RÉSUMÉ
Homochirality, the phenomenon by which one of two virtually identical (non-superimposable mirror images) compounds is favored over the other in the chemistry of life, has been regarded as a requisite for the emergence of all living things on earth. Spontaneous mirror symmetry breaking has been proposed to produce the imbalance. Under this framework, Frank presented, in his foundational article "On spontaneous asymmetric synthesis", a simple chemical reaction network that displays spontaneous symmetry breaking for a specific set of reaction rates. Research has since focused on finding more complex and plausible models, each one with its advantages and disadvantages. Nevertheless, finding reaction rate values that make a model exhibit spontaneous symmetry breaking is a complex task, even for specially crafted models. LInear STability ANALysis of CHEmical Mechanism, Listanalchem, is a method and software for the search for appropriate reaction rates. It includes four different algorithms inspired by the analysis of Frank's network. Two classical algorithms are also included in Listanalchem: the Trace-Determinant plane and the Stoichiometric Network Analysis by Bruce Clarke. Listanalchem reads a chemical reaction network from plain text and runs one or more of the available algorithms according to the user selection. Listanalchem is tested and verified by studying classical, modified, and recent models proposed to explain the origin of biological homochirality.â¢Listanalchem allows a fast and reliable search for instability behavior in chemical mechanisms that pretend to explain spontaneous mirror symmetry breaking.â¢Listanalchem contains several model examples, including the most cited in the related literature.â¢Listanalchem is a tool that tests models that pretend to explain the origin of biological homochirality, helps find errors, and aids in designing new models.
RÉSUMÉ
Antiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized by arterial, venous, or small vessel thrombosis and recurrent early pregnancy loss, fetal loss, or pregnancy morbidity in the context of persistent antiphospholipid antibodies. Characterized by the development of multiple thrombotic manifestations, simultaneously or within a short period of time; being portal vein thrombosis (DVT) a rare and serious clinical manifestation and a predictor of poor prognosis.The case of an elderly patient with abdominal pain and portal vein thrombosis associated with APS with antithrombotic treatment and analgesics of favorable evolution is presented.
El síndrome antifosfolípido (SAF) es un trastorno sistémico autoinmunitario caracterizado por trombosis arterial, venosa o de vasos pequeños y/o pérdida temprana recurrente del embarazo, pérdida fetal o morbilidad del embarazo en el contexto de antifosfolípidos persistentes persistentes. Caracterizada por el desarrollo de múltiples manifestaciones trombóticas, de manera simultánea o dentro de un corto período de tiempo; siendo la trombosis de la vena porta (TVP) una manifestación clínica rara, grave y un predictor de mal pronóstico.Se presenta el caso de un paciente de edad avanzada,con dolor abdominal y portadora de trombosis venosa portal asociada a SAF con tratamiento antitrombótico y analgésicos de evolución favorable.
RÉSUMÉ
Abstract CHEMicalKINetics SimuLATOR (Chemkinlator) is a Graphical User Interface for the simulation of reaction mechanisms. The interface allows the user to see and change the parameters of a reaction network within a single window. Chemkinlator comes with built-in support for three types of kinetic simulations: Time Series, which computes the concentration of all species in an interval of time for the defined model; Bifurcation diagrams, which are the result of running several Time Series simulations over gradually different kinetic rate constants; and Flow/Temperature time series, which takes into account the effect of flow in the Continuous-flow well-Stirred Tank Reactor, and the effect of temperature on the rates constants according to the Arrhenius equation. In our research group, Chemkinlator has been the primary tool used to test the predictions made by algorithms that analyze homochirality phenomena. Chemkinlator is written in C++14 and Qt, and it uses the Fortran subroutine DLSODE to solve the differential equations associated with the reaction networks. Chemkinlator is open source software under the Apache 2.0 license and can be downloaded freely from https://gitlab.com/homochirality/chemkinlator.
Resumen CHEMical KINetics SimuLATOR (Chemkinlator) es una interfaz gráfica para realizar simulaciones de mecanismos de reacción. La interfaz le permite al usuario ver y cambiar los parámetros de una red de reacciones en una única ventana. Chemkinlator puede realizar tres tipos de simulaciones cinéticas: Time Series, calcula la concentración de cada especie en un intervalo de tiempo del modelo estudiado; Bifurcation, es el resultado de ejecutar varias veces las simulaciones del modo Time Series, cambiando gradualmente diferentes constantes de velocidad; y Flow/ Temperature es una serie de tiempo en la que se tiene en cuenta el efecto del flujo considerando un Reactor de Flujo Continuo bien Agitado y el efecto de la temperatura sobre las constantes de velocidad según la ecuación de Arrhenius. En nuestro grupo de investigación, Chemkinlator ha sido la herramienta principal para verificar las predicciones hechas por los algoritmos que analizan el fenómeno de homochiralidad. Chemkinlator está escrito en C++14 y Qt, y usa la subrutina de Fortran DLSODE para resolver las ecuaciones diferenciales relacionadas con los mecanismos de reacción. Chemkinlator es software de código abierto bajo la licencia Apache 2.0 y se puede descargar libremente de https://gitlab.com/homochirality/chemkinlator.
Resumo O CHEMical KINetics SimuLATOR (Chemkinlator) é uma interface gráfica para realizar simulações de mecanismos de reação. A interface permite ao usuário visualizar e alterar os parâmetros de uma rede de reação em uma única janela. O Chemkinlator pode realizar três tipos de simulações cinéticas: Time Series, calcula a concentração de cada espécie em um intervalo de tempo do modelo estudado; Bifurcation, é o resultado de executar várias vezes as simulações do modo Time Series, modificando gradualmente diferentes constantes de velocidade; e Flow/Temperature é uma serie de tempo que se considera o efeito do fluxo considerando um Reator de Fluxo Continuo bem Agitado e o efeito da temperatura sobre as constantes de velocidade pela equação de Arrhenius. No nosso grupo de investigação, o Chemkinlator tem sido a principal ferramenta para verificar as predições realizadas pelos algoritmos que analisam o fenómeno de homoquiralidade. O Chemkinlator está escrito em C++14 e Qt, e usa a sub-rotina de Fortran DLSODE para resolver as equações diferenciais relacionadas com os mecanismos de reação. O Chemkinlator é um software de código aberto baixo a licença Apache 2.0 e pode ser descarregado livremente em https://gitlab.com/homochirality/chemkinlator.
RÉSUMÉ
The goal of our research is the development of algorithmic tools for the analysis of chemical reaction networks proposed as models of biological homochirality. We focus on two algorithmic problems: detecting whether or not a chemical mechanism admits mirror symmetry-breaking; and, given one of those networks as input, sampling the set of racemic steady states that can produce mirror symmetry-breaking. Algorithmic solutions to those two problems will allow us to compute the parameter values for the emergence of homochirality. We found a mathematical criterion for the occurrence of mirror symmetry-breaking. This criterion allows us to compute semialgebraic definitions of the sets of racemic steady states that produce homochirality. Although those semialgebraic definitions can be processed algorithmically, the algorithmic analysis of them becomes unfeasible in most cases, given the nonlinear character of those definitions. We use Clarke's system of convex coordinates to linearize, as much as possible, those semialgebraic definitions. As a result of this work, we get an efficient algorithm that solves both algorithmic problems for networks containing only one enantiomeric pair and a heuristic algorithm that can be used in the general case, with two or more enantiomeric pairs.