Modeling the effect of soil meso- and macropores topology on the biodegradation of a soluble carbon substrate

Soil structure and interactions between biotic and abiotic processes are increasingly recognized as important for explaining the large uncertainties in the outputs of macroscopic SOM decomposition models. We present a numerical analysis to assess the role of meso- and macropore topology on the biodegradation of a soluble carbon substrate in variably water saturated and pure diffusion conditions . Our analysis was built as a complete factorial design and used a new 3D pore-scale model, LBioS, that couples a diffusion Lattice-Boltzmann model and a compartmental biodegradation model. The scenarios combined contrasted modalities of four factors: meso- and macropore space geometry, water saturation, bacterial distribution and physiology. A global sensitivity analysis of these factors highlighted the role of physical factors in the biodegradation kinetics of our scenarios. Bacteria location explained 28% of the total variance in substrate concentration in all scenarios, while the interactions among location, saturation and geometry explained up to 51% of it

El desarrollo y financiación de la infraestructura en Colombia

El suministro eficiente de los servicios de infraestructura es uno de los aspectos más importantes de las políticas de desarrollo, especialmente en aquellos países que han orientado su crecimiento hacia el exterior, razón por la cual el desarrollo de infraestructura física vial es una parte importante para el crecimiento económico. Y la opción estudiada en éste artículo plantea el modelo del Project Finance como alternativa para la construcción eficiente y desarrollo nacional

INTERNACIONALIZACIÓN DEL CLORO DENSO DE LA EMPRESA CUCUTEÑA COSMOGREEN HACIA ECUADOR

This research paper aims to execute an internationalization plan allowing the export of the product Cloro Denso produced by Cosmogreen, located in the Free Zone of Cúcuta. Based on the analysis and study of the areas of the company, its structure and the portfolio of products offered, taking into account its legislation, the type of Free Zone to which it belongs and the user who identifies the company.Then, examine the process of making the cleaning product, and as described, to study possible markets to obtain a suitable target market and establish the logistic procedure from its production in the country of origin to its final destination in Ecuador. Taking into account the necessary documents for an export and the agents involved in the process, in order to propose internationalization strategies that allow continuous improvement and cover different areas of the company.El presente artículo de investigación pretende ejecutar un plan de internacionalización permitiendo la exportación del producto Cloro Denso producido por Cosmogreen, ubicada en la Zona Franca de Cúcuta. A partir del análisis y estudio de las áreas de la empresa, su estructura y el portafolio de productos ofrecidos, teniendo en cuenta su legislación, el tipo de Zona Franca a la que pertenece y el usuario que identifica a la empresa.Posteriormente, examinar el proceso de elaboración del producto de limpieza, y conforme a lo descrito, estudiar posibles mercados para obtener un mercado objetivo adecuado y establecer el procedimiento logístico desde su producción en el país de origen hasta su destino final en Ecuador. Teniendo en cuenta los documentos necesarios para una exportación y los agentes que intervienen en el proceso, con el fin de proponer estrategias de internacionalización que permitan la mejora continua y abarquen distintas áreas de la empresa

INTERNACIONALIZACIÓN DEL CLORO DENSO DE LA EMPRESA CUCUTEÑA COSMOGREEN HACIA ECUADOR

El presente artículo de investigación pretende ejecutar un plan de internacionalización permitiendo la exportación del producto Cloro Denso producido por Cosmogreen, ubicada en la Zona Franca de Cúcuta. A partir del análisis y estudio de las áreas de la empresa, su estructura y el portafolio de productos ofrecidos, teniendo en cuenta su legislación, el tipo de Zona Franca a la que pertenece y el usuario que identifica a la empresa. Posteriormente, examinar el proceso de elaboración del producto de limpieza, y conforme a lo descrito, estudiar posibles mercados para obtener un mercado objetivo adecuado y establecer el procedimiento logístico desde su producción en el país de origen hasta su destino final en Ecuador. Teniendo en cuenta los documentos necesarios para una exportación y los agentes que intervienen en el proceso, con el fin de proponer estrategias de internacionalización que permitan la mejora continua y abarquen distintas áreas de la empresa

Lavado de activos

El siguiente artículo de revisión documental analiza los riesgos y consecuencias socioeconómicas del lavado de activos en la zona fronteriza de Colombia y Venezuela (Norte de Santander-Táchira), por medio de la minería de textos y la exploración documental, con la finalidad de identificar los principales efectos negativos que trae consigo el blanqueo de capitales en el desarrollo del país y las consecuencias adversas que dicha actividad acarrea para el crecimiento económico de la región; se caracterizan factores específicos, como la economía subterránea, y los efectos desfavorables para el desarrollo de la sociedad. Se llega a la conclusión de que en las zonas fronterizas tiene mayor incidencia esta práctica delictiva, ya que el contrabando, que es una forma frecuente de blanquear capital, está allí más presente que en zonas céntricas del país. Esto puede deberse a la dificultad, por parte del Estado, de auditar las operaciones bilaterales fronterizas

Global biochemical and structural analysis of the type IV pilus from the Gram-positive bacterium Streptococcus sanguinis

Type IV pili (Tfp) are functionally versatile filaments, widespread in prokaryotes, that belong to a large class of filamentous nanomachines known as type IV filaments (Tff). Although Tfp have been extensively studied in several Gram-negative pathogens where they function as key virulence factors, many aspects of their biology remain poorly understood. Here, we performed a global biochemical and structural analysis of Tfp in a recently emerged Gram-positive model, Streptococcus sanguinis. In particular, we focused on the five pilins and pilin-like proteins involved in Tfp biology in S. sanguinis. We found that the two major pilins, PilE1 and PilE2, (i) follow widely conserved principles for processing by the prepilin peptidase PilD and for assembly into filaments; (ii) display only one of the post-translational modifications frequently found in pilins, i.e. a methylatedN terminus; (iii) are found in the same heteropolymeric filaments; and (iv) are not functionally equivalent. The 3D structure of PilE1, solved byNMR,revealed a classical pilin-fold with a highly unusual flexible C terminus. Intriguingly, PilE1 more closely resembles pseudopilins forming shorter Tff than bona fide Tfp-forming major pilins, underlining the evolutionary relatedness among different Tff. Finally, we show that S. sanguinis Tfp contain a low abundance of three additional proteins processed by PilD, the minor pilins PilA, PilB, and PilC. These findings provide the first global biochemical and structural picture of a Gram-positive Tfp and have fundamental implications for our understanding of a widespread class of filamentous nanomachines

A simplified mesoscale 3D model for characterizing fibrinolysis under flow conditions

One of the routine clinical treatments to eliminate ischemic stroke thrombi is injecting a biochemical product into the patient’s bloodstream, which breaks down the thrombi’s fibrin fibers: intravenous or intravascular thrombolysis. However, this procedure is not without risk for the patient; the worst circumstances can cause a brain hemorrhage or embolism that can be fatal. Improvement in patient management drastically reduced these risks, and patients who benefited from thrombolysis soon after the onset of the stroke have a significantly better 3-month prognosis, but treatment success is highly variable. The causes of this variability remain unclear, and it is likely that some fundamental aspects still require thorough investigations. For that reason, we conducted in vitro flow-driven fibrinolysis experiments to study pure fibrin thrombi breakdown in controlled conditions and observed that the lysis front evolved non-linearly in time. To understand these results, we developed an analytical 1D lysis model in which the thrombus is considered a porous medium. The lytic cascade is reduced to a second-order reaction involving fibrin and a surrogate pro-fibrinolytic agent. The model was able to reproduce the observed lysis evolution under the assumptions of constant fluid velocity and lysis occurring only at the front. For adding complexity, such as clot heterogeneity or complex flow conditions, we propose a 3-dimensional mesoscopic numerical model of blood flow and fibrinolysis, which validates the analytical model’s results. Such a numerical model could help us better understand the spatial evolution of the thrombi breakdown, extract the most relevant physiological parameters to lysis efficiency, and possibly explain the failure of the clinical treatment. These findings suggest that even though real-world fibrinolysis is a complex biological process, a simplified model can recover the main features of lysis evolution.</p

Evaluation of DNA Methylation Episignatures for Diagnosis and Phenotype Correlations in 42 Mendelian Neurodevelopmental Disorders.

Genetic syndromes frequently present with overlapping clinical features and inconclusive or ambiguous genetic findings which can confound accurate diagnosis and clinical management. An expanding number of genetic syndromes have been shown to have unique genomic DNA methylation patterns (called episignatures ). Peripheral blood episignatures can be used for diagnostic testing as well as for the interpretation of ambiguous genetic test results. We present here an approach to episignature mapping in 42 genetic syndromes, which has allowed the identification of 34 robust disease-specific episignatures. We examine emerging patterns of overlap, as well as similarities and hierarchical relationships across these episignatures, to highlight their key features as they are related to genetic heterogeneity, dosage effect, unaffected carrier status, and incomplete penetrance. We demonstrate the necessity of multiclass modeling for accurate genetic variant classification and show how disease classification using a single episignature at a time can sometimes lead to classification errors in closely related episignatures. We demonstrate the utility of this tool in resolving ambiguous clinical cases and identification of previously undiagnosed cases through mass screening of a large cohort of subjects with developmental delays and congenital anomalies. This study more than doubles the number of published syndromes with DNA methylation episignatures and, most significantly, opens new avenues for accurate diagnosis and clinical assessment in individuals affected by these disorders

Understanding type IV pili mediated adhesion in streptococcus sanguinis.

Type IV pili (T4P) are widespread and highly dynamic hair-like bacterial appendages mediating a wide range of functions: DNA uptake, motility, adhesion etc. The bona fide T4P is mainly composed of major pilins but also contains minor pilins, whose functions are likely to be diverse but remain poorly defined. How T4P mediate adhesion is not understood as in other well characterised adhesive pili where tip-located adhesin subunits mediate direct binding to human cells and/or structures. In my thesis, I have addressed this question using the Gram-positive opportunistic pathogen Streptococcus sanguinis, which assembles retractable T4P using a simpler machinery. Importantly, S. sanguinis filaments have two unusual features: they are composed of two major pilins in a 4/3 ratio (PilE1 and PilE2), and they contain three additional pilin-like proteins with a conserved N-terminal pilin domain (PilA, PilB and PilC). The last two have specific additional domains grafted at their C-terminus. My work has shown that PilB, suggested to be tip-localised, exhibits an unusual bimodular pilin structure with a bulky vWA module which shows preferential binding to host components. PilB VWA domain also harbors a canonical MIDAS, which preferential binding to Mg2+ and Mn2+ is involved in twitching motility and binding to eukaryotic cells. I also found that PilC utilises a graft ConA-like domain which most likely recognises sialylated glycans. In parallel, I was also able to observe S. sanguinis T4P dynamics in real-time, demonstrating that it is similar to Gram-negative species. By identifying a new wide class of modular pilins and providing a detailed structure/function of one of them, this study significantly improves the general understanding of the molecular mechanisms of T4P-mediated adhesion.Open Acces