Classical-path integral adaptive resolution in molecular simulation: towards a smooth quantum-classical coupling

Simulations that couple different classical molecular models in an adaptive way by changing the number of degrees of freedom on the fly, are available within reasonably consistent theoretical frameworks. The same does not occur when it comes to classical-quantum adaptivity. The main reason for this is the difficulty in describing a continuous transition between the two different kind of physical principles: probabilistic for the quantum and deterministic for the classical. Here we report the basic principles of an algorithm that allows for a continuous and smooth transition by employing the path integral description of atoms.Comment: 8 pages 4 figure

Synthesis of Curcumin Derivatives and Analysis of Their Antitumor Effects in Triple Negative Breast Cancer (TNBC) Cell Lines

We analyzed antitumor effects of a series of curcumin analogues. Some of them were obtained by reaction of substitution involving the two phenolic OH groups of curcumin while the analogues with a substituent at C-4 was prepared following an original procedure that regards the condensation of benzenesulfenic acid onto the nucleophilic central carbon of the curcumin skeleton. We analyzed cytotoxic effects of such derivatives on two TNBC (triple negative breast cancer) cell lines, SUM 149 and MDA-MB-231, but only three of them showed an IC50 in a lower micromolar range with respect to curcumin. We also focused on these three derivatives that in both cell lines exhibited a higher or at least equivalent pro-apoptotic effect than curcumin. The analysis of molecular mechanisms of action of the curcumin derivatives under study has highlighted that they decreased NF-κB transcriptional factor activity, and consequently the expression of some NF-κB targets. Our data confirmed once again that curcumin may represent a very good lead compound to design analogues with higher antitumor capacities and able to overcome drug resistance with respect to conventional ones, even in tumors difficult to treat as TNBC

Advances in molecularly imprinted polymers as drug delivery systems

Despite the tremendous efforts made in the past decades, severe side/toxic effects and poor bioavailability still represent the main challenges that hinder the clinical translation of drug molecules. This has turned the attention of investigators towards drug delivery vehicles that provide a localized and controlled drug delivery. Molecularly imprinted polymers (MIPs) as novel and versatile drug delivery vehicles have been widely studied in recent years due to the advantages of selective recognition, enhanced drug loading, sustained release, and robustness in harsh conditions. This review highlights the design and development of strategies undertaken for MIPs used as drug delivery vehicles involving different drug delivery mechanisms, such as rate-programmed, stimuli-responsive and active targeting, published during the course of the past five years

Gender quota on corporate boards in Italy: spillover effects and financial performance

This paper analyzes the impact of the introduction of mandatory gender quotas for the boards of directors of listed firms and state-participated companies (LP) in Italy. It investigates its effects on firms directly targeted by the new regulation as well as its indirect effects on firms that are not. To this aim, we use difference-in-difference and panel fixed-effects estimations. Our main results are that quotas directly increased female presence on boards of LP companies and produced some “positive spillover effects”, i.e., a higher proportion of women in top executive positions in LP firms and a higher share of women on boards of non-listed firms and non-participated firms (NLNP), even if the latter were not targeted by the law. We also find evidence for a positive impact of higher board gender diversity on firm performance in specific conditions, such as boards of small size and NLNP companies

PHOTOACTIVE MATERIALS FOR SOLAR FUELS PRODUCTION

In the course of my PhD project, my research has been focused on the synthesis, characterization and application of heterogeneous catalysts for photo- and photoelectrochemical solar energy conversion into so-called solar fuels. Most of the attention has been paid to the development of Metal-Organic Frameworks as photocatalysts for carbon dioxide reduction. In particular, porphyrins and dipyrrins have been employed as organic linkers in ZrIV-containing frameworks. In addition, Au-doped TiO2 powder samples for photocatalytic steam reforming of methanol at different temperatures and CuWO4 photoanodes for photoelectrochemical water splitting were investigated as well

Molecular Insight into the Self-Assembly Process of Cellulose I beta Microfibril

The self-assembly process of β-D-glucose oligomers on the surface of cellulose Iβ microfibril involves crystallization, and this process is analyzed herein, in terms of the length and flexibility of the oligomer chain, by means of molecular dynamics (MD) simulations. The characterization of this process involves the structural relaxation of the oligomer, the recognition of the cellulose I microfibril, and the formation of several hydrogen bonds (HBs). This process is monitored on the basis of the changes in non-bonded energies and the interaction with hydrophilic and hydrophobic crystal faces. The oligomer length is considered a parameter for capturing insight into the energy landscape and its stability in the bound form with the cellulose I microfibril. We notice that the oligomer–microfibril complexes are more stable by increasing the number of hydrogen bond interactions, which is consistent with a gain in electrostatic energy. Our studies highlight the interaction with hydrophilic crystal planes on the microfibril and the acceptor role of the flexible oligomers in HB formation. In addition, we study by MD simulation the interaction between a protofibril and the cellulose I microfibril in solution. In this case, the main interaction consists of the formation of hydrogen bonds between hydrophilic faces, and those HBs involve donor groups in the protofibril

Green manuring as sustainable management for southern Italy extensive cultivated areas

In the extensively-managed agricultural areas of Sicily, rainfall is often so limited that economically effective annual productions are not feasible. Bare fallow, the most extreme dry-farming technique, seems to be, under such conditions, the only suitable strategy. The introduction in these cropping systems of an annual legume to put early into the soil, as an alternative to bare fallow, may represent a technique able not only to prevent soil erosion, but also to improve the low soil organic matter reserves, with a direct benefit on the following yields and on the whole environment. The trial was aimed to verify the bioagronomical and qualitative behaviour of durum wheat managed under different cropping systems. Results, heavily influenced by very low rainfall (320 mm), stressed the extraordinary productive response of durum wheat cultivated after the green manure legume