Background: Current scores do not adequately predict cardiovascular risk in patients with chronic kidney disease who are at a very high CV risk in short and medium term. Aim: The aim of our analysis was to create a Bayesian network to predict the 2-year occurrence of a cardiovascular event in patients with chronic kidney disease. Methods and results: The data originated from the observational and prospective Photo-Graphe V3 cohort. Sixty-two nephrologists in 20 French regions included 1144 non-dialysed patients with chronic kidney disease. Seven hundred and thirty patients with known medical status at 2 years were analysed. An initial Bayesian model was first built using 26 variables related to the characteristics of the patients, their medical background, and treatments. A cardiovascular event (heart failure, acute coronary syndrome, transient ischemic attack, stroke or cardiovascular death) occurred in 20.0% of the patients after two years of follow-up. The model was first optimized using synthetic data (created from the original database) to increase its reliability. The number of variables was then reduced using the 13 most informative variables to increase its clinical applicability. The10-fold cross validation showed that the optimized clinical model with 13 variables had an area under the ROC curve of 0.90+0.02, a sensitivity of 82.5+5.9%, a specificity of 80.6+5.1%, a predictive positive value of 81.2+3.4% and a negative predictive value of 82.5+4.4%. The percentage of misclassified subjects was 18.4+2.6%. Conclusion: Using artificial intelligence methods, a new clinical tool to predict cardiovascular events in patients with chronic kidney disease is proposed.

This thesis examines the concept of medical futility and its importance for the practice of medicine nowadays. It presents an overview of the development of the concept throughout history and it discusses the main arguments in favor and against a determination of futile treatment in the clinical setting. The notion of futility, in broad terms, describes the situation in which certain medical interventions no longer benefit the patient and therefore, it follows that there must be a derived moral obligation to stop said intervention. Such an idea brings forward numerous problematic pitfalls that are discussed in this thesis, among which are the debate about the limits of medicine, the tension between the notions of patient autonomy and physician authority and the practice of medical rationing in hospitals. This thesis aims to provide a new perspective on the subject in hopes that it will help to keep the ongoing debate running so in the near future, more experts will decide to contribute themselves with their expertise. Situations where a medical intervention ceases to benefit the patient will continue to occur at the bedside; what is more, these ethical conundrums will become more and more problematic as the technological imperative intensifies and the possibilities of biotechnology increase. The leading question that directed the development of the thesis was “when enough it’s enough?” in other words, what are the ethical considerations on the limits of medicine? The paper concludes that the concept of medical futility has a heuristic value, and thus it has helped yield more clarity about relevant matters such as the differentiation between futility and rationing, the fact that more research is needed to test what works and what does not and it has brought to the spotlight the importance of more robust standards of practice that, for example, prevent physicians from practicing defensive medicine. Resumen: Esta tesis examina el concepto de futilidad médica y su importancia para la práctica de la medicina en la actualidad. Presenta una visión general del desarrollo del concepto a lo largo de la historia y discute los principales argumentos a favor y en contra de la determinación de un tratamiento fútil en el ámbito clínico. La noción de futilidad, en términos generales, describe la situación en la que ciertas intervenciones médicas ya no benefician al paciente y, por lo tanto, se deduce que debe existir una obligación moral derivada de detener dicha intervención. Esta idea plantea numerosos asuntos problemáticos que se discuten en esta tesis, entre los que se encuentran el debate sobre los límites de la medicina, la tensión entre las nociones de autonomía del paciente y autoridad del médico, y la práctica del racionamiento médico en los hospitales. Esta tesis pretende aportar una nueva perspectiva sobre el tema con la esperanza de que esta ayude a mantener el debate vigente, de manera que, en un futuro próximo, más expertos decidan aportar su experiencia. Las situaciones en las que una intervención médica deja de beneficiar al paciente seguirán; más aún, estos debates éticos se volverán cada vez más problemáticos a medida que se intensifique el imperativo tecnológico y aumenten las posibilidades de la biotecnología. La pregunta principal que dirigió el desarrollo de la tesis fue ""¿cuándo es momento de parar?"", es decir, ¿cuáles son las consideraciones éticas sobre los límites de la medicina? El documento concluye que el concepto de futilidad médica tiene un valor heurístico y, por lo tanto, ha contribuido a aclarar cuestiones pertinentes como la diferenciación entre futilidad y racionamiento, el hecho de que se necesita más investigación para probar lo que funciona y lo que no, y ha puesto de relieve la importancia de contar con normas de práctica más sólidas que, por ejemplo, impidan a los médicos practicar la medicina defensiva.

Mutations in PCDH19 gene are associated with Early Infantile Epileptic Encephalopathy type 9 (EIEE-9), a very rare disorder characterized by early onset of seizures, intellectual disability and psychiatric comorbidities with an unusual form of X-linked inheritance in which only females and mosaic male patients are affected. Materials and Methods: We report three patients, one male and two females carrying PCDH19 variants (D233G, V589Cfs*8 and N1103K) found by Whole exome sequencing (WES). One is a novel missense mutation (N1103K) while the others had been previously reported in female affected patients. Although, there is the first time that variant V589Cfs*8 is reported in a male patient. We performed a complete phenotype evaluation of our cases and establish the pathogenicity of each variant by in silico and functional analysis accessing many aspects of Protocadherin-19 including subcellular localization and protein expression. Results: Two of the three variants are predicted to be deleterious to protein function. The variant D233G is predicted to affect the calcium binding site and avoids cadherin strands swapping compromising the cell adhesion activity and the structural stability of the protein. While, the variant V589Cfs*8 introduced a premature stop codon which led to the loss of the transmembrane domain of the protein as well as to the cytoplasmic domain, including all predicted nuclear localization signals, suggesting the variant might affect the subcellular localization of Pcdh-19. The last findings were corroborated by western blotting and immunolabelling comparing the protein localization in patient and control fibroblasts. Conclusions: Our findings enhance understanding of molecular functions of Protocadherin-19, as well as highlighting the importance of functional testing of variants that emerge from NGS studies. Resumen: Las mutaciones en el gen PCDH19 están asociadas con la encefalopatía epiléptica infantil temprana tipo 9 (EIEE-9), un trastorno muy raro caracterizado por la aparición temprana de convulsiones, discapacidad intelectual y comorbilidades psiquiátricas con una forma inusual de herencia ligada al cromosoma X en la que solo las mujeres y mosaico pacientes masculinos se ven afectados. Materiales y métodos: Reportamos tres pacientes, un hombre y dos mujeres con variantes en el gen PCDH19 (D233G, V589Cfs*8 y N1103K) encontrados por secuenciación de exoma completo (WES). Una es una nueva mutación sin sentido (N1103K) mientras que las otras habían sido reportadas previamente en pacientes femeninas afectadas. Aunque, es la primera vez que se informa la variante V589Cfs*8 en un paciente masculino. Realizamos una evaluación completa del fenotipo de nuestros casos y establecimos la patogenicidad de cada variante mediante análisis in silico y funcional accediendo a muchos aspectos de la Protocadherin-19, incluida la localización subcelular y la expresión de proteínas. Resultados: se predice que dos de las tres variantes son perjudiciales para la función de la proteína. La variante D233G afecta el sitio de unión al calcio y evita el intercambio de hebras de caderina que comprometen la actividad de adhesión celular y la estabilidad estructural de la proteína. Mientras que la variante V589Cfs*8 introdujo un codón de parada prematuro que condujo a la pérdida del dominio transmembrana de la proteína, así como al dominio citoplasmático, incluidas todas las señales de localización nuclear esperadas, lo que sugiere que la variante podría afectar la localización subcelular de la proteína. Los últimos hallazgos fueron corroborados por Western blot e inmunomarcaje comparando la localización de la proteína en fibroblastos de pacientes y controles. Conclusiones: Nuestros hallazgos mejoran la comprensión de las funciones moleculares de Protocadherin-19, así como resaltan la importancia de las pruebas funcionales de las variantes que surgen de los estudios de secuenciación de siguiente generación (NGS).

Abstract: Background: Multidrug resistant TB cases have been on the rise, risking advances in TB prevalence and control. Early diagnosis and targeted initial treatment are paramount for effective management and control of spreading of MDR/XDR-TB cases Methods: 161 isolates from patients with L-J culture confirmed TB in Lima, Peru, were tested with MODS+ assay, the diagnostic test and Sensititre, the reference standard. Analysis of growth patterns of bacteria in both methods were used to determine susceptibility/resistance of each isolate to three first line and six second line anti-TB agents, using two different critical concentrations (CC) for each antibiotic. Results: Agreement between susceptibility profiles and operational characteristics of diagnostic test yielded high performance and strong agreement with rifampicin 1μg/ml (agreement percent 90%, Kappa value 0.80) and amikacin 1μg/ml (agreement percent 96%, Kappa value 0.81), moderate for isoniazid 0.4μg/ml (agreement percent 89.4%, Kappa value 0.78), moxifloxacin at both CC’s 0.5μg/ml and 0.25μg/ml (agreement percent 93 and kappa values 0.73 for both), levofloxacin 2μg/ml (agreement 93%, kappa 0.69) and amikacin 2μg/ml (agreement 96%, Kappa 0.81), minimal for levofloxacin at CC 1.5μg/ml (agreement 90%, kappa 0.57) kanamycin at both CC’s 10μg/ml and 5μg/ml (agreement 87%, kappa 0.52) and ethionamide 5μg/ml (agreement 89%, kappa 0.46), weak for PAS 10μg/ml (agreement percent 93.9, kappa value 0.29), and none for ethambutol (Kappa value 0.02 for CC 10μg/ml, 0.07 for CC 5μg/ml). Conclusions: MODS+ assay is a cost-effective option for the diagnosis of TB and MDR/XDRTB, specially, in low resource settings with high TB incidence. Further operational research using lower CC’s, results read on different days and placed in settings with high and low TB and MDR/XDRTB burden could offer better sensitivities and wider applicability of results.

Background: Data are rare about the incidence of severe Fontan-associated liver disease (FALD) and its association with mortality. We sought to: (1) estimate the probability of developing severe FALD in patients who undergo the Fontan procedure (Fontan patients), compared with severe liver complications in patients with a ventricular septal defect; (2) assess the severe FALD-mortality association; and (3) identify risk factors for developing severe FALD. Methods and Results: Using the Quebec Congenital Heart Disease database, a total of 512 Fontan patients and 10232 patients with a ventricular septal defect were identified. Kaplan-Meier curves demonstrated significantly higher cumulative risk of severe FALD in Fontan patients (11.95% and 52.24% at 10 and 35years, respectively), than the risk of severe liver complica- tions in patients with a ventricular septal defect (0.50% and 2.75%, respectively). At 5years, the cumulative risk of death was 12.60% in patients with severe FALD versus 3.70% in Fontan patients without FALD (log-rank P=0.0171). Cox proportional hazard models identified significant associations between the development of severe FALD and congestive heart failure and supraventricular tachycardia, with hazard ratios (HRs) of 2.36 (95% CI, 1.38–4.02) and 2.45 (95% CI, 1.37–4.39), respectively. More recent Fontan completion was related to reduced risks of severe FALD, with an HR of 0.95 (95% CI, 0.93–0.97) for each more recent year. Conclusions: This large-scale population-based study documents that severe FALD in Fontan patients was associated with a >3-fold increase in mortality. The risk of FALD is time-dependent and can reach >50% by 35years after the Fontan operation. Conditions promoting poor Fontan hemodynamics were associated with severe FALD development.

Background: Post-stroke fatigue (PSF) is one of the most challenging clinical consequences to manage after stroke as no effective treatment has been developed. However, the mechanisms of PSF remain unclear. Aims: This study aimed to replicate Vecchio et al (2017) using resting-state EEG in stroke patients suffering from varying degrees of fatigue to describe the functional organisation within sensory and motor networks. Methods: Resting-state eyes-open EEG was recorded in 22 strokesurvivors. Upper limb functional tests (grip strength, Nine Hole Peg Test), symbol digit modalities test (SDTM), anxiety and depression scale (HADS), Fatigue Severity Scale (FSS-7), state fatigue, and Neurological Fatigue Index (NFI-stroke) were measured. Graph theory was used to calculate the small-world (SW) index. SW was calculated in four separate networks, motor and sensory within the left and right hemispheres. Exact low-resolution brain electromagnetic tomography (eLORETA) was applied using seven frequency bands (delta, theta, alpha1, alpha2, beta1, beta2, and gamma). Results: Correlation analysis demonstrated a positive association between SW in the right motor network in beta2 band and higher FSS-7 score and a negative correlation between SW in the left sensory network in alpha1 and higher state fatigue. Conclusion: Beta oscillations have been associated with top-down processes which are crucial for perceptual inference and alpha oscillations are involved in sensorimotor information processing. The interaction between the top-down and bottom-up processes, and perceived error explains the sensory attenuation model of fatigue. Our results were consistent this model of fatigue as stroke survivors had difficulty in attenuating the sensory input leading to higher perceived effort.

Abstract: Objective: Intestinal parasitic infections (IPIs) are a public health challenge in developing countries such as Colombia, causing anaemia and delayed growth and development in children. We aimed to estimate the geographical and prevalence trend of IPIs in the last 30years in school and preschool children in Colombia. Methods: We conducted a systematic review and meta-analysis. We identified potential manuscripts through PubMed, EMBASE, Web of Science, LILACS, Scielo and Google Scholar on the IPIs prevalence in school and preschool children in Colombia. Articles included in the qualitative analysis were published between 1990 and 2020 in English or Spanish and met the inclusion criteria. Subsequently, a random-effects meta-analysis, a meta-regression and a trend analysis were performed. Results: We identified 2292 articles; 109 were included in the qualitative review, and 79 articles were included in the meta-analysis. The estimated IPI prevalence was 55% (95% CI: 48–63). By age group, the prevalence in preschool children was 37% (95% CI: 26–49) and 66% (95% CI: 52–78) in schoolchildren. The prevalence by region was heterogeneous, with the Amazon being the highest (69%) and the Santanderes the lowest (28%). In the last 20years, the prevalence of helminthiasis has decreased (from 64.66% in 1990–1995 to 22.09% in 2016–2020). Conclusion: The prevalence of IPIs is high (>30%) in three of the seven regions in Colombia. Biannual administration of mass deworming in schoolchildren is recommended in the Amazon region. Public policies aiming to control IPIs should be reinforced. Further prevalence studies should include Cesar, Guaviare, Vichada and Vaupés, where the epidemiology of IPIs is unknown. Resumen: Objetivo: Las infecciones parasitarias intestinales (IPIs) son un desafío para la salud pública en los países en desarrollo como Colombia, ya que causan anemia y retraso en el crecimiento y desarrollo de los niños. El objetivo de este estudio fue estimar la tendencia de la prevalencia y la distribución geográfica de las IPIs en niños en edad escolar y preescolar en Colombia en los últimos 30 años. Métodos: Se llevó a cabo una revisión sistemática y un metaanálisis. Se identificaron estudios potenciales a través de PubMed, EMBASE, Web of Science, LILACS, Scielo y Google Scholar cuyo objetivo era estimar la prevalencia de las IPIs en niños en edad escolar y preescolar en Colombia. Se incluyeron artículos publicados entre 1990 y 2020, tanto en inglés como en español, que cumplieran con los criterios de inclusión. Posteriormente, se realizó un metaanálisis de efectos aleatorios, una meta-regresión y un análisis de tendencias. Resultados: Identificamos 2,292 artículos; 109 se incluyeron en la revisión cualitativa y 79 en el metaanálisis. La prevalencia estimada de las IPIs fue del 55% (IC del 95%: 48-63%). Según el grupo de edad, la prevalencia en niños preescolares fue del 37% (IC del 95%: 26-49%), y en niños en edad escolar fue del 66% (IC del 95%: 52-78%). La prevalencia por región fue heterogénea, siendo el departamento del Amazonas donde se ubicó la prevalencia más alta (69%) y los Santanderes la más baja (28%). En los últimos 20 años, la prevalencia de helmintiasis ha disminuido del 64.66% en 1990-1995 al 22.09% en 2016-2020. Conclusión: La prevalencia de las IPIs es alta (>30%) en tres de las siete regiones de Colombia. Se recomienda la administración bianual masiva de antiparasitarios en niños en edad escolar en la región del Amazonas. Las políticas públicas destinadas a controlar las IPIs deben reforzarse. Futuros estudios de prevalencia deben incluir a los departamentos de Cesar, Guaviare, Vichada y Vaupés, ya que son departamentos donde la epidemiología de las IPIs es desconocida.

Abstract: Danger-associated molecular patterns (DAMPs) may be implicated in the pathophysiological pathways associated with an unfavorable outcome after acute brain injury (ABI). Differences in vCSF protein expression over time were evaluated using linear models and selected for functional network analysis using the PANTHER and STRING databases. The primary exposure of interest was the type of brain injury (traumatic vs. nontraumatic), and the primary outcome was the vCSF expression of DAMPs. Secondary exposures of interest included the occurrence of intracranial pressure ?20 or ? 30 mm Hg during the 5 days post- ABI, intensive care unit (ICU) mortality, and neurological outcome (assessed using the Glasgow Outcome Score) at 3 months post-ICU discharge. Secondary outcomes included associations of these exposures with the vCSF expression of DAMPs. A network of 6 DAMPs (DAMP_trauma; protein-protein interaction [PPI] P= 0.04) was differentially expressed in patients with ABI of traumatic origin compared with those with nontraumatic ABI. ABI patients with intracranial pressure ?30 mm Hg differentially expressed a set of 38 DAMPS (DAMP_ICP30; PPI P< 0.001). Proteins in DAMP_ICP30 are involved in cellular proteolysis, complement pathway activation, and post-translational modifications. Specific patterns of vCSF DAMP expression differentiated between traumatic and nontraumatic types of ABI and were associated with increased episodes of severe intracranial hypertension. Resumen: Los patrones moleculares asociados al peligro (DAMP) pueden estar implicados en las vías fisiopatológicas asociadas con un resultado desfavorable después de una lesión cerebral aguda (LCA). Las diferencias en la expresión proteíca vCSF a lo largo del tiempo se evaluaron utilizando modelos lineales y se seleccionaron para el análisis de redes funcionales utilizando las bases de datos PANTHER y STRING. La principal exposición de interés fue el tipo de lesión cerebral (traumática versus no traumática), y el resultado primario fue la expresión de DAMP en vCSF. Las exposiciones secundarias de interés incluyeron la aparición de presión intracraneal ?20 o ? 30 mm Hg durante los 5 días posteriores a la LCA, mortalidad en la unidad de cuidados intensivos (UCI) y resultado neurológico (evaluado mediante el Glasgow Outcome Score) 3 meses después del alta de la UCI. Una red de 6 DAMP (DAMP_trauma; interacción proteínaproteína [PPI] P = 0,04) se expresó diferencialmente en pacientes con LCA de origen traumático en comparación con aquellos con LCA no traumática. Los pacientes con ITB con presión intracraneal ?30 mm Hg expresaron diferencialmente un conjunto de 38 DAMPS (DAMP_ICP30; PPI P <0,001). Las proteínas en DAMP_ICP30 participan en la proteólisis celular, la activación de la vía del complemento y las modificaciones postraduccionales. Los patrones específicos de expresión de vCSF DAMP diferenciaron entre tipos de LCA traumática y no traumática y se asociaron con un aumento de episodios de hipertensión intracraneal severa.

Abstract: Objective: To evaluate and compare the mechanical properties, water sorption, water solubility, and degree of double bond conversion of three different commercially available threedimensional (3D) printing resins used for the fabrication of flexible occlusal splints. Methods: A digital printer was used to generate specimens from the evaluated splint materials (KeySplint Soft, IMPRIMO LC Splint flex, and V-Print splint comfort). The specimens were equally divided and tested either dry or after water storage at 37 ? C for 30 days. A three-point bending test was used to assess flexural strength, elastic modulus, and fracture toughness. A two-body wear test was performed using a dual-axis chewing simulator. Water sorption and water solubility were measured after 30 days. The degree of double bond conversion was determined by FTIR-spectrometry. All data for the evaluated properties were collected and statistically analyzed. Results: Both material and storage conditions had a significant effect on the flexural strength (P < 0.001), elastic modulus (P < 0.001), fracture toughness (P < 0.001), and wear (P < 0.001). The highest water sorption was noticed with IMPRIMO LC Splint flex (1.9 ± 0.0 %), while V-Print splint comfort displayed the lowest water solubility (0.2 ± 0.0 %). For the degree of conversion, it was statistically nonsignificant among the different materials (P = 0.087). Significance: Different flexible 3D-printed splints available in the market displayed variations in the evaluated properties and clinicians should consider these differences when choosing occlusal device materials. Among the tested flexible splint materials, KeySplint Soft had the greatest flexural strength, elastic modulus, fracture toughness, wear resistance, and degree of conversion. It also showed the lowest water sorption. Resumen: Objetivo: Evaluar y comparar las propiedades mecánicas, sorción de agua, solubilidad en agua y grado de conversión de doble enlace de tres resinas de impresión tridimensionales (3D) diferentes, disponibles comercialmente, utilizadas para la fabricación de férulas oclusales flexibles. Métodos: Se utilizó una impresora digital para generar muestras a partir de los materiales de férula evaluados (KeySplint Soft, IMPRIMO LC Splint flex y V-Print splint comfort). Las muestras se dividieron equitativamente y se probaron en seco o después del almacenamiento en agua a 37 ? C durante 30 días. Se utilizó una prueba de flexión de tres puntos para evaluar la resistencia a la flexión, la elasticidad módulo y tenacidad a la fractura. Se realizó una prueba de desgaste de dos cuerpos utilizando un simulador de masticación de doble eje. La sorción y la solubilidad en agua se midieron después de 30 días. El grado de conversión del doble enlace fue determinado por espectrometría FTIR. Todos los datos de las propiedades evaluadas fueron recopilados y analizados estadísticamente. Resultados: Tanto el material como las condiciones de almacenamiento tuvieron un efecto significativo sobre la resistencia a la flexión (P < 0,001), módulo de elasticidad (P <0,001), tenacidad a la fractura (P <0,001) y desgaste (P <0,001). La mayor sorción de agua fue notado con IMPRIMO LC Splint flex (1,9 ± 0,0 %), mientras que la férula V-Print comfort mostró la menor solubilidad al agua (0,2 ± 0,0 %). Para el grado de conversión, no hubo diferencia significativa estadísticamente entre los diferentes materiales (P = 0,087). Importancia: Las diferentes férulas flexibles impresas en 3D disponibles en el mercado mostraron variaciones en las propiedades evaluadas y los clínicos deben considerar estas diferencias al elegir los materiales para dispositivos oclusales. Entre los materiales de férula flexibles probados, KeySplint Soft tuvo la mayor resistencia a la flexión, módulo elástico, tenacidad, resistencia al desgaste y grado de conversión. También mostró la menor sorción de agua.

Abstract: The aim of this in vitro study was to evaluate the wear and surface hardness of nine materials for conventional manufacturing, subtractive milling, and 3D printing of occlusal splints, as well as to evaluate the differences in wear and surface hardness between rigid and flexible 3D-printed occlusal splint materials. Two-body wear and Vickers hardness tests were performed. The vertical wear depth and Vickers hardness values were statistically analyzed. Vertical wear depth and surface hardness values were statistically significant among the investigated materials (p<0.05). The lowest vertical wear depth was observed for the heat-cured resin (27.5±2.4 ?m), PMMA-based milled material (30.5±2.8 ?m), and autopolymerizing resin (36.7±6.3 ?m), with no statistical difference (p<0.05). Flexible 3D-printed and CAD-CAM milled polycarbonate-based splint materials displayed lower surface hardness and higher wear than the PMMA-based materials. PMMA-based splint materials displayed the most consistent surface hardness and wear resistance regardless of the manufacturing technology. Resumen: El objetivo de este estudio in vitro fue evaluar el desgaste y la dureza superficial de nueve materiales para la fabricación convencional, fresado sustractivo e impresión 3D de férulas oclusales, así como para evaluar las diferencias en el desgaste y la dureza de la superficie entre Materiales rígidos y flexibles para férulas oclusales impresas en 3D. Se realizaron pruebas de desgaste de dos cuerpos y dureza Vickers. Se analizaron estadísticamente los valores de profundidad y dureza Vickers. Los valores de profundidad de desgaste vertical y dureza superficial fueron estadísticamente significativa entre los materiales investigados (p<0,05). La profundidad de desgaste vertical más baja se observó para la resina termocurada (27,5 ± 2,4?m), material molido a base de PMMA (30,5±2,8 ?m) y resina autopolimerizable (36,7±6,3 ?m), sin diferencia estadística (p<0,05). Los materiales flexibles para férulas a base de policarbonato impresos en 3D y fresados con CAD-CAM mostraron una menor dureza superficial y un mayor desgaste que los materiales basados en PMMA. Los materiales para férulas a base de PMMA mostraron la dureza superficial y la resistencia al desgaste más consistentes independientemente de la tecnología de fabricación.