Abstract The study of corneal biomechanics has become relevant in recent years due to its possible applications in the diagnosis, management, and treatment of various diseases such as glaucoma, keratorefractive surgery and different corneal diseases. The clinical biomechanical investigation has become of great importance in the setting of refractive surgery to identify patients at higher risk of developing iatrogenic ectasia. This review focuses on two of the technologies available for clinical use, the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Buffalo, NY, USA) and the Corvis ST (Oculus Optikgergäte GmbH, Wetzlar, Germany). Both are non-contact tonometers that provided a clinical evaluation of corneal biomechanics. The fundamentals and main parameters of each device are described, as well as their use in eye surgery and the corneal biomechanical behavior in eye diseases. Finally, we will discuss the more recent Brillouin microscopy biomechanical analysis, and the integration Scheimpflug-based corneal tomography and biomechanical data with artificial intelligence to increase accuracy to detect risk of ectasia.

Resumen El estudio de la biomecánica corneal ha cobrado relevancia en los últimos años debido a sus posibles aplicaciones en el diagnóstico, el manejo y el tratamiento de diversas enfermedades, como glaucoma, cirugía queratorrefractiva y diferentes enfermedades corneales. La investigación de la biomecánica corneal es de mucha importancia en el contexto de cirugía refractiva, pues podría identificar pacientes en riesgo de desarrollar una ectasia corneal iatrogénica. Esta revisión se centra en dos de las tecnologías disponibles para uso clínico: el Ocular Response Analyzer (Reichert Ophthalmic Instruments, Buffalo, NY, EE. UU.) y el Corvis ST (Oculus Optikgergäte GmbH, Wetzlar, Alemania). Ambos son tonómetros de no contacto que proporcionan una evaluación clínica de la biomecánica corneal. Se describen los fundamentos y los principales parámetros de cada dispositivo, así como su uso en cirugía ocular y el comportamiento biomecánico corneal en las enfermedades oculares. Finalmente, se mencionan los dispositivos más recientes de análisis biomecánico, como la microscopía de Brillouin, así como la integración de los datos biomecánicos y topográficos basados en Scheimpflug con la inteligencia artificial para aumentar la precisión en la detección del riesgo de ectasias.

Resumen Introducción: El trasplante renal es el tratamiento de elección de la enfermedad renal en etapa terminal (ERT). Desde marzo de 2020, la actividad de trasplantes en México se ha visto afectada debido a la pandemia de COVID-19. Objetivo: Determinar el impacto en la mortalidad de pacientes en lista de espera (LE) para trasplante renal de donante cadavérico en un hospital de referencia en Yucatán, por suspensión de actividades debido a la pandemia. Material y métodos: Pacientes > 18 años en LE para trasplante renal en este hospital. En caso de muerte de un paciente, se investigó la causa, especialmente si estaba asociada a COVID-19. Un valor de p de dos colas ≤ 0.05 se consideró significativo en todos los análisis. Resultados: La razón de probabilidad de muerte por COVID-19 en un paciente con ERT en la LE en 2020 fue OR = 5.04 (IC 95%: 1.65-7.14, p = 0.023). La razón de probabilidad de morir con ERT en la LE con retraso en las consultas de seguimiento fue de OR = 6.59 (IC 95%: 2.7-16.28, p = 0.008). Conclusión: La probabilidad de muerte de un paciente con ERT en la LE con retraso en las consultas de seguimiento y retención del trasplante es estadísticamente más alta que la probabilidad de muerte por COVID-19.

Abstract Introduction: Kidney transplantation is the treatment of choice for end-stage renal disease (ESRD). Since March 2020, transplant activity in Mexico has been affected due to the COVID-19 pandemic. Objective: The aim of the study was to determine the impact on mortality of patients on the waiting list (WL) for cadaveric donor kidney transplantation in a referral hospital in Yucatán, due to suspension of activities due to the pandemic. Material and methods: Patients over 18 years of age on the waiting list for kidney transplantation at this hospital. In the event of a patient's death, the cause was investigated, especially if it was associated with COVID-19. A two-tailed p ≤ 0.05 was considered significant in all analyzes. Results: The odds ratio (OR) of death from COVID-19 in a patient with ESRD in the WL in 2020 was OR = 5.04 (95% CI: 1.65-7.14, p = 0.023). The OR of dying with ESRD in the WL with a delay in the follow-up visits was OR = 6.59 (95% CI: 2.7-16.28, p = 0.008). Conclusion: The probability of death of a patient with ESRD with delayed follow-up visits and transplant retention is statistically higher than the probability of death from COVID-19.

Resumen El género Enterococcus puede ser encontrado en agua, suelo y en general en todo ambiente, son parte de la microbiota intestinal de animales, incluyendo a humanos. La prevalencia en alimentos se debe principalmente a la resistencia que presentan a las condiciones adversas del ambiente. Setenta y tres aislados de vísceras de pollo fueron confirmados como pertenecientes al género a través de pruebas bioquímicas y fermentación de carbohidratos. La caracterización bioquímica indicó que la especie predominante fue E. casseliflavus. La resistencia de los aislados a antimicrobianos fue notoria para amikacina (42 %), kanamicina (38 %), estreptomicina (55 %), y eritromicina (33 %). El análisis obtenido por ERIC-PCR mostró una alta variabilidad genética entre los aislados. Así también, los aislados mostraron relación entre los perfiles obtenidos con la susceptibilidad a antimicrobianos y por ERIC-PCR. Estos resultados muestran la multiresistencia de Enterococcus en vísceras de pollo expedidos comercialmente, con una alta variabilidad genética. Además, estos Enterococcus pueden ser potencialmente patógenos en individuos como una bacteria nosocomial y además transferir la resistencia en especies que son estrictamente patógenas y causan enfermedades al humano.

Abstract The genus Enterococcus can be found in water, soil, and food, and above all, they are part of the animal (including human) intestinal microbiota. Food prevalence is mainly due to their resistance to adverse environmental conditions. Seventy-three isolates from chicken viscera were confirmed to belong to the Enterococcus genus by biochemical tests and carbohydrate fermentation. Phenotypic characterization of the species indicates that E. casseliflavus was the predominant specie. Antimicrobial resistance to amikacin (42 %), kanamycin (38 %), streptomycin (55 %) and erythromycin (33 %) in the isolates was notorious. The analysis obtained from ERIC-PCR profiles shows a high genetic variability among the isolates. In addition, a relationship between the antimicrobial and ERIC-PCR profiles was observed among isolates. These results indicate the presence of multiresistant Enterococcus in commercial chicken viscera with high genetic variability, which could be a potential nosocomial bacterium or transfer this resistance to another pathogenic species causing human diseases.

Resumen Sitophilus granarius, es un pequeño insecto el cual bajo condiciones favorable llega a afectar al trigo almacenado hasta en un 85 %. Los esfuerzos investigativos están siendo orientados hacia el desarrollo de bioproductos a base de hongos o bacterias con acción entomopatógena, con utilidad potencial como bioinsecticidas. Estudios relacionados con Trichoderma harzianum y espinosina en el control del coleópteros-plaga de granos almacenados son mínimos y es en este contexto, el objetivo del presente trabajo consistió en evaluar el efecto de Trichoderma y la espinosina en el control de Sitophilus granarius en trigo almacenado. Para el desarrollo del estudio, el grano de todos los tratamientos fue impregnado primeramente con espinosina; tres concentraciones (tres tratamientos) de conidias de T. harzianum fueron asperjadas (T1:103, T2:106 y T3:109 conidias.mL-1), con cinco repeticiones cada tratamiento. En el estudio fueron considerados controles sin tratamientos. Los resultados muestran que, Trichoderma harzianum presenta un efecto biorregulador sobre S. granarius, el cual es significativo cuando se combina con la espinosina. Este efecto bioregulador se enfatiza cuando se inoculan concentraciones superiores de 109 condias/mL. Se deben realizar estudios relacionados con la coinoculación y el uso de la espinosina, asimismo, evaluar la viabilidad de la semilla y propiedades organolépticos del grano.

Abstract Sitophilus granarius, is a small insect which, under favorable conditions, affects up to 85 % of stored wheat. Research efforts are being directed towards the development of bioproducts based on fungi or bacteria with entomopathogenic action, with potential utility as bioinsecticides. Studies related to Trichoderma harzianum and spinosyn in the control of the beetle pest of stored grains are minimal and it is in this context, that the objective of this work was to evaluate the effect of Trichoderma and spinosyn in the control of Sitophilus granarius in stored wheat. For the development of the study, the grain of all treatments was first impregnated with spinosyn; three concentrations (three treatments) of T. harzianum conidia were sprayed (T1:103, T2:106 y T3:109 conidias.mL-1), with five repetitions for each treatment. In the study they were considered controls without treatments. The results show that Trichoderma harzianum has a bioregulatory effect on S. granarius, which is significant when combined with spinosyn. This bioregulatory effect is emphasized when higher concentrations than 109 condia/mL are inoculated. Studies related to coinoculation and the use of spinosyn should be carried out, as well as evaluating the viability of the seed and the organoleptic properties of the grain.

Abstract The photoluminescent behavior of Eu-doped Sr3Al2O6 obtained by highly efficient solution combustion synthesis is reported. In order to understand the influence of the fuel on the synthesis, the stoichiometric quantity and an excess of fuel were evaluated. By adjusting the amount of fuel, different luminescence responses were obtained, allowing europium cations incorporation into the Sr3Al2O6 lattice to serve as effective luminescence activators in such a short time during the rapid combustion synthesis process. The higher amount of fuel in the presence of the oxidizing agent produced Sr3Al2O6:Eu particles with higher phosphorescence brightness, owing to the increase of the reduction process from Eu3+ to Eu2+. The synthesized phosphor showed an intense band emission centered at 515 nm and could be excited over a broad spectral range in the UV-visible region. Particles having nanostructured flake-type morphology were obtained, which was considered a micro-nanofunctional candidate for practical applications.

Objectives of this research were to examine differential gene expression profiles of Nguni and Bonsmara cattle fed diets differing in their energy density. The ultimate goal was to improve understanding of the mechanisms that underlie differences between these breeds and the potential interactions of the differences between breeds with the nutritive environment. The experiment was designed as a 2 χ 2 factorial arrangement of breed and diet (12.5 MJ/kg DM vs. 10.9 MJ/kg DM). The initial feeding trial had 10 bull calves per treatment. However, financial constraints limited RNA sequencing to six animals per treatment and the RNA generated from one animal was of insufficient quality to be useful. Transcripts with false discovery rate P-values <0.05 and fold-changes >2.0 were considered significant. Bonsmara had a faster growth rate, heavier live and carcass weights, and better feed conversion compared to Nguni. However, lower levels of fat were observed in Nguni. Twenty different genes were differentially expressed, with three exhibiting interaction effects and all 20 having differences in transcript abundance between the breeds. A dietary effect was only observed for the one gene and that gene was also subject to an interaction effect with breed. Observed differences in gene expression between Bonsmara and Nguni by several genes affecting the structure or function of the mitochondria imply differences in energy metabolism between the breeds. Interaction effects on the abundance of some gene transcripts indicate the need to consider the diet when evaluating breed differences and conversely, consider breed when evaluating diets.

Abstract Chenopodium quinoa Willd. it is an Andean cereal of great importance for human consumption due to its high nutritional value. In Colombia there is a high phenotypic and genotypic variability within quinoa crops, which has not been studied and has been maintained by the same farmers cycle after production cycle. The objective of this study was to carry out an interpopulation characterization of quinoa cultivated in different producing municipalities of the department of Boyacá, in Colombia, for which 19 morphological descriptors were used, which were evaluated in situ in nine municipalities and analyzed through descriptive statistics, principal component analysis, correlation and conglomerates. In the evaluation of the quantitative traits for all the populations, it was observed that the most variable descriptors were Number of teeth lower leaf (DHI), Lower leaf length (LHI), Width upper leaf (AHI) and Number of teeth upper leaf (DHS). Great segregation between and within individuals of Blanca de Jericó and Piartal was observed for panicle and leaf color and shape, stem color, presence of teeth, and axils on upper and lower leaves. A classification key is proposed that allows in the field to be able to morphologically differentiate the genotypes of Piartal and Blanca de Jericó. This research shows that among the most cultivated genotypes in the department of Boyacá, there is still an important phenotypic diversity given at the inter and intra-individual level, due to the phenological state and the agroclimatological conditions of the different producing regions.

Resumo Chenopodium quinoa Willd. é um cereal andino de grande importância para a alimentação humana por causa do seu alto valor nutricional. Na Colômbia, existe uma alta variabilidade fenotípica e genotípica nos cultivos de quinoa, que não foi estudada e tem sido mantida pelo mesmo produtor ciclo após ciclo de produção. O objetivo deste estudo foi realizar uma caracterização interpopulacional da quinoa cultivada em diferentes municípios produtores do departamento de Boyacá, na Colômbia. Para tanto, foram utilizados 19 descritores morfológicos, avaliados in situ em nove municípios e analisados por meio de estatísticas descritivas, análise de componentes principais, correlação e conglomerados. Na avaliação dos caracteres quantitativos para todas as populações, observou-se que os descritores mais variáveis foram: número de dentes da folha inferior (DHI), comprimento da folha inferior (LHI), largura da folha superior (AHI) e número de dentes da folha superior (DHS). Entre os indivíduos de Blanca de Jericó e Piartal e dentro deles, observou-se grande segregação quanto à cor, formato da panícula e folha, cor do caule, presença de dentes e axilas nas folhas superiores e inferiores. É proposta uma chave de classificação que permite no campo poder diferenciar morfologicamente os genótipos de Piartal e Blanca de Jericó. Esta pesquisa mostra que, entre os genótipos mais cultivados no departamento de Boyacá, ainda existe uma importante diversidade fenotípica em nível inter e intraindividual, em razão do estado fenológico e das condições agroclimatológicas das diferentes regiões produtoras.

Abstract Background Reliable devices that quantitatively monitor the level of neuromuscular blockade after neuromuscular blocking agents’ administration are crucial. Electromyography and acceleromyography are two monitoring modalities commonly used in clinical practice. The primary outcome of this study is to compare the onset of neuromuscular blockade, defined as a Train-Of-Four Count (TOFC) equal to 0, as measured by an electromyography-based device (TetraGraph) and an acceleromyography-based device (TOFscan). The secondary outcome was to compare intubating conditions when one of these two devices reached a TOFC equal to 0. Methods One hundred adult patients scheduled for elective surgery requiring neuromuscular blockade were enrolled. Prior to induction of anesthesia, TetraGraph electrodes were placed over the forearm of patients’ dominant/non-dominant hand based on randomization and TOFscan electrodes placed on the contralateral forearm. Intraoperative neuromuscular blocking agent dose was standardized to 0.5 mg.kg−1 of rocuronium. After baseline values were obtained, objective measurements were recorded every 20 seconds and intubation was performed using video laryngoscopy once either device displayed a TOFC = 0. The anesthesia provider was then surveyed about intubating conditions. Results Baseline TetraGraph train-of-four ratios were higher than those obtained with TOFscan (Median: 1.02 [0.88, 1.20] vs. 1.00 [0.64, 1.01], respectively, p < 0.001). The time to reach a TOFC = 0 was significantly longer when measured with TetraGraph compared to TOFscan (Median: 160 [40, 900] vs. 120 [60, 300] seconds, respectively, p < 0.001). There was no significant difference in intubating conditions when either device was used to determine the timing of endotracheal intubation. Conclusions The onset of neuromuscular blockade was longer when measured with TetraGraph than TOFscan, and a train-of-four count of zero in either device was a useful indicator for adequate intubating conditions. Clinical trial number and registry URL NCT05120999, https://clinicaltrials.gov/ct2/show/NCT05120999.

Abstract The litterfall that accumulates in the forest soil and its further decomposition play an important roll in the maintenance of productivity in different terrestrial ecosystems since its constitute the main flow of nutrients to the soil. The objective of this study was to evaluate the production of litterfall, its nutrient return thru litterfall deposition and macronutrient use efficiency. The study was conducted in Linares, Crucitas and Los Ramones, state of Nuevo León, México. Average litterfall deposition was 5 800, 5 270 and 6 596 kg ha−1 year−1 for Linares, Crucitas and Los Ramones, respectively. Total nutrient return thru litterfall followed the sequence: Linares > Crucitas > Los Ramones, with value of 135, 122 and 101 kg ha−1 year−1, respectively. Even though the return of P thru litterfall was the lowest, P nutrient use efficiency was higher with respect to Ca, Mg and K. Greatest nutrient use efficiency in terms of Ca and Mg was observed in Los Ramones, K in Crucitas and P in Linares. The results showed that there exist spatial and temporal variation in the production of litterfall, nutrient return and nutrient use efficiency between studied sites. Thus, litterfall deposition, nutrient return and nutrient use efficiency between sites depend on stand composition and richness, edaphic properties, litterfall quality, and plant phenology.

Resumen La hojarasca que se acumula sobre el piso forestal y su posterior descomposición juegan un papel importante en el mantenimiento de la productividad de los diferentes ecosistemas terrestres al constituir el principal flujo de nutrientes al suelo. El objetivo del estudio fue evaluar la producción de hojarasca y retorno de nutrientes a través de la caída de la hojarasca y la eficiencia en el uso de macro-nutrientes. El estudio se realizó en los sitios de Linares, Crucitas y Los Ramones, en el Estado de Nuevo León, México. El promedio de caída de hojarasca fue de 5 800, 5 270 a 6 596 kg ha−1 año−1 para Linares, Crucitas y Los Ramones, respectivamente. El retorno total de nutrientes siguió la secuencia: Linares > Crucitas > Los Ramones con valores de 135, 122 y 101 kg ha−1 año−1, respectivamente. A pesar de que el retorno de P en la hojarasca fue menor, la eficiencia del uso de este nutriente fue mayor que la presentada por el Ca, Mg ó K. La mayor eficiencia de uso de nutrientes en términos de Ca y Mg se observó en Los Ramones, el K en Crucitas y el P en linares. Existe variación espacial y temporal en la producción de hojarasca, retorno de nutrientes y la eficiencia en su uso entre los sitios evaluados. Por tanto, la caída de hojarasca, retorno de nutrientes y uso eficiente en estos sitios dependen de la riqueza de especies, diferencias edáficas, calidad de la hojarasca y fenología de las diferentes especies.

Abstract Objective: This study aims to analyze the probability of an increase in mortality due to venous thrombosis of the lower limbs (VTLL), and it´s relation to days of hospital stay. Materials and methods: We included all hospital records of patients with thrombosis in the lower limbs as main diagnosis from open access national datasets, we obtained epidemiological description of diagnosis, length of stay and mortality. Results: Deep vein thrombosis (DVT) constituted 69% (1223/1785) of cases. From all the patients registered, 47 (2.63%) died. The highest mortality rate was observed in older adults, and patients with a longer hospital stay. Conclusions: Patients diagnosed with DVT, who endure a longer hospital stay, face a major risk of death.

Resumen Objetivo: Analizar la probabilidad de un aumento de la mortalidad por trombosis venosa de miembros inferiores (TVMI) y su relación con los días de estancia hospitalaria. Material y métodos: Se incluyeron los registros de egreso hospitalario con el diagnóstico de VTLL, obtenido de las bases de datos de los hospitales públicos de México. Resultados: El diagnóstico más frecuente fue la trombosis venosa profunda (TVP) con el 69% (1223/1785) de los casos. Del total de casos se registraron 47 (2.63%) muertes, la mortalidad fue más alta a mayor edad y estancia hospitalaria. Conclusiones: Los pacientes diagnosticados por TVP y con estancia hospitalaria prolongada, presentaron mayor mortalidad.

ABSTRACT Action planning and decision-making in the sugarcane management chain depend on yield estimates, which, in turn, vary with the soil. This study aimed to describe an applicable method of classifying sugarcane productivity into three categories, based on soil properties (medium, low, and high), determining which is most associated with biomass production. To this end, we applied the machine learning methods Naïve Bayes, Decision Trees, and Random Forest, as they proved to be useful tools for faster and more accurate results. Our results indicate that Random Forest is the most suitable for classifying all yield categories, and Naïve Bayes had good results for classification into “medium” and “low” and potential for solving multiclass problems in agriculture. Organic matter was the property most closely related to sugarcane biomass yield by the Random Forest and Decision Trees algorithms. The methods described can be used to obtain subsidies for sugarcane chain management, contributing to more sustainable decisions.

Resumen En esta investigación se planteó como objetivo caracterizar color, textura y calidad sanitaria de pan adicionado con maíz criollo y cúrcuma. Se realizaron 14 diferentes panes empleando seis tipos de maíces (M1, M2, M3, M4, M5 y M6). Los principales hallazgos fueron a) El color de los maíces, harinas nixtamalizada y masas tuvieron diferencia significativa (p < 0.05) al comparar valores medios de parámetros de Luminosidad, a* y b*. Los maíces azules y rojizo M2 (37.01), M3 (44.06) y M6 (41.07) y, amarillos y amarillo-naranja M1 (21.26), M4 (15.92) y M5 (26.01) presentaron los valores inferiores en L* y superiores en b*, respectivamente. La menor diferencia en color ∆E encontrada en el proceso de transformación de maíz a harina y masa, fue para maíces amarillos. b) En el pan de maíz se encontraron diferencias significativas en variable a* al compararse el mismo tipo de pan durante tres días consecutivos, en los panes BM1, BM5 y BM6, con una disminución de 7.5, 2.6 y 16.9%, con respecto al primer día. c) La calidad sanitaria del pan de trigo mejora con la adición de maíz nixtamalizado y cúrcuma. En los panes adicionados de maíz los que presentaron menor cantidad de colonias de hongos fueron los maíces azules y rojo (M2, M3 y M6). d) La dureza del pan de maíz criollo y cúrcuma no presentó diferencias durante tres días consecutivos beneficiando su conservación. El pan de maíz amarillo y cúrcuma BM1-C mostró incrementos en la dureza en los días 2 y 3.

Abstract The objective of this research was to characterize the color, texture and sanitary quality of bread added with creole corn and turmeric. Fourteen different breads were made using six types of corn (M1, M2, M3, M4, M5 and M6). The main findings were a) The color of the corn, nixtamalized flours and doughs had a significant difference (p < 0.05) when comparing mean values of Luminosity, a* and b* parameters. Blue and reddish corn M2 (37.01), M3 (44.06) and M6 (41.07) and, yellow and yellow orange M1 (21.26), M4 (15.92) and M5 (26.01) presented the lowest values in L* and highest in b*, respectively. The smallest difference in color ∆E found in the transformation process from corn to flour and dough, was for yellow corn. b) In corn bread, significant differences in variable a* were found when comparing the same type of bread for three consecutive days, in breads BM1, BM5 and BM6, with a decrease of 7.5, 2.6 and 16.9%, with respect to the first day. c) The sanitary quality of wheat bread improves with the addition of nixtamalized corn and turmeric. The blue and red corn (M2, M3 and M6) showed the lowest number of fungal colonies in the breads with corn additives. d) The hardness of the bread made with creole corn and turmeric did not show differences during three consecutive days, benefiting its conservation. The yellow corn and turmeric bread BM1-C showed increases in the hardness on days 2 and 3, and the yellow corn and turmeric bread BM1-C showed increases in the hardness on days 2 and 3.

ABSTRACT This article proposes two methodologies for the detection of lesions in the retina, which may indicate the presence of diabetic retinopathy (DR). Through the use of digital image processing techniques, it is possible to isolate the pixels that correspond to a lesion of RD, to achieve segmenting microaneurysms, the edges of the objects contained in the image are highlighted in order to detect the contours of the objects to select by size those that meet an area of 15 to 25 pixels in the case of 512x512 images and identify the objects as possible microaneurysms, while for the detection of exudates the green channel is selected to contrast the luminous objects in the retinography and from the conversion to gray scale, a histogram is graphed to identify the ideal threshold for the segmentation of the pixels that belong to the exudates at the end of the optical disk previously identified by a specialist. A confusion matrix supervised by an ophthalmologist was created to quantify the results obtained by the two methodologies, obtaining a specificity of 0.94 and a sensitivity of 0.97, values that are outstanding to proceed with the classification stage.

RESUMEN Este artículo propone dos metodologías para la detección de lesiones en la retina, que pueden significar la presencia de retinopatía diabética (RD). Mediante el uso de técnicas de procesamiento de imágenes digitales se logra aislar los pixeles que corresponden a una lesión propia de RD, para lograr segmentar microaneurismas se resaltan los bordes de los objetos contenido en la imagen con la finalidad de detectar los contornos de los objetos para seleccionar por tamaño los que cumplan con un área de 15 a 25 pixeles en el caso de imágenes de 512x512 y se identifiquen los objetos como posibles microaneurismas, mientras que para la detección de exudados se selecciona el canal verde para contrastar los objetos luminosos en la retinografía y a partir de la conversión a escala de grises se grafica un histograma para identificar el umbral idóneo para la segmentación de los pixeles que pertenecen a los exudados al final eliminar el disco óptico previamente identificado por un especialista. Se creó una matriz de confusión supervisada por un oftalmólogo para cuantificar los resultados obtenidos por las dos metodologías obteniendo una especificidad del 0.94 y una sensibilidad del 0.97, unos valores que son sobresalientes para proceder con la etapa de clasificación.

BACKGROUND: Sickle cell anaemia is a common global life-threatening haematological disorder. Most affected births occur in sub-Saharan Africa where children usually go undiagnosed and die early in life. Uganda's national sickle cell screening programme was developed in response to a 2014 sickle cell surveillance study that documented a high disease prevalenceOBJECTIVE: This study describes the temporal and financial aspects of Uganda's 2014-2019 sickle cell screening programmeMETHODS: National sickle cell screening data from Uganda's Central Public Health Laboratories were used to calculate turn-around times (TATs) from sample collection to delivery, testing, and result reporting for blood samples collected from February 2014 to March 2019. The parameters affecting specific TATs were assessed. The exact programme expenditures were analysed to determine cost per test and per positive sickle cell disease case detectedRESULTS: A total of 278 651 samples were analysed. The median TAT from sample collection to laboratory receipt was 8 days (interquartile range [IQR]: 6-12), receipt to testing was 3 days (IQR: 1-7), and testing to result reporting was 6 days (IQR: 3-12). Altogether, the sample continuum averaged 16 days (IQR: 11-24). Lower level healthcare facilities were associated with longer sample delivery TATs. Calendar months (January and December) and larger sample volumes impacted testing and result reporting TATs. The cost per test was $4.46 (United States dollars [USD]) and $483.74 USD per positive case detectedCONCLUSION: Uganda's sickle cell screening programme is efficient and cost-effective. Universal newborn screening is the best strategy for detecting sickle cell anaemia in Uganda

ABSTRACT Objective: The aim of this study was to develop a risk prediction model for major postoperative infection (MPI) after pediatric heart surgery and to validate the model of the Society of Thoracic Surgeons (STS). Materials and methods: We analyzed a retrospective cohort of 1,025 children who underwent heart surgery with cardiopulmonary bypass (CPB) from 2000 to 2010. We used a logistic regression model, which was validated. Results: Of the 1,025 patients, 59 (5.8%) had at least one episode of MPI (4.8% had sepsis, 1% had mediastinitis, 0% had endocarditis). Hospital mortality (63% vs. 13%; p < 0.001), as well as duration of postoperative ventilation (301.6 vs. 34.3 hours; p < 0.001) and intensive care unit stay (20.9 vs. 5.1 days; p < 0.001) were higher in patients with MPI. The predictive factors found were age, sex, weight, cyanotic heart disease, RACHS-1 3-4, Ross-modified functional class IV, previous hospital stay, and previous history of mechanical ventilation. The proposed model had a c-statistic of 0.80 (95% CI: 0.74-0.86) and was considered as clinically useful. The STS model showed a c-statistic of 0.78 (95% CI: 0.71-0.84) and a Hosmer-Lemeshow of 18.2 (P = 0.020). A comparison between the two models was made using an accurate Fisher test. Conclusion: A model with good performance and calibration was developed to preoperatively identify children at high risk for severe infection after cardiac surgery with CPB. The STS model was also validated and was found to have a moderate discrimination performance.

RESUMEN Objetivo: Desarrollar un modelo de predicción de riesgo para infección posoperatoria mayor (IPM) a cirugía cardiaca pediátrica y validar el de la Society of Thoracic Surgeons (STS). Materiales y métodos: Se analizó una cohorte retrospectiva de 1025 niños sometidos a cirugía cardiaca con circulación extracorpórea (CEC) del 2000 al 2010. Se empleó un modelo de regresión logística y se validó el modelo. Resultados: De los 1025 pacientes, 59 (5,8%) tuvieron al menos un episodio de IPM (4,8% sepsis, 1% mediastinitis, 0% endocarditis). La mortalidad hospitalaria (63% vs. 13%; p<0,001), al igual que la duración de la ventilación posoperatoria (301,6 vs. 34,3 horas; p<0,001) y la estancia en la unidad de cuidados intensivos (20,9 vs. 5,1 días; p <0,001) fueron mayores en los pacientes con IPM. Los factores predictores fueron: edad, sexo, peso, cardiopatía cianótica, RACHS-1 3-4, clase funcional IV modificada por Ross, estancia hospitalaria previa y antecedente de ventilación mecánica. El modelo tuvo un c-estadístico de 0,80 (intervalo de confianza [IC] al 95%: 0,74-0,86) y es clínicamente útil. El modelo de la STS mostró un c-estadístico de 0,78 (IC 95%: 0,71-0,84) y Hosmer-Lemeshow de 18,2 (p = 0,020). Se realizó una comparación entre ambos modelos empleando una prueba exacta de Fisher. Conclusión: Se desarrolló un modelo para identificar preoperatoriamente a niños con alto riesgo de infección grave después de una cirugía cardiaca con CEC con buen desempeño y calibración. Asimismo, se validó el modelo de la STS con moderada discriminación.