Flavonol glucosides in Allium species: A comparative study by means of HPLC–DAD–ESI-MS–MS

Cultivars and consumption typologies of some Allium species can significantly vary from a chemical point of view and even small differences can be important for their characterization and differentiation. Bulbs of three varieties and four consumption typologies of onion (Allium cepa L.) and two varieties of shallot (Allium ascalonicum Hort.) were subjected to HPLC–DAD–ESI-MS–MS analysis. Seven flavonol glucosides were identified in all the samples, two of which, quercetin 3,4′-diglucoside and quercetin 4′-glucoside, represent about the 90% of the overall contents. Cultivars and consumption typologies of the Allium species under study show significant differences in flavonol contents, from the very low quantity of antioxidant compounds in white onion, about 7 mg/kg against 600–700 mg/kg that were found in red and gold varieties, to the enormous content of flavonols that are present in onions of prompt consumption, where quercetin 4′-glucoside exceeds 1 g/kg and quercetin 3-glucoside is present in a ratio higher then 10:1 with respect to its value in the other onion typologies. Shallots are very rich in the two major flavonols.     

Effect of storage on biochemical and microbiological parameters of edible truffle species

The effects of different storage treatments on the most common edible truffle species, such as Tuber magnatum and Tuber borchii (white truffles), Tuber melanosporum and Tuber aestivum (black truffles), were analysed. Biochemical and microbiological profiles were monitored, in order to evaluate possible alterations during truffle preservation. After harvesting, some fresh samples were kept at 4 °C for 30 days, other samples were frozen at −20 °C for one month, thawed and preserved at 4 °C; the remainder were autoclaved.     

Application of a radical scavenging activity test to measure the total antioxidant activity of poultry meat

The antioxidant activity of the hydrophilic and lipophilic fraction of poultry meat was determined in terms of ‘radical scavenging activity’ (RSA) using a modified ABTS radical cation decolorization method.The method uses the extraction of hydrophilic and lipophilic fractions in water and methanol–chloroform, respectively. The determination of the RSA of the lipophilic fraction was conducted using a chloroform extract and maintaining a constant chloroform:ethanol ratio in the solution of analysis. The method was tested on nine samples of poultry breasts and thigh meats and permitted to quantify the RSA in terms of μmol Trolox equivalent antioxidant capacity (TEAC) with a mean relative standard deviation of less than 5%.The contribution of the hydrophilic fraction to the total RSA was much higher than that of the lipid soluble fraction. Breast showed a higher RSA than thigh meat due to its lower total lipids content. The total RSA value (TEAC = 2.4 μmol g⁻¹) suggests that poultry meat could significantly contribute to the antioxidant activity of the diet.     

A 3D printed melt-compounded antibiotic loaded thermoplastic polyurethane heart valve ring design: an integrated framework of experimental material tests and numerical simulations

Abstract

Heart diseases are one of the commonest causes of death worldwide. These include valve pathologies such as valve stenosis, regurgitation, failure and similar, for which usually a valve substitution procedure is required. Different prosthesis alternatives (both biological and artificial) are nowadays available in the heart surgery panorama, but there are still issues and aspects to improve. The principal requirements for heart valve prostheses are an efficient fluid dynamic function and long-term durability without the need for anticoagulation therapy, coupled with the possibility of patient-specific customization. Given this scenario, the presented tasks might be fulfilled by the recent advances of additive manufacturing technology (AM), which offers versatility of shapes and materials to be printed.

In this work, the full flexibility of AM technique has been exploited to demonstrate the feasibility of a custom drug-loaded polymeric heart valve ring for crimpable prostheses. Two different medical-grade polymeric filaments for AM have been extruded: an aromatic Polyester-Based Thermoplastic Polyurethane (TPU-E) and a Thermoplastic Silicone-Polycarbonate-urethane compound filament (TSPCU). Both materials find different applications in medical fields, thanks to their mechanical and biocompatibility features.

A drug-loading procedure has been set to obtain an antibiotic-filled polymer material and the relative biocompatibility has been consequently investigated. Specimens have been printed with a Fused Deposition Method and uniaxial traction tests have been performed at different printing temperatures and infill orientation angles. To evaluate the damaging risk given by the HVR crimping process, a Finite Element (FE) simulation of the crimping load has been set.

The TSPCU has appeared to be the best material to realize the prosthesis in terms of tensile stress values. The ultimate mechanical characteristics of TSPCU have resulted to be higher if compared with TPU-E, regardless of raster orientation angle and temperature. The qualitative characterization of the drug loading process of TSPCU has been successful: standard disc diffusion method has revealed a well-defined inhibition zone on the bacterial culture. The effectiveness of the antibiotic has been maintained even after the extrusion and the printing process. The simulated crimping procedure on the HVR has revealed that the maximum Von Mises stress value is below the ultimate stress taken from experimental tests. The reported results demonstrate the feasibility of a crimpable antibiotic loaded HVR realized through TSPCU 3D printing.     

Development and performance analysis of PCL/silica nanocomposites for bone regeneration

In the present article, several developments of biocomposites containing silica nanoparticles intended for bone regeneration are reported. Nanocomposites of poly(ε-caprolactone) (PCL) and silica, in which either the silica nanoparticles or the PCL have been modified in order to improve interfacial adhesion through chemical graft between the phases are hereafter described. The composites are characterized with respect to their chemical–physical and mechanical properties. Their biocompatibility and capacity to induce the osteoblastic phenotype in human bone marrow mesenchymal stem cells have been assessed.     

Time-resolved diffuse optical spectroscopy: a differential absorption approach

A method is presented for the estimate of spectral changes in the absorption properties of turbid media from time-resolved diffuse optical spectroscopy. The method relies on the hypothesis of constant scattering over the wavelength range of interest, but no limitations come from the sample size and shape as the method is derived directly from the Beer-Lambert law. The effects of a moderate spectral dependence of the scattering properties and of the non-ideal instrument response function were investigated theoretically, and the results were confirmed experimentally, showing that the method can be profitably applied in cases of practical interest.     

Enhancing the optical excitation efficiency of a single self-assembled quantum dot with a plasmonic nanoantenna

We demonstrate how the controlled positioning of a plasmonic nanoparticle modifies the photoluminescence of a single epitaxial GaAs quantum dot. The antenna particle leads to an increase of the luminescence intensity by about a factor of 8. Spectrally and temporally resolved photoluminescence measurements prove an increase of the quantum dot’s excitation rate.     

Heat recovery from Diesel engines: A thermodynamic comparison between Kalina and ORC cycles

In the context of heat recovery for electric power generation, Kalina cycle (a thermodynamic cycle using as working fluid a mixture of water and ammonia) and Organic Rankine Cycle (ORC) represent two different eligible technologies. In this work a comparison between the thermodynamic performances of Kalina cycle and an ORC cycle, using hexamethyldisiloxane as working fluid, was conducted for the case of heat recovery from two Diesel engines, each one with an electrical power of 8900 kWe. The maximum net electric power that can be produced exploiting the heat source constituted by the exhaust gases mass flow (35 kg/s for both engines, at 346 °C) was calculated for the two thermodynamic cycles. Owing to the relatively low useful power, for the Kalina cycle a relatively simple plant layout was assumed. Supposing reasonable design parameters and a logarithmic mean temperature difference in the heat recovery exchanger of 50 °C, a net electric power of 1615 kW and of 1603 kW respectively for the Kalina and for the ORC cycle was calculated.Although the obtained useful powers are actually equal in value, the Kalina cycle requires a very high maximum pressure in order to obtain high thermodynamic performances (in our case, 100 bar against about 10 bar for the ORC cycle). So, the adoption of Kalina cycle, at least for low power level and medium–high temperature thermal sources, seems not to be justified because the gain in performance with respect to a properly optimized ORC is very small and must be obtained with a complicated plant scheme, large surface heat exchangers and particular high pressure resistant and no-corrosion materials.     

A long acidic domain affects the chromatographic behaviour of a neuronal adaptor protein on DEAE-Sepharose

The stepwise chromatographic behaviour on DEAE-Sepharose of rat Fe65, a neuronal protein, was tested, using as eluants KCl, CaCl2, and MgCl2. Assays by western blot showed that Fe65 was eluted by CaCl2, at a ionic strength 20% lower than that of MgCl2 or KCl. Interestingly, in the case of a truncated Fe65, lacking a glutamic acid rich region at the N-terminus, the ionic strengths of the various eluants were almost identical. These results suggested a possible inhibitory role of calcium ions in the binding of the protein to DEAE and a specific affinity of these ions for long acidic stretches.     

Preservation of the superior hemorrhoidal artery in resection of the colon and rectum

As an alternative to anterior resection of the rectum requiring ligature of the inferior mesenteric artery at its origin, it is proposed to carry out this procedure preserving the inferior mesenteric artery and freeing it as far as the origin of the superior hemorrhoidal artery and its division into rectal branches to improve the blood supply to the rectal stump. The results of this new procedure were compared with those of anterior resection. Post-operatively, the blood supply of the rectum was studied by means of angiography. The results of 84 anterior resections for neoplastic disease of the colon were studied. In 56 patients, the inferior mesenteric artery was preserved and in 28 the inferior mesenteric artery was ligated. Postoperative complications due to leakage of the colorectal anastomosis rarely occurred in the first group and were frequent in the latter. In patients in whom the inferior mesenteric artery was preserved, arteriograms showed that vascularization of the preserved rectal stump is supplied essentially by the branches of the superior hemorrhoidal artery.