•For the first time, expansive concretes with photocatalytic activity were developed.•Photocatalytic agent promotes higher expansion when using expansive agent type K.•Photocatalytic activity ...decreases due to the interaction with the expansive agents.
For the first time, the sustainability and functionality of expansive concretes have been increased through the addition of a photocatalytic agent (PhAg). The inclusion of the PhAg mainly modifies the properties of the fresh concrete and the resulting expansion obtained in different curing conditions. PhAg particles act as nucleation sites that increase and accelerate the formation of the expansion hydrates with the subsequent enhancement in the expansion performance. In fact, some modifications in the chemical composition of the expansive hydrates formed is detected due to the inclusion of the PhAg. However, since expansive hydrates are expected to growth in the surface of the PhAg, the photocatalytic activity decreases.
One of the most accepted engineering construction concepts of underground repositories for high level waste considers the use of low pH cementitious materials. This research is focused on the ...development of those based on Calcium Aluminate Cements (CAC) with high mineral admixture contents that significantly modify their microstructural properties. Once their short-term hydration is known, this paper deals with the modifications generated in the pore solutions and in the solid phases of low-pH cement pastes based on CAC after 2years of hydration, observing a high stability of the solid phases formed in the short-term. This paper also deals with the resistance of these materials to long term groundwater aggression using two types of aggressive agents: deionised water and groundwater from the real site of Äspö. Leaching tests show a good resistance of low-pH concretes against groundwater aggression but dependent on the leaching agent and on the concrete composition.
To investigate the effects of new two low-shrinkage composites SDR
®
and Venus
®
Bulk Fill on the cell viability, cellular damage and expression of mesenchymal markers on dental stem cells. Specimens ...from two low-shrinkage composites were eluted with culture medium for 24 h. After 24 h of incubation, cytotoxicity of elutes were evaluated by MTT assay; apoptosis was determined using the DNA-specific fluorochrome Hoechst 33342 and the mesenchymal stem cells markers expression was analyzed by immunofluorescence staining. After 24 h of cell exposure to each extract media, dental stem cells expressed MSCs markers. The interaction among the material and cell line was not significantly correlated F(1,60) = 2.251,
P
= 0.39, whereas statistically significant differences among cells lines were observed F(1,60) = 9.157,
P
= 0.004, being dental pulp stem cells more resistant that periodontal ligament stem cells. Also, we did not find any significant effect between the tested materials F(1,60) = 0.090,
P
= 0.765. Furthermore, a very low proportion of exposed cells showed condensed or fragmented nuclei, typical of apoptotic cells at 24 h. The results suggest that SDR
®
and Venus
®
Bulk fill and should be considered when selecting an appropriate resin-based dental restorative material.
Background
There is not an ideal biomaterial for tissue‐engineered skin substitutes (TESSs), and most of the studies or existing therapies use xenogeneic origin natural biomaterials or biosynthetic ...scaffolds.
Objective
To analyse clinical, histological integration and homeostasis parameters of a human TESS manufactured with fibrin–hyaluronic acid biomaterial (HA‐Skin), grafted in immunodeficient mice for 8 weeks, and compared with the gold standard treatment (Autograft), a human TESS manufactured with fibrin–agarose biomaterial (AG‐Skin) and secondary wound healing dressings.
Methods
Human TESSs and autografts were implanted into BALB/c mice after surgical excision. Secondary wound healing approach was achieved with biosynthetic collagen wound dressing (Biobrane®) and fibrin–hyaluronic acid or fibrin–agarose biomaterial without cells (Total N = 44). Clinical integration and homeostasis parameters were evaluated every two weeks for two months. Histological and immunohistochemical analyses were performed four and eight weeks after grafting.
Results
HA‐Skin, AG‐Skin and Autograft groups showed a proper clinical integration and epithelization eight weeks later. Scar evaluation revealed better results for Autograft and HA‐Skin. Homeostasis analysis indicated similar values of transepidermal water loss and elasticity between HA‐Skin (6.42 ± 0.75 g/h/m2, 0.42 ± 0.08 AU), Autograft (6.91 ± 1.28 g/h/m2, 0.40 ± 0.08 AU) and healthy mouse skin (6.40 ± 0.43 g/h/m2, 0.35 ± 0.03 AU). Histological results showed that human TESSs and autografts presented better skin structuration and higher expression of cytokeratins.
Conclusions
This study suggests that human TESS based on fibrin–hyaluronic acid biomaterial could be suitable for clinical application in the treatment of several dermatological pathologies (wound healing).
We study the application of fatigue loads as an activation agent of the self-healing mechanism of concrete. This can lead to improvements in the strength of the material, contrary to the idea that ...cyclic loads can only generate damage. A fiber-reinforced concrete was produced and characterized under compressive fatigue. The strength of runout specimens, which resisted from a minimum of 165000 cycles until more than a million, showed a mean increase of 23%. Microstructure analyses were performed to confirm this increment as the result of a self-healing process, including X-ray Diffraction, Thermogravimetric and Differential Thermal Analyses, Back Scattering Electron Microscopy, and Mercury Intrusion Porosimetry. Results show the presence of new hydration products and a reduction of porosity, which explain the improvement of the concrete capacity. As a mechanical result, the relationship between strain rate and fatigue life is found to be unique for every fatigue stress level.
Presence of microcracks in concrete can diminish the service life of a structure. The injection of materials for filling the crack is proposed for facing this problem. The traditional materials used ...for sealing cracks present some drawbacks, such as the difficulties of inorganic materials for flowing to all the depth of the crack and the lack of compatibility with the cementitious matrix in the case of organic materials. In this work, the injection of colloidal nanosilica dispersed in water is proposed for filling microcracks in mortars. The effect of the injection procedure on the sealing performance of the colloidal nanosilica has been assessed. The ability of colloidal nanosilica for penetrating through the crack and its posterior gelification-solidification inside the crack after a curing period have been confirmed. The microscopic analysis of a cross-section of the crack indicates that the sealing ability of the nanosilica seems to be not only due to the filling of the crack but also to chemical interactions with the cementitious phases of the surrounding crack sides.
Maintenance of paroxysmal atrial fibrillation (AF) by fast rotors in the left atrium (LA) or at the pulmonary veins (PVs) is not fully understood. To gain insight into this dynamic and complex ...process, we studied the role of the heterogeneous distribution of transmembrane currents in the PVs and LA junction (PV-LAJ) in the localization of rotors in the PVs. We also investigated whether simple pacing protocols could be used to predict rotor drift in the PV-LAJ. Experimentally observed heterogeneities in IK1, IKs, IKr, Ito, and ICaL in the PV-LAJ were incorporated into two- and pseudo three-dimensional models of Courtemanche-Ramirez-Nattel-Kneller human atrial kinetics to simulate various conditions and investigate rotor drifting mechanisms. Spatial gradients in the currents resulted in shorter action potential duration, minimum diastolic potential that was less negative, and slower upstroke and conduction velocity for rotors in the PV region than in the LA. Rotors under such conditions drifted toward the PV and stabilized at the shortest action potential duration and less-excitable region, consistent with drift direction under intercellular coupling heterogeneities and regardless of the geometrical constraint in the PVs. Simulations with various IK1 gradient conditions and current-voltage relationships substantiated its major role in the rotor drift. In our 1:1 pacing protocol, we found that among various action potential properties, only the minimum diastolic potential gradient was a rate-independent predictor of rotor drift direction. Consistent with experimental and clinical AF studies, simulations in an electrophysiologically heterogeneous model of the PV-LAJ showed rotor attraction toward the PV. Our simulations suggest that IK1 heterogeneity is dominant compared to other currents in determining the drift direction through its impact on the excitability gradient. These results provide a believed novel framework for understanding the complex dynamics of rotors in AF.
Indoor-kept concentrate-fed light lambs (n=54) were supplemented with 500mg of dl-α-tocopheryl acetate/kg concentrate for 0, 10, 20 and 30d before slaughtering at 22–24kg BW. Simultaneously, 8 lambs ...with their dams were alfalfa-grazed and the lambs were slaughtered at the same weight. The age at slaughter and carcass characteristics were more affected by grazing than by supplementation with α-tocopherol. The grazing lambs had similar α-tocopherol levels to the lambs fed concentrate with dl-α-tocopheryl acetate for 10days before slaughter. The length of the feeding period affected the evolution of the color, delaying the blooming and discoloration of the meat. Feeding lambs α-tocopherol enriched concentrate during the last 10days of life or grazing them on alfalfa drastically diminished the lipid oxidation of the meat. Alfalfa grazing is a feasible alternative to increase light lamb meat shelf life without using additives.
► Finishing period length did not affect to carcass characteristics and muscle pH. ► A finishing period of 10 d achieved similar α-tocopherol content than grazing lambs. ► Alfalfa grazing delayed lipid oxidation and metmyoglobin formation. ► The finishing period of 10 d diminished significantly lipid and pigments oxidation.
There is, at present, considerable interest in the storage and dispatchability of photovoltaic (PV) energy, together with the need to manage power flows in real-time. This paper presents a new ...system, PV-on time, which has been developed to supervise the operating mode of a Grid-Connected Utility-Scale PV Power Plant in order to ensure the reliability and continuity of its supply. This system presents an architecture of acquisition devices, including wireless sensors distributed around the plant, which measure the required information. It is also equipped with a high-precision protocol for synchronizing all data acquisition equipment, something that is necessary for correctly establishing relationships among events in the plant. Moreover, a system for monitoring and supervising all of the distributed devices, as well as for the real-time treatment of all the registered information, is presented. Performances were analyzed in a 400 kW transformation center belonging to a 6.1 MW Utility-Scale PV Power Plant. In addition to monitoring the performance of all of the PV plant's components and detecting any failures or deviations in production, this system enables users to control the power quality of the signal injected and the influence of the installation on the distribution grid.
Background. Staphylococcus aureus bacteremia (SAB) is associated with significant morbidity and mortality. Several aspects of clinical management have been shown to have significant impact on ...prognosis. The objective of the study was to identify evidence-based quality-of-care indicators (QCIs) for the management of SAB, and to evaluate the impact of a QCI-based bundle on the management and prognosis of SAB. Methods. A systematic review of the literature to identify QCIs in the management of SAB was performed. Then, the impact of a bundle including selected QCIs was evaluated in a quasi-experimental study in 12 tertiary Spanish hospitals. The main and secondary outcome variables were adherence to QCIs and mortality. Specific structured individualized written recommendations on 6 selected evidence-based QCIs for the management of SAB were provided. Results. A total of 287 and 221 patients were included in the preintervention and intervention periods, respectively. After controlling for potential confounders, the intervention was independently associated with improved adherence to follow-up blood cultures (odds ratio OR, 2.83; 95% confidence interval CI, 1.78–4.49), early source control (OR, 4.56; 95% CI, 2.12–9.79), early intravenous cloxacillin for methicillin-susceptible isolates (OR, 1.79; 95% CI, 1.15–2.78), and appropriate duration of therapy (OR, 2.13; 95% CI, 1.24–3.64). The intervention was independently associated with a decrease in 14-day and 30-day mortality (OR, 0.47; 95% CI, .26–.85 and OR, 0.56; 95% CI, .34–.93, respectively). Conclusions. A bundle orientated to improving adherence to evidence-based QCIs improved the management of patients with SAB and was associated with reduced mortality.
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