2,062 research outputs found
Multiscale Molecular Modelling of ATP‐Fueled Supramolecular Polymerisation and Depolymerisation**
No full textRaw research data supporting the publication Perego C. et al., ChemSystemsChem 2021, DOI: https://doi.org/10.1002/syst.20200003
Antitumor Platinum(II) Hybrid Compounds Based on a Glucosylglycerol Scaffold
No full textPlatinum(II) drugs such as cisplatin, carboplatin and oxaliplatin are antineoplastic drugs
clinically available for the treatment of different kinds of cancers, including ovarian
carcinoma. However, their use is limited by the occurrence of severe systemic side effects and
resistance [1, 2]. For these reasons, the development of new platinum-based compounds
endowed with higher selectivity against cancer cells and able to overcome resistance is an
active research field. A promising strategy to pursuit these goals is the design of hybrid
platinum(II) compounds bearing bioactive ligands able to selectively target cancer cells,
improve the platinum-mediated antitumor activity and/or overcome resistance by interacting
with selected targets known for their involvement in cancer resistance [3]. In this context, due
to its peculiar structure, 2-O-β-D-glucosylglycerol (a natural compound named Lilioside B)
[4] could be efficiently used at the same time as the complexing agent of platinum(II) and as
the point of attachment of cancer involved bioactive compounds. Thus, the present
communication will show some preliminary results on the synthesis and cytotoxicity data, on
ovarian cancer cells, of a water soluble platinum(II) hybrid compound in which, similarly to
carboplatin, a properly modified 2-O-β-D-glucosylglycerol is able to complex platinum(II).
References
1. Khoury, A.; Deo, K.M.; Aldrich-Wright, J.R. J. Inorg. Biochem., 2020, 207, 111070.
2. Rottenberg, S., Disler, C., & Perego, P. Nature reviews. Cancer, 2021, 21, 37.
3. Zuccolo, M,; Arrighetti, N.; Perego, P.; Colombo, D. Curr. Med. Chem., 2022, 29, 2566.
4. Kaneda, M.; Mizutani, K.; Takahashi, Y.; Kurono, G.; Nishikawa, Y. Tetrahedron Lett., 1974, 15,
3937
A Cannibalistic Approach to Grand Canonical Crystal Growth
No full textCanonical molecular dynamics simulations of crystal growth from solution suffer from severe finite-size effects. As the crystal grows, the solute molecules are drawn from the solution to the crystal, leading to a continuous drop in the solution concentration. This is in contrast to experiments in which the crystal grows at an approximately constant supersaturation of a bulk solution. Recently, Perego et al. [J. Chem. Phys. 2015, 142, 144113] showed that in a periodic setup in which the crystal is represented as a slab, the concentration in the vicinity of the two surfaces can be kept constant while the molecules are drawn from a part of the solution that acts as a molecular reservoir. This method is quite effective in studying crystallization under controlled supersaturation conditions. However, once the reservoir is depleted, the constant supersaturation conditions cannot be maintained. We propose a variant of this method to tackle this depletion problem by simultaneously dissolving one side of the crystal while letting the other side grow. A continuous supply of particles to the solution due to the crystal dissolution maintains a steady solution concentration and avoids reservoir depletion. In this way, a constant supersaturation condition can be maintained for as long as necessary. We have applied this method to study the growth and dissolution of urea crystal from water solution under constant supersaturation and undersaturation conditions, respectively. The computed growth and dissolution rates are in good agreement with those obtained in previous studies
Molecular dynamics simulations of solutions at constant chemical potential
No full textMolecular dynamics studies of chemical processes in solution are of great value in a wide spectrum of applications, which range from nano-technology to pharmaceutical chemistry. However, these calculations are affected by severe finite-size effects, such as the solution being depleted as the chemical process proceeds, which influence the outcome of the simulations. To overcome these limitations, one must allow the system to exchange molecules with a macroscopic reservoir, thus sampling a grand-canonical ensemble. Despite the fact that different remedies have been proposed, this still represents a key challenge in molecular simulations. In the present work, we propose the Constant Chemical Potential Molecular Dynamics (CμMD) method, which introduces an external force that controls the environment of the chemical process of interest. This external force, drawing molecules from a finite reservoir, maintains the chemical potential constant in the region where the process takes place. We have applied the CμMD method to the paradigmatic case of urea crystallization in aqueous solution. As a result, we have been able to study crystal growth dynamics under constant supersaturation conditions and to extract growth rates and free-energy barriers
Study on local effects of aggressive environmental conditions on masonry strengthened with FRCM
No full textAggressive environmental conditions as moisture, temperature and presence of salts, may affect the interfacial behaviour of FRCM bonded to masonry. To check the effectiveness of intervention solid clay brick samples and masonry assemblages including mortar joints were investigated. Strips of carbon fibre nets were applied with a cementitious or a lime based matrices. Specimens were exposed to salt crystallisation tests, according to a RILEM procedure, and to thermal cycles with a temperature variation ranging between -10°C and +70°C. The characteristic size of damage of the samples were monitored by visual observation and laser profilometer; the loss of bond of the composites was verified by pull-off test. Tests results showed different behaviour between the inorganic matrices applied on bricks having different strengths. Moreover, the adhesion strength was affected by the presence of bed joints. The adherence of the specimens of cement matrix depends from the type of substrate and his damage. Specimens of lime matrix do not seem to have a relation between damage of the substrate and adherence, as the failure occurred at the interface matrix/strengthening
Repertorio bibliografico su parafrasi, riformulazione, ripetizione
No full textIl contributo propone una bibliografia ragionata sui fenomeni della riformulazione, della parafrasi e della ripetizione
Differential localisation of nPKC delta during cell cycle progression
No full textnPKC delta is a phospholipid-dependent and calcium-independent PKC isoform, whose over expression in BL6T murine melanoma cells, modifies their proliferative and metastatic potential in vivo. We focus here on the possible relationship between the subcellular localisation of nPKC delta and distinct phase of the cell cycle. Our findings show a dynamic localisation of nPKC delta in dependence of the phase of the cell cycle. Actually, this isoform is preferentially localised to the cytoplasm in serum-starved cells, shifting to the nucleus during the S-phase and becoming peri-nuclear, associated to the Golgi apparatus, in G2-M phase. Therefore, taken together our findings demonstrate that the subcellular localisation of nPKC delta changes dynamically during the cell cycle in dependence of the requirement of the enzyme at a particular place of the cell
Chemical potential calculations in non-homogeneous liquids
No full textThe numerical computation of chemical potential in dense non-homogeneous fluids is a key problem in the study of confined fluid thermodynamics. To this day, several methods have been proposed; however, there is still need for a robust technique, capable of obtaining accurate estimates at large average densities. A widely established technique is the Widom insertion method, which computes the chemical potential by sampling the energy of insertion of a test particle. Non-homogeneity is accounted for by assigning a density dependent weight to the insertion points. However, in dense systems, the poor sampling of the insertion energy is a source of inefficiency, hampering a reliable convergence. We have recently presented a new technique for the chemical potential calculation in homogeneous fluids. This novel method enhances the sampling of the insertion energy via well-tempered metadynamics, reaching accurate estimates at very large densities. In this paper, we extend the technique to the case of non-homogeneous fluids. The method is successfully tested on a confined Lennard-Jones fluid. In particular, we show that, thanks to the improved sampling, our technique does not suffer from a systematic error that affects the classic Widom method for non-homogeneous fluids, providing a precise and accurate result
BRAIN id: NLO28 – pollen dataset
No full textLavagnone.
Dataset including pollen counts from sediment samples collected from the site of Lavagnone, a Bronze Age pile dwelling site in northern Italy (Desenzano del Garda, Brescia; 45°26'12.67"N 10°32'16.75"E, 101 m asl). The site is included in the BRAIN database (https://brainplants.successoterra.net/; site id: NLO28)
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