Nonlocal Harnack inequalities

We state and prove a general Harnack inequality for minimizers of nonlocal, possibly degenerate, integro-differential operators, whose model is the fractional p-Laplacian.     

Determination of As(III) by anodic stripping voltammetry using a lateral gold electrode: experimental conditions, electron transfer and monitoring of electrode surface

The aim of this work is to evaluate the efficiency of the determination of As(III) by anodic stripping voltammetry (ASV) using a lateral gold electrode and to study the modifications of the electrode surface during use. Potential waveforms (differential pulse and square wave), potential scan parameters, deposition time, deposition potential and surface cleaning procedure were examined for they effect on arsenic peak intensity and shape. The best responses were obtained with differential pulse potential wave form and diluted 0.25 M HCl as supporting electrolyte. The repeatability, linearity, accuracy and detection limit of the procedure and the interferences of cations and anions in solution were evaluated. The applicability of the procedure for As(III) determination in drinking waters was tested. Cyclic voltammetry (CV) was used to study the electrochemical behaviour of As(III) and for the daily monitoring of electrode surface. Also scanning electron microscopy (SEM) analysis was used to control the electron surface. Finally we evaluated the possibility to apply the equations valid for flow systems also to a stirred system, in order to calculate the number of electrons transferred per molecule during the stripping step.     

Global estimates for nonlinear parabolic equations

We consider nonlinear parabolic equations of the type $$u_t - {\rm div}a(x, t, Du)= f(x, t) \quad {\rm on}\quad \Omega_T =\Omega\times (-T,0),$$ under standard growth conditions on a, with f only assumed to be integrable. We prove general decay estimates up to the boundary for level sets of the solutions u and the gradient Du which imply very general estimates in Lebesgue and Lorentz spaces. Assuming only that the involved domains satisfy a mild exterior capacity density condition, we provide global regularity results.     

On the Aleksandrov–Bakelman–Pucci estimate for the infinity Laplacian

We prove L ^∞ bounds and estimates of the modulus of continuity of solutions to the Poisson problem for the normalized infinity and p-Laplacian, namely $$\begin{array}{ll} -\Delta_p^N u=f\quad{\rm for } \; n < p \leq\infty.\end{array}$$ We are able to provide a stable family of results depending continuously on the parameter p. We also prove the failure of the classical Alexandrov–Bakelman–Pucci estimate for the normalized infinity Laplacian and propose alternate estimates.     

Optimization of DNA extraction from dental remains

Efficient DNA extraction procedures is a critical step involved in the process of successful DNA analysis of such samples. Various protocols have been devised for the genomic DNA extraction from human tissues and forensic stains, such as dental tissue that is the skeletal part that better preserves DNA over time. However DNA recovery is low and protocols require labor‐intensive and time‐consuming step prior to isolating genetic material. Herein, we describe an extremely fast procedure of DNA extraction from teeth compared to classical method. Sixteen teeth of 100‐year‐old human remains were divided into two groups of 8 teeth and we compared DNA yield, in term of quantity and quality, starting from two different sample preparation steps. Specifically, teeth of group 1 were treated with a classic technique based on several steps of pulverization and decalcification, while teeth of group 2 were processed following a new procedure to withdraw dental pulp. In the next phase, the samples of both group underwent the same procedure of extraction, quantification and DNA profile analysis. Our findings provide an alternative protocol to obtain a higher amount of good quality DNA in a fast time procedure, helpful for forensic and anthropological studies.     

Excited states of porphyrin macrocycles

S1 --> S(n) spectra of porphyrin, diprotonated porphyrin, and tetraoxaporphyrin dication have been measured in the energy range 2-3 eV above S1 at room temperature in solution by means of transient absorption spectroscopy exciting with femtosecond pulses. Highly excited pi pi* states not active in the conventional S0 --> S(n) spectrum have been observed. The experimental data are discussed on the basis of the time dependent density functional theory taking advantage of large scale calculations of configuration interaction between singly excited configurations (DF/SCI). The DF/SCI calculation on porphyrin has allowed to assign g states active in the S1 --> S(n) spectrum. Applying the same calculation method to tetraoxaporphyrin dication the S0 --> S(n) spectrum is reproduced relatively to the Q and B (Soret) bands as well as to the weaker E(u) bands at higher energy. According to our calculation the S1 --> S(n) transient spectrum is related to states of g symmetry mainly arising from excitations between doubly degenerate pi and pi* orbitals such as 2e(g) --> 4e(g). In the case of diprotonated porphyrin it is shown that the complex of the macrocycle with two trifluoroacetate anions plays a significant role for absorption. Charge transfer excitations from the anions to the macrocycle contribute to absorption above the Soret band, justifying the intensity enhancement of the S0 --> S(n) spectrum with respect to the other two macrocyclic systems.     

A high-voltage lithium-ion battery prepared using a Sn-decorated reduced graphene oxide anode and a LiNi<Subscript>0.5</Subscript>Mn<Subscript>1.5</Subscript>O<Subscript>4</Subscript> cathode

This paper describes the preparation and characterization of a high-voltage lithium-ion battery based on Sn-decorated reduced graphene oxide and LiNi_0.5Mn_1.5O₄ as the anode and cathode active materials, respectively. The Sn-decorated reduced graphene oxide is prepared using a microwave-assisted hydrothermal synthesis method followed by reduction at high temperature of a mixture of (C₆H₅)₂SnCl₂ and graphene oxide. The so-obtained anode material is characterized by thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, and electron diffraction spectroscopy. The LiNi_0.5Mn_1.5O₄ is a commercially available product. The two materials are used to prepare composite electrodes, and their electrochemical properties are investigated by galvanostatic charge/discharge cycles at various current densities in lithium cells. The electrodes are then used to assemble a high-voltage lithium-ion cell, and the cell is tested to evaluate its performance as a function of discharge rate and cycle number.     

Synthesis of deuterium-labelled substrates for the study of oleuropein biosynthesis in Olea europaea callus cultures

We propose the cell culture approach to investigate oleuropein (1) biogenesis in Olea europaea L. We suggest employing olive callus cultures to identify the iridoidic precursor of oleuropein. In fact, we confirmed that callus cells from olive shoot explants are able to produce key secoiridoid as 1. To enable this approach, we synthesised and characterised deuterium-labelled iridoidic precursors belonging both to the loganin and the 8-epiloganin series. These iridoids are [7,8-²H₂]-7-deoxy-8-epi-loganin (2^D), [8,10-²H₂]-8-epi-loganin (4^D) and [7,8-²H₂]-7-deoxy-loganin (3^D).     

A dizinc complex for selective fluorescence sensing of uridine and uridine-containing dinucleotides

A dizinc complex with a polyamine macrocycle is able to selectively bind and sense uridine (U) as well as the uridine-containing ribodinucleotides U(3'-5')pU and U(3'-5')pA, thanks to an exciplex emission arising from a pi-stacked complex involving the dipyridine unit and Zn(II)-bound uridine moieties.