2,255 research outputs found
Sustainable development of an Ultra-High Performance Fibber Reinforced Concrete (UHPFRC): towards partial replacement of cement by slags
The global production of concrete represents, every year, more than 5% of the anthropogenic emissions of carbon dioxide, mainly from the production of cement. This negative factor can be improved by incorporating supplementary cementitious materials in order to replace cement.
In the last few decades, research has been conducted on what it is known as Ultra High Performance Fibber Reinforced Concrete (UHPFRC). The term includes a broad range of materials such as defect-free, dense particle, engineered composite, multi-scale particle and fibber-reinforced cementitious materials, with enhanced properties. UHPFRC has better mechanical and durability properties compared to normal strength concrete. Other benefits of using UHPFRC on a structure includes the reduction of concrete sections, concrete formwork, labour, equipment and time of construction. Despite of the benefits associated to this material, the UHPFRC is still struggling to be universally applied, mainly due to its high cost and its high environmental impact. UHPFRC cost is higher than normal concrete, due to a very high powder content and steel fibber addition. However, the production of UHPFRC using locally available materials, under normal curing conditions, should reduce its cost and turned it into a more attractive construction product.
In this paper, the fresh and hardened properties of a specific UHPFRC composition are presented. The mixture replaces a significant percentage of cement by slags, and the results reveal the viability of the proposed mix. The environmental performance of the mixture confirmed the improvement on the material sustainability and allowed the identification of some potential future studies.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Intermittent inotropic support with levosimendan in advanced heart failure as destination therapy: The LEVO-D registry
Advanced heart failure; Inotropes; Palliative careInsuficiencia cardiaca avanzada; Inotropos; Cuidados paliativosInsuficiència cardíaca avançada; Inòtrops; Cures pal·liativesAim
Patients with advanced heart failure (AHF) who are not candidates to advanced therapies have poor prognosis. Some trials have shown that intermittent levosimendan can reduce HF hospitalizations in AHF in the short term. In this real-life registry, we describe the patterns of use, safety and factors related to the response to intermittent levosimendan infusions in AHF patients not candidates to advanced therapies.
Methods and results
Multicentre retrospective study of patients diagnosed with advanced heart failure, not HT or LVAD candidates. Patients needed to be on the optimal medical therapy according to their treating physician. Patients with de novo heart failure or who underwent any procedure that could improve prognosis were not included in the registry. Four hundred three patients were included; 77.9% needed at least one admission the year before levosimendan was first administered because of heart failure. Death rate at 1 year was 26.8% and median survival was 24.7 [95% CI: 20.4–26.9] months, and 43.7% of patients fulfilled the criteria for being considered a responder lo levosimendan (no death, heart failure admission or unplanned HF visit at 1 year after first levosimendan administration). Compared with the year before there was a significant reduction in HF admissions (38.7% vs. 77.9%; P 12 g/dL (+1.5), amiodarone use (−1.5) HF visit 1 year before levosimendan (−1.5) and heart rate >70 b.p.m. (−2). Patients with a score less than −1 had a very low probability of response (21.5% free of death or HF event at 1 year) meanwhile those with a score over 1.5 had the better chance of response (68.4% free of death or HF event at 1 year). LEVO-D score performed well in the ROC analysis.
Conclusion
In this large real-life series of AHF patients treated with levosimendan as destination therapy, we show a significant decrease of heart failure events during the year after the first administration. The simple LEVO-D Score could be of help when deciding about futile therapy in this population
Impact of targeting Kt instead of Kt/V
Producción CientíficaBackground. Patients must receive an adequate dialysis dose in each hemodialysis (HD) session. Ionic dialysance (ID) enables the dialysis dose to be monitored in each session. The aim of this study was to compare the achievement of Kt versus eKt/V values and to analyse the main impediments to reaching
the dialysis dose. Methods. Of 5316 patients from 54 Fresenius Medical Care centers in Spain undergoing their usual HD regime, 3275 received ID and were included in the study.
Results. The minimum prescribed dose of eKt/V was reached in 91.2% of the patients, while the minimum recommended dose of Kt was reached in only 66.8%. Patients not receiving the minimum Kt dose were older, had spent 7 months less on dialysis, had a dialysis duration of 6 min less, had 5.7 kg more
of body weight and Qb was 47 mL/min lower. The target Kt was not reached by 62% of patients with catheters and by 37% of women. With each quintile increase of body weight, eKt/V decreased and Kt increased. Of patients with a body weight >80 kg, 1.4%, mostly men, reached the target Kt but not prescribed eKt/V. Conclusions. The impact of monitoring the dose with Kt instead of Kt/V is that identifies 25.8% of patients who did not reach the minimum Kt while achieving Kt/V. The main impediments
to achieving an adequate dialysis dose were catheter use, female sex, advanced age, greater body weight, shorter dialysis time and lower Qb
Importance of a deficiency in S-adenosyl-L-methionine synthesis in the pathogenesis of liver injury
One of the features of liver cirrhosis is an abnormal metabolism of methionine--a characteristic that was described more than a half a century ago. Thus, after an oral load of methionine, the rate of clearance of this amino acid from the blood is markedly impaired in cirrhotic patients compared with that in control subjects. Almost 15 y ago we observed that the failure to metabolize methionine in cirrhosis was due to an abnormally low activity of the enzyme methionine adenosyltransferase (EC 2.5.1.6). This enzyme converts methionine, in the presence of ATP, to S-adenosyl-L-methionine (SAMe), the main biological methyl donor. Since then, it has been suspected that a deficiency in hepatic SAMe may contribute to the pathogenesis of the liver in cirrhosis. The studies reviewed here are consistent with this hypothesis
Reference Scenarios and Key Performance Indicators for 5G Ultra-dense Networks
The so-called 5G will revolutionize the way we live, and work. In order to demonstrate the profound changes, we can expect to experience within the next 5 to 10 years, we present use cases for the planned research within the TeamUp5G project. Some use cases are strongly linked to the network layer and aim at developing solutions capable of optimizing the main promising benefits of 5G: extremely low latency and extremely high bandwidth (e.g., handle video streams, traffic congestion, user profiles), in the most efficient way possible. Other use cases focus on commercial applications that make use of middleware applications to enhance their performance. The latter fall into two main areas: real-time virtual reality and live video streaming, which are extremely demanding in terms of latency and bandwidth to provide an acceptable QoE/QoS to multiple users. The use cases presented are built assuming that 5G is essential for their support with appropriate QoE/QoS. Key performance indicators and their range of variation are also identified.info:eu-repo/semantics/acceptedVersio
S-Adenosylmethionine revisited: its essential role in the regulation of liver function
Dietary methionine is mainly metabolized in the liver where it is converted into S-adenosylmethionine (AdoMet), the main biologic methyl donor. This reaction is catalyzed by methionine adenosyltransferase I/III (MAT I/III), the product of MAT1A gene, which is exclusively expressed in this organ. It was first observed that serum methionine levels were elevated in experimental models of liver damage and in liver cirrhosis in human beings. Results of further studies showed that this pathological alteration was due to reduced MAT1A gene expression and MAT I/III enzyme inactivation associated with liver injury. Synthesis of AdoMet is essential to all cells in the organism, but it is in the liver where most of the methylation reactions take place. The central role played by AdoMet in cellular function, together with the observation that AdoMet administration reduces liver damage caused by different agents and improves survival of alcohol-dependent patients with cirrhosis, led us to propose that alterations in methionine metabolism could play a role in the onset of liver disease and not just be a consequence of it. In the present work, we review the recent findings that support this hypothesis and highlight the mechanisms behind the hepatoprotective role of AdoMet
Regulation of mammalian liver methionine adenosyltransferase
S-adenosylmethionine (SAM) is an essential metabolite in all cells. SAM is the most important biological methyl group donor and is a precursor in the synthesis of polyamines. Methionine adenosyltransferase (MAT; EC 2.5.1.6) catalyzes the only known SAM biosynthetic reaction from methionine and ATP. In mammalian tissues, three different forms of MAT (MAT I, MAT III and MAT II) have been identified that are the product of two different genes (MAT1A and MAT2A). Although MAT2A is expressed in all mammalian tissues, the expression of MAT1A is primarily restricted to adult liver. In mammals, up to 85% of all methylation reactions and as much as 48% of methionine metabolism occurs in the liver, which indicates the important role of this organ in the regulation of blood methionine. Recent evidence indicates that not only is SAM the main biological methyl group donor and an intermediate metabolite in methionine catabolism, but it is also an intracellular control switch that regulates essential hepatic functions such as liver regeneration and differentiation as well as the sensitivity of this organ to injury. Therefore, knowledge of factors that regulate the activity of MAT I/III, the specific liver enzyme, is essential to understand how cellular SAM levels are controlled
Histological and ultrastructural comparison of cauterization and thrombosis stroke models in immune-deficient mice
Background: Stroke models are essential tools in experimental stroke. Although several models of stroke have
been developed in a variety of animals, with the development of transgenic mice there is the need to develop a
reliable and reproducible stroke model in mice, which mimics as close as possible human stroke.
Methods: BALB/Ca-RAG2-/-gc-/- mice were subjected to cauterization or thrombosis stroke model and sacrificed at
different time points (48hr, 1wk, 2wk and 4wk) after stroke. Mice received BrdU to estimate activation of cell
proliferation in the SVZ. Brains were processed for immunohistochemical and EM.
Results: In both stroke models, after inflammation the same glial scar formation process and damage evolution
takes place. After stroke, necrotic tissue is progressively removed, and healthy tissue is preserved from injury
through the glial scar formation. Cauterization stroke model produced unspecific damage, was less efficient and
the infarct was less homogeneous compared to thrombosis infarct. Finally, thrombosis stroke model produces
activation of SVZ proliferation.
Conclusions: Our results provide an exhaustive analysis of the histopathological changes (inflammation, necrosis,
tissue remodeling, scarring...) that occur after stroke in the ischemic boundary zone, which are of key importance
for the final stroke outcome. This analysis would allow evaluating how different therapies would affect wound and
regeneration. Moreover, this stroke model in RAG 2-/- gC -/- allows cell transplant from different species, even
human, to be analyzed
Gender differences in attentional bias after owning a virtual avatar with increased weight
Introduction: Eating Disorder (ED) patients selectively attend to appearance cues in preference to other information, in a phenomenon known as Attentional Bias (AB). The latest VR Head Mounted Displays (HMD) offer the chance to include Eye-Tracking (ET) devices, and thus provide more objective measures of body-related attention. This study aims to combine VR and ET technologies and use a VR-based embodiment technique while measuring real-time attention patterns. Specifically, we assess gender differences in eye-gaze behaviors towards specific weight-related or non-weight-related body parts when participants own a virtual avatar with different body sizes. Method: Thirty-five college students (25 women and 10 men) were exposed to an immersive virtual environment in which they were embodied in three avatars with different body sizes: first, one with the same body size as the participant; second, one larger than the participant; and finally, repetition of the avatar with the same body size as the participant. To analyze the gaze data Weight-related Areas of Interest (WAOIs) and Non-Weight-related Areas of Interest (NW-AOIs) were defined. Fixation points and complete fixation time on each AOI were recorded at the three different assessment times. Raw data from the Pupil Labs eye tracking add-on for the HTC-Vive headset were subsequently transformed into percentages for further analysis. Results: Mixed between (Gender)-within (Time) analyses of variance showednon-statistically significant interaction between gender and time (p>.05) and a non-statistically significant difference in fixation points and complete fixation times (p>.05), over the three assessment times. However, a statistically significant gender difference was found in fixation points (F (1.33) =10,030, p= .003, η2 = 0.233) and complete fixation time (F (1.33) =13,017, p= .001, η2 = 0.28. Overall, women reported significantly higher levels of fixation points and complete fixation times in W-AOIs than men. Women showed an increasing gaze pattern towards W-AOIs at the three different assessment times, while men showed an opposite gaze pattern towards NW-AOIs at the three different times. Interestingly, the greatest differences between men and women were found at the third assessment, when they once again owned an avatar with the same body size as themselves. Conclusion: This study provides useful information about gender differences in gaze pattern behaviors while participants owned a virtual avatar with different body sizes. To our knowledge, this is the first study to compare gaze pattern behaviors between women and men using VR-based embodiment techniques and ET attentional bias assessment. The use of these two technologies opens a promising new area in the assessment or treatment of Eating Disorders and body image disturbances
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