A Maltol-Containing Ruthenium Polypyridyl Complex as a Potential Anticancer Agent

Cancer is one of the main causes of death worldwide. Chemotherapy, despite its severe side effects, is to date one of the leading strategies against cancer. Metal-based drugs present several potential advantages when compared to organic compounds and they have gained trust from the scientific community after the approval on the market of the drug cisplatin. Recently, we reported the ruthenium complex ([Ru(DIP)₂(sq)](PF₆) (where DIP is 4,7-diphenyl-1,10-phenantroline and sq is semiquinonate) with a remarkable potential as chemotherapeutic agent against cancer, both in vitro and in vivo. In this work, we analyse a structurally similar compound, namely [Ru(DIP)₂(mal)](PF₆), carrying the flavour-enhancing agent approved by the FDA, maltol (mal). To possess an FDA approved ligand is crucial for a complex, whose mechanism of action might include ligand exchange. Herein, we describe the synthesis and characterisation of [Ru(DIP)₂(mal)](PF₆), its stability in solutions and under conditions that resemble the physiological ones, and its in-depth biological investigation. Cytotoxicity tests on different cell lines in 2D model and on HeLa MultiCellular Tumour Spheroids (MCTS) demonstrated that our compound has higher activity than cisplatin, inspiring further tests. [Ru(DIP)₂(mal)](PF₆) was efficiently internalised by HeLa cells through a passive transport mechanism and severely affected the mitochondrial metabolism.     

Non parametric estimation of the diffusion coefficients of a diffusion with jumps

In this article, we consider a jump diffusion process ${\left(X_t\right)}_{t\ge 0}$, with drift function $b$, diffusion coefficient $\sigma$ and jump coefficient ${\xi }^2$. This process is observed at discrete times $t=0,\Delta ,\dots ,n\Delta$. The sampling interval $\Delta$ tends to 0 and the time interval $n\Delta$ tends to infinity. We assume that ${\left(X_t\right)}_{t\ge 0}$ is ergodic, strictly stationary and exponentially $\beta$-mixing. We use a penalized least-square approach to compute adaptive estimators of the functions ${\sigma }^2+{\xi }^2$ and ${\sigma }^2$. We provide bounds for the risks of the two estimators.     

Electromechanical effect in surface stabilized and unwound SC* liquid crystals

Applying an A.C. electric field to a planar oriented S_C* liquid crystal sample, a shear flow occurs parallel to the bounding plates and perpendicular to the helical axis. We have investigated this so-called electromechanical effect by applying different D.C. bias electric fields superposed on a constant A.C. field. The amplitude of the mechanical vibration was measured versus the bias field in different samples. From the results, structural models of the surface stabilized and unwound samples were tested.     

Effect of bulk density on flame resistance of rockwool in combined fire-resistant facings

Journal of Thermal Analysis and Calorimetry - Fire protection of steel structures is playing an increasingly important role nowadays. The fire protection of steel structures can be solved with...     

AN INDIVIDUAL‐BASED MODEL FOR FERAL HOGS IN GREAT SMOKY MOUNTAINS NATIONAL PARK

The expansion of feral hog (Sus scrofa) populations in the United States has resulted in increased efforts to develop and implement control strategies designed to minimize the impacts done by this invasive species. We describe an individual‐based model for feral hogs in Great Smoky Mountains National Park (GSMNP). The objectives of the model are to provide an understanding of the population dynamics of this feral hog population and to determine the efficacy of the annual harvest as a population control method. Results suggest that the dynamics of the population are driven by fall hard mast production and the GSMNP harvests currently limit growth of the population, but these control efforts have not reduced the population.     

A Bis(pyridine N‐oxide) Analogue of DOTA: Relaxometric Properties of the GdIII Complex and Efficient Sensitization of Visible and NIR‐Emitting Lanthanide(III) Cations Including PrIII and HoIII

We report the synthesis of a cyclen‐based ligand (4,10‐bis[(1‐oxidopyridin‐2‐yl)methyl]‐1,4,7,10‐tetraazacyclododecane‐1,7‐diacetic acid= L1 ) containing two acetate and two 2‐methylpyridine N‐oxide arms anchored on the nitrogen atoms of the cyclen platform, which has been designed for stable complexation of lanthanide(III) ions in aqueous solution. Relaxometric studies suggest that the thermodynamic stability and kinetic inertness of the Gd^III complex may be sufficient for biological applications. A detailed structural study of the complexes by ¹H NMR spectroscopy and DFT calculations indicates that they adopt an anti‐Δ(λλλλ) conformation in aqueous solution, that is, an anti‐square antiprismatic (anti‐SAP) isomeric form, as demonstrated by analysis of the ¹H NMR paramagnetic shifts induced by Yb^III. The water‐exchange rate of the Gd^III complex is ${k{{298\hfill \atop {\rm ex}\hfill}}}$ =6.7×10⁶ s^?1, about a quarter of that for the mono‐oxidopyridine analogue, but still about 50 % higher than the ${k{{298\hfill \atop {\rm ex}\hfill}}}$ of GdDOTA (DOTA=1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid). The 2‐methylpyridine N‐oxide chromophores can be used to sensitize a wide range of Ln^III ions emitting in both the visible (Eu^III and Tb^III) and NIR (Pr^III, Nd^III, Ho^III, Yb^III) spectral regions. The emission quantum yield determined for the Yb^III complex (${Q{{{\rm L}\hfill \atop {\rm Yb}\hfill}}}$ =7.3(1)×10^?3) is among the highest ever reported for complexes of this metal ion in aqueous solution. The sensitization ability of the ligand, together with the spectroscopic and relaxometric properties of its complexes, constitute a useful step forward on the way to efficient dual probes for optical imaging (OI) and MRI.