Observer-based control for plasma glucose regulation in type 1 diabetes mellitus patients with unknown input delay.

This article introduces an observer-based control strategy tailored for regulating plasma glucose in type 1 diabetes mellitus patients, addressing challenges like unknown time-varying delays and meal disturbances. This control strategy is based on an extended Bergman minimal model, a nonlinear glucose-insulin model to encompass unknown inputs, such as unplanned meals, exercise disturbances, or delays. The primary contribution lies in the design of an observer-based state feedback control in the presence of unknown long delays, which seeks to support and enhance the performance of the traditional artificial pancreas by considering realistic scenarios. The observer and control gains for the observer-based control are computed through linear matrix inequalities formulated from Lyapunov conditions that guarantee closed-loop stability. This design deploys a soft and gentle dynamic response, similar to a natural pancreas, despite meal disturbances and input delays. Numerical tests demonstrate the scheme's effectiveness in glycemic level regulation and hypoglycemic episode avoidance.

Insights into the mechanisms of L. salivarius CECT5713 resistance to freeze-dried storage.

Ligilactobacillus salivarius is a lactic acid bacterium exhibiting several health benefits. However, it is sensitive to freeze-drying and storage in the dried state, thus limiting its commercial exploitation. Our objective was to identify markers of cell resistance by applying multiscale characterization to L. salivarius CECT5713 cell populations exhibiting different resistance to freeze-dried storage. Cells were produced under two different sets of production conditions differing in the culture parameters (temperature, neutralizing solution, and harvesting time) and the protective formulation composition. The culturability, membrane integrity, and cell biochemical composition assessed by Fourier transform infrared (FTIR) micro-spectroscopy were evaluated after freezing, freeze-drying, and subsequent storage at 37 °C. Membrane properties (fatty acid composition, membrane fluidity, and phospholipid organization), as well as matrix physical properties (glass transition temperature and water activity), were determined. The most resistant cells to freeze-dried storage exhibited the highest cyclic fatty acid content and the most rigid membrane. Freeze-drying and storage induced damage to membrane integrity, proteins, nucleic acids, and constituents of the peptidoglycan cell wall. From the FTIR spectra analysis, we propose the minimization of the variations of the 1058 and 1714 cm-1 vibration bands (that arise mainly from symmetric C-O-C stretching and CO stretching, respectively) induced by the freeze-drying process as a marker of storage stability. We confirmed that a matrix with a glass transition temperature at least 50 °C higher than the storage temperature is crucial for L. salivarius CECT5713 storage stability. In addition, this work explored promising FTIR methods for a better understanding of the protection mechanisms involved.

Effect of protective agents on the storage stability of freeze-dried Ligilactobacillus salivarius CECT5713.

Ligilactobacillus salivarius is a lactic acid bacterium exhibiting several health benefits but remains commercially underexploited due to its inability to survive during long-term storage in the dried state. Our objective was to study the effect of various protective molecules (maltodextrin, trehalose, antioxidants, and fructooligosaccharides), being efficient on other bacteria, on the freeze-dried stability of L. salivarius CECT5713. The culturability was evaluated after freezing, freeze-drying, and subsequent storage at 37 °C, as well as the biochemical composition of cells in an aqueous environment using Fourier transform infrared (FTIR) micro-spectroscopy. The assignment of principal absorption bands to cellular components was performed using data from the literature on bacteria. The membrane fatty acid composition was determined after freeze-drying and storage. Glass transition temperature of the liquid and freeze-dried bacterial suspensions and water activity of the freeze-dried samples were measured. The best storage stability was observed for the formulations involving maltodextrin and antioxidants. The analysis of the FTIR spectra of freeze-thawed cells and rehydrated cells after freeze-drying and storage revealed that freeze-drying induced damage to proteins, peptidoglycans of the cell wall and nucleic acids. Storage stability appeared to be dependent on the ability of the protective molecules to limit damage during freeze-drying. The inactivation rates of bacteria during storage were analyzed as a function of the temperature difference between the product temperature during sublimation or during storage and the glass transition temperature, allowing a better insight into the stabilization mechanisms of freeze-dried bacteria. Maintaining during the process a product temperature well below the glass transition temperature, especially during storage, appeared essential for L. salivarius CECT5713 storage stability. KEY POINTS: • L. salivarius CECT5713 highly resisted freezing but was sensitive to freeze-drying and storage. • Freeze-drying and storage mainly altered cell proteins, peptidoglycans, and nucleic acids. • A glassy matrix containing maltodextrin and an antioxidant ensured the highest storage stability.

Nutritional and technological properties of a quinoa (Chenopodium quinoa Willd.) spray-dried powdered extract.

The relevance of an appropriate nutrition requires innovation in the design of food ingredients. The goal of this work was to obtain a powdered extract of quinoa by using spray-drying. To this aim, quinoa flour was suspended in water to obtain a soluble fraction mainly composed of proteins, starch, fiber, lipids, antioxidants and minerals. The spray-drying conditions of this quinoa soluble fraction were set-up in terms of inlet temperatures (150, 160, 170 and 180 °C) and feed flow (4.5, 7.5, 10.5 mL/min). The obtained powders were characterized by determining the proximate composition, antioxidant activity, microstructure, fatty acids' profile, and starch and proteins' structures. A correlation among the drying parameters and the chemical and functional attributes of the powders was addressed using principal component analysis. From a technological viewpoint the use of moderate feed flows (7.5 mL/min) and high inlet temperatures (180 °C) was the best combination to obtain high powder yields (85% d.b.), low aw (0.047 ± 0.005) and high solids content (0.956 ± 0.005). The drying temperature positively affected the structure of starch, improving swelling and favoring moderate agglomeration which increases the encapsulation properties of quinoa. These results support the use of spray-drying as a suitable method to obtain powdered extracts of quinoa without affecting the nutritional value, thus supporting their use as functional ingredients in the formulation of ready-to-eat foods.

Alcance de una estrategia educativa por competencias en el desarrollo del proceso de enfermería / Scope of an educational strategy based on skills in the development of nursing process

Resumen:

Introducción: la enfermera utiliza como herramienta fundamental el proceso de enfermería, que le permite asegurar cuidados que vinculen el conocimiento teórico con la práctica clínica; de ahí la importancia del desarrollo de la competencia profesional de enfermería mediante una estrategia educativa. Objetivo: evaluar el alcance de una estrategia educativa en el desarrollo de competencias en el proceso de enfermería.

Metodología: estudio cuasiexperimental; se aplicó una estrategia habitual a un grupo control (GC), formado por 10 enfermeras generales que cursaban el octavo semestre de la licenciatura en enfermería; asimismo, se aplicó una estrategia educativa por competencias a un grupo de intervención (Gl), formado por 10 enfermeras generales de un hospital de segundo nivel. Para estimar el grado de desarrollo de competencias en el proceso de enfermería, para el núcleo declarativo se construyó un instrumento validado con 0.85 (prueba de Kuder-Richardson); en el núcleo procedimental se evaluó el registro clínico de enfermería; para el núcleo actitudinal se desarrolló una lista de cotejo basada en trato digno; para el análisis estadístico se aplicaron pruebas no paramétricas, U de Mann-Whitney y prueba de Wilcoxon. Resultados: la medición basal de ambos grupos fue semejante al aplicar U de Mann-Whitney. En la aplicación de Wilcoxon, después de las intervenciones en el Gl se encontraron cambios significativos en los tres núcleos. En el GC se encontró un cambio significativo solo en el núcleo actitudinal. Conclusiones: la aplicación de un método de enseñanza en la práctica asistencial de la enfermera, con un enfoque deliberado para resolver problemas, favoreció el desarrollo de la competencia.

Abstract:

Introduction: The nurse uses as a basic tool the nursing process, with which she links theoretical knowledge with clinical practice; therefore, developing nursing professional competence through educational strategies is essencial.

Objective: To evaluate the scope of an educational strategy in the development of skills in nursing process.

Methods: Quasi-experimental study; we applied a common strategy in a control group (CG), which consisted of 10 general nurses; also, we applied an educational strategy competency in an intervention group (IG), consisting of 10 general nurses from a secondary hospital. To estimate the degree of development of skills in nursing process, to the declarative core we constructed an instrument, validated with 0.85 by Kuder-Richardson; in the procedural core we evaluated the nursing clinical record; to the attitudinal core we developed a list comparison based on fair treatment. For statistical analysis we used Mann-Whitney U and Wilcoxon test. Results: In the baseline measurement both groups were similar when we applied the Mann Whitney U. When we applied the Wilcoxon test, after the interventions in the IG, we found significant changes in the three cores. In the CG we found only one change in the core attitudinal. Conclusions: The application of a teaching method in clinical practice of nurse, with a deliberate approach to problem solving, favored the development of competition.

Teorías y modelos de enfermería. Una aproximación a la lectura crítica / Nursing theories and models. An approach to critical reading

Resumen

Introducción: la educación en enfermería a través del tiempo ha sido rutinaria y pasiva lo que requiere desarrollar aptitudes de tipo reflexivo, que reflejen una actuación profesional de calidad para la atención del paciente, para ello demanda tener habilidades como la lectura crítica que al desarrollarla permite el florecimiento de una actitud crítica la cual lleva implícito el desarrollo de la autocrítica.

Objetivo: comparar el nivel de desarrollo para la habilidad de lectura crítica de textos de teorías y modelos de enfermería alcanzada mediante dos estrategias educativas diferenciadas.

Metodología: estudio cuasiexperimental, con un grupo experimental (GE) integrado por 12 alumnos del 7° semestre de Licenciatura de Enfermería y un grupo control (GC) conformado por 11 alumnos del mismo semestre. Para estimar el grado de desarrollo de habilidad para la lectura crítica de textos teóricos se utilizó un instrumento cuyo índice de confiabilidad fue de 0.96. El GE fue sometido a una estrategia que promueve ambientes propicios para la reflexión y crítica, el grupo control fue continuo con la enseñanza habitual.

Resultados: en la medición basal no se encontraron diferencias significativas entre ambos grupos. Al comparar los grupos posterior a la intervención, encontramos diferencia estadísticamente significativa para el GE.

Conclusiones: un ambiente propicio para confrontar la experiencia con la literatura científica y someterla a la crítica en este caso sobre teorías y modelos de enfermería favorece el desarrollo de la aptitud para la lectura crítica de textos teórico.

Summary

Introduction: through the years nursing education has been monotonous and passive so it requires to develop reflexive skills that reflect a professional performance and quality patient care, thus it is necessary to apply abilities such as critical reading that allows the development of a critical attitude which implies the evolution to self-criticism.

Objective: in order to compare the level of skill development for critical reading of texts, in nursing theories and models, achieved by two different educational strategies.

Methodology: a quasi-experimental study was conducted with an experimental group (GE) composed of 12 students of 7th semester of Bachelor in Nursing and a control group (GC) composed of 11 students in the same semester. To estimate the degree of skill development for critical reading of theoretical texts an instrument of which reliability index was 0.96 was used. The GE was subjected to a strategy that fosters reflective and critical environments, the GC kept regular education.

Results: in the baseline measurement there were no significant differences between groups. When comparing post-intervention groups, we found statistically significant difference for the GE.

Conclusions: a conducive environment to confront the experience with scientific literature and to subject it to criticism, in this case on nursing theories and models, favors the development of skills for critical reading of theoretical texts.

Aproximación a la lectura crítica de textos teóricos de enfermería. Elaboración y validación de un instrumento / Approaching to critical reading of theoretical nursing texts. Elaboration and validation of an instrument

Introducción: Desarrollar aptitudes que faciliten el camino para el aprendizaje y la elaboración del conocimiento a los alumnos de la licenciatura de enfermería es básico para su formación, entre ellas la lectura crítica de textos teóricos. Considerar estos atributos en el proceso educativo requiere de poner énfasis a la forma en que se construyen instrumentos que se aproximen a la realidad objetiva de la evaluación. Objetivo: Construir y validar un instrumento que permita identificar la forma en que los alumnos de licenciatura de enfermería se aproximan a las fuentes de información de textos teóricos durante su proceso formativo. Metodología: Se construyó y validó un instrumento de lectura crítica de textos teóricos en enfermería, posterior a la revisión y análisis por un grupo de expertos en lectura crítica, el instrumento quedó conformado por 86 items y se aplicó a un grupo piloto (estudiantes del 7º semestre de la licenciatura en enfermería). Resultados: La consistencia interna se determinó mediante la prueba de Kuder-Richardson No. 21, resultando un índice de 0.96. Discusión: El proceso de construcción y validación de un instrumento requiere de una vigilancia epistemológica del desarrollo y fortalecimiento de una postura que dé coherencia, pertinencia y congruencia a la educación como parte del acto educativo.

Introduction: Developing aptitudes to facilitate the pathway toward the learning process and the elaboration of knowledge in students of baccalaureate in nursing is basic for their formation, among those, the critical reading of theoretical texts. In order to consider these attributes in the learning process, a special emphasis on the way in which the instruments of evaluation are built is required. These instruments need to be close to the objective reality of the evaluation. Objetive: To construct and validate an instrument that allows identifying the way how baccalaureates in nursing students approach to theoretical sources of information during their formation process. Methodology: An instrument of critical reading of theoretical texts was constructed and validated, after a reviewing and analysis by a group of experts in critical reading. The instrument was integrated by 86 items and was applied to a pilot group (students in the level of the seventh semester of baccalaureate in nursing). Results: The internal consistency was determined through the Kuder-Richardson test, number 21, and coming out score of 0.96. Discussion: Construction and validity process for an instrument need to be survillace on its epistemology development and reinforcement in order to get a posture with coherence, pertinence and congruence as a part of evaluation on the educative process.