Adsorption performance of mesoporous silicas towards a cationic dye. Influence of mesostructure on adsorption capacity

The dye adsorption performance of four mesoporous silicas with different structure and textural properties, MCM-41, MCM-48, SBA-15 and mesocellular silica foam (MCF), was studied and compared by using toluidine blue O (TBO) as dye model in aqueous solution. These materials were characterized by X-ray diffraction (XRD), small-angle X-ray scattering, nitrogen adsorption-desorption analyses, and transmission electron microscopy (TEM). The effect of some parameters such as adsorbent dosage, contact time, temperature, and pH on the TBO removal in aqueous solution was studied. Results showed that adsorption capacity raised when adsorbent dosage, contact time and pH solution were increased while an increase in temperature decreased the adsorption of TBO. Langmuir, Freundlich and Temkin isotherm models were employed to elucidate the adsorption mechanism while the adsorption rate data were analyzed according to the pseudo-first and second-order kinetic models. Results showed that adsorption of TBO onto MCM-48, SBA-15, and MCF fitted well the Freundlich isotherm model while the kinetic studies showed that adsorption process could be better described by the pseudo-second-order model for all mesoporous silicas. Finally, some solvents were evaluated to carried out dye desorption from the TBO-loaded mesoporous silicas founding that acetic acid was the most efficient.     

Spectroelectrochemistry of Quantum Dots

Spectroelectrochemistry (SEC) is a set of techniques with many advantages in the study and characterization of materials. Although SEC has not yet been widely used to study quantum dots (QDs), the information extracted from SEC experiments about these nanostructures is very useful. Most of the works that use SEC to study QDs are high‐quality pieces of research. This review intends to show how to perform SEC in an easy way and what information can be obtained using these techniques. Most of the examples shown in this review are related to semiconductor and carbon QDs. After a brief introduction, some optoelectronic properties of QDs and the main SEC techniques are described. The capabilities of SEC for the study of QDs are illustrated with examples extracted from literature. Finally, the needs of SEC to become a user‐friendly technique and its evolution to become more powerful are commented in the last section of the review.     

Short SiC fiber/Ti3SiC2 MAX phase composites: Fabrication and creep evaluation

The compressive creep of silicon carbide fiber reinforced Ti₃SiC₂ MAX phase with both fine and coarse microstructure was investigated in the temperature range of 1000-1300°C. Comparison of only steady-state creep was done to understand the response of fabricated composite materials toward creep deformation. It was demonstrated that the fibers are more effective in reducing the creep rates for the coarse microstructure by an increase in activation energy compared to the variant with a finer microstructure, being partly a result of the enhanced creep rates for the microstructure with larger grain size. Grain boundary sliding along with fiber fracture appears to be the main creep mechanism for most of the tested temperature range. However, there are indications for a changed creep mechanism for the fine microstructure for the lowest testing temperature. Local pores are formed to accommodate differences in strain related to creeping matrix and predominantly elastically deformed fibers during creep. Microstructural analysis was done on the material before and after creep to understand the deformation mechanics.     

Effect of Functionalization Synthesis Type of Amino-MCM-41 Mesoporous Silica Nanoparticles on Its RB5 Adsorption Capacity and Kinetics

Silicon - This study was undertaken to evaluate the adsorption of Reactive Black 5 dye (RB5), in aqueous solution, onto MCM-41 mesoporous silica nanoparticles (MSNs) functionalized with...     

Study of the influence of notch radii and temperature on the probability of failure: A methodology to perform a combined assessment

The fracture assessment of notched components based on cracked components approaches leads to over‐conservative failure predictions. In the research literature, several approaches are proposed to overcome this problem using an apparent fracture toughness, . Nevertheless, most of these approaches are based on deterministic assumptions despite the large and variable scatter exhibited by for different notch radii (ρ) or temperatures (T). This paper proposes a methodology for deriving a probabilistic field including the effect of temperature on the failure of notched components. First, the theory of critical distances is applied to transform each apparent fracture toughness into the equivalent fracture toughness for ρ = 0. Then, the temperature is supposed to act as a scale effect in the Weibull cumulative distribution function of the equivalent fracture toughness, and the corresponding scale effect function is derived. Finally, the applicability of the proposed methodology is illustrated by an example using two ferritic‐pearlitic steels: S275JR and S355J2.     

Rare Titin (TTN) Variants in Diseases Associated with Sudden Cardiac Death

A leading cause of death in western countries is sudden cardiac death, and can be associated with genetic disease. Next-generation sequencing has allowed thorough analysis of genes associated with this entity, including, most recently, titin. We aimed to identify potentially pathogenic genetic variants in titin. A total of 1126 samples were analyzed using a custom sequencing panel including major genes related to sudden cardiac death. Our cohort was divided into three groups: 432 cases from patients with cardiomyopathies, 130 cases from patients with channelopathies, and 564 post-mortem samples from individuals showing anatomical healthy hearts and non-conclusive causes of death after comprehensive autopsy. None of the patients included had definite pathogenic variants in the genes analyzed by our custom cardio-panel. Retrospective analysis comparing the in-house database and available public databases also was performed. We identified 554 rare variants in titin, 282 of which were novel. Seven were previously reported as pathogenic. Of these 554 variants, 493 were missense variants, 233 of which were novel. Of all variants identified, 399 were unique and 155 were identified at least twice. No definite pathogenic variants were identified in any of genes analyzed. We identified rare, mostly novel, titin variants that seem to play a potentially pathogenic role in sudden cardiac death. Additional studies should be performed to clarify the role of these variants in sudden cardiac death.     

Antioxidant and antibacterial activities of a starch film with bioextracts microencapsulated from cactus fruits (Opuntia oligacantha)

Food Science and Biotechnology - The use of unconventional sources is very relevant in the food area. In the present study the development of active films with the addition of bioextract (BE) or...