Nickel-titanium (NiTi) file separation during endodontic treatment is an undesirable event. This phenomenon needs to be understood by knowing the factors influencing fracture in endodontic files. There is a large amount of literature where these factors and their influence have been studied, increasing the knowledge about the mechanisms involved, mainly related to wire technology, file shapes and geometry, operator manipulation, the anatomy of the root canal, and the irrigation and sterilization processes. As many factors are involved, the complexity of the fracture phenomena increases and the isolated correlation of one factor with the file fracture becomes a small part of comprehending the separation phenomena. This thematic review aims to compile important reports from 2014 to 2022 on the factors influencing NiTi file separation. The information obtained was classified into wire technology, file geometry, operational aspects, irrigation and sterilization, and anatomy. For this purpose, the Scopus, Web of Science and ScienceDirect databases were consulted using a search string. Filters were applied to consolidate the final set of relevant papers covering the subject of factors influencing endodontic file separation. It was found that the fracture of NiTi files incorporates different mechanisms that operate simultaneously during the endodontic procedure and strongly affect the instrument performance. The collected information promotes good practices to prevent file separation.

This paper develops and analyzes four energy scenarios for Colombia that consider the El Niño phenomenon and the inclusion of renewable energies in the energy generation matrix for the period 2020–2035. A comparative analysis is presented between the results of the different scenarios proposed. The most relevant finding is the use of the reserve margin as an indicator of system reliability. A scenario which included 7214 MW of large-scale non-conventional renewable energy, 10,000 MW of distributed generation, and 12,240 MW of hydroelectric power was assumed, with a reserve margin of over 50%. Additionally, it was found that for the scenarios in which a generation capacity with non-conventional renewable energies of less than 10,000 MW in 2034 was assumed, the reserve margin of the system in the seasons of the El Niño phenomenon will be less than historical records of the system. Alternatively, it was found that the scenarios in which the inclusion of at least 9600 MW of the electric power generation capacity of non-conventional renewable energies proposed by 2034 offer benefits in the reduction in greenhouse gas (GHG) emissions, which contributes to the achievement of the emission reduction objectives of the Paris Agreement.

The phenomena of climatic variability such as El Niño affect the expansion planning of electricity supply systems with hydroelectric power plants due to the uncertainty presented in the variables of rainfall patterns, temperature, wind, solar radiation changes, among others. The El Niño affects the electricity generation in Colombia, Venezuela and northwestern Brazil due to severe droughts that reduce water flows in rivers and water volume in dams. While in Peru, Paraguay, Bolivia, Uruguay, Argentina and southern Brazil, causes heavy rains that lead to an increase in reservoirs. Recent findings provide sufficient evidence on how climate change modifies the patterns of duration, frequency and intensity of El Niño and therefore will introduce additional uncertainties to the expansion planning of electricity generation systems in countries that uses predominantly hydroelectric power. The vulnerability of electricity supply systems with a significant participation of hydroelectric power plants in Colombia, Brazil, Ecuador, Peru, Panama, Canada, Norway, Costa Rica and New Zealand is associated with fluctuations in the availability of water resources. This document aims to analyze the current plans for the expansion of electric power generation systems by the aforementioned countries in the context of climate change in medium and long term. Additionally, this document provides a detailed analysis of the situation of electricity supply systems in Colombia. Keywords: El Niño phenomenon, Vulnerability, Colombia, Water Resource. Development Planning. JEL Classifications: L94, O20, Q4 DOI: https://doi.org/10.32479/ijeep.9813

Bone wear caused by injury or deterioration due to age leads to the use of autologous and allogeneic implants that are sometimes rejected by the body. Currently, work is being carried out on the development of composites that induce bone repair. In this study, composites with montmorillonite clay (MMT), hydroxyapatite (HAp), and gelatin were prepared. Initially, various ratios of HAp/MMT composites (1:1, 2:1, and 1:2) were examined, and the 2:1 ratio provided a better biological response. Finally, the HAp/MMT/Gel ternary mixtures were prepared using different percentages of gelatin: 10, 50, and 90% and maintaining the 2:1 HAp/MMT ratio. All materials were assayed in a biomineralization proof using simulated biological fluids. In the HAp/MMT/Gel diffraction pattern, the peaks associated with MMT and HAp are preserved at 20 and 32° in 2θ, respectively; the addition of gelatin promotes structural changes. Biocompatibility studies show that there are no morphological changes in the platelets since it does not exceed 5 μm of pseudopodia, which suggests that there is no rejection of the material. On the other hand, the biomineralization study, followed by SEM and FTIR characterization, showed the generation of apatite and demonstrated its potential application in bone tissue regeneration.

The potential for generating electricity with photovoltaic systems is high in Colombia given its geographical position in the tropic. Some departments in Colombia have low electricity coverage and high rates. In the department of Putumayo there is a low coverage rate and high energy costs, while the solar radiation potential is high. Due to the geographical differences of the Putumayo subregions, the radiation potential for electricity generation is unknown. In addition, in this department the energy tariffs are above the national average. The objective of this paper is to determine the effective potential for solar photovoltaic power generation in the Putumayo department with a detailed methodology considering the information of different remote database and meteorological stations and some technical conditions. It was found that the highest effective solar potential occurs in the Amazon region, and the lowest in the Andean region in the Putumayo. On the other hand, when evaluating electricity consumption and tariffs in the regions, it is concluded that consumption can be satisfied with photovoltaic systems by producing self-generating electricity and distributed generation.