Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Introducción: El índice pronóstico nutricional es un marcador inmuno-nutricional que puede ser útil como factor pronóstico en tumores gastrointestinales. Objetivo: Evaluar supervivencia de pacientes con adenocarcinoma pancreático avanzado tratados con quimioinmunoterapia según índice pronóstico nutricional, según parámetros clínico-patológicos y tratamiento. Métodos: Se realizó estudio retrospectivo y observacional en pacientes que recibieron quimioterapia gemcitabina-oxaliplatino combinado a nimotuzumab (n=118), en el Hospital Ameijeiras, entre 2014 y 2019. Se evaluó supervivencia por método Kaplan-Meier, y regresión de Cox, para determinar los factores pronósticos independientes de supervivencia. Resultados: El punto de corte seleccionado fue 40 (sensibilidad 52,9 % y especificidad 85,7 % (p = 0,019), con área bajo la curva de 0,693. Para pacientes con índice menor de 40, la supervivencia fue más baja respecto a los pacientes con índice ≥ 40 (11,4 meses frente a 16,0 meses; p=0,001), con un HR de 1,7 (1,13-2,60; p=0,011). Las variables mayormente asociadas con índice pronóstico nutricional altos son pacientes con sesenta años o menos; ECOG cero, índice de masa corporal ≥25 Kg/m2 y albúmina sérica >3,5g/dL (x² < 0,05). Los pacientes con índice ≥ 40 tienen medianas de supervivencia más altas que pacientes con índice < 40 en las variables seleccionadas con p < 0,05, excepto el índice de masa corporal. Conclusiones: Este trabajo constituye el primer reporte nacional de utilización del índice pronóstico nutricional como pronóstico de supervivencia en pacientes con cáncer de páncreas avanzado.Palabras clave: cáncer de páncreas avanzado; pronóstico; albúmina; linfocito; supervivencia; nimotuzumab.

Introduction: Sickle cell disease is a highly prevalent hemoglobinopathy worldwide. Sickle cell hemolysis produces significant endothelial dysfunction by multiple mechanisms that include a significant state of oxidative stress and dyslipidemia accentuated in the vaso-occlusive crisis.Objective: To characterize the asymptomatic and crisis states in sickle cell patients based on the evaluation of the redox state and the lipid profile.Methods: From a cross-sectional analytical study, carried out at the Hematological Center of Santiago de Cuba, the asymptomatic states and vaso-occlusive crisis were compared using the contrast of means. The variables were related to the use of Pearson's correlation.Results: A significant difference was observed in the evaluated groups regarding the concentrations of triacylglycerides (p = 0.003) and HDL-cholesterol (p = 0.009), as well as malonyldialdehyde as an indicator of oxidative damage to lipids (p = 0.001) and the glutathione (p = 0.001) and catalase (p = 0.005) expressing antioxidant response in patients. Similarly, triacylglycerides and cholesterol, LDL-cholesterol and cholesterol, LDL-cholesterol and triacylglycerides were positively related and, negatively, malonyldialdehyde and HDL-cholesterol, malonyldialdehyde and catalase, as well as malonyldialdehyde and glutathione.Conclusions: During the vaso-occlusive crisis state, the marked oxidative damage to lipids and depression of antioxidant mechanisms reflected in this study is evident. The use of biomarkers evaluating redox status allowed a better characterization of them, contributing to the evaluation of patients, so they could be used as a tool during their follow-up.

Managing commuting in urban centers implies attending to critical factors regarding the experiencein the use of transport and urban space. This paper investigates how urban mobility apps contributeand improve the user experience in public passenger transport. Thus, this work analyzed thesocioeconomic characteristics of the users, the frequency of use, the types of mobility applicationsand the users' perception of the mobility as a service (MaaS). Therefore, a survey was carried outwith 138 users of the urban passenger transport system in the Metropolitan Region of São Paulo.For data analysis, descriptive statistics and Simple Correspondence Analysis were applied. Thework obtained statistically significant differences among the MaaS and the frequency of use(Google Maps, X² = 120.22, p&lt;0.05) and (Moovit, X² = 39.1, p&lt;0.05). The authors also observedstatistical and significant differences of the quality Google Maps and Moovit services (p&lt;0.05).This result indicates that the participants have positive experiences with the use MaaS and itcontribute to the effective planning of daily commuting. The work concluded that MaaS contributeto decision-making in daily commuting planning, with emphasis on route planning services,obtaining real-time and traffic information, preference of transport mode and the trip fare value.

Colombia is one of the Latin American countries that still has difficulties with the adoption of newtechnologies that contribute to the digital transformation, these difficulties arise due to thegeographical complexity of the country, which prevents the benefits of the digital era to reach theentire territory. Studies show that 50 % of Colombian households do not use the internet, and 38 %of people do not have access to data. This is the case where the Unidad Agroambiental El Vergel islocated, a rural area that does not have internet services. Taking into account this, an alternative tosolve the communication problem is presented, such as radio link systems, which are systems thateasily adapt to the geographical conditions where they are implemented, in addition to this; they arewireless systems that work through the propagation of electromagnetic waves. In this way it isdesired to provide data to the Unidad Agroambiental El Vergel from the Universidad deCundinamarca in the city of Facatativá, under the Longley-Rice model it is obtained as a result that&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; the transmission output power under the technical specifications (Pt=105.95 dBm), is higher thanthe theoretical transmission output power (Pt= 38.58 dBm). This suggests that the radio-link systemequipment is 174.62 % efficient, thus concluding that the system responds efficiently to the need toprovide data or internet services in a rural area lacking such benefit.

For years, industrial processes have been seeking the minimum expenditure of resources withoutlosing quality in the finished process. The oil refinery of Cienfuegos is no stranger to this currentsituation, which is why every day efforts are made to achieve efficiency in each of its processes,without reducing the quality of products. In a process of continuous improvement, it is necessary todetect every day possible factors that weaken an organization, to know them and correct oreliminate them. In a visual inspection, a problem was detected in pump P-01-321, with throttlingregulation method. This equipment is a Soviet model НПС 65/35-500 multi-stage centrifugal pumpthat operates the gas washing system of the diesel hydrofinisher. The throttling in the system was&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; causing an oversizing of the equipment for the process, of the 500 m of load and 55 m3/h of flowthat the machine, can deliver only 6 m3/h are needed in the process. Due to this, temperatures of60°C are detected, 20°C above the 40°C at which the fluid operates. In addition, vibrations reachvalues that can cause damage because the operating point is far from the range of 70 to 120 % ofnominal flow recommended for minimum vibrations. Finally, it is shown that the replacement ofthe centrifugal pump by a volumetric pump avoids possible breakage due to equipment malfunctionand at the same time reduces the demand for electricity.

Well cementing is a routine activity in the oil industry, but requires a series of care, as it is anexpensive activity that, when not carried out properly, can cause extra expenses in addition toenvironmental damage. This work aimed to determine statistically defined compositions of amaterial that can efficiently replace Special Portland Cement for oil wells. For this, thecharacterization of the materials was carried out by means of laser granulometric analysis, chemicalanalysis, X-ray diffraction, and thermal analysis. The compositions were determined using themixture design methodology, using the central composite experimental design (CCD), andsubjected to simple compressive strength tests and thermal analysis, to determine optimalcompositions with the closest approximation to the characteristics of Special Portland Cement. foroil wells. The results obtained pointed to the feasibility of using the mixtures found, allowing thedefinition of 9 compositions that presented satisfactory performance, and can be used for thispurpose. Therefore, it was concluded that the compositions found and the models developedpresented a potentially satisfactory performance for use as an alternative material for oil wells,requiring mechanical and economic validation for its use.

This work presents a technical diagnostic algorithm for the Hyundai Himsen 9H25/33 engines ofthe Habana 220 Fuel-Oil Power Plant, located at the western part of Havana, based on theintegration of technologies and tools for diagnosis. The proposal is pertinent because it promoteshigh precision in the determination of the failure modes of the defects. It began with the study ofthe documentation and the observation of the maintenance and operation activities, which allowsunderstanding the set of functional systems and the interrelation between them. In addition, 19technical and technological parameters of the engine and the way to measure, record and comparethem with their damning limits were identified. In the location of generator sets, a concurrentanalysis was carried out where it was patented that the failure mode of the temperature higher than380ºC, is the defective functioning of the injector, due to the fact that the injector does not atomizethe fuel correctly inside the combustion chamber. The proposal of the technical diagnosis algorithmmakes it possible, to the extent that the defects do not transcend to failures and the failures do nottranscend to failures, to reduce maintenance costs and the impact on production, positivelyimpacting the availability and energy efficiency, and the care for the environment.

Reducing waste disposal from the rock industry and reducing sand consumption in the civilconstruction sector is important for sustainable development. One strategy to minimize theseproblems is to use waste as partial substitutes in the production of structural concrete. Thus, thisstudy aims to analyze the physical and mechanical properties of structural concrete modified by theaddition of micronized ceramic waste of marble and quartzite and evaluate the feasibility of usingthese materials in civil construction. The dosage and molding of the specimens in the dimensions of10 cm x 20 cm was carried out, with partial replacement in the 20 % content for both residues,individually. Physical and chemical characterizations were carried out for the materials used, andthen the physical and mechanical performance of the concretes was evaluated through tests ofabsorption, simple compression strength, and tensile strength by diametrical compression. Theincorporation of these residues provided an increase in absorption and again in tensile strength.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Concrete modified with marble residue showed loss of compressive strength and concrete modifiedwith quartzite residue gained compressive strength. Therefore, the use of micronized marble andquartzite waste, as a partial substitute for the conventional fine aggregate, is a viable alternative forinserting material in a new production cycle.

The worldwide production of tires grows due to the increase in the automobile industry, and it istough to dispose of waste tires as the availability and capacity of landfills decreases. Therefore, themain objective of this study is to evaluate the performance of concrete with the replacement of fineaggregate by rubber waste from waste tires. Therefore, a study of the dosage and molding of thespecimens in the dimensions of 10 x 20 cm was carried out, with replacement of the fine aggregate(quartz sand) by 10 and 20 % of rubber residues, and the properties of the concrete were evaluatedby through the tests of Compression Strength, Tensile Strength by Diametral Compression, andDetermination of Water Absorption. The results allowed us to conclude that the replacement ofconventional fine aggregate by rubber residues promoted a reduction in the compressive and tensilestrength of concrete and increased water absorption. Therefore, treatment of these residues isnecessary since the concrete modification with tire rubber residues without prior treatment provideda significant loss in strength.