Melamine Foams Decorated with In-Situ Synthesized Gold and Palladium Nanoparticles

Producción CientíficaA versatile and straightforward route to produce polymer foams with functional surface through their decoration with gold and palladium nanoparticles is proposed. Melamine foams, used as polymeric porous substrates, are first covered with a uniform coating of polydimethylsiloxane, thin enough to assure the preservation of their original porous structure. The polydimethylsiloxane layer allows the facile in-situ formation of metallic Au and Pd nanoparticles with sizes of tens of nanometers directly on the surface of the struts of the foam by the direct immersion of the foams into gold or palladium precursor solutions. The effect of the gold and palladium precursor concentration, as well as the reaction time with the foams, to the amount and sizes of the nanoparticles synthesized on the foams, was studied and the ideal conditions for an optimized functionalization were defined. Gold and palladium contents of about 1 wt.% were achieved, while the nanoparticles were proven to be stably adhered to the foam, avoiding potential risks related to their accidental release

In Vitro High-Throughput Toxicological Assessment of Nanoplastics

Sub-micrometer particles derived from the fragmentation of plastics in the environment can enter the food chain and reach humans, posing significant health risks. To date, there is a lack of adequate toxicological assessment of the effects of nanoplastics (NPs) in mammalian systems, particularly in humans. In this work, we evaluated the potential toxic effects of three different NPs in vitro: two NPs obtained by laser ablation (polycarbonate (PC) and polyethylene terephthalate (PET1)) and one (PET2) produced by nanoprecipitation. The physicochemical characterization of the NPs showed a smaller size, a larger size distribution, and a higher degree of surface oxidation for the particles produced by laser ablation. Toxicological evaluation performed on human cell line models (HePG2 and Caco-2) showed a higher toxic effect for the particles synthesized by laser ablation, with PC more toxic than PET. Interestingly, on differentiated Caco-2 cells, a conventional intestinal barrier model, none of the NPs produced toxic effects. This work wants to contribute to increase knowledge on the potential risks posed by NPs

Physicochemical Characterization Cascade of Nanoadjuvant–Antigen Systems for Improving Vaccines

Adjuvants have been used for decades to enhance the immune response to vaccines, in particular for the subunit-based adjuvants. Physicochemical properties of the adjuvant-protein antigen complexes, such as size, morphology, protein structure and binding, influence the overall efficacy and safety of the vaccine. Here we show how to perform an accurate physicochemical characterization of the nanoaluminum–ovalbumin complex. Using a combination of existing techniques, we developed a multi-staged characterization strategy based on measurements of increased complexity. This characterization cascade has the advantage of being very flexible and easily adaptable to any adjuvant-protein antigen combinations. It will contribute to control the quality of antigen–adjuvant complexes and immunological outcomes, ultimately leading to improved vaccines

Time- and frequency-domain analysis of repolarization phase during recovery from exercise in healthy subjects

Background/aim: Recently, data from temporal dispersion of myocardial repolarization analysis have gained a capital role in the sudden cardiac death risk stratification. Aim of this study was to evaluate the influence of heart rate, autonomic nervous system and controlled breathing on different myocardial repolarization markers in healthy subjects. Method: Myocardial repolarization dispersion markers from short period (5-minutes) ECG analysis (time and frequency domain) have been obtained in 21 healthy volunteers during these conditions: free breathing (rest); controlled breathing (resp); the first 5-minutes of post-exercise recovery phases (exercisePeak); maximum sympathetic activation, and during the second five minutes of post-exercise recovery phases (exerciseRecovery), intermediate sympathetic activation. Finally, we analyzed the whole repolarization (QTe), the QT peak (QTp) and T peak - T end intervals (Te). Results: During the exercisePeak major part of repolarization variables changed in comparison to the rest and resp conditions. Particularly, QTe, QTp, Te standard deviations (QTeSD, QTpSD, TeSD), variability indexes (QTeVI, QTpVI), normalized variances (QTeVN, QTpVN, TeVN), the ratio between short term QTe, QTp, Te variability RR (STVQTe/RR, STVQTp/RR and STVTe/RR increased. During exerciserecovery QTpSD (p<0.05), QTpVI (p<0.05), QTeVN (p<0.05), QTpVN (p<0.001), TeVN (p<0.05), STVQTe/RR (p<0.05), STVQTp/RR (p<0.001) and STVTe/RR (p<0.001) were significantly higher in comparison with the rest. The slope between QTe (0.24±0.06) or QTp (0.17±0.06) and RR were significantly higher than Te (0.07±0.06, p<0.001). Conclusion: Heart rate and sympathetic activity, obtained during exercise, seem able to influence the time domain markers of myocardial repolarization dispersion in healthy subjects whereas they do not alter any spectral components

Regulation of UV-B-Induced Inflammatory Mediators by Activity-Dependent Neuroprotective Protein (ADNP)-Derived Peptide (NAP) in Corneal Epithelium

The corneal epithelium, representing the outermost layer of the cornea, acts as a barrier to protect the eye against external insults such as ultraviolet B (UV-B) radiations. The inflammatory response induced by these adverse events can alter the corneal structure, leading to visual impairment. In a previous study, we demonstrated the positive effects of NAP, the active fragment of activity-dependent protein (ADNP), against oxidative stress induced by UV-B radiations. Here, we investigated its role to counteract the inflammatory event triggered by this insult contributing to the disruption of the corneal epithelial barrier. The results indicated that NAP treatment prevents UV-B-induced inflammatory processes by affecting IL-1β cytokine expression and NF-κB activation, as well as maintaining corneal epithelial barrier integrity. These findings may be useful for the future development of an NAP-based therapy for corneal disease

Short-period temporal repolarization dispersion in subjects with atrial fibrillation and decompensated heart failure

Background/objectives: The association between chronic heart failure (CHF) and permanent atrial fibrillation is very frequent. The repolarization duration was already found predictive for atrial fibrillation. Aim of this study was to evaluate the influence of atrial fibrillation on short period repolarization variables in decompensated CHF patients. Method: We used 5 minutes ECG recordings to assess the mean, standard deviation (SD) and normalized variance (NV) of the following variables: QT end (QTe), QT peak (QTp) and T peak to T end (Te) in 121 decompensated CHF, of whom 40 had permanent atrial fibrillation, too. We reported also the 30-day mortality. Results: QTpSD (p<0.01), TeSD (p<0.01), QTpVN (p<0.01) and TeVN (p<0.01) were higher in the atrial fibrillation than among sinus rhythm CHF subjects. Multivariable logistic analysis selected only TeSD (odd ratio, o.r.: 1.32, 95% confidence interval, c.i.: 1.06-1.65, p: 0.015) associated with atrial fibrillation. A total of 27 patients died during the 30-days follow-up (overall mortality rate 22%), 7 (18%) and 20 (25%) respectively in the atrial fibrillation and sinus rhythm patients. Furthermore, the following variables were associated to the morality risk: NT-pro Brain Natriuretic Peptide (o.r.: 1.00, 95% c.i.: 1.00-1.00, p:0.041), left ventricular end diastolic diameter (o.r.: 0.81, 95% c.i.: 0.67-0.96, p: 0.010) and Te mean (o.r.: 1.04, 95% c.i.: 1.02-1.09, p:0.012). Conclusion: In decompensated CHF subjects, Te mean seems be associated to mortality and TeSD to the permanent atrial fibrillation. We could hypothesize that, during severe CHF, the multi-level ionic CHF channel derangement could be critical in influencing these non-invasive markers. (ClinicalTrials.gov number, NCT04127162) This article is protected by copyright. All rights reserved. Keywords: Chronic heart failure; QT; QTVI; Tpeak-Tend; mortality; permanent atrial fibrillation; temporal dispersion of repolarization phase

Laser Ablation as a Versatile Tool To Mimic Polyethylene Terephthalate Nanoplastic Pollutants: Characterization and Toxicology Assessment

The presence of micro- and nanoplastics in the marine environment is raising strong concerns since they can possibly have a negative impact on human health. In particular, the lack of appropriate methodologies to collect the nanoplastics from water systems imposes the use of engineered model nanoparticles to explore their interactions with biological systems, with results not easily correlated with the real case conditions. In this work, we propose a reliable top-down approach based on laser ablation of polymers to form polyethylene terephthalate (PET) nanoplastics, which mimic real environmental nanopollutants, unlike synthetic samples obtained by colloidal chemistry. PET nanoparticles were carefully characterized in terms of chemical/physical properties and stability in different media. The nanoplastics have a <i>ca</i>. 100 nm average dimension, with significant size and shape heterogeneity, and they present weak acid groups on their surface, similarly to photodegraded PET plastics. Despite no toxic effects emerging by <i>in vitro</i> studies on human Caco-2 intestinal epithelial cells, the formed nanoplastics were largely internalized in endolysosomes, showing intracellular biopersistence and long-term stability in a simulated lysosomal environment. Interestingly, when tested on a model of intestinal epithelium, nano-PET showed high propensity to cross the gut barrier, with unpredictable long-term effects on health and potential transport of dispersed chemicals mediated by the nanopollutants

Time‐ and frequency‐domain analysis of repolarization phase during recovery from exercise in healthy subjects

Background/aim: Recently, data from temporal dispersion of myocardial repolarization analysis have gained a capital role in the sudden cardiac death risk stratification. Aim of this study was to evaluate the influence of heart rate, autonomic nervous system and controlled breathing on different myocardial repolarization markers in healthy subjects. Method: Myocardial repolarization dispersion markers from short period (5-minutes) ECG analysis (time and frequency domain) have been obtained in 21 healthy volunteers during these conditions: free breathing (rest); controlled breathing (resp); the first 5-minutes of post-exercise recovery phases (exercisePeak); maximum sympathetic activation, and during the second five minutes of post-exercise recovery phases (exerciseRecovery), intermediate sympathetic activation. Finally, we analyzed the whole repolarization (QTe), the QT peak (QTp) and T peak - T end intervals (Te). Results: During the exercisePeak major part of repolarization variables changed in comparison to the rest and resp conditions. Particularly, QTe, QTp, Te standard deviations (QTeSD, QTpSD, TeSD), variability indexes (QTeVI, QTpVI), normalized variances (QTeVN, QTpVN, TeVN), the ratio between short term QTe, QTp, Te variability RR (STVQTe/RR, STVQTp/RR and STVTe/RR increased. During exerciserecovery QTpSD (p&lt;0.05), QTpVI (p&lt;0.05), QTeVN (p&lt;0.05), QTpVN (p&lt;0.001), TeVN (p&lt;0.05), STVQTe/RR (p&lt;0.05), STVQTp/RR (p&lt;0.001) and STVTe/RR (p&lt;0.001) were significantly higher in comparison with the rest. The slope between QTe (0.24±0.06) or QTp (0.17±0.06) and RR were significantly higher than Te (0.07±0.06, p&lt;0.001). Conclusion: Heart rate and sympathetic activity, obtained during exercise, seem able to influence the time domain markers of myocardial repolarization dispersion in healthy subjects whereas they do not alter any spectral components