Some reflections on the proposed redefinition of the unit for the amount of substance and of other SI units

Proposals on the floor at CIPM are aiming at defining basic units by stipulating a consensus value for a number of fundamental constants. The paper indicates the author’s viewpoint about a number of issues that, in his view, should be better understood before such a choice becomes indisputable. They include the count nature of the Avogadro number; the correct expression of its stipulated numerical value; the check for the consistency of the SI system; the shift to the unit of the experimental uncertainty; the loss of the concept of base unit; the possibility of checking the correctness of the future standards; implications for the future reductions in uncertainty; the meaning of ‘fundamental’ related to the constants; and some lexical problems.     

Three solutions to a perturbed nonlinear discrete Dirichlet problem

Using critical point theory, we study the existence of at least three solutions for a perturbed nonlinear Dirichlet boundary value problem for difference equations depending on two positive parameters.     

Carbonic anhydrase inhibitors: X-ray crystallographic studies for the binding of N-substituted benzenesulfonamides to human isoform II

N-substituted benzenesulfonamides, incorporating the N-amino-, N-hydroxy- and N-methoxy-moieties at the sulfonamide zinc binding group, have been investigated as CAIs by means of inhibition and structural studies, unraveling interesting aspects related to their inhibition mechanism.     

Anticancer Drugs: Recent Strategies to Improve Stability Profile,Pharmacokinetic and Pharmacodynamic Properties

In past decades, anticancer research has led to remarkable results despite many of the approved drugs still being characterized by high systemic toxicity mainly due to the lack of tumor selectivity and present pharmacokinetic drawbacks, including low water solubility, that negatively affect the drug circulation time and bioavailability. The stability studies, performed in mild conditions during their development or under stressing exposure to high temperature, hydrolytic medium or light source, have demonstrated the sensitivity of anticancer drugs to many parameters. For this reason, the formation of degradation products is assessed both in pharmaceutical formulations and in the environment as hospital waste. To date, numerous formulations have been developed for achieving tissue-specific drug targeting and reducing toxic side effects, as well as for improving drug stability. The development of prodrugs represents a promising strategy in targeted cancer therapy for improving the selectivity, efficacy and stability of active compounds. Recent studies show that the incorporation of anticancer drugs into vesicular systems, such as polymeric micelles or cyclodextrins, or the use of nanocarriers containing chemotherapeutics that conjugate to monoclonal antibodies can improve solubility, pharmacokinetics, cellular absorption and stability. In this study, we summarize the latest advances in knowledge regarding the development of effective highly stable anticancer drugs formulated as stable prodrugs or entrapped in nanosystems.     

A finite differences MATLAB code for the numerical solution of second order singular perturbation problems

We show the main features of the MATLAB code HOFiD_UP for solving second order singular perturbation problems. The code is based on high order finite differences, in particular on the generalized upwind method. Within its simplicity, it uses order variation and continuation for solving any difficult nonlinear scalar problem. Several numerical tests on linear and nonlinear problems are considered. The best performances are reported on problems with perturbation parameters near the machine precision, where most of the codes for two-point BVPs fail.     

Nuove formule di Geometria integrale relative agli ovali

Sunto Si dimostra, estendendola, una cospicua formula di Geometria integrale per gli ovali, indicata da C.B.S. Cavallin [la (28)]. Si dimostrano, in modo analogo, due nuove relazioni per gli ovali [(48) e (53)]. Delle predette formule si mettono in evidenza vari casi particolari notevoli. A Enrico Bompiani in occasione del suo Giubileo scientifico.     

La hessiana e i suoi problemi

This lecture shows synthetically the developments of the researches on the Hessian of an algebraic hypersurface ofd dimensions, with a particular view of the plane case (d = 2), and points out several solved and unsolved problems on this subject.     

Molecular recognition: A thermodynamic study of non bonded interactions in aqueous solutions of iminoacids. Effects of steric and geometric isomerism

Enthalpies of dilution of binary and ternary aqueous solutions containing L-and D-proline, cis-L- and cis-D-4-hydroxy proline, trans-L-4-hydroxy proline, have been determined by flow calorimetry at 25°C. Pairwise self-and cross-interaction coefficients of the virial expansion of the excess enthalpies were evaluated. They are positive for solutions of unsubstituted prolines. On the contrary, upon the introduction of a hydroxy group, they become negative, reaching the largest value for the cis-L-lcis-D-4-hydroxy proline system. The results are interpreted in terms of preferential configurations, stabilized by interactions between the hydrophilic groups.     

E → C phase transition in fatty acids: a spectroscopic study

Contrary to previous literature reports, crystallisation of behenic and lignoceric acids from warm acetone is found to give the crystalline modification E. The phase transition from E to the more stable C form was studied with Fourier Transform Infrared Spectroscopy. The structural evolution with temperature through the phase transition is discussed.