Preparación y ensayos de morteros de cal de nueva factura para su empleo en restauración del patrimonio

Dada la similitud de propiedades, a la hora de la restauración de obras del Patrimonio Edificado, es sensata la utilización del mortero de cal más afín al de la propia construcción. La pérdida de conocimientos, debida al desuso, del mortero de cal ha impulsado este trabajo, en el que se analizan las modificaciones de composición durante el fraguado y la evolución de propiedades fisicoquímicas y mecánicas en morteros de nueva factura preparados con cal aérea. Se ha analizado en cada caso la influencia de diversos factores, como son el tiempo de curado, la dosificación conglomerante-árido, las características del árido y la porosidad del mortero. En general, los áridos calizos ofrecieron mejores resultados que los silíceos, aunque el comportamiento es fuertemente dependiente de su granulometría. La porosidad es mayor a mayores cantidades de conglomerante, lo que, en el caso de la cal, permite su mejor carbonatación al favorecer la difusión del CO2 en el mortero. La dosificación más adecuada de las testadas fue la 1:1, y se realizaron ensayos de durabilidad con esta dosificación para morteros de cal aérea e hidráulica: estos últimos resultaron ser mejores materiales para soportar alteraciones climáticas y por contaminación por SO2​

Dolomitic lime: thermal decomposition of nesquehonite

Nesquehonite (MgCO3·3H2O) (N) can be obtained from a dolomitic quicklime paste in a CO2-rich atmosphere. Thermal decomposition of this synthetic nesquehonite has been studied by TG-DTA analysis. It is very similar to the hydromagnesite (HY) thermal decomposition, as it show similarities in the decarbonations at 440 and 550 °C, and an exothermic phenomenon at 510 °C. It has been reported in the literature that some intermediate in N→HY transformation occur, but this process cannot be directly detected during the heating. Samples were heated at 115, 230, 280, 370, 460, 520, 600, 800 and 1000 °C and XRD and FT-IR were used in order to determine the structural changes in nesquehonite and the intermediate phases formed. Results show that nesquehonite transforms at lower temperatures (115 °C) into a stable amorphous magnesium carbonate with chemical composition very close to that of HY. Thermal decomposition of nesquehonite, during a gradual temperature increase, proceeds via the formation of this compound. At higher temperatures (460 °C/short heating times), nesquehonite transforms into HY. The occurrence of an exothermic peak at 510 °C has been also discussed

Dolomitic limes: evolution of the slaking process under different conditions

Dolomitic lime-based pastes were prepared in order to study the evolution of the compounds during the slaking process. Thermal studies as well as X-ray diffraction and FT-IR spectroscopy were used to confirm the formed compounds. The rate of the hydration of calcium and magnesium oxides has been determined under different conditions: atmospheric conditions, CO2-rich and enclosed environment without CO2. Also the lime powder evolution without water added was studied. Whereas CaO hydrates at a higher rate, MgO is very dependent by its particle size distribution and stirring. The paper also focuses on the carbonation process. Given that carbonation is the most usual hardening process in lime pastes, its knowledge is necessary to understand the mechanical behavior of these pastes. In an excess of water, calcium hydroxide carbonates giving calcite if exposed to CO2. In lime powder, another mechanism has been established through vaterite formation. Magnesium hydroxide does not carbonate under normal conditions. In a CO2 atmosphere nesquehonite (MgCO3·3H2O) has been checked found as a result of carbonation

Adding genetic scores to risk models in colorectal cancer

Colorectal cancer (CRC) represents the second most common cancer worldwide and the third leading cause of cancer death. Most CRCs arise from premalignant colorectal lesions (mainly adenomas) that require years to develop an invasive disease..

Patient benefit–risk in arthritis—a rheumatologist’s perspective

There is a range of pharmacological options available to the rheumatologist for treating arthritis. Non-selective NSAIDs or Cox-2 selective inhibitors are widely prescribed to reduce inflammation and alleviate pain; however, they must be used with caution in individuals with an increased cardiovascular, renal or gastrointestinal (GI) risk. The potential cardiovascular risks of Cox-2 selective inhibitors came to light over a decade ago. The conflicting nature of the study data reflects some context dependency, but the evidence shows a varying degree of cardiovascular risk with both Cox-2 selective inhibitors and non-selective NSAIDs. This risk appears to be dose dependent, which may have important ramifications for arthritis patients who require long-term treatment with high doses of anti-inflammatory drugs. The renal effects of non-selective NSAIDs have been well characterized. An increased risk of adverse renal events was found with rofecoxib but not celecoxib, suggesting that this is not a class effect of Cox-2 selective inhibitors. Upper GI effects of non-selective NSAID treatment, ranging from abdominal pain to ulceration and bleeding are extensively documented. Concomitant prescription of a proton pump inhibitor can help in the upper GI tract, but probably not in the lower. Evidence suggests that Cox-2 selective inhibitors are better tolerated in the entire GI tract. More evidence is required, and a composite end-point is being evaluated. Appropriate treatment strategies are needed depending on the level of upper and lower GI risk. Rheumatologists must be vigilant in assessing benefit–risk when prescribing a Cox-2 selective inhibitor or non-selective NSAID and should choose appropriate agents for each individual patient

Causally estimating the effect of YouTube's recommender system using counterfactual bots

In recent years, critics of online platforms have raised concerns about the ability of recommendation algorithms to amplify problematic content, with potentially radicalizing consequences. However, attempts to evaluate the effect of recommenders have suffered from a lack of appropriate counterfactuals -- what a user would have viewed in the absence of algorithmic recommendations -- and hence cannot disentangle the effects of the algorithm from a user's intentions. Here we propose a method that we call "counterfactual bots" to causally estimate the role of algorithmic recommendations on the consumption of highly partisan content. By comparing bots that replicate real users' consumption patterns with "counterfactual" bots that follow rule-based trajectories, we show that, on average, relying exclusively on the recommender results in less partisan consumption, where the effect is most pronounced for heavy partisan consumers. Following a similar method, we also show that if partisan consumers switch to moderate content, YouTube's sidebar recommender "forgets" their partisan preference within roughly 30 videos regardless of their prior history, while homepage recommendations shift more gradually towards moderate content. Overall, our findings indicate that, at least on YouTube, individual consumption patterns mostly reflect individual preferences, where algorithmic recommendations play, if anything, a moderating role

Management of Helicobacter Pylori infection and effectiveness rates in daily clinical practice in Spain: 2010–2019

The management and effectiveness of the treatment of Helicobacter pylori infection are heterogeneous worldwide, despite the publication of international consensus conferences and guidelines, which have been widely available for years. The aim of the study was to describe the clinical management and the eradication rates in a region of Southern Europe (Spain). Between 2010 and 2019, we conducted a retrospective analysis of patients with H. pylori infection attended by gastroenterologists in two defined areas of the National Health System in Aragón. We compared the appropriateness of therapies according to guidelines, and described the effectiveness of each treatment. A total of 1644 penicillin non-allergic patients were included. The most prescribed therapy between 2010 and 2013 was the ‘classic’ triple therapy PCA (80%), whereas the ’concomitant’ therapy PCAM was chosen by 90% of the gastroenterologists in 2015. After 2016, the use of the quadruple bismuth-containing therapy in a single capsule (Pylera®) quickly increased, representing almost half of the overall prescriptions in 2019. Throughout the decade, adherence to guidelines was 76.4% and global efficacy was 70.7% (ITT). Triple therapies’ eradication rates were lower than 70% (ITT), whereas eradication rates with quadruple therapies achieved or were over 80% (ITT). In conclusion, despite the use of quadruple therapies and optimized treatments, the effectiveness of H. pylori management in daily clinical practice is far from the target of 90%

Mistakes in the diagnosis and treatment of Helicobacter pylori infection in daily clinical practice

Background: An adequate diagnostic and therapeutic approach to Helicobacter pylori (H. pylori) infection is the cornerstone to avoid overdiagnosis, overuse of health resources, and increase in antibiotic resistances. The aim of the study was to evaluate the most common errors in clinical practice and the associated risk factors. Materials and Methods: This is a retrospective observational study including patients with H. pylori infection and no previous treatment belonging to two defined areas of the National Health System in Spain; some of them were enrolled in the European Registry on H. pylori management (Hp-EuReg). Patients were attended by gastroenterologists between 2010 and 2019. According to current guidelines, we evaluated indications for H. pylori investigation, appropriateness of diagnostic test used in dyspeptic patients and discontinuation of surveillance after treatment. Results: A total of 1730 patients were included, receiving 2260 eradication regimens. H. pylori infection was investigated in 1.7% cases in absence of a formal indication. Oral endoscopy was incorrectly used in 56% of patients with dyspepsia under 55 years without alarm signs, and urea breath test (UBT) was incorrectly used in 22.4% of patients with dyspepsia ≥55 years or red flags. Levofloxacin containing regimens were used as first-line therapy in 7.5% of non-allergic to penicillin patients. After first-line failure, clarithromycin was repeated in 2.6% of the patients who received second-line therapy. Confirmatory test of H. pylori status was absent in 2.5% cases. Men, patients under 55 years, and patients diagnosed by UBT had a higher risk of not undergoing a confirmatory test. Conclusions: Investigation of H. pylori infection by gastroenterologists is rare in absence of a formal indication; however, endoscopy is commonly used for dyspeptic patients <55 years without red flags and non-invasive tests are still used for dyspeptic patients ≥55 years or presenting alarm signs. Men, patients under 55 years, and patients diagnosed by UBT have an increased risk of being lost to follow-up after eradication treatment