Thermally-activated shape memory effect on biodegradable nanocomposites based on PLA/PCL blend reinforced with hydroxyapatite

[EN] In this work, the effect of the addition of different amount of nanosized hydroxyapatite (nHA) on the shape memory behavior of blends based on poly (lactic acid) (PLA) and poly (epsilon-caprolactone) (PCL) has been studied. In particular PLA/PCL blend with 70 wt % PLA has been reinforced with 0.5, 1 and 3 wt % nHA. Moreover, the relationship between the morphology and the final properties of the nanocomposites has been investigated by field emission scanning electron microscopy, confocal Raman spectroscopy and atomic force microscopy. In particular, PeakForce has been used to study quantitative nanomechanical properties of the multifunctional materials leading to conclusion that nHA increase the phase separation between PLA and PCL as well as act as reinforcements for the PCL-rich phase of the nanocomposites. Furthermore, excellent thermally-activated shape memory response has been obtained for all the nanocomposites at 55 degrees C. Finally, the disintegration under composting conditions at laboratory scale level was studied in order to confirm the biodegradable character of these nanocomposites. Indeed, these materials are able to be used for biomedical issues as well as for packaging applications where both thermally-activated shape memory effect and biodegradability are requested.Authors thank the Spanish Ministry of Economy, Industry and Competitiveness, MINEICO, (MAT2017-88123-P) and the Regional Government of Madrid (S2013/MIT-2862) for the economic support. M.P.A. and L.P. acknowledge the Juan de la Cierva (FJCI-2014-20630) and Ramon y Cajal (RYC-2014-15595) contracts from the MINEICO, respectively. The authors also thanks CSIC for the I-Link project (I-Link1149).Peponi, L.; Sessini, V.; Arrieta, MP.; Navarro-Baena, I.; Sonseca Olalla, Á.; Dominici, F.; Giménez Torres, E.... (2018). Thermally-activated shape memory effect on biodegradable nanocomposites based on PLA/PCL blend reinforced with hydroxyapatite. Polymer Degradation and Stability. 151:36-51. https://doi.org/10.1016/j.polymdegradstab.2018.02.019S365115

Effectiveness of Fosfomycin for the Treatment of Multidrug-Resistant Escherichia coli Bacteremic Urinary Tract Infections

IMPORTANCE The consumption of broad-spectrum drugs has increased as a consequence of the spread of multidrug-resistant (MDR) Escherichia coli. Finding alternatives for these infections is critical, for which some neglected drugs may be an option. OBJECTIVE To determine whether fosfomycin is noninferior to ceftriaxone or meropenem in the targeted treatment of bacteremic urinary tract infections (bUTIs) due to MDR E coli. DESIGN, SETTING, AND PARTICIPANTS This multicenter, randomized, pragmatic, open clinical trial was conducted at 22 Spanish hospitals from June 2014 to December 2018. Eligible participants were adult patients with bacteremic urinary tract infections due to MDR E coli; 161 of 1578 screened patients were randomized and followed up for 60 days. Data were analyzed in May 2021. INTERVENTIONS Patients were randomized 1 to 1 to receive intravenous fosfomycin disodium at 4 g every 6 hours (70 participants) or a comparator (ceftriaxone or meropenem if resistant; 73 participants) with the option to switch to oral fosfomycin trometamol for the fosfomycin group or an active oral drug or pa renteral ertapenem for the comparator group after 4 days. MAIN OUTCOMES AND MEASURES The primary outcome was clinical and microbiological cure (CMC) 5 to 7 days after finalization of treatment; a noninferiority margin of 7% was considered. RESULTS Among 143 patients in the modified intention-to-treat population (median [IQR] age, 72 [62-81] years; 73 [51.0%] women), 48 of 70 patients (68.6%) treated with fosfomycin and 57 of 73 patients (78.1%) treated with comparators reached CMC (risk difference, -9.4 percentage points; 1-sided 95% CI, -21.5 to infinity percentage points; P = .10). While clinical or microbiological failure occurred among 10 patients (14.3%) treated with fosfomycin and 14 patients (19.7%) treated with comparators (risk difference, -5.4 percentage points; 1-sided 95% CI. -infinity to 4.9; percentage points; P = .19), an increased rate of adverse event-related discontinuations occurred with fosfomycin vs comparators (6 discontinuations [8.5%] vs 0 discontinuations; P = .006). In an exploratory analysis among a subset of 38 patients who underwent rectal colonization studies, patients treated with fosfomycin acquired a new ceftriaxone-resistant or meropenem-resistant gram-negative bacteria at a decreased rate compared with patients treated with comparators (0 of 21 patients vs 4 of 17 patients [23.5%]; 1-sided P = .01). CONCLUSIONS AND RELEVANCE This study found that fosfomycin did not demonstrate noninferiority to comparators as targeted treatment of bUTI from MDR E coli; this was due to an increased rate of adverse event-related discontinuations. This finding suggests that fosfomycin may be considered for selected patients with these infections

Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio

Virtually guided visits as an educational tool

This study explores the possibility of creating interactive films that can replace guided visits in an educational environment. This interactive film is made up by using 360º videos, thanks to which the student can explore the surrounding environment. Preliminary results are promising, as the level of acceptance has been relatively high in all categories in which students have been asked, highliting the possitive comments from students about the immersion offered by the videos. As a future work, a chatbot will be added to answer questions and improve the navigation between different concepts, to make the transition straightforward.Número de páginas:

Biodegradable nanocomposites based on poly(ester-urethane) and nanosized hydroxyapatite: Plastificant and reinforcement effects

The processing and characterization of biodegradable nanocomposites based on poly(ester-urethane) reinforced with different amounts (0.5, 1 and 3 wt %) of nanosized hydroxyapatite (nHA) are reported. The selected poly(ester-urethane) was synthesized starting from a tri-block copolymer based on poly(epsilon-caprolactone) (PCL) and poly(L-lactic acid) (PLLA). The nanocomposites were prepared by extrusion and by press molding. Several techniques were applied to investigate the properties of the nanocomposites. Electron microscopy revealed that the poly(ester-urethane) matrix is able to phase separate and that the addition of well-dispersed nanofillers modifies the dimension of the segregated phase. The thermal stability of the PU matrix, regulated by the PLLA block, decreased when low contents of nHA (0.5 and 1 wt %) were added, even if the thermal stability of the PCL-block was increased for each nHA amount. The good mechanical response of the nanocomposites confirmed the absence of agglomerates in the dispersion of the nanofillers in the polymeric matrix. The nHA presence also increased the surface hydrophilicity. Furthermore, rheology measurements, mechanical and thermal tests demonstrated the different behavior induced by the addition of nHA in different amounts. In fact, nHA acts as plasticizer at low concentrations (0.5, 1 wt %) and as reinforcement at a higher nHA amount (3 wt %). In vitro degradation tests were performed using a phosphate buffer solution. The results reported here are relevant for the development of nanocomposites based on a biodegradable and biocompatible polymeric matrix reinforced with small amounts of biocompatible nanofillers for different applications, especially in the biomedical field. (C) 2015 Elsevier Ltd. All rights reserved.We are indebted to the Spanish Ministry of Science and Innovation (MICINN) for their economic support of this research (MAT2013-48059-C2-1-R and MAT2014-55778-REDT) as well as the Regional Government of Madrid (S2013/MIT-2862). LP acknowledges also, the support of a JAEDoc grant from CSIC cofinanced by FSE. We thank the technical support of Prof. Juan Lopez Martinez from Universitat Politecnica de Valencia (Spain) for his assistance with water contact angle measurements, as well as Marco Rallini and Franco Dominici from the STM group of the University of Perugia for FE-SEM photographs and microextruder blending, respectively.Navarro-Baena, I.; Arrieta, MP.; Sonseca Olalla, A.; Torre, L.; López, D.; Giménez Torres, E.; Kenny, JM.... (2015). Biodegradable nanocomposites based on poly(ester-urethane) and nanosized hydroxyapatite: Plastificant and reinforcement effects. Polymer Degradation and Stability. 121:171-179. https://doi.org/10.1016/j.polymdegradstab.2015.09.002S17117912

Effect of the addition of polyester-grafted-cellulose nanocrystals on the shape memory properties of biodegradable PLA/PCL bionanocomposites

In this work the thermally-activated shape memory response of biodegradable nanocomposites based on PLA/PCL blend reinforced with different type of cellulose nanocrystals has been reported, and compared with those of the neat matrix, at the same transition temperature of 55 °C and at the same different deformations, 50%, 100% and 150%. In particular, cellulose nanocrystals have been synthesized and then functionalized by "grafting from" reaction by ring opening polymerization of both PLLA and PCL using the &-OH groups onto the cellulose nanocrystals surface as initiators for the reaction. The morphology, thermal and mechanical analysis have been performed in order to obtain the parameters for the thermo-mechanical shape memory cycles. Moreover, the addition of the CNC-based nanofillers on the compatibility of PLA-PCL blends in 70:30 proportion has been evaluated. All the biodegradable nanocomposite formulations showed excellent shape memory response, similar to those of the neat matrix, with strain recovery ratio and strain fixity ratio higher than 80% and 90%, respectively. This fact indicates that in this case, the shape memory response of the nanocomposites is mainly controlled by the response of the neat blend and they are slightly influenced by the increase of compatibility between the components of the blend. In addition, all nanocomposite films were fully disintegrated under composting conditions confirming their biodegradable nature, obtaining that the presence of CNC-based nanofillers speeds up the disintegration rate of the nanocomposites in comparison with the pure matrix