Classical and accelerated evaluation of neutron escape probability

Neutron escape probability from a monodimensional plane medium is determined by resorting to the integral neutron transport equation.Both a projection procedure and an appropriate variational approach, yielding an acceleration of the convergence rate, are employed; their numerical results are reported and discussed.The theory is presented in a general form, since it can be applied directly to many basic problems in other branches of applied sciences.

---

Riassunto La probabilità di fuga di un neutrone da un mezzo monodimensionale piano viene determinata nell'ambito della teoria integrale del trasporto. Vengono impiegati sia un procedimento proiezionale classico, che un opportuno metodo variazionale in grado di produrre un'accelerazione della velocità di convergenza; i relativi risultati numerici sono riportati e discussi. La teoria è esposta nella sua forma generale, in quanto può essere applicata direttamente a diversi problemi di base in altri rami delle scienze applicate.

---

---

Work supported by the National Group for Mathematical Physics of C.N.R.     

Solid-state interactions and drug release of teicoplanin in binary combinations with peracetylated α-, β-, and γ-cyclodextrins

Triacetyl α-cyclodextrin, triacetyl β-cyclodextrin and triacetyl γ-cyclodextrin were tested as possible hydrophobic carriers to prolong the release of hydrophilic teicoplanin (TCP). Physical–chemical characterization of individual components, drug-carrier physical mixtures at 0.5, 0.67 and 0.75 mass fraction of carrier, and the respective interaction products by kneading or evaporative crystallization under microwave irradiation was carried out using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). In vitro drug release in pH 7.4 phosphate buffer at 37 °C was determined by intrinsic dissolution rate (IDR) measurements on non disintegrating compressed discs. Solid-state interactions of TCP with triacetyl α-cyclodextrin by evaporative crystallization and kneading and with triacetyl β-cyclodextrin by evaporative crystallization (probably resulting in carrier amorphization) were demonstrated. The role of carrier hydrophobicity, carrier mass fraction and preparation method of solid drug-carrier combinations on solid-state drug-carrier interactions and slowing down of TCP release was assessed. Modulation of drug release can be achieved using TCP-triacetyl γ-cyclodextrin combinations at 0.5 mass fraction of carrier.     

Covariant polarization bases for spin=12, 1, 32 particles and their use

A simple method is presented for evaluating transition amplitudes between massive states with $\text{spin}\text{=}\text{1}\text{2}\text{, 1}$ and definite polarization. The $\text{spin}\text{-}\text{3}\text{2}$ case is also briefly discussed. Applications to testing the decay and production of vector bosons are considered.