Investigation of the cytotoxicity of bioinspired coumarin analogues towards human breast cancer cells

Molecular Diversity - Coumarins possess a wide array of therapeutic capabilities, but often with unclear mechanism of action. We tested a small library of 18 coumarin derivatives against human...     

Per-2,3-O-alkylated β-cyclodextrin duplexes connected with disulfide bonds

Per-2,3-di-O-methyl- and per-2,3-di-O-allyl-β-cyclodextrin duplexes held by two disulfide bonds between their primary faces have been prepared. Permethylation significantly increased the solubility of the cyclodextrin duplexes in a wide range of solvents from water to chlorinated hydrocarbons. Per-2,3-di-O-methylated duplexes are able to form inclusion complexes with organic molecules in aqueous solutions, yet the stability constants are lower by 4–5 orders of magnitude as compared to analogous non-alkylated β-cyclodextrin duplexes.     

Temperature Driven Transformation of the Flexible Metal–Organic Framework DUT-8(Ni)

DUT-8(Ni) metal–organic framework (MOF) belongs to the family of flexible pillared layer materials. The desolvated framework can be obtained in the open pore form (op) or in the closed pore form (cp), depending on the crystal size regime. In the present work, we report on the behaviour of desolvated DUT-8(Ni) at elevated temperatures. For both, op and cp variants, heating causes a structural transition, leading to a new, crystalline compound, containing two interpenetrated networks. The state of the framework before transition (op vs. cp) influences the transition temperature: the small particles of the op phase transform at significantly lower temperature in comparison to the macroparticles of the cp phase, transforming close to the decomposition temperature. The new compound, confined closed pore phase (ccp), was characterized by powder X-ray diffraction and spectroscopic techniques, such as IR, EXAFS, and positron annihilation lifetime spectroscopy (PALS). Thermal effects of structural transitions were studied using differential scanning calorimetry (DSC), showing an overall exothermic effect of the process, involving bond breaking and reformation. Theoretical calculations reveal the energetics, driving the observed temperature induced phase transition.     

The capillary and porous structure of the protein-cellulose complexes of Arctic brown algae Laminaria digitata and Saccharina latissima

Cellulose - Due to their specific physicochemical, capillary, and porous properties, the cellulosic sorbents from macrophytes have a high number of possible uses. The number of studies of...     

Regularized nonlinear least squares methods for hit position reconstruction in small gamma cameras

In order to improve the performance of a gamma camera, it’s fundamental to accurately reconstruct the photon hit position on the detector surface. In the last years, the increasing demand of small highly-efficient PET systems led to the development of new hit position estimation methods, with the purpose of improving the performances near the edges of the detector, where most of the information is typically lost. In this paper we apply iterative optimization methods, based on the regularization of the nonlinear least squares problem, to estimate the photon hit position. Numerical results show that, compared with the classic Anger algorithm, the proposed methods allow to recover more information near the edges.     

Vapour pressure and enthalpy of vaporization of aliphatic poly-amines

Molar enthalpies of vaporization of aliphatic poly-amines: 1,4-dimethylpiperazine [106-58-1], 1-(2-aminoethyl)-piperazine, [140-31-8], 1-(2-aminoethyl)-4-methyl-piperazine [934-98-5], and triethylenetetramine [112-24-3] were obtained from the temperature dependence of the vapour pressure measured by the transpiration method. A large number of the primary experimental results on temperature dependences of vapour pressures of the parent compounds have been collected from the literature and have been treated uniformly in order to derive vaporization enthalpies of poly-amines at the reference temperature 298.15 K. An internal consistency check was performed on enthalpy of vaporization values for poly-amines studied in this work.