Protein Folding and Aggregation into Amyloid: The Interference by Natural Phenolic Compounds

Amyloid aggregation is a hallmark of several degenerative diseases affecting the brain or peripheral tissues, whose intermediates (oligomers, protofibrils) and final mature fibrils display different toxicity. Consequently, compounds counteracting amyloid aggregation have been investigated for their ability (i) to stabilize toxic amyloid precursors; (ii) to prevent the growth of toxic oligomers or speed that of fibrils; (iii) to inhibit fibril growth and deposition; (iv) to disassemble preformed fibrils; and (v) to favor amyloid clearance. Natural phenols, a wide panel of plant molecules, are one of the most actively investigated categories of potential amyloid inhibitors. They are considered responsible for the beneficial effects of several traditional diets being present in green tea, extra virgin olive oil, red wine, spices, berries and aromatic herbs. Accordingly, it has been proposed that some natural phenols could be exploited to prevent and to treat amyloid diseases, and recent studies have provided significant information on their ability to inhibit peptide/protein aggregation in various ways and to stimulate cell defenses, leading to identify shared or specific mechanisms. In the first part of this review, we will overview the significance and mechanisms of amyloid aggregation and aggregate toxicity; then, we will summarize the recent achievements on protection against amyloid diseases by many natural phenols.     

Volatile and semi-volatile components of oak wood chips analysed by Accelerated Solvent Extraction (ASE) coupled to gas chromatography–mass spectrometry (GC–MS)

Volatile and semi-volatile compounds of French and American oak wood used in wine and spirits ageing were extracted by an Accelerated Solvent Extractor (ASE) and analysed by gas chromatography–mass spectrometry. More than 90 compounds were isolated, characterised and quantified after being separated on two chromatographic columns with distinct polarity. The main oak wood components were quantitatively determined by using standard reference compounds. In addition, a number of compounds, mainly guaiacol and syringol derivatives, were detected and characterised. In particular, 10 compounds were tentatively identified as lignin dimers derivatives, whose presence in oak wood chips or barrels for wine and spirits ageing had not been previously described. Several of the characterised compounds enabled a distinction to be drawn between medium and high toasted wood chips, independently of their geographical origin.     

Tailoring dialysis and resuming low‐protein diets may favor chronic dialysis discontinuation: Report on three cases

Renal function recovery (RFR), defined as the discontinuation of dialysis after 3 months of replacement therapy, is reported in about 1% of chronic dialysis patients. The role of personalized, intensive dialysis schedules and of resuming low‐protein diets has not been studied to date. This report describes three patients with RFR who were recently treated at a new dialysis unit set up to offer intensive hemodialysis. All three patients were females, aged 73, 75, and 78 years. Kidney disease included vascular‐cholesterol emboli, diabetic nephropathy and vascular and dysmetabolic disease. At time of RFR, the patients had been dialysis‐dependent from 3 months to 1 year. Dialysis was started with different schedules and was progressively discontinued with a “decremental” policy, progressively decreasing number and duration of the sessions. A moderately restricted low‐protein diet (proteins 0.6 g/kg/day) was started immediately after dialysis discontinuation. The most recent update showed that two patients are well off dialysis for 5 and 6 months; the diabetic patient died (sudden death) 3 months after dialysis discontinuation. Within the limits of small numbers, our case series may suggest a role for personalized dialysis treatments and for including low‐protein diets in the therapy, in enhancing long‐term RFR in elderly dialysis patients.     

Bioaccumulation of dioxin-like substances and selected brominated flame retardant congeners in the fat and livers of black pigs farmed within the Nebrodi Regional Park of Sicily

An observational study was designed to assess the bioaccumulation of polychlorodibenzodioxins (PCDD) and polychlorodibenzofurans (PCDF), dioxin-like polychlorobiphenyls (DL-PCB), and 13 selected polybromodiphenylethers (PBDE) in autochthonous pigs reared in the Nebrodi Park of Sicily (Italy). Perirenal fat and liver samples were drawn from animals representative of three different outdoor farming systems and from wild pigs and then analyzed for the chemicals mentioned previously. The highest concentrations of PCDD + PCDF and DL-PCB were detected in the fat (0.45 and 0.35 pg World Health Organization toxicity equivalents [WHO-TE] per g of fat base [FB], respectively) and livers (12.7 and 3.28 pg WHO-TE per g FB) of the wild group, whereas the free-ranging group showed the lowest levels (0.05 and 0.03 pg WHO-TE per g FB in fat and 0.78 and 0.27 pg WHO-TE per g FB in livers). The sum of PBDE congeners was highest in wild pigs (0.52 ng/g FB in fat and 5.64 ng/g FB in livers) and lowest in the farmed group (0.14 ng/g FB in fat and 0.28 ng/g FB in livers). The contamination levels in fat and livers of outdoor pigs had mean concentration values lower than those levels reported for intensively indoor-farmed animals. In wild pigs, bioaccumulation was associated with their free grazing in areas characterized by bush fires. The results of this study aid to emphasize the quality of the environment as a factor to guarantee food safety in typical processed pig meat products, specifically from outdoor and extensive Nebrodi farming systems.     

Comparison of nutritional and nutraceutical properties in cultivated fruits of Fragaria vesca L. produced in Italy

Individual sugars, organic acids, total polyphenols, vitamin C and antiradical activity (as measured by DPPH method) were quantified in cultivated Fragaria vesca berries, comparing different varieties (Regina delle Valli, Alpine, Sara and Valitutto) and different environments with regard to altitude. Cultivar effect mainly influenced the concentration of total polyphenols and antiradical activity which are strongly correlated (R² = 0.91; P = 0.001); conversely, altitude seemed to exert an influence in sugar and organic acid composition. The comparison of the general quality of the most diffused cultivar of F. vesca (Regina delle Valli and Alpine) evidenced that both cultivars have the same nutritional properties, whereas Regina delle Valli is better than Alpine from the point of view of total polyphenolic content (716 vs 471 mg catechin/100 g fresh weight) and radical scavenging activity (301 vs 219 ml DPPH solution/100 g fresh weight), thus resulting more attractive from the health protecting attributes point of view. F. vesca berries showed also a concentration of sugars, citric acid, malic acid and total polyphenols much higher than those reported in literature for Fragaria x ananassa.     

A theoretical analysis of a buffer frame size conversion algorithm for audio applications ensuring minimum latency

In implementing digital signal processing (DSP) algorithms for audio real-time applications, one is frequently faced with problems regarding incompatibilities between the hardware buffer length (the internal buffer of a professional sound card) and the software buffer size imposed by the underlying algorithm (due to i.e. multirate or FFT constraints). This mismatch is solved by proper frame size conversion algorithms which inevitably introduce delay. In this context, this paper presents a buffering scheme together with a theoretical proof of the minimum delay property shown by it. Some examples derived from frequently encountered issues in DSP applications are reported.     

Moisture-induced stresses perpendicular to grain in cross-sections of timber members exposed to different climates

In variable humidity conditions, wood absorbs or desorbs moisture from the air. Unless the change in humidity is very slow, this will develop moisture gradients in the wood sections. These gradients will develop stresses due to constrained swelling or shrinkage strains. These stresses are named moisture-induced stresses. The present paper investigates the main parameters affecting such moisture-induced stresses, including the type of climate, the size of the timber cross-section, and the type of protective coating. A first attempt to identify moisture-induced stresses in different European climatic regions was made. For each climatic region, relative humidity and temperature histories were identified, and characteristic and mean values of yearly and daily variations were calculated. Using a finite element model implemented in Abaqus, the moisture content and stress distribution were computed on different timber cross-sections exposed to the climatic regions and protected with different types of coating. A Fickian moisture transfer model was used to compute the moisture distribution, and a mechanical model for time-dependent behaviour of wood was implemented to calculate the corresponding stress distribution. The variation of moisture was found to result in stresses of magnitudes that would probably cause cracking of wood in the perimeter of any uncoated cross-section size. The use of a protective coating, however, reduced considerably the moisture-induced stresses, and can be regarded as an effective protective measure to avoid cracking due to humidity variations. Considering European climates, Northern climates were found to result in higher surface tensile stresses than Southern climates.     

Static analysis of a Bickford beam by means of the DQEM

In this paper the recently proposed differential quadrature element method is employed in order to solve the equilibrium equations of a higher-order beam. A simple five-node element is introduced, in which the vertical displacement is approximated by a sixth-order polynomial, whereas the rotation is consistently approximated by a fourth-order polynomial, and the resulting weighting coefficient matrix is given. Moreover, a general procedure is outlined, for an N-node element, in which vertical displacements and rotations are given by polynomials of order N+1 and N-1, respectively. Numerical examples are aimed both at checking the convergence of the results for increasing values of the nodes, and at comparing the used cubic beam theory with the simpler, linear, Timoshenko theory.