is comparable to that documented at national level. Moreover, and surprisingly enough, we show that the extension of the group organizational form is significant also in industrial districts, suggesting that ownership linkages among firms do play a role and should not be neglected in the analysis of these production systems. Although the analysis requires some further investigation, these results support the view that also in Emilia Romagna the actual size of firms is larger and the number of owners is lower than official statistics reveal. This result has important economic policy implications, as the industrial policy of Emilia Romagna has traditionally been oriented to supporting small and very small firms.

The influence of the environment of the hydroxyl group on the course of the oxidation of 20-hydroxy-steroids with lead tetraacetate has been investigated. It could be shown that, whenever the normal reaction — ether formation between C-18 and C-20 — is inhibited by steric factors, fragmentation processes occur, resulting in the formation of 17α-acetoxy compounds and of saturated ring D unsubstituted compounds respectively.

Results previously reported on the fragmentation of monohydric alcohols with lead tetraacetate are extended and correlated on the basis of new experimental evidence.

The partial synthesis of aldosterone from readily available steroidal starting materials is described.

A new approach to androsterone and 19-norandrosterone from androst-5-ene-3β-ol-17-one and 19-nortestosterone is described. The synthesis is accomplished by a stereospecific hydroboration of Δ 3 - 5α-steroids.

Treatment of 3β-acetoxy-20β-hydroxy-5α-pregnane (11) with lead tetraacetate in benzene allows the selective introduction of an oxygen function at the no11 activated angular methyl group C-18. The main product of this reaction is the 18,20β-oxido compound I11 as proved by its conversion into the lactone V and the lactol VI.

The preparation of the (18 → 11β)-lactone ofΔ5-3-ethylenedioxy-11β-hydroxy-21-acetoxy-20-oxo-pregnen-18-oic acid (XV) is reported. Since this compound has previously been transformed into aldosterone, the reactions described represent the first partial synthesis of this important hormone from readily available 18-unsubstituted natural steroids.

The preparation of different C-18 oxygenated pregnane derivatives from (20R)-3β-acetoxy-18,20-oxido-pregnane (II) is described.

The sterical formula I represents the structure of aescigenin, a product of the acid hydrolysis of the sapogenin aescin. Aescigenin is therefore a further representative of the β-amyrin-oleanolic acid subgroup of the pentacyclic triterpenes.

Trisporic-C acid is the major component of a biologically active acidic fraction isolated from submerged cultures of Choanephora trispora . On the basis of the chemical and spectrochemical data and synthesis, structure I′—a monocyclic trienic hydroxyketo acid—has been assigned to the product. Trisporic-B acid differs from the C acid by the absence of an alcoholic hydroxyl group.

It has been demonstrated that the hydroboration of 7-dehydrocholesterol takes place according to a 1:2 mechanism, leading to an allylic boron compound in which boron atom is in the 6α position. Treatment of this boron compound with acetic acid or acetic anhydride-acetic acid, leads through protonolysis and simultaneous migration of the double bond, to Δ 6 -3β hydroxy cholestene.

Δ4,6-Cholestadien-3-one (1) yields on irradiation a dimeric product C54H84O2 for which structure 2a is proposed.

The reaction of 1,1-dihalo-alkanes with magnesium and magnesium amalgam has been studied. Methylene bromide and iodide yield, under suitable conditions, a stable solution of methylene magnesium halide which easily olefinates aldehydes and ketones affording the corresponding methylenic olefins in good yields. Other alkylidene halides, under the conditions studied, do not give any stable geminal dimagnesium compound although geminal species are probably present during the in situ reaction between alkylidene halides, carbonyl compounds and magnesium amalgam. A general carbonyl olefination scheme taking into account the majority of the known reactions of this kind is proposed.