Influence of the thermal processing and doping on LaMnO3 and La0.8A0.2MnO3 (A = Ca, Sr, Ba) perovskites prepared by auto-combustion for removal of VOCs

Single-phase oxygen stoichiometric LaMnO3 and doped La0.8A0.2MnO3 (A = Ca, Sr, Ba) perovskites have been prepared by a simple one-step auto-combustion method. Cation-deficient LaMnO3+δ and La0.8A0.2MnO3+δ were obtained by calcination of the former samples in air at 750 ◦C. The samples were characterized by X-ray powder diffraction, X-ray photoelectron spectroscopy, temperature-programmed reduction, temperature-programmed oxygen desorption, and N2 ph ysisorption in order to apply them as catalysts in the complete catalytic oxidation of acetone as a model volatile organic compound. The studied phases show the expected orthorhombic and rhombohedral perovskite crystal structures. Catalytic experiments performed with all the samples show measurable activity already at 100 ◦C. At 200 ◦C, doped La0.8A0.2MnO3 samples show higher activity than undoped LaMnO3, with increasing conversion with larger A-cation size. Calcined samples also show higher activity than as-prepared ones making La0.8Ba0.2MnO3+δ the best catalyst at this temperature. All doped samples show >95% acetone conversion at T ≥ 250 ◦C with a weak dependence on the sample processing or A cation doping. The collected evidence confirms that the most important factors for the catalytic activity of these oxides are the Mn4+/Mn3+ molar ratio on the surface of the samples and the cation-deficiency of the bulk perovskite structure. In addition, increasing the symmetry of the bulk crystal structure appears to have an additional favourable effect. Despite the observation of the presence of surface carbonates, we show that it is possible to use the as-prepared samples without further thermal treatment with good results in the oxidation of acetone

Diseño Estructural del Pavimento Flexible de la Prolongación Avenida Dos con Calle 50 del Centro Poblado Alto Trujillo ,El Porvenir, Trujillo, Perú 2021

La presente tesis de investigación tiene como objetivo principal determinar el diseño estructural del pavimento flexible de la Prolongación Avenida Dos con Calle 50 del Centro Poblado Alto Trujillo, esta vía a pesar de tener afluencia vehicular no cuenta con una vía pavimentada, ocasionando a la población posibles problemas de salud, generando tiempos de espera, mala distribución en la transitabilidad vehicular. Para este diseño hemos considerado realizarlo con la metodología AASHTO 93 teniendo presente nuestras normativas peruanas para vías urbanas; por tanto se realizaron los estudios topográficos para obtener el levantamiento de terreno de la zona, así mismo se efectuaron las excavaciones de las calicatas con propósitos de extraer muestras para ser ensayas en el laboratorio y así obtener los resultados de los estudios de mecánica de suelos con fines de pavimentación, obteniendo que el tipo de suelo predominante es de una arena mal graduada con un CBR de 9.8% para la Avenida Dos y 9.9% para la Calle 50; siguiendo con el procedimiento se realizó el estudio de tráfico realizando la recolección de datos en situ a fin de efectuar el proceso de hallar el ESAL de diseño, para la Avenida Dos tenemos un ESAL de 4’178574 y para la Calle 50 de 1’636325 ; teniendo todos nuestros estudios base hemos procedido a determinar los parámetros de diseño teniendo como resultado final nuestra alternativa de espesores de capa para ambas víasThe main objective of this research tesis is to determine the srtuctural designo f the flexible pavement of the extension of Avenue Dos with 50th Street of the Alto Trujillo Populated Center,this road despite having vehicular influx,doesn´t have a paved road,causing the population posible health problems,generating waiting times,por distribution in vehicular traffic. For this design We have considered doing it with the AASHTO 93,methodology,keeping in mind our Peruvian regulations of Urban Roads;Therefore,the topographical studies were carried out to obtain the land survey of the area,as well as the excavations of the test pits with the porpuse of extracting simples to be tested in the laboratory and this obtain the results of the soil mechanics studies with paving purposes,obtaining that the predominant soil type is poorly graded sand with a CBR of 9.8% for Avenue Dos and 9.9% for 50th Street;continuing with the procedure, the traffic study was carried out,collecting data in situ in order to carry out the process of finding the design ESAL,for Avenue Dos We have an ESAL of 4’178574 and for 50th Street of 1’636325;having all our base studies,We have proceeded to determine the design parameters,having as a final result our layer thickness alternative for both routesTesi

Influence of the Thermal Processing and Doping on LaMnO3 and La0.8A0.2MnO3 (A = Ca, Sr, Ba) Perovskites Prepared by Auto-Combustion for Removal of VOCs

Single-phase oxygen stoichiometric LaMnO3 and doped La0.8A0.2MnO3 (A = Ca, Sr, Ba) perovskites have been prepared by a simple one-step auto-combustion method. Cation-deficient LaMnO3+δ and La0.8A0.2MnO3+δ were obtained by calcination of the former samples in air at 750 °C. The samples were characterized by X-ray powder diffraction, X-ray photoelectron spectroscopy, temperature-programmed reduction, temperature-programmed oxygen desorption, and N2 physisorption in order to apply them as catalysts in the complete catalytic oxidation of acetone as a model volatile organic compound. The studied phases show the expected orthorhombic and rhombohedral perovskite crystal structures. Catalytic experiments performed with all the samples show measurable activity already at 100 °C. At 200 °C, doped La0.8A0.2MnO3 samples show higher activity than undoped LaMnO3, with increasing conversion with larger A-cation size. Calcined samples also show higher activity than as-prepared ones making La0.8Ba0.2MnO3+δ the best catalyst at this temperature. All doped samples show >95% acetone conversion at T ≥ 250 °C with a weak dependence on the sample processing or A cation doping. The collected evidence confirms that the most important factors for the catalytic activity of these oxides are the Mn4+/Mn3+ molar ratio on the surface of the samples and the cation-deficiency of the bulk perovskite structure. In addition, increasing the symmetry of the bulk crystal structure appears to have an additional favourable effect. Despite the observation of the presence of surface carbonates, we show that it is possible to use the as-prepared samples without further thermal treatment with good results in the oxidation of acetone

Phase II Trial of Palbociclib in Recurrent Retinoblastoma-Positive Anaplastic Oligodendroglioma: A Study from the Spanish Group for Research in Neuro-Oncology (GEINO)

[Background]: The cell cycle checkpoint G1/S, dependent on cyclin-dependent kinase (CDK) 4 amplification/overexpression and retinoblastoma phosphorylation, is altered in most anaplastic oligodendrogliomas (AOs). [Objective]: We aimed to evaluate the efficacy of palbociclib, an oral inhibitor of CDK4/6 with proven efficacy in breast cancer, in patients with AO. The primary endpoint was progression-free survival at 6 months. [Patients and Methods]: We conducted a multicenter, open-label, phase II trial evaluating the efficacy and safety of palbociclib in patients with AO who progressed on radiotherapy and chemotherapy with histologically and molecularly confirmed grade 3 oligodendroglioma and conserved retinoblastoma protein (pRb) expression by immunohistochemistry. Patients were treated with palbociclib (125 mg/day) for 3/1 weeks on/off. [Results]: Overall, 34 patients were enrolled across 10 hospitals in the Spanish Group of Neuro-Oncology (GEINO) study. The study was stopped early owing to the lack of efficacy, with 74% of evaluable patients progressing within 6 months, which was insufficient to consider palbociclib as an active drug in this population. Within the median follow-up of 12 months, the median progression-free survival was 2.8 months [95% confidence interval (CI) 2.6–3.1] and the median overall survival was 32.1 months (95% CI 5.1–59.2). There were no partial or complete responses; only 13 patients (38%) achieved stable disease as the best response. Palbociclib was well tolerated, with neutropenia (grade 3 or higher: 58.8%) and thrombocytopenia (grade 3 or higher: 14.7%) as the most common adverse events (AEs). Both AEs had no significant impact. [Conclusion]: Despite the good tolerance, palbociclib monotherapy did not show favorable efficacy against recurrent AO.Palbociclib was provided by Pfizer under a cooperative research agreement with the Spanish Group for Research in NeuroOncology (GEINO). Funding research was supported by Pfzer under the Investigator-Initiated Research Award, number WI174842