PVA/ alginate/ tannic acid crosslinked aerogels with low flammability and high mechanical resistance

Aerogels are ultra-light, highly porous materials derived from gels in which the solvent has been replaced by gas. Aerogels based on renewable and biodegradable materials are gained attention as environmentally friendly alternatives to conventional foam [1]. This study focuses on the mechanical, thermal, and combustion behavior of a polyvinyl alcohol (PVA), sodium alginate (SA) and tannic acid (TA) aerogel obtained by freeze-drying and ion crosslinking (Ca2+ and B - ). Aerogels containing 5g of PVA, 3g of TA, and 2g of SA exhibit the highest compressive resistance, which was increased by 30% after crosslinking (87.4 MPa/gcm -3 ). In comparison to pure PVA, the addition of TA and SA to the blends decreased its thermal degradation rate. The crosslinking further contributed to an 81% of reduction of the degradation rate (0.16 %/ºC) making samples high thermally stable. Regarding flammability samples burnt after being exposed to radiation due to the presence of the highly combustible PVA. However, the heat release rate (HRR) and fire growth (FIGRA) parameters decreased by 67% and 50% respectively when TA and SA was added to pure PVA aerogel. After crosslinking, an additional decrement of 35% in HRR and 54% in FIGRA respectively was obtained (76 kW/m2 and 1.96 kW/m2 s), which corresponds to a very low flame intensity. These results are down below of previous values reported by Wu et al.[2], who worked on PVA/SA crosslinking aerogels filled with inorganic montmorillonite. Hence, the cross-linked aerogels presented here can be considered a very promising sustainable alternative to conventional fossil-derived foams

Cross-cultural adaptation of the Victorian institute of sports assessment - Hamstrings (VISA-H) questionnaire for Spanish speaking athletes with proximal hamstring tendinopathy.

OBJECTIVE: To cross-culturally adapt and validate the Victorian Institute of Sports Assessment - Hamstrings (VISA-H) scale into Spanish. DESIGN: Clinical measurement study (psychometric analysis). SETTING: Sports clubs and physiotherapy clinics. PARTICIPANTS: The Spanish version of the VISA-H (VISA-H-Sp) scale was administered to 101 subjects: 50 healthy runners and 51 patients with a clinical diagnosis of PHT. MAIN MEASURES: The Victorian Institute of Sports Assessment - Hamstrings. RESULTS: Cronbach's alpha for the VISA-H-Sp was >0.8. The ICC 2,1 was 0.993 (95%CI 0.991-0.995). In the exploratory factor analysis, a one-factor solution explained 72.1% of the total variance. Athletes with PHT scored significantly lower in the VISA-H-Sp than healthy subjects (P 0.6; P < 0.001), and low or non-significant association with psychological dimensions. The standard error of measurement was 1.45 whereas the minimal detectable change was 4.02 points. The responsiveness indicators included an effect size of 2.75, and a standardised response mean of 3.1 at discharge. CONCLUSION: The VISA-H-Sp shows adequate psychometric properties for assessing the severity of symptoms in Spanish-speaking athletes who suffer from PHT

Efficacy of an asynchronous telerehabilitation program in post-COVID-19 patients: A protocol for a pilot randomized controlled trial

Background: About 40% of patients who have had COVID-19 still have symptoms three months later whereas a 10% may experience physical and/or psychological consequences two years later. Therefore, it is necessary to perform preventive interventions when patients are discharged from the hospital to decrease the aforementioned sequelae. The purpose of this pilot-controlled trial will be to determine the efficacy of a rehabilitation program on functional status and psychosocial factors for post-COVID-19 patients when it is delivered through a tele-care platform versus a booklet-based rehabilitation. Methods: The estimated sample size will be of 50 participants who have been discharged after COVID-19 and have a level of fatigue equal or greater than 4 on the Fatigue Severity Scale. The primary outcome will be the severity of fatigue. Participants will be randomly allocated to an "asynchronous telerehabilitation group"or to a "booklet-based rehabilitation group". Treatment in both groups will be the same and will consist of a combination of therapeutic exercise and an educative program. Treatment outcomes will be evaluated the last day of the intervention and at three- and six-months follow-up. Discussion: The telerehabilitation intervention appears to be a viable and efficacy option in decreasing severe fatigue and other fitness variables such as strength and aerobic capacity, similar to other traditional rehabilitation formats such as through an explanatory booklet

Core-less Multiphase Converter with Transformer Coupling

A coupled multiphase converter where the coupling among the phases is done using core-less planar transformers is presented in this paper. Operating principle of the transformer-coupled converter has been presented previously in the literature and in this paper this concept is applied to develop a core-less converter. Two prototypes operating at high frequency (4 MHz), with low profile (3 mm - 4 mm) and 60 W of output power, with two different core-less transformers are presented. Main advantages of applying this concept at high frequency are size reduction and operation with core-less transformers. This topology can be considered as a dc-dc transformer and applications for this topology can be `dc-dc transformers' for two-stage power supply systems and voltage scaling power supplies

Materiales utilizados en la policromía de la fachada de Pedro I (Real Alcázar de Sevilla, España)

This research has been conducted on the architectural decoration of the façade of the Palace of King Pedro I (The Royal Alcazar of Seville, Spain). The stratigraphic study of pictorial layers has revealed numerous interventions made on the polychrome decorations that have been related to those referenced in historical documents. Mineralogical and compositional studies of the natural and synthetic pigments and their alteration have provided an independent chronology for the polychrome decorations. Finally, this study has revealed the importance of colour of the decorative elements over the history of the palace.El estudio de la fachada del palacio de Pedro I ha puesto de manifiesto la existencia de un gran número de policromías realizadas con una amplia variedad de pigmentos de diferentes cronologías. Mediante diversas técnicas analíticas han sido diferenciadas y caracterizadas química y mineralógicamente. El estudio estratigráfico detallado de las diferentes policromías ha permitido relacionarlas con las sucesivas intervenciones documentadas, comprobando así la gran importancia que el color ha tenido en todas las épocas o momentos históricos del Palacio

Effectiveness of pre-treatment method to hinder rebar corrosion in concrete

This paper aims to evaluate the ability of phosphate pretreatments applied on steel rebars to hinder the corrosion reinforcements using synthetic pore electrolyte and mortar contaminated by chloride ions. The electrochemical behaviour of the pretreated substrate was assessed by corrosion potential, polarisation resistance and electrochemical impedance spectroscopy measurements. The results have demonstrated that the treatment of the rebar by immersion in the Na3PO4 (0·5M) solution favours the formation of a passive layer on the steel rebar surface, which increases the resistance to corrosion initiation up to 0·3M Cl– instead of 0·1M Cl– without treatment. The pretreatment also provides enhancement of corrosion protection of the steel rebar in mortar. The evolution of the impedance spectra in function of chloride concentration is in a fairly good agreement with the results obtained from RP measurements

P-P Total Cross Sections at VHE from Accelerator Data

Comparison of P-P total cross-sections estimations at very high energies - from accelerators and cosmic rays - shows a disagreement amounting to more than 10 %, a discrepancy which is beyond statistical errors. Here we use a phenomenological model based on the Multiple-Diffraction approach to successfully describe data at accelerator energies. The predictions of the model are compared with data On the basis of regression analysis we determine confident error bands, analyzing the sensitivity of our predictions to the employed data for extrapolation. : using data at 546 and 1.8 TeV, our extrapolations for p-p total cross-sections are only compatible with the Akeno cosmic ray data, predicting a slower rise with energy than other cosmic ray results and other extrapolation methods. We discuss our results within the context of constraints in the light of future accelerator and cosmic ray experimental results.Comment: 26 pages aqnd 11 figure

Association between -T786C NOS3 polymorphism and resistant hypertension: a prospective cohort study

<p>Abstract</p> <p>Background</p> <p>It is estimated that 5% of the hypertensive patients are resistant to conventional antihypertensive therapy. Polymorphisms in the endothelial nitric oxide synthase (NOS3) gene have been associated with high blood pressure levels, but not with resistant hypertension. The aim of the present study was to investigate if the -786T>C and G894T (Glu298Asp) polymorphisms of the NOS3 gene were associated with resistant hypertension.</p> <p>Methods</p> <p>A prospective case-control observational study was performed. From a series of 950 consecutive patients followed up during 42 months, 48 patients with resistant hypertension were detected. 232 patients with controlled high blood pressure were also included.</p> <p>Results</p> <p>No differences were observed in the distribution of G894T (Glu298Asp) NOS3 genotypes between the resistant hypertension group and the controlled hypertension patients. However, genotype -786CC was more frequent in the group of patients with resistant hypertension (33.3%) than in the group of patients with controlled high blood pressure (17.7%) (p 0.03). Furthermore carriers of allele T (-786TC and -786TT) were more frequent in patients with controlled hypertension (82.3%) than those with resistant hypertension (66.7%) (Multivariate analysis; RR 2.09; 95% CI 1.03–4.24; p 0.004).</p> <p>Conclusion</p> <p>Our results indicate that genotype -786CC of the NOS3 gene increase the susceptibility to suffer resistant hypertension, which suggest that resistance to conventional therapy could be determined at the endothelial level.</p

Anti-microbiota vaccines modulate the tick microbiome in a taxon-specific manner

The lack of tools for the precise manipulation of the tick microbiome is currently a major limitation to achieve mechanistic insights into the tick microbiome. Anti-tick microbiota vaccines targeting keystone bacteria of the tick microbiota alter tick feeding, but their impact on the taxonomic and functional profiles of the tick microbiome has not been tested. In this study, we immunized a vertebrate host model (Mus musculus) with live bacteria vaccines targeting keystone (i.e., Escherichia-Shigella) or non-keystone (i.e., Leuconostoc) taxa of tick microbiota and tested the impact of bacterial-specific antibodies (Abs) on the structure and function of tick microbiota. We also investigated the effect of these anti-microbiota vaccines on mice gut microbiota composition. Our results showed that the tick microbiota of ticks fed on Escherichia coli-immunized mice had reduced Escherichia-Shigella abundance and lower species diversity compared to ticks fed on control mice immunized with a mock vaccine. Immunization against keystone bacteria restructured the hierarchy of nodes in co-occurrence networks and reduced the resistance of the bacterial network to taxa removal. High levels of E. coli-specific IgM and IgG were negatively correlated with the abundance of Escherichia-Shigella in tick microbiota. These effects were not observed when Leuconostoc was targeted with vaccination against Leuconostoc mesenteroides. Prediction of functional pathways in the tick microbiome using PICRUSt2 revealed that E. coli vaccination reduced the abundance of lysine degradation pathway in tick microbiome, a result validated by qPCR. In contrast, the gut microbiome of immunized mice showed no significant alterations in the diversity, composition and abundance of bacterial taxa. Our results demonstrated that anti-tick microbiota vaccines are a safe, specific and an easy-to-use tool for manipulation of vector microbiome. These results guide interventions for the control of tick infestations and pathogen infection/transmission. © Copyright © 2021 Mateos-Hernández, Obregón, Wu-Chuang, Maye, Bornères, Versillé, de la Fuente, Díaz-Sánchez, Bermúdez-Humarán, Torres-Maravilla, Estrada-Peña, Hodžic, Šimo and Cabezas-Cruz