Synthesis, biological evaluation and metadynamics simulations of novel -methyl β-sheet breaker peptides as inhibitors of Alzheimer's β-amyloid fibrillogenesis.

Several scientific evidences report that a central role in the pathogenesis of Alzheimer's disease is played by the deposition of insoluble aggregates of β-amyloid proteins in the brain. Because Aβ is self-assembling, one possible design strategy is to inhibit the aggregation of Aβ peptides using short peptide fragments homologous to the full-length wild-type Aβ protein. In the past years, several studies have reported on the synthesis of some short synthetic peptides called β-sheet breaker peptides (BSBPs).

Measurement of Sea Waves.

Sea waves constitute a natural phenomenon with a great impact on human activities, and their monitoring is essential for meteorology, coastal safety, navigation, and renewable energy from the sea. Therefore, the main measurement techniques for their monitoring are here reviewed, including buoys, satellite observation, coastal radars, shipboard observation, and microseism analysis. For each technique, the measurement principle is briefly recalled, the degree of development is outlined, and trends are prospected.

Investigation on Spectrum Estimation Methods for Bimodal Sea State Conditions.

The reliable monitoring of sea state parameters is a key factor for weather forecasting, as well as for ensuring the safety and navigation of ships. In the current analysis, two spectrum estimation techniques, based on the Welch and Thomson methods, were applied to a set of random wave signals generated from a theoretical wave spectrum obtained by combining wind sea and swell components with the same prevailing direction but different combinations of significant wave heights, peak periods, and peak enhancement factors. A wide benchmark study was performed to systematically apply and compare the two spectrum estimation methods.

Game-theoretical model for the sustainable use of thermal water resources: the case of Ischia volcanic Island (Italy).

The Island of Ischia, one of the Italian active volcanoes, is a famous tourist resort for spa treatments. Spas are supplied by withdrawals from groundwaters which are characterized by a wide range of chemical compositions, salinity and temperature. In natural conditions, the hydrogeological system is recharged by rainfall and by deep fluids; the discharge is towards the sea and the springs.

Comparison of Spectrum Estimation Methods for the Accurate Evaluation of Sea State Parameters.

The monitoring of sea state conditions, either for weather forecasting or ship seakeeping analysis, requires the reliable assessment of the sea spectra encountered by the ship, either as a final result or intermediate step for the measurement of the relevant wave-motion parameters. In current analyses, different spectrum estimation methods, namely the Welch, Thomson and ARMA models, have been applied and compared based on a set of random wave signals, with different durations, representative of several sea state conditions. Subsequently, two sea spectrum reconstruction techniques were described and applied in order to detect the main sea state parameters, namely the significant wave height, the mean wave period and the spectrum peak enhancement factor.

Sustainable Yield of a Hydrothermal Area: From Theoretical Concepts to the Practical Approach.

Sustainable use of groundwater in the hydrothermal area of Viterbo (Central Italy) was analyzed. In this area, multipurposes utilization of groundwater coexists: several thermal springs and wells supply spas and public pools, cold and fresh water is used for irrigation and drinking-water. Starting from theoretical concepts, a management plan has been developed to ensure groundwater sustainability in response to the increased demand of withdrawal from thermal wells, by integrating previous hydrogeological studies, new investigations and a new finite-difference model.

Antioxidant efficacy of iridoid and phenylethanoid glycosides from the medicinal plant Teucrium chamaedris in cell-free systems.

Twelve glycosides, seven iridoids and five phenylethanoids, have been isolated from leaf and root methanolic extracts of Wall Germander (Teucrium chamaedrys), a Mediterranean species historically used as a medicinal plant. Among them, three iridoid and one phenylethanoid glycosides have been isolated and characterized for the first time. All of the structures have been elucidated on the basis of their spectral data, especially 1D and 2D NMR experiments.

Isolation and structure elucidation of antioxidant polyphenols from quince (Cydonia vulgaris) peels.

Thirteen new compounds, as well as 16 already known, have been isolated from organic extracts of peels of Cydonia vulgaris, a fruit of a shrub belonging to the same tribe as the apple. All of the structures were elucidated by EI- or ESI-MS and (1)H and (13)C NMR after purification of individual compounds by HPLC. Thirteen fatty acid esters of cinnamyl alcohols, three fatty acid esters of hydroxybenzoic acid, three fatty acid esters of hydroxybenzaldehyde, three glucosides of aromatic acids, four chlorogenic acids, two flavonols, and a benzylamine have been identified.

Spectroscopic identification and antioxidant activity of glucosylated carotenoid metabolites from Cydonia vulgaris fruits.

Carotenoid metabolites are common plant constituents with significant importance for the flavor and aroma of fruits. Three new carotenoid derivatives, (2E,4E)-8-hydroxy-2,7-dimethyl-2,4-decadiene-1,10-dioic acid 1-O-beta-D-glucopyranosyl ester (1), (2Z,4E)-8-beta-D-glucopyranosyloxy-2,7-dimethyl-2,4-decadiene-1,10-dioic acid (3), and 3,9-dihydroxymegastigmast-5-ene-3-O-[beta-D-glucopyranosyl-(1-->6)]-beta-D-glucopyranoside (5), as well as three known compounds, have been isolated from the ethanolic extract of peels of Cydonia vulgaris, the fruit of a shrub belonging to the same family as the apple. All the compounds were identified by spectroscopic techniques, especially 1D and 2D NMR.

Free-radical-scavenging and antioxidant activities of secondary metabolites from reddened cv. Annurca apple fruits.

Forty-three secondary metabolites were isolated and characterized from cv. Annurca apple fruit, an apple variety cultivated in the south of Italy. This apple cultivar undergoes a typical reddening treatment after collection.

Elucidation of two O-chain structures from the lipopolysaccharide fraction of Agrobacterium tumefaciens F/1.

Agrobacterium tumefaciens F/1 produces two different O-chains, both are constituted of rhamnose and glucosamine: the less abundant has a linear disaccharidic repeating unit 3)-alpha-L-Rhap-(1-->3)-beta-D-GlcpNAc-(1--> and the second one 4)-alpha-L-Rhap-(1-->3)-beta-D-GlcpNAc-(1-->. The two intact antigenic moieties were studied in mixture by 2D NMR. Additional supporting data were obtained by periodate degradation, the major component was cleaved selectively, leading to a glucosamine glycoside, whereas the minor one was recovered unaffected.

Observed and calculated 1H- and 13C-NMR chemical shifts of substituted 5H-pyrido[3,2-a]- and 5H-pyrido[2,3-a]phenoxazin-5-ones and of some 3H-phenoxazin-3-one derivatives.

Carbon and proton NMR spectra of several substituted 5H-pyrido[3,2-a]-, 5H-pyrido[2,3-a]phenoxazin-5-ones and 3H-phenoxazin-3-one derivatives have been assigned, and the experimental chemical shifts have been compared with the results of density functional calculations employing large basis sets. Solvent effects were explored by means of the polarizable continuum method (PCM), while the (limited) side-chain flexibility of the compounds has been addressed by Boltzmann averaging of the computed spectral parameters over different conformational minima. Overall, the calculated shifts reproduce well the experiment results; thus, the computational procedure represents a feasible and useful complement to multidimensional NMR experiments in the assignment process.

Structural determination of the complex exopolysaccharide from the virulent strain of Cryphonectria parasitica.

The structure of a new exopolysaccharide from the virulent strain of Cryphonectria parasitica was elucidated by means of 2D NMR spectroscopy and selective degradations (mild hydrolysis and acetolysis). The polysaccharide is built up of mannose, galactose and rhamnose and has a rather complex non-repetitive structure that can be idealised as follows: