Bio-based nanocomposite coating to preserve quality of Fior di latte cheese

The aim of this study was to evaluate the effects of a bio-based coating containing silver-montmorillonite nanoparticles combined with modified-atmosphere packaging (MAP) on microbial and sensory quality decay of Fior di latte cheese. Different concentrations of silver nanoparticles (0.25, 0.50, and 1.00 mg/mL) were dispersed in a sodium alginic acid solution (8% wt/vol) before coating the cheese. Modified-atmosphere packaging was made up of 30% CO₂, 5% O₂, and 65% N₂. The combination of silver-based nanocomposite coating and MAP enhanced Fior di latte cheese shelf life. In particular, product stored in the traditional packaging showed a shelf life of about 3 d, whereas coated cheese stored under MAP reached a shelf life of more than 5 d, regardless of the concentration of silver nanoparticles. The synergistic effects between antimicrobial nanoparticles and initial headspace conditions in the package could allow diffusion of dairy products beyond the local area.     

Polycyclic aromatic hydrocarbons (PAHs) levels in propolis and propolis-based dietary supplements from the Italian market

Propolis and propolis-based extracts, attained from beekeepers and the local market, were analysed for the presence of 13 polycyclic aromatic hydrocarbons (PAHs), including eight high molecular weight PAHs (PAH8), recently indicated by the European Food Safety Authority (EFSA) as suitable indicators of the presence of carcinogenic and genotoxic PAH in foods. An analytical procedure based on microwave assisted saponification/extraction, high performance liquid chromatography (HPLC) and spectrofluorometric detection, has been developed. About half of the samples analysed presented benzo[a]pyrene (BaP) concentrations exceeding 2 μg/kg, which is proposed as a regulatory limit for dietary supplements. A product-by-product approach (based on maximum recommended dosage) was used to calculate PAH exposure. Even thought the majority of the samples gave low exposure levels when compared to exposure levels from other diet constituents, PAH intakes deriving from a daily consumption of some of the investigated products provided an important contribution to the total dietary intake and lead to margin of exposure (MOE) values which are of concern for human health.     

Clinical and Functional Study of a De Novo Variant in the PVP Motif of Kv1.1 Channel Associated with Epilepsy,Developmental Delay and Ataxia

Mutations in the KCNA1 gene, encoding the voltage-gated potassium channel Kv1.1, have been associated with a spectrum of neurological phenotypes, including episodic ataxia type 1 and developmental and epileptic encephalopathy. We have recently identified a de novo variant in KCNA1 in the highly conserved Pro-Val-Pro motif within the pore of the Kv1.1 channel in a girl affected by early onset epilepsy, ataxia and developmental delay. Other mutations causing severe epilepsy are located in Kv1.1 pore domain. The patient was initially treated with a combination of antiepileptic drugs with limited benefit. Finally, seizures and ataxia control were achieved with lacosamide and acetazolamide. The aim of this study was to functionally characterize Kv1.1 mutant channel to provide a genotype–phenotype correlation and discuss therapeutic options for KCNA1-related epilepsy. To this aim, we transfected HEK 293 cells with Kv1.1 or P403A cDNAs and recorded potassium currents through whole-cell patch-clamp. P403A channels showed smaller potassium currents, voltage-dependent activation shifted by +30 mV towards positive potentials and slower kinetics of activation compared with Kv1.1 wild-type. Heteromeric Kv1.1+P403A channels, resembling the condition of the heterozygous patient, confirmed a loss-of-function biophysical phenotype. Overall, the functional characterization of P403A channels correlates with the clinical symptoms of the patient and supports the observation that mutations associated with severe epileptic phenotype cluster in a highly conserved stretch of residues in Kv1.1 pore domain. This study also strengthens the beneficial effect of acetazolamide and sodium channel blockers in KCNA1 channelopathies.     

Role of Draw Rate and Molecular Weight when Electrospun Nanofibers are Post-Drawn with Residual Solvent

The postdrawing process is poorly understood for polymer nanofibers due to the difficulty of manipulating nanofiber structures. Here, an angled track system facilitates postdrawing of individual nanofibers with control of parameters including molecular weight, draw rate, draw ratio, and solvent evaporation time. In this study, the effects of molecular weight, draw rate, and relative residual solvent content on final nanofiber properties are investigated. Molecular weight is first investigated to clarify any influence polymer chain length can have on drawing in facilitating or hindering chain extensibility. Polyacrylonitrile nanofibers with 50 and 150 kDa molecular weights behave similarly with postdrawing resulting in reduced diameters and enhanced mechanics. Since solvent quantity during drawing is a time sensitive component it is meaningful to assess the impact of draw rate on the chemical and structural makeup of postdrawn fibers. Chemical bond vibrations and chain orientation are sensitive to draw rate when polycaprolactone nanofibers are dried for 3 minutes prior to postdrawing, but this dependency to draw rate is not observed when fibers are postdrawn immediately upon collection. These findings demonstrate that the amount of retained solvent at collection is relevant to this postprocessing approach, and highlights the dynamics of solvent evaporation during postdrawing.     

The action of organo-phosphate additives in polysiloxane fluids

The four ball wear test apparatus was used to study the antiwear properties of four organo-phosphate additives in dimethyl-, phenyl methyl-, and two chlorophenyl methyl siloxane fluids as a function of load, additive concentration and viscosity. In most cases an antagonistic ‘prowear’ effect is observed refuting the commonly held belief that the lack of antiwear activity is the result of the additive not getting to the surface or being displaced from the surface by polysiloxane fluids.     

Deuterated grease thickener

The ‘Deuterium Isotope Effect’ was investigated as a means of further increasing the oxidation resistance of soap-thickened greases utilized in miniature bearing applications. Using lithium stearate as a model compound, the bearing performance life and induction period for oxidation were determined on four different greases prepared from non-deuterated and deuterated base oil and thickener. The expected increase in oxidation resistance and bearing performance life was observed for the deuterated base fluid; however, the use of a deuterated thickener did not provide any significant improvement. Details concerning the preparation of thickener and grease formulations and their properties are presented.