Exothermic synthesis of ceramic materials based on barium and strontium aluminosilicates

Ceramic materials were synthesized in the RO(R=Ba, Sr)–Al2O3–SiO2 system using exothermic synthesis from solutions containing barium and strontium nitrates, silica and organic reducing agents (glycine and carbamide). It was shown that only the use of a mixture of glycine and carbamide as well as the addition of ammonium nitrate allows carrying out a complete exothermic synthesis with the formation of an X-ray amorphous product with a small fraction of the crystalline phase. It was established that monophase materials based on barium and strontium aluminosilicates (BaAl2Si2O8 and SrAl2Si2O8) are formed when the obtained X-ray amorphous product is heat-treated at the temperatures above 10000C. Ceramics from synthesized materials sintered at 15500C has a high refractoriness, open porosity of 0–1.0%, compressive strength of 115–120 MPa; dielectric constant of 3.25–6.0 (at the frequency of 1 MHz) and the loss tangent of (1.5–5.2)10–3. The results shows that the exothermic synthesis ensures the preparation of nano- and sub-microcrystalline powders in the system RO(R=Ba, Sr)–Al2O3–SiO2. Materials based on the obtained aluminosilicates can be used in the manufacture of protective structures for devices operating in the radio frequency band, in radar installations of aviation and rocket technology, in microwave elements, etc.

Insights into an Immunotherapeutic Approach to Combat Multidrug Resistance in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) has emerged as one of the most lethal cancers worldwide because of its high refractoriness and multi-drug resistance to existing chemotherapies, which leads to poor patient survival. Novel pharmacological strategies to tackle HCC are based on oral multi-kinase inhibitors like sorafenib; however, the clinical use of the drug is restricted due to the limited survival rate and significant side effects, suggesting the existence of a primary or/and acquired drug-resistance mechanism. Because of this hurdle, HCC patients are forced through incomplete therapy. Although multiple approaches have been employed in parallel to overcome multidrug resistance (MDR), the results are varying with insignificant outcomes. In the past decade, cancer immunotherapy has emerged as a breakthrough approach and has played a critical role in HCC treatment. The liver is the main immune organ of the lymphatic system. Researchers utilize immunotherapy because immune evasion is considered a major reason for rapid HCC progression. Moreover, the immune response can be augmented and sustained, thus preventing cancer relapse over the post-treatment period. In this review, we provide detailed insights into the immunotherapeutic approaches to combat MDR by focusing on HCC, together with challenges in clinical translation.

Fabricación de crisoles con caolinita de Combita - Boyacá para la caracterización de minerales de oro

La región boyacense cuenta con grandes riquezas minerales y una de ellas es la roca sedimentaria de arcilla caolinitica, con excelentes propiedades para la industria cerámica tradicional. Al realizar pruebas de caracterización a este material se encontró en el análisis propiedades plásticas, de alta refractariedad, bajo punto de fusión, resistencia a los choques térmicos y resistencia a la rotura. A partir de estos resultados se crearon crisoles resistentes a altas temperaturas, por diferentes tipos de fabricación, obteniéndose crisoles aptos para utilizarlos en ensayos de fusión a temperaturas de 1200°C. The Boyacá region has great mineral wealth and one of them is the sedimentary rock of kaolinitic clay, with excellent properties for the traditional ceramic industry. When performing characterization tests on this material, its plastic properties, high refractoriness, low melting point, resistance to thermal shocks and resistance to breakage were defined. These properties are due to its kaolinitic composition, aluminum silicate and the presence of magnesium in the clay. From these results, crucibles resistant to high temperatures were created by different types of manufacture, suitable for use in fusion tests at temperatures of 1200 ° C, and especially in fire tests for the characterization of gold ore.

Molecular Bases of Drug Resistance in Hepatocellular Carcinoma

The poor outcome of patients with non-surgically removable advanced hepatocellular carcinoma (HCC), the most frequent type of primary liver cancer, is mainly due to the high refractoriness of this aggressive tumor to classical chemotherapy. Novel pharmacological approaches based on the use of inhibitors of tyrosine kinases (TKIs), mainly sorafenib and regorafenib, have provided only a modest prolongation of the overall survival in these HCC patients. The present review is an update of the available information regarding our understanding of the molecular bases of mechanisms of chemoresistance (MOC) with a significant impact on the response of HCC to existing pharmacological tools, which include classical chemotherapeutic agents, TKIs and novel immune-sensitizing strategies. Many of the more than one hundred genes involved in seven MOC have been identified as potential biomarkers to predict the failure of treatment, as well as druggable targets to develop novel strategies aimed at increasing the sensitivity of HCC to pharmacological treatments.

Neurosurgical Treatment for Drug Addiction: Systematic Review

Substance-related disorders are psychiatric conditions that have a worldwide impact. Their multifactorial cycle has been treated pharmacologically and with therapeutic support. However, high refractoriness rates and difficulty to control relapses are among the pitfalls associated with these disorders. Thus, recent studies have shown that deep brain stimulation (DBS) is a promising treatment, with a direct intervention in the neurocircuitry of addiction. The results of the present systematic review of the use of DBS for the treatment of drug addiction show that this surgical procedure can reduce the desire for the drug, and, in some cases, establish abstinence, improve psychiatric symptoms related to mood and quality of life, and reintroduce the patient into the social and family environments. Nevertheless, this approach is still limited to the academic realm, based mainly on case reports, with ethics and therapeutic protocols still to be defined. Further in-depth scientific investigations are required to recommend its clinical application.

Boron Diffusion in Steel 20

As is known, boriding is carried out to increase the wear resistance and corrosion resistance of iron-carbon alloys. Along with high hardness, borides, unfortunately, have very high fragility and high refractoriness. An effective way to counter the fragility of boride layers is to form a composite structure consisting of inclusions of solid borides in a more plastic matrix. Such coatings can be obtained by volumetric heating in a muffle furnace using a boron paste that besides a mixture of iron and boron powders contained ammonium hydroxide and activated carbon with or without liquid glass. Boriding of a surface is carried out at high temperatures =1000 °С for 5 minutes. It is experimentally found that the microhardness of the surface layer increased by about 30% compared with the microhardness of the substrate, and that the thickness of the boride layer depends on the presence of liquid glass in the coating. It has been established that specially calculated proportions of ammonia, liquid glass, and charcoal contribute to the formation of an extensive diffusion zone of iron borides, the formation of which is due to the anomalously high diffusion mass transfer of boron into the matrix.

Influence of Fly Ash Addition in the Raw Mixture on Synthesis and Properties of Forsterite

The aim of this article is to characterize the synthesis and properties of forsterite ceramics in dependence on different amount of fly ash in the raw material mixture. Forsterite ceramics is not currently produced in the Czech Republic. Forsterite is used in industry for its high refractoriness and for its coefficient of linear thermal expansion which is close to metals. The primary objective is to synthesize forsterite via solid state reaction using different amounts of fly ash in the raw material mixture. Fly ash is a secondary energy product from coal combustion in power plants. Therefore, it is inexpensive, and its recycling is important for the environment and sustainable development. Slovakia offers the import of talc, magnesite and its products. The article assessed the influence of different amounts of fly ash in the raw material mixture on the synthesis and properties of forsterite in terms of mineralogy, physico-mechanical properties of fired body and refractoriness.

Diagnostic Issues in Early-Onset Obsessive-Compulsive Disorder and their Treatment Implications

Background: The lifespan approach and recent shift in the conceptualization of Obsessive- Compulsive Disorder (OCD) promoted by the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition (DSM5) along with novel insights into the pathogenesis of this heterogeneous disorder are driving the development of new outcome measures and new treatments for a disease that, on the other hand, is characterized by high rates of refractoriness. Objective and Methods: The aim of this review is to provide a discussion of the translational evidence about Early Onset OCD (EO) in compliance with a neurodevelopmental and RdoC perspective. Results and Conclusion: O might be considered the neurodevelopmental subtype of OCD. Indeed there is evidence that different clusters of symptoms and dimensions at an early stage predict different trajectories in phenotype and that distinct neurocircuit pathways underpin the progression of the disorder. Despite the development of high refractoriness in the course of the disorder, evidence suggests that EO may be particularly treatment responsive in the early stages, thus showing the need for early recognition and additional recovery oriented studies in this subgroup. : Consistent with the neurodevelopmental perspective, immunity and glutamate neurotransmission are emerging as novel pathways for parsing out the neurobiology of OCD, the EO form, in particular, supporting the implementation of new multisystemic models of the OCD phenotype. Brain connectivity patterns, immune and microbiome profiles are standing out as promising areas for biomarkers with the potential for targeted personalized therapies in EO.

Effect of Aluminum Hydroxide Addition on Properties of Fired Refractory Clay Brick

The pottery of Ratchaburi is very famous especially dragon jar which was fired by using dragon kiln. The kiln was made of unfired clay bricks, which its properties including high refractoriness, low thermal shrinkage and durable are desired. Aluminum hydroxide is an interesting material for improving brick’s properties, providing high active alumina (gamma-alumina) content after decomposition, high melting point and also reasonable cost. The study evaluated the effect of an additive, Al (OH)3, on the fried properties of refractory clay brick. In this study, four difference proportions of Al (OH)3 to clay , including 0:100, 25:75, 49:51 and 76:24 were studied. The specimens of 5x5x5 cm3 were formed by hand molding, then were fired at 1200, 1300 and 1400°C. The properties including refractoriness, volume shrinkage, strength, bulk density, water absorption, and slaking time were investigated. The samples of 25:75 ratio of Al (OH)3 to clay, which was fired at 1300°C exhibited high in refractoriness, low volume shrinkage of 5% and relatively low density of 1.69 g/cm3 as compared to those of 1400°C fired. Moreover, the moderate water adsorption of 15 % and useable compressive strength of 12.4 MPa was also observed. As a result, these properties suitable for using in firebox of dragon kiln of Ratchaburi province.

Study on Hydration and Strengthening of High Alumina Cements

Refractory concretes based on aluminous cements are used with great success in areas where high temperatures are required. The mineralogical composition of the high alumina cement is the main factor which gives the physical and mechanical properties at high temperatures of refractory monolithic materials.It is therefore desirable to use high alumina cements based on mineralogical compounds with high refractoriness, because in the end those beneficial properties can be found in the final product - refractory concrete.The aim of this paper is to design, realize and characterize different compositions of high alumina cements based on mineralogical compounds with the highest refractory from the CaO-Al2O3 binary system (i.e. CA, CA2, and CA6), and to find ways of hydraulic activation of calcium hexa aluminate, also.