New Antifungal Terpenoid Glycosides from Alibertia edulis (Rubiaceae)

Phytochemical investigation from the stems of Alibertia edulis led to the isolation and identification of a new iridoid 6β‐hydroxy‐7‐epigardoside methyl ester ( 1 ) and a new saponin 3β‐O‐[α‐L ‐rhamnopyranosyl‐(1→2)‐O‐β‐D ‐glucopyranosyl‐(1→2)‐O‐β‐D ‐glucopyranosyl]‐28‐O‐β‐D ‐glucopyranoside pomolate ( 2 ), along with three known compounds, shanzhiside methyl ester ( 3 ), ixoside ( 4 ), and 3,4,5‐trimethoxyphenyl 1‐O‐β‐D ‐apiofuranosyl‐(1→6)‐O‐β‐D ‐glucopyranoside ( 5 ). The structures of 1 and 2 were established on the basis of their spectroscopic data. Iridoid 1 and saponin 2 exhibited moderate inhibitory activities against Candida albicans and C. krusei in a dilution assay.     

Physical Characterization of Blends Based on Liquid Crystalline Polyesters and Amorphous Polymers

In this work the effect of the inclusion of low percentages of theliquid crystal polymer PET/PHBGO on the rheological and mechanical behaviour of Polycarbonate is described.     

DNA Binding Studies and Cytotoxicity of a Dinuclear PtII Diazapyrenium‐Based Metallo‐supramolecular Rectangular Box

The interaction with native DNA of a 2,7‐diazapyrenium‐based ligand 1 and its Pt^II rectangular metallacycle 2 is explored through circular and linear dichroism and fluorescence spectroscopies. The metal‐free ligand 1 binds through intercalation, with a binding constant of approximately 5×10⁵ M ^?1, whereas the metallacycle 2 binds and bends the DNA with a binding constant of 7×10⁶ M ^?1. PCR assays show that metallo‐supramolecular box 2 interferes with DNA transactions in vitro whereas the intercalator 1 does not. The metallacycle is active against four human cancer cell lines, with IC₅₀ values ranging between 3.1 and 19.2 μM and shows similar levels of efficacy, but a different spectrum of activity, to cisplatin.     

HCN channels and heart rate

Hyperpolarization and Cyclic Nucleotide (HCN) -gated channels represent the molecular correlates of the "funny" pacemaker current (I(f)), a current activated by hyperpolarization and considered able to influence the sinus node function in generating cardiac impulses. HCN channels are a family of six transmembrane domain, single pore-loop, hyperpolarization activated, non-selective cation channels. This channel family comprises four members: HCN1-4, but there is a general agreement to consider HCN4 as the main isoform able to control heart rate. This review aims to summarize advanced insights into the structure, function and cellular regulation of HCN channels in order to better understand the role of such channels in regulating heart rate and heart function in normal and pathological conditions. Therefore, we evaluated the possible therapeutic application of the selective HCN channels blockers in heart rate control.     

Direct imaging rapidly-rotating non-Kerr black holes

Recently, two of us have argued that non-Kerr black holes in gravity theories different from General Relativity may have a topologically non-trivial event horizon. More precisely, the spatial topology of the horizon of non-rotating and slow-rotating objects would be a 2-sphere, like in Kerr space–time, while it would change above a critical value of the spin parameter. When the topology of the horizon changes, the black hole central singularity shows up. The accretion process from a thin disk can potentially overspin these black holes and induce the topology transition, violating the Weak Cosmic Censorship Conjecture. If the astrophysical black hole candidates are not the black holes predicted by General Relativity, we might have the quite unique opportunity to see their central region, where classical physics breaks down and quantum gravity effects should appear. Even if the quantum gravity region turned out to be extremely small, at the level of the Planck scale, the size of its apparent image would be finite and potentially observable with future facilities.     

Intermolecular π‐Electron Perturbations Generate Extrinsic Visible Contributions to Eumelanin Black Chromophore in Model Polymers with Interrupted Interring Conjugation

The key structural factors underlying the unique black chromophore of eumelanin biopolymers have so far defied elucidation. Capitalizing on the ability of 1% polyvinylalcohol (PVA) to prevent pigment precipitation during melanogenesis in vitro, we have investigated the visible chromophore properties of soluble eumelanin‐like polymers produced by biomimetic oxidation of 5,6‐dihydroxyindole (DHI) and 5,6‐dihydroxyindole‐2‐carboxylic (DHICA) in 1% PVA‐containing buffer at pH 7. Upon dilution DHI‐eumelanin solutions exhibited almost linear visible absorbance changes, whereas DHICA‐eumelanin displayed a remarkable deviation from linearity in simple buffer, but not in PVA‐containing buffer. It is suggested that in DHICA polymers, exhibiting repeated interruptions of interring conjugation due to lack of planar conformations, the black chromophore is not due to an overlap of static entities defined intrinsically by the conjugation length across the carbon frame, but results largely from aggregation‐related intermolecular perturbations of the π‐electron systems which are extrinsic in character.     

Multiple-view fluorescence optical tomography reconstruction using compression of experimental data

We report on the experimental demonstration of a fast reconstruction method for multiview fluorescence diffuse optical tomography by using a wavelet-based data compression. We experimentally demonstrate that the use of data compression combined with the multiview approach makes it possible to perform a fast reconstruction of high quality. A structured illumination approach, guided by the compression scheme, has been adopted to further reduce the acquisition time. The reconstruction algorithm is based on the finite element method, and hence is suitable for samples of any arbitrary shape.     

New insights into the titanium-mediated enantioselective oxidation of fluorinated aryl benzyl sulfides and aryl phenacyl sulfides

A fruitful switch from tert-butyl to cumene hydroperoxide was able to overcome a difficulty arose in the enantioselective oxidation of fluorinated aryl benzyl sulfide with hydroperoxides in the presence of a titanium/(S, S)-hydrobenzoin catalyst. New experiments show the complementarity of the old and the new protocols and indicate unequivocally the right choice leading to the corresponding highly enantioenriched sulfoxides. Moreover, in a totally unexpected way, the new protocol was able to overcome another difficulty arose in another field of research, that is the enantioselective oxidation of a fluorinated aryl phenacyl sulfide. Also in this case, the complementarity of behavior is acting. Finally, this investigation gives new support to the attribution of configuration of sulfoxides with ECD techniques, but only if the protocol outlined in our past research was followed thoroughly.     

Effect of natural antioxidants on the stability of polypropylene films

A preliminary study on the efficiency of agri-food industry wastes as stabilizers for polypropylene (PP) films is reported. Several analytical techniques were employed to evaluate the stabilization effectiveness of the additives. DSC and CL analysis performed on unaged samples confirmed the antioxidant activity of natural additives, and provided the following order of efficiency: red grape seeds > white grape seeds > tomato extracts. The films were also artificially aged at 70 °C, and FTIR spectroscopy confirmed the stabilization trend obtained from the unaged films. Kinetic analysis of TG data alongside tensile tests indicated that the tomato extract is a good thermal and processing stabilizer, but it is sensitive to oxidation. In contrast, grape seeds provide long-term stabilization to PP under conditions of oxidative degradation. Our results show that tomato and wine processing by-products have good potential to be exploited as a low-cost source of value-added phytochemicals.