ABSTRACT:A physical and mechanical characterization of blends of Nylon 6 (PA6) and very low density polyethylene (VLDPE), functionalized with maleic anhydride (MA) or diethylmaleate (DEM) is reported. The functionalization of VLDPE with MA and DEM was performed by reactive extrusion in a twin-screw (Berstoff) extruder in the presence of dicumylperoxide. The PA6/VLDPE, PA6/VLDPE-g-MA, and PA6/VLDPE-g-DEM blends with composition ratio of 80 : 20 (wt %) were obtained by using a twin-screw Werner & Pfleiderer extruder. An industrial-type blend based on PA6 and MA-grafted ultra low density polyethylene (ULDPE-g-MA) was also tested for comparison. All blends were then characterized by optical and scanning electron microscopy, differential scanning calorimetry, and dynamic mechanical thermal analysis. The results of slow fracture and impact tests showed that the ductile-brittle transition temperature of the examined blends depends on the type of functional group and test speed.

Hydrogen sulfide (H2S) is an endogenous gasotransmitter that promotes multiple biological effects in many organs and tissues. An imbalanced biosynthesis of H2S has been observed in animal models of age-related pathological conditions. However, the results from human studies are inconsistent. We performed a systematic review with meta-analysis of studies searched in Medline, Embase, Scopus, and CENTRAL databases. We included observational studies on patients with age-related diseases showing levels of H2S in blood, plasma, or serum. All the analyses were carried out with R software. 31 studies were included in the systematic review and 21 in the meta-analysis. The circulating levels of H2S were significantly reduced in patients with progressive, chronic, and degenerative diseases compared with healthy people (standardized mean difference, SMD: −1.25; 95% confidence interval, CI: −1.98; −0.52). When we stratified results by type of disorder, we observed a significant reduction in circulating levels of H2S in patients with vascular disease (e.g., hypertension) (SMD: −1.32; 95% CI: −2.43; −0.22) or kidney disease (SMD: −2.24; 95% CI: −4.40; −0.08) compared with the control group. These results could support the potential use of compounds targeting the “H2S system” to slow down the progression of many diseases in the elderly.

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The sweat test (ST) is the current diagnostic gold standard for cystic fibrosis (CF). Many CF centres have switched from the Gibson–Cooke method to the Macroduct system-based method. We used these methods simultaneously to compare CF screening outcomes. STs using both methods were performed simultaneously between March and December 2022 at CF Centre in Florence. We included newborns who underwent newborn bloodspot screening (NBS), newborns undergoing transfusion immediately after birth, and children with CF screen-positive, inconclusive diagnosis (CFSPID). We assessed 72 subjects (median age 4.4 months; range 0–76.7): 30 (41.7%) NBS-positive, 18 (25.0%) newborns who underwent transfusion, and 24 (33.3%) children with CFSPID. No significant differences were found between valid sample numbers, by patient ages and groups (p = 0.10) and between chloride concentrations (p = 0.13), except for sweat chloride (SC) measured by the Gibson–Cooke and Macroduct methods in CFSPID group (29.0, IQR: 20.0–48.0 and 22.5, IQR: 15.5–30.8, respectively; p = 0.01). The Macroduct and Gibson–Cooke methods showed substantial agreement with the SC values, except for CFSPID, whose result may depend on the method of sweat collection. In case of invalid values with Macroduct, the test should be repeated with Gibson–Cooke method.