Vicente Jesús Hernández-Abad

This work presents a theoretical study of the squeeze-film flow of a complex fluid confined between two parallel disks of radius [[EQUATION]]a, separated by a time-dependent gap [[EQUATION]]H(t). The fluid is initially placed on the lower disk, while the upper disk approaches at a constant velocity, generating a radial flow. The analysis assumes quasi-steady, isothermal, incompressible flow with no-slip boundary conditions. An exponential structural model is employed to describe the fluid rheology by accounting for flow-induced microstructural evolution through prey–predator dynamics combined with the Phan-Thien formalism. The structural evolution is represented by a flow-induced Arrhenius equation associated with the minimum irreversible work required to modify the internal structure.The resulting nonlinear partial differential equations are solved using a perturbation method based on the ratio of two characteristic lengths, yielding analytical solutions. The zeroth-order solution shows that the normal squeezing force is governed by the shear-dependent viscosity and naturally captures non-Newtonian effects such as shear thinning, shear thickening, and yield stress. The first-order solution reveals the contribution of fluid elasticity.Model predictions are compared with experimental data for a CTAT polymer solution. The results demonstrate that shear-thinning behavior is required to enhance the flow relative to a Newtonian fluid under identical conditions. Furthermore, an analytical expression for the yield stress is obtained, suggesting an alternative method for estimating this property using a parallel-plate squeeze-flow configuration. These findings provide a theoretical basis for future experimental validation and characterization of structured complex fluids.

INPLASY202650022 Effect of nursing interventions on improving medication adherence in patients with type 2 diabetes mellitus Keywords: Adherence, nursing interventions, diabetes mellitus. Read and …

Each heartbeat generates pulse waves that travel through the arterial system; various cardiovascular properties, such as arterial stiffness and blood rheology, determine their shape and the form they propagate. Cardiovascular models are an important tool for studying the cardiovascular system. Most one-dimensional models consider the blood as a Newtonian fluid. Incorporating non-Newtonian effects into them is essential for accurately simulating blood flow, especially under conditions that affect blood rheology, such as elevated cholesterol. To study the effect of elevated cholesterol on pulse waves, we incorporated the experimentally measured storage and loss moduli of blood samples with different cholesterol levels into a one-dimensional cardiovascular formulation. We applied the proposed formulation to single vessel models and to a 116-artery systemic circulation model. A low-frequency analysis provided a mechanistic explanation for the results. We found that blood samples with high cholesterol levels exhibited greater zero-shear-rate viscosity, which, according to the low-frequency analysis, implies a higher vascular resistance and effective vascular compliance, leading to higher blood pressure and lower pulse wave velocity (PWV). Our results showed that high cholesterol levels are associated with higher systolic, diastolic, mean, and pulse pressures, while reducing carotid to femoral pulse wave velocity and decreasing mean and peak blood flow. Our results suggest that the effects of high cholesterol levels are more significant in small arteries. Integrating blood rheology into cardiovascular modeling provides a framework for evaluating various conditions that affect it. It may also enhance the interpretation of pulse wave indices, contributing to the development of noninvasive diagnostic methods.

In this work, the viscoelastic behavior of a complex structured liquid in a continuous squeeze flow is analyzed. This flow is simulated allowing a continuous flow of liquid into the narrow gap between two circular plates though the lower plate. The complex liquid is characterized by the exponential structure rheological (ESR) constitutive equation, which is a generalized exponential thixotropic-elasto-viscoplastic-banded model, chosen for this study due to its capacity to predict non-Newtonian and complex behavior such as (i) shear-thinning, (ii) shear-thickening, (iii) yield stress, (iv) thixotropy, (iv) rheopexy, and (v) shear banding flow behavior. The exponential rheological equation of state is defined by a class of exponential Phan-Thien–Tanner-type models, which includes specific cases documented in the literature. The viscoelastic, kinetic, and structural mechanisms in the ESR model are characterized by the association of non-dimensional numbers to each mechanism. To solve the set of non-linear partial differential equations, a perturbation scheme is suggested, based on a small parameter that represents the ratio between two characteristic lengths. At zeroth order (neglecting the inertial mechanisms of the momentum equation), it is found that the normal force on the upper disk is directly related to shear dependent viscosity (thixotropy, shear-thinning, shear-thickening, yield stress behavior, and concentration effects). At first order, the normal force is related to the effects of the elasticity, and it is parallel to the first normal stress difference associated with the elasticity of the ESR structured fluid.

Se busca documentar y difundir el proceso de planeación, construcción, inauguración y puesta en marcha del nuevo edificio de la Biblioteca Dr. José Manuel Álvarez Manilla de la Peña de Campus II de la Facultad de Estudios Superiores Zaragoza (FES Zaragoza), en la Universidad Nacional Autónoma de México (UNAM), inmueble que sustituye a las construcciones anteriores y representa una oportunidad de servicios bibliotecarios, bibliotecológicos y de información base para resignificar el concepto de centro de recursos para la enseñanza y el aprendizaje, redimensionando el espacio bibliotecario del siglo XXI. La biblioteca de Campus II busca establecer un marco de biblioteca universitaria que centre sus esfuerzos en atender las necesidades de los usuarios y en la comunicación científica; es decir, contribuir por medio de recursos de información a la satisfacción de sus necesidades informativas y recreativas, porque la cultura y la lectura informal son también un disfrute y vinculación social.

Flexoelectric actuation employs an applied electric field to induce membrane curvature, which is the mechanism utilized by the outer hair cells (OHC) present in the inner ear. The model developed for this study, representing the OHC, integrates two key components: (i) an approximation of the flexoelectric membrane shape equation for circular membranes attached to the inner surface of a circular capillary, and (ii) the coupled capillary flow of contacting liquid viscoelastic phases characterized by the Tanner-Power law rheological equation of state. A second-order non-linear differential equation for average curvature has been derived, and a robust numerical method has been programmed. This model simplifies to a linear model used previously. The main challenge involves identifying and describing the enhancement in curvature change rate. It was observed that low symmetry, low viscosity, and soft membrane and shear-thickening behavior of the phases enhance the curvature change rate. Additionally, there exists a critical electric field frequency value that maximizes the curvature change rate (resonance effect). The current theory, model, and computational simulations add to the ongoing development comprehension of how biological membrane shape actuation through electromechanical couplings.

Se estudia el comportamiento informativo de alumnos y docentes de la Facultad de Estudios Superiores Zaragoza (FESZ), de la Universidad Nacional Autónoma de México (UNAM), durante la pandemia ocasionada por el SARS-CoV-2, en la Biblioteca Digital UNAM ante el cierre total de las bibliotecas, lo que limitó la consulta presencial de libros y revistas impresas. Se llevó a cabo una investigación cuantitativa con la técnica de análisis de datos estadísticos a partir de las bitácoras de acceso a la Biblioteca Digital (BIDI UNAM) que en suma contempló 15,597 accesos, en comparación a dos periodos, antes y durante la pandemia, obteniendo como resultado un incremento en los accesos, sumado al impulso de estrategias de alfabetización informacional para el uso y aprovechamiento de los recursos de información, mismos que pueden ser integrados en los procesos de enseñanza y aprendizaje, fortaleciendo el modelo educativo de la FESZ.

Alpha-lipoic acid (ALA) has been used as a dietary supplement at different doses in patients with diabetes mellitus type 2 (T2DM) due to its antioxidant, anti-inflammatory, and hypoglycemic effects. However, the reports on the effects of ALA are controversial. For this reason, the purpose of the present study was to determine the effect of 600 mg/day of ALA on the markers of oxidative stress (OxS) and inflammation and RAGE in older adults with T2DM. A quasiexperimental study was carried out with a sample of 135 sedentary subjects (98 women and 37 men) with a mean age of64±1years, who all had T2DM. The sample was divided into three groups: (i) experimental group (EG) with 50 subjects, (ii) placebo group (PG) with 50 subjects, and control group (CG) with 35 subjects. We obtained the following measurements in all subjects (pre- and posttreatment): glycosylated hemoglobin (HbA1c), receptor for advanced glycation end products (RAGE), 8-isoprostane, superoxide dismutase (SOD), glutathione peroxidase (GPx), total antioxidant status (TAS), and inflammatory (CRP, TNF-α, IL-6, IL-8, and IL-10) markers. Regarding the effect of ALA on HbA1c, a decrease was observed in the EG (baseline8.9±0.2vs. posttreatment8.6±0.3) and the PG (baseline8.8±0.2vs. posttreatment8.4±0.3) compared to the CG (baseline8.8±0.3vs. six months9.1±0.3) although the difference was not statistically significant (p<0.05). There was a statistically significant decrease (p<0.05) in the blood concentration of 8-isoprostane in the EG and PG with respect to the CG (EG: baseline100±3vs. posttreatment57±3, PG: baseline106±7vs. posttreatment77±5, and CG: baseline94±10vs. six months107±11pg/mL). Likewise, a statistically significant decrease (p<0.05) in the concentration of the RAGE was found in the EG (baseline1636±88vs. posttreatment1144±68) and the PG (baseline1506±97vs. posttreatment1016±82) compared to CG (baseline1407±112vs. six months1506±128). A statistically significant decrease was also observed in all markers of inflammation and in the activity of SOD and GPx in the CG with respect to the EG and PG. Our findings suggest that the administration of ALA at a dose of 600 mg/day for six months has a similar effect to that of placebo on oxidative stress, inflammation, and RAGE in older adults with T2DM. Therefore, higher doses of ALA should be tried to have this effect. This trial is registered with trial registration numberISRCTN13159380.

In this work, a new simplified method to find the fluidity enhancement of a non-Newtonian liquid under a pulsating (time-dependent) pressure gradient is analyzed. The fluidity enhancement is predicted by means of a Taylor series expansion of the flow rate in the vicinity of the applied wall stress. This expansion is shown to render the same results as several perturbation techniques used at length in the literature. Both new and the conventional perturbation methods are equivalent in their predictions of the fluidity enhancement. Even though the flow and rheology behavior are modeled using the Bautista-Manero-Puig constitutive equation, it is shown that the prediction of the fluidity enhancement does not depend on the constitutive model employed, but a condition of shear thinning behavior of the fluid is necessary for it. Flow enhancement is predicted using rheological data for blood since this fluid naturally flows under a pulsatile pressure gradient. The flow enhancement equation is found to have a similar form as the equation of the Rabinowitsch formalism in fully developed Poiseuille flow. This simplified technique will help in saving machine time for numerical predictions in computational blood flow simulations.

Introduction. Acute lymphoblastic leukemia (ALL) is the most common hematologic malignancy in childhood. Current chemotherapy regimens have substantially increased survival; however, they are associated with a high burden of adverse drug reactions (ADRs), particularly in the pediatric population.Objective. To critically analyze the patterns, frequencies, and severity of ADRs reported in the treatment of ALL in the Mexican pediatric population. The study aims to identify the most frequent ADRs per drug, variability in incidence according to protocols and regions, and the limitations and gaps within the national pharmacovigilance system. Materials and Methods. A systematic review was conducted following the PRISMA 2020 guidelines. International (PubMed / MEDLINE, Scopus, Cochrane) and regional (SciELO, LILACS) scientific databases were consulted, along with pharmacovigilance databases (VigiBase - WHO, FDA, EMA, COFEPRIS) for studies published between 2010-2024. Inclusion criteria were: Mexican pediatric population (<18 years), oncological treatment for ALL, and documented ADRs. Four independent reviewers applied eligibility criteria, extracted standardized data, and assessed the risk of bias using the STROBE tool. Bradford Hill criteria were applied to evaluate causality. Results. From 102 identified records, eight studies were included after applying selection criteria. The total sample size is 1,247 patients. The most frequent ADRs were febrile neutropenia (68 %), hepatotoxicity (48 %), mucositis (33 %), nausea / vomiting (29 %), and neurotoxicity (8-12 %), mainly associated with vincristine, methotrexate, L-asparaginase, and anthracyclines. The application of Bradford Hill criteria confirmed strong causal associations for febrile neutropenia and hepatotoxicity. Significant methodological heterogeneity was identified among the studies. Discussion. This systematic review identified febrile neutropenia (68 %), hepatotoxicity (48 %), and mucositis (33 %) as the most frequent ADRs in Mexican pediatric patients with acute lymphoblastic leukemia (ALL). While febrile neutropenia rates were comparable to international reports, differences were observed in hepatotoxicity rates and lower reported neurotoxicity. The review revealed significant methodological heterogeneity, probable underreporting, absence of pharmacogenetic studies (TPMT, NUDT15), and weaknesses in the national pharmacovigilance system. These findings highlight the need for national standardization, implementation of active pharmacovigilance strategies, and prospective multicenter studies to improve treatment safety in this population. Conclusions. There is an evident underreporting of ADRs in the Mexican pediatric population with ALL. The reported incidence of neurotoxicity (8 %) is lower than international reports (10-12 %), suggesting under - notification. There is an urgent need to implement active pediatric pharmacovigilance systems, integrate pharmacogenetic studies (TPMT / NUDT15) tailored to the Mexican mestizo population, and establish long - term monitoring for toxicities such as cardiotoxicity and neurocognitive alterations.