Nonlocal isoperimetric problems

We characterize the volume-constrained minimizers of a nonlocal free energy given by the difference of fractional perimeters. Exploiting the quantitative fractional isoperimetric inequality, we show that balls are the unique minimizers if the volume is sufficiently small, while the existence vs. nonexistence of minimizers for large volumes remains open. We also consider the corresponding isoperimetric problem and prove existence and regularity of minimizers

Coupled cluster calculations on TiO2 nanoclusters

The excitation energies of the four lowest-lying singlet excited states of the TiO2, Ti2O4, and Ti3O6 clusters are calculated by a variety of different Equation-of-Motion Coupled Cluster (EOM-CC) approaches in order to obtain benchmark values for the optical excitations of titanium dioxide clusters. More specifically we investigate what the effect is of the inclusion of triple excitations “triples” in the (EOM-)CC scheme on the calculated excited states of the clusters. While for the monomer and dimer the inclusion of triples is found to only cause a rigid shift in the excitation energies, in the case of the trimer the crossing of the excited states is observed. Coupled cluster approaches where triples are treated perturbatively were found to offer no advantage over EOM-CCSD, whereas the active-space methods (EOM-CCSDt(II/I)) were demonstrated to yield results very close to full EOM-CCSDT, but at a much reduced computational cost

Pulmonary veins stenosis relief after an inappropriate radiofrequency catheter ablation of atrial fibrillation in a young non-competitive athlete

One of the major complications of radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) is pulmonary vein stenosis (PVS). The natural history of PVS, especially when it involves more than one vein, leads to severe and irreversible pulmonary hypertension with end-stage right heart failure that can require, in extreme cases, even heart-lung transplantation. We report the case of a young patient who underwent RFCA for a single lasting episode of AF and developed PVS years later. He was treated with ballon venoplasty followed by stent implantation in left pulmonary vein because of PVS relief. This reported case emphasizes the need of an adequate indication for RFCA for AF, considering the benefit-risk ratio especially in young patients with normal cardiac function

Maximising the hydrogen evolution activity in organic photocatalysts by co-polymerisation

The hydrogen evolution activity of a polymeric photocatalyst was maximised by co-polymerisation, using both experimental and computational screening, for a family of 1,4-phenylene/2,5-thiophene co-polymers. The photocatalytic activity is the product of multiple material properties that are affected in different ways by the polymer composition and microstructure. For the first time, the photocatalytic activity was shown to be a function of the arrangement of the building blocks in the polymer chain as well as the overall composition. The maximum in hydrogen evolution for the co-polymer series appears to result from a trade-off between the fraction of light absorbed and the thermodynamic driving force for proton reduction and sacrificial electron donor oxidation, with the co-polymer of p-terphenyl and 2,5-thiophene showing the highest activity

Il duomo di Teramo

IL DUOMO DI TERAMO, un volume fortemente innovativo e ricco di documenti e testimonianze inedite. I testi, rigorosissimi, sono a firma di Berardo Pio, Enrico Santangelo e Marcello Sgattoni. Contributi di Michele Seccia, Aldino Tomassetti, Paola Di Felice e Luca Falconi Di Francesco. Fotografie di Giampiero Marcocci. Uno straordinario volume dall'elegante veste grafico-editoriale, 228 pagine riccamente illustrate, rilegato in copertina rigida. Volume realizzato in collaborazione con la Diocesi di Teramo-Atri. Il Piano dell'Opera Presentazione, di Mons. Michele Seccia, Vescovo di Teramo-Atri Saluto, di Mons. Aldino Tomassetti, Parroco della Cattedrale Il vescovo, la cattedrale e la citt\ue0, di Berardo Pio L\u2019architettura, di Enrico Santangelo Le opere d\u2019arte, di Marcello Sgattoni Note di archeologia, di Paola Di Felice Il restauro del XXI secolo, di Luca Falconi Di Francesc

DFT Modeling of 45S5 and 77S Soda-Lime Phospho-Silicate Glass Surfaces: Clues on Different Bioactivity Mechanism

The reactivity of bioglasses, which is related to the dissolution of cations and orthosilicate groups in the physiological fluid, strongly depends on the key structural features present at the glass surfaces. On the basis of the composition and the synthetic routes employed to make the glass, surfaces with very different characteristics and thus presenting different mechanisms of dissolution can be observed. In this paper, the surface structures of two very different bioglass compositions, namely 45S5 (46.1 SiO2, 24.4 Na2O, 26.9 CaO, and 2.6 P2O5 mol %) and 77S (80.0 SiO2, 16.0 CaO, and 4.0 P2O5 mol %), have been investigated by means of periodic DFT calculations based on a PBE functional and localized Gaussian basis set as encoded in the CRYSTAL code. Our calculations show that the two glass surfaces differ by the relative amount of key structural sites such as NBOs, exposed ions, orthosilicate units, and small rings. We have demonstrated how the number of these sites affects the surface stability and reactivity (bioactivity)

DFT Modeling of 45S5 and 77S Soda-Lime Phospho-Silicate Glass Surfaces: Clues on Different Bioactivity Mechanism

The reactivity of bioglasses, which is related to the dissolution of cations and orthosilicate groups in the physiological fluid, strongly depends on the key structural features present at the glass surfaces. On the basis of the composition and the synthetic routes employed to make the glass, surfaces with very different characteristics and thus presenting different mechanisms of dissolution can be observed. In this paper, the surface structures of two very different bioglass compositions, namely 45S5 (46.1 SiO2, 24.4 Na2O, 26.9 CaO, and 2.6 P2O5 mol %) and 77S (80.0 SiO2, 16.0 CaO, and 4.0 P2O5 mol %), have been investigated by means of periodic DFT calculations based on a PBE functional and localized Gaussian basis set as encoded in the CRYSTAL code. Our calculations show that the two glass surfaces differ by the relative amount of key structural sites such as NBOs, exposed ions, orthosilicate units, and small rings. We have demonstrated how the number of these sites affects the surface stability and reactivity (bioactivity)