Modification of ASTM B107 AZ31 alloy with TiO2 particles using the dip-coating method

Introduction− Magnesium alloys have been known for its bio-compatible characteristics and tissue restoration properties. On the other hand, TiO2 has been found to decrease the corrosion rates of the magnesium alloys.Objective−In this work, the dip-coating technique was used to coat the magnesium alloy with TiO2 particles in order to evalu-ate its corrosion resistance.Methodology−The particles were analyzed by Scanning Elec-tron Microscopy (SEM) and visual inspection. Additionally, hy-drogen evolution tests were performed to understand the effect of adding TiO2 in corrosion rates of Mg-alloys.Results− The results showed the positive effect of TiO2 in the improvement of the ASTM B107 AZ31B Mg alloys corro-sion by an indirect measurement through hydrogen evolution tests. The bare ASTM B107 AZ31B showed a corrosion 29 times faster compared to the coated alloy. The thickness of the coatings obtained using the dip-coating method is thin-ner than 20 nm. Conclusions−TiO2 particles were aggregated on the surface of the ASTM B107 AZ31B alloy with a controlled speed. SEM images have shown the improvement of the coating when the H2O concentration in the sol increased. Another important parameter is the withdrawal speed during the dip-coat process which was found to be better at a speed of 3mm/min. Hydrogen evolution in the acid solution showed that coated ASTM B107 AZ31B has less hydrogen production during the corrosion test. The dip-coating technique can also be used to coat polypropyl-ene discs entirely.Introducción− Las aleaciones de magnesio son conocidas por sus ca-racterísticas biocompatibles y propiedades de restauración de tejidos; por otro lado, se ha encontrado que el TiO2 disminuye las velocidades de corrosión de las aleaciones de magnesio.Objetivo− En este trabajo, la técnica de recubrimiento por inmersión se usó para recubrir una aleación de magnesio con partículas de TiO2 y evaluar su comportamiento a corrosión.Metodología− Las partículas se analizaron por microscopía electrónica de barrido (SEM) e inspección visual. Además, se realizaron pruebas de evolución de hidrógeno para comprender el efecto de la adición de TiO2en la velocidad de corrosión de la aleación de Mg.Resultados− Los resultados mostraron el efecto positivo de TiO2 en la mejora de la corrosión de aleaciones de ASTM B107 AZ31B Mg mediante una medición indirecta a través de pruebas de evolución de hidrógeno. La aleación ASTM B107 AZ31B sin recubrimiento muestra una corro-sión 29 veces más rápida en comparación con la aleación recubierta. El espesor obtenido mediante el método de recubrimiento por inmersión es inferior a 20 nm. Conclusiones− Las partículas de TiO2 se agregaron en la superficie de la aleación ASTM B107 AZ31B con una velocidad controlada. Las imáge-nes SEM mostraron la mejora del recubrimiento cuando aumenta la con-centración de H2O en el sol. Otro parámetro importante es la velocidad de extracción durante el proceso de recubrimiento por inmersión, que resultó ser mejor a una velocidad de 3 mm/min. La evolución del hidró-geno en la solución mostró que la aleación ASTM B107 AZ31B recubierta reportó menos producción de hidrógeno durante la prueba de corrosión. La técnica de recubrimiento por inmersión puede realizarse en polipro-pileno y, finalmente, obtener una superficie completamente recubierta

Workgroup Report: Review of Genomics Data Based on Experience with Mock Submissions—View of the CDER Pharmacology Toxicology Nonclinical Pharmacogenomics Subcommittee

Over the past few years, both the U.S. Food and Drug Administration (FDA) and the pharmaceutical industry have recognized the potential importance of pharmacogenomics and toxicogenomics to drug development. To resolve the uncertainties surrounding the use of microarray technology and the presentation of genomics data for regulatory purposes, several pharmaceutical companies and genomics technology providers have provided the FDA with reports of genomics studies that included supporting toxicology data (e.g., serum chemistry, histopathology). These studies were not associated with any active drug application and were exploratory or hypothesis generating in nature. For training purposes, these reports were reviewed by the Nonclinical Pharmacogenomics Subcommittee consisting of the Center for Drug Evaluation and Research pharmacology and toxicology researchers and reviewers. In this article, we describe some of these submissions and report on our assessment of data content, format, and quality control metrics that were useful for evaluating these nonclinical genomics submissions, specifically in relation to the proposed MIAME/MINTox (minimum information about a microarray experiment/minimum information needed for a toxicology experiment) recommendations. These genomics submissions allowed both researchers and regulators to gain experience in the process of reviewing and analyzing toxicogenomics data. The experience will allow development of recommendations for the submission and review of these data as the state of the science evolves

The mesolimbic system and the loss of higher order network features in schizophrenia when learning without reward

IntroductionSchizophrenia is characterized by a loss of network features between cognition and reward sub-circuits (notably involving the mesolimbic system), and this loss may explain deficits in learning and cognition. Learning in schizophrenia has typically been studied with tasks that include reward related contingencies, but recent theoretical models have argued that a loss of network features should be seen even when learning without reward. We tested this model using a learning paradigm that required participants to learn without reward or feedback. We used a novel method for capturing higher order network features, to demonstrate that the mesolimbic system is heavily implicated in the loss of network features in schizophrenia, even when learning without reward.MethodsfMRI data (Siemens Verio 3T) were acquired in a group of schizophrenia patients and controls (n=78; 46 SCZ, 18 ≤ Age ≤ 50) while participants engaged in associative learning without reward-related contingencies. The task was divided into task-active conditions for encoding (of associations) and cued-retrieval (where the cue was to be used to retrieve the associated memoranda). No feedback was provided during retrieval. From the fMRI time series data, network features were defined as follows: First, for each condition of the task, we estimated 2nd order undirected functional connectivity for each participant (uFC, based on zero lag correlations between all pairs of regions). These conventional 2nd order features represent the task/condition evoked synchronization of activity between pairs of brain regions. Next, in each of the patient and control groups, the statistical relationship between all possible pairs of 2nd order features were computed. These higher order features represent the consistency between all possible pairs of 2nd order features in that group and embed within them the contributions of individual regions to such group structure.ResultsFrom the identified inter-group differences (SCZ ≠ HC) in higher order features, we quantified the respective contributions of individual brain regions. Two principal effects emerged: 1) SCZ were characterized by a massive loss of higher order features during multiple task conditions (encoding and retrieval of associations). 2) Nodes in the mesolimbic system were over-represented in the loss of higher order features in SCZ, and notably so during retrieval.DiscussionOur analytical goals were linked to a recent circuit-based integrative model which argued that synergy between learning and reward circuits is lost in schizophrenia. The model’s notable prediction was that such a loss would be observed even when patients learned without reward. Our results provide substantial support for these predictions where we observed a loss of network features between the brain’s sub-circuits for a) learning (including the hippocampus and prefrontal cortex) and b) reward processing (specifically constituents of the mesolimbic system that included the ventral tegmental area and the nucleus accumbens. Our findings motivate a renewed appraisal of the relationship between reward and cognition in schizophrenia and we discuss their relevance for putative behavioral interventions

Resistance, rebound, and recurrence regrowth patterns in pediatric low-grade glioma treated by MAPK inhibition: A modified Delphi approach to build international consensus-based definitions—International Pediatric Low-Grade Glioma Coalition

Pediatric low-grade glioma (pLGG) is the most common childhood brain tumor group. The natural history, when curative resection is not possible, is one of a chronic disease with periods of tumor stability and episodes of tumor progression. While there is a high overall survival rate, many patients experience significant and potentially lifelong morbidities. The majority of pLGGs have an underlying activation of the RAS/MAPK pathway due to mutational events, leading to the use of molecularly targeted therapies in clinical trials, with recent regulatory approval for the combination of BRAF and MEK inhibition for BRAFV600E mutated pLGG. Despite encouraging activity, tumor regrowth can occur during therapy due to drug resistance, off treatment as tumor recurrence, or as reported in some patients as a rapid rebound growth within 3 months of discontinuing targeted therapy. Definitions of these patterns of regrowth have not been well described in pLGG. For this reason, the International Pediatric Low-Grade Glioma Coalition, a global group of physicians and scientists, formed the Resistance, Rebound, and Recurrence (R3) working group to study resistance, rebound, and recurrence. A modified Delphi approach was undertaken to produce consensus-based definitions and recommendations for regrowth patterns in pLGG with specific reference to targeted therapies

HDO del guaiacol mediante el uso de catalizadores NiMo soportados sobre carbón activado obtenido a partir de la torta de higuerilla

Se prepararon dos carbones activados a partir de la torta de higuerilla; como métodos para su obtención se usaron la activación física y la activación química. Para la activación física se usó una mezcla H2O/CO2 como agente activante, y para la activación química, K2CO3. Las propiedades químicas y texturales de ambos carbones activados fueron caracterizados por isotermas de adsorción-desorción de N2, análisis termogravimétrico (TGA), espectroscopia infrarroja (FT-IR), reducción a temperatura programada (TPR), fluorescencia de rayos X (XRF) y microscopía electrónica de barrido (SEM). Los carbones activados se usaron como soporte en catalizadores NiMo sulfurados, los cuales fueron preparados por impregnación húmeda y reducidos in-situ para la reacción de hidrodesoxigenación del guaiacol (GUA), compuesto modelo de los aceites de pirólisis. La reacción de hidrodesoxigenación (HDO) se realizó en un reactor tipo batch a 5 MPa de H2 y 350 °C. Con el fin de comparar, los catalizadores comerciales también se probaron en reacción.  A pesar de que los catalizadores comerciales mostraron una mayor conversión de GUA, los catalizadores sintetizados exhibieron una mayor actividad y un mayor rendimiento en la producción de compuestos saturados y no oxigenados.Physical and chemical activation methods were used to prepare two different activated carbons (ACs) from castor de-oiled cake. H2O/CO2 mixture was used as the physical activating agent, and for chemical activation potassium carbonate (K2CO3) was used. For both materials, textural and chemical properties were characterized by N2 adsorption–desorption isotherms, thermogravimetric analysis (TGA), Fourier Transform Infrared Spectroscopy (FTIR), thermal programmed reduction (TPR), X-ray fluorescence (XRF), and scanning electron microscopy (SEM). The ACs were used as supports for NiMo sulfide catalysts, which were prepared by wetness impregnation and in-situ sulfided for the hydrodeoxygenation (HDO) of guaiacol (GUA) as a model compound of bio-oil. The HDO reaction was carried out in a typical batch reactor at 5 MPa of H2 and 350 °C. Under the same test conditions, commercial catalysts were also tested in the reaction. Although the commercial catalysts displayed higher GUA conversion, the prepared catalysts showed higher activity and non-oxygenated and saturated products yield