Neuroprotective Effects of Curcumin in Methamphetamine-Induced Toxicity

Curcumin (CUR), a natural polyphenol extracted from rhizome of the Curcuma longa L, has received great attention for its multiple potential health benefits as well as disease prevention. For instance, CUR protects against toxic agents acting on the human body, including the nervous system. In detail, CUR possesses, among others, strong effects as an autophagy activator. The present study indicates that CUR counteracts methamphetamine (METH) toxicity. Such a drug of abuse is toxic by disturbing the autophagy machinery. We profited from an unbiased, low variable cell context by using rat pheochromocytoma PC12 cell line. In such a system, a strong protection was exerted by CUR against METH toxicity. This was associated with increased autophagy flux, merging of autophagosomes with lysosomes and replenishment of autophagy vacuoles with LC3, which instead is moved out from the vacuoles by METH. This is expected to enable the autophagy machinery. In fact, while in METH-treated cells the autophagy substrates α-synuclein accumulates in the cytosol, CUR speeds up α-synuclein clearance. Under the effects of CUR LC3 penetrate in autophagy vacuoles to commit them to cell clearance and promotes the autophagy flux. The present data provide evidence that CUR counteracts the neurotoxic effects induced by METH by promoting autophagy.     

A Review on Coordination Properties of Al(III) and Fe(III) toward Natural Antioxidant Molecules: Experimental and Theoretical Insights

This review focuses on the ability of some natural antioxidant molecules (i.e., hydroxycinnamic acids, coumarin-3-carboxylic acid, quercetin, luteolin and curcumin) to form Al(III)- and Fe(III)-complexes with the aim of evaluating the coordination properties from a combined experimental and theoretical point of view. Despite the contributions of previous studies on the chemical properties and biological activity of these metal complexes involving such natural antioxidants, further detailed relationships between the structure and properties are still required. In this context, the investigation on the coordination properties of Al(III) and Fe(III) toward these natural antioxidant molecules might deserve high interest to design water soluble molecule-based metal carriers that can improve the metal’s intake and/or its removal in living organisms.     

Asymmetric synthesis by chiral ruthenium complexes : VI. Enantiomer-discrimination in the hydrogen transfer from racemic alcohols to prochiral ketones in the presence of H4Ru4(CO)8[(−)-diop]2

Hydrogen transfer from racemic alcohols to prochiral ketones in the presence of H₄Ru₄(CO)₈[(?)-DIOP]₂ has been examined. The enantiomer-discrimination is influenced by the structure of the reactants, temperature and the excess of phosphine present.     

First-principles study of aqueous hydroxide solutions

Car-Parrinello molecular dynamics simulations have been carried out for aqueous NaOH and KOH solutions under ambient conditions over a wide range of concentrations. From these simulations, we have observed a continuous change of the water structure with added hydroxide, characterized by a significant shift of the second peak of the OO radial distribution functions to shorter distances. At the highest concentration investigated, the normal tetrahedral coordination of pure water is completely missing, a result that is consistent with a recent neutron diffraction experiment. The added hydroxide also gives rise to some unique spectroscopic features, including a "free" O-H stretch, a broadening of the normal water OH stretching band, and a large blue shift of both the librational band and the low-frequency translation. These results are in good agreement with the experimental data. Finally, it was demonstrated that the structural and dynamical behavior is inextricably linked to the formation of compact hydroxide-water complexes.     

ac-Driven double quantum dots as spin pumps and spin filters

We propose and analyze a new scheme of realizing both spin filtering and spin pumping by using ac-driven double quantum dots in the Coulomb blockade regime. By calculating the current through the system in the sequential tunneling regime, we demonstrate that the spin polarization of the current can be controlled by tuning the parameters (amplitude and frequency) of the ac field. We also discuss spin relaxation and decoherence effects in the pumped current.     

Magnetite, a model system for mixed-valence oxides, does not show charge ordering

We have investigated the charge ordering (CO) in magnetite below the Verwey transition. A new set of half-integer and mixed-integer superlattice reflections of the low-temperature phase have been studied by x-ray resonant scattering. None of these reflections show features characteristic of CO. We demonstrate the absence of CO along the c axis with the periodicity of either the cubic lattice q=(001) or the doubled cubic lattice q=(001/2). This result suggests that the Verwey transition is caused by strong electron-phonon interaction instead of an electronic ordering on the octahedral Fe atoms.     

Development of a laser photothermoacoustic frequency-swept system for subsurface imaging: theory and experiment

In conventional biomedical photoacoustic imaging systems, a pulsed laser is used to generate time-of-flight acoustic information of the subsurface features. This paper reports the theoretical and experimental development of a new frequency-domain (FD) photo-thermo-acoustic (PTA) principle featuring frequency sweep (chirp) and heterodyne modulation and lock-in detection of a continuous-wave laser source at 1064 nm wavelength. PTA imaging is a promising new technique which is being developed to detect tumor masses in turbid biological tissue. Owing to the linear relationship between the depth of acoustic signal generation and the delay time of signal arrival to the transducer, information specific to a particular depth can be associated with a particular frequency in the chirp signal. Scanning laser modulation with a linear frequency sweep method preserves the depth-to-delay time linearity and recovers FD-PTA signals from a range of depths. Preliminary results performed on rubber samples and solid tissue phantoms indicate that the FD-PTA technique has the potential to be a reliable tool for biomedical depth-profilometric imaging.     

A solid-phase approach towards the development of 3-aza-6,8-dioxabicyclo[3.2.1]octane scaffolds

The development of new strategies for solid-phase synthesis of 3-aza-6,8-dioxabicyclo[3.2.1]octane scaffolds, named BTKa, is described. The preparation was made possible by the combination of three components: amines, alpha-halo-acetophenones, and sugar or tartaric acid derivatives. By anchoring each of the three components it was possible to synthesize BTKa compounds either as amino alcohols or amido esters. The compatibility of the protocols with different classes of amines and substituted alpha-halo-acetophenones was demonstrated.     

A dinuclear copper(II) complex with adeninate bridge ligands and prominent DNA cleavage activity. Structural and spectroscopic characterization and magnetic properties

A new dinuclear copper(II) complex has been synthesized and structurally characterized: [Cu(mu-ade)(tolSO3)(phen)]2.2H2O (Hade = adenine, tolSO3- = toluenesulfonate anion). Its magnetic properties and electronic paramagnetic resonance (EPR) spectra have been studied in detail. The compound has two metal centers bridged by two adeninate NCN groups. The coordination geometry of the copper(II) ions in the dinuclear entity is distorted square pyramidal, with the four equatorial positions occupied by two phenanthroline N atoms and two N atoms from different adenine molecules. The axial position is occupied by one sulfonate O atom. Magnetic susceptibility data show antiferromagnetic behavior with an estimated exchange constant of -2J = 65 cm-1. The EPR spectrum has been obtained at both X- and Q-band frequencies; a study at different temperatures has been carried out at the latter. Above 20 K, the Q-band spectra are characteristic of S = 1 species with a small zero-field splitting parameter (D = 0.0970 cm-1). A detailed study of the DNA-complex interaction has been performed. The title complex efficiently cleaves the pUC18 plasmid in the presence of reducing agents. Both the kinetics and the mechanism of the cleavage reaction are examined and described herein.     

A rapid and economical method for profiling feature heights during microfabrication

Quality control is an important and integral part to any microfabrication process. While the widths of features often can be easily assessed by light microscopy, the heights of the fabricated structures are more difficult to determine. Here, we present a rapid, accurate, and low-cost method to measure the heights of microfabricated structures during and after the fabrication process. This technique is based on white-light interferometry, which offers accuracy on the submicrometre scale.