Effect of Austenite Deformation on the Microstructure Evolution and Grain Refinement Under Accelerated Cooling Conditions

Although there has been much research regarding the effect of austenite deformation on accelerated cooled microstructures in microalloyed steels, there is still a lack of accurate data on boundary densities and effective grain sizes. Previous results observed from optical micrographs are not accurate enough, because, for displacive transformation products, a substantial part of the boundaries have disorientation angles below 15 deg. Therefore, in this research, a niobium microalloyed steel was used and electron backscattering diffraction mappings were performed on all of the transformed microstructures to obtain accurate results on boundary densities and grain refinement. It was found that with strain rising from 0 to 0.5, a transition from bainitic ferrite to acicular ferrite occurs and the effective grain size reduces from 5.7 to 3.1 μm. When further increasing strain from 0.5 to 0.7, dynamic recrystallization was triggered and postdynamic softening occurred during the accelerated cooling, leading to an inhomogeneous and coarse transformed microstructure. In the entire strain range, the density changes of boundaries with different disorientation angles are distinct, due to different boundary formation mechanisms. Finally, the controversial influence of austenite deformation on effective grain size of low-temperature transformation products was argued to be related to the differences in transformation conditions and final microstructures

Atmospheric Degradation of CH₂C(CH₃)C(O)OCH₃ Initiated by OH Radicals: Mechanistic Study and Quantification of CH₃C(O)C(O)OCH₃ in NO_<i>x</i> Free Air

The product distribution of the gas-phase reaction of OH radicals with methyl methacrylate (CH₂C­(CH₃)­C­(O)­OCH₃, MMA) in the absence of NO_<i>x</i> was studied at 298 K and atmospheric pressure of air. The experiments were performed in a Teflon chamber using solid-phase microextraction (SPME) with GC–MS and GC–FID for product identification and quantification, respectively. In the absence of NO<i>_x</i>, methyl pyruvate (CH₃C­(O)­C­(O)­OCH₃) was identified with a yield of 76 ± 13% in accordance with the decomposition of the 1,2-hydroxyalkoxy radicals formed. In addition, a detailed quantum chemical study of the degradation of MMA was performed by density functional theory (DFT) methods using the MPWB1K functional. This calculation suggests that formation of methyl pyruvate, from C1–C2 scission of 1,2-hydroxyalkoxy radical, is kinetically and thermodynamically the most favorable reaction path taking into account the electronic properties of reaction intermediates and transition states. The difference observed on the degradation mechanism of MMA in the presence and absence of NO<i>_x</i> was explained in terms of the associated thermochemistry. Furthermore, this study propose that reaction between peroxy radical (RO₂^•) and hydroxyl radical (OH) became relevant at NO<i>_x</i>-free environments. This statement is in agreement with recent studies concerning small peroxy radicals such as CH₃OO^•

Selective and eco-friendly procedures for the synthesis of benzimidazole derivatives. The role of the Er(OTf)3 catalyst in the reaction selectivity

An improved and greener protocol for the synthesis of benzimidazole derivatives, starting from o-phenylenediamine, with different aldehydes is reported. Double-condensation products were selectively obtained when Er(OTf)3 was used as the catalyst in the presence of electron-rich aldehydes. Conversely, the formation of mono-condensation products was the preferred path in absence of this catalyst. One of the major advantages of these reactions was the formation of a single product, avoiding extensive isolation and purification of products, which is frequently associated with these reactions.Theoretical calculations helped to understand the different reactivity established for these reactions. Thus, we found that the charge density on the oxygen of the carbonyl group has a significant impact on the reaction pathway. For instance, electron-rich aldehydes better coordinate to the catalyst, which favours the addition of the amine group to the carbonyl group, therefore facilitating the formation of double-condensation products.Reactions with aliphatic or aromatic aldehydes were possible, without using organic solvents and in a one-pot procedure with short reaction time (2–5 min), affording single products in excellent yields (75–99%). This convenient and eco-friendly methodology offers numerous benefits with respect to other protocols reported for similar compounds

New live attenuated tuberculosis vaccine MTBVAC induces trained immunity and confers protection against experimental lethal pneumonia

Among infectious diseases, tuberculosis is the leading cause of death worldwide, and represents a serious threat, especially in developing countries. The protective effects of Bacillus Calmette-Guerin (BCG), the current vaccine against tuberculosis, have been related not only to specific induction of T-cell immunity, but also with the long-term epigenetic and metabolic reprogramming of the cells from the innate immune system through a process termed trained immunity. Here we show that MTBVAC, a live attenuated strain of Mycobacterium tuberculosis, safe and immunogenic against tuberculosis antigens in adults and newborns, is also able to generate trained immunity through the induction of glycolysis and glutaminolysis and the accumulation of histone methylation marks at the promoters of proinflammatory genes, facilitating an enhanced response after secondary challenge with non-related bacterial stimuli. Importantly, these findings in human primary myeloid cells are complemented by a strong MTBVAC-induced heterologous protection against a lethal challenge with Streptococcus pneumoniae in an experimental murine model of pneumonia.M.G.N. was supported by an ERC Advanced grant (#833247) and by a Spinoza Grant of the Netherlands Organization for Scientific Research (https://erc.europa.eu/). UNIZAR Team was supported by Ministry of Science and Universities Grant RTI2018-097625-B-100 (http://www.ciencia.gob.es/portal/site/MICINN/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.S

. 24 (1990) abril-septiembre. Historias. Revista de la Dirección de Estudios Históricos

- Una revista, sesenta años después. Los Annales por María Teresa Solana. - Para una historia de la lectura Henri-Jean Martin. - Entre el soliloquio y el diálogo por Emilio Uranga. - San Rafael: Un pueblo y una empresa. Imágenes de su historia en el proceso de trabajo, 1890-1940 por Laura Espejel López. - La historiografía mexicana y lo contemporáneo por Hira de Gortari Rabiela. - Las apariciones de Cihuacóatl por Rodrigo Martínez. - La urbanización moderna del pueblo de Tiquicheo a fines de la época colonial por Marta Teran. - Raíz colonial de la tradición otomiana en la región. Guanajuato-Querétaro por Ana Maria Crespo y Beatriz Cervantes J. - Apoyo y antagonismo en torno al establecimiento del consulado de Veracruz por Matilde Souto Mantecon. - Comercio y Estado en el México colonial e independiente por Inés Herrera y Armando Alvarado. - La visión de los salvados. Los retablos de la revolución y la guerra cristera por Patricia Arias y Jorge Durand. - Una ventana a la ciudad. Bibliografía de orientación en la Puebla de los Angeles, siglos XIX y XX por Leticia Gamboa Ojeda y Carlos Contreras Cruz. - De la tradición a su leyenda por Antonio Saborit. - Ocharte, sucesor de Juan Pablos por Emma Rivas. - Asuntos de familia por Guillermo Turner. - Imágenes de la imagen por Julia Tuñón. – Crestomanía por José Mariano Leyva

An international perspective on hospitalized patients with viral community-acquired pneumonia

Background: Who should be tested for viruses in patients with community acquired pneumonia (CAP), prevalence and risk factors for viral CAP are still debated. We evaluated the frequency of viral testing, virus prevalence, risk factors and treatment coverage with oseltamivir in patients admitted for CAP. Methods: Secondary analysis of GLIMP, an international, multicenter, point-prevalence study of hospitalized adults with CAP. Testing frequency, prevalence of viral CAP and treatment with oseltamivir were assessed among patients who underwent a viral swab. Univariate and multivariate analysis was used to evaluate risk factors. Results: 553 (14.9%) patients with CAP underwent nasal swab. Viral CAP was diagnosed in 157 (28.4%) patients. Influenza virus was isolated in 80.9% of cases. Testing frequency and viral CAP prevalence were inhomogeneous across the participating centers. Obesity (OR 1.59, 95%CI: 1.01-2.48; p = 0.043) and need for invasive mechanical ventilation (OR 1.62, 95%CI: 1.02-2.56; p = 0.040) were independently associated with viral CAP. Prevalence of empirical treatment with oseltamivir was 5.1%. Conclusion: In an international scenario, testing frequency for viruses in CAP is very low. The most common cause of viral CAP is Influenza virus. Obesity and need for invasive ventilation represent independent risk factors for viral CAP. Adherence to recommendations for treatment with oseltamivir is poor