675 research outputs found

    Catch Bonds in Sickle Cell Disease: Shear-Enhanced Adhesion of Red Blood Cells to Laminin

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    Could the phenomenon of catch bonding—force-strengthened cellular adhesion—play a role in sickle cell disease, where abnormal red blood cell (RBC) adhesion obstructs blood flow? Here we investigate the dynamics of sickle RBCs adhering to a surface functionalized with the protein laminin (a component of the extracellular matrix around blood vessels) under physiologically relevant micro-scale flow. First, using total internal reflectance microscopy we characterize the spatial fluctuations of the RBC membrane above the laminin surface before detachment. The complex dynamics we observe suggest the possibility of catch bonding, where the mean detachment time of the cell from the surface initially increases to a maximum and then decreases as a function of shear force. We next conduct a series of shear-induced detachment experiments on blood samples from 25 sickle cell disease patients, quantifying the number and duration of adhered cells under both sudden force jumps and linear force ramps. The experiments reveal that a subset of patients does indeed exhibit catch bonding. By fitting the data to a theoretical model of the bond dynamics, we can extract the mean bond lifetime versus force for each patient. The results show a striking heterogeneity among patients, both in terms of the qualitative behavior (whether or not there is catch bonding) and in the magnitudes of the lifetimes. Patients with large bond lifetimes at physiological forces are more likely to have certain adverse clinical features, like a diagnosis of pulmonary arterial hypertension and intracardiac shunts. By introducing an in vitro platform for fully characterizing RBC-laminin adhesion dynamics, our approach could contribute to the development of patient-specific anti-adhesive therapies for sickle cell disease. The experimental setup is also easily generalizable to studying adhesion dynamics in other cell types, for example leukocytes or cancer cells, and can incorporate disease-relevant environmental conditions like oxygen deprivation

    La medicina rural: una visión mirando al futuro

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    The management of any large building stock with limited resources poses a problem of prioritization of refurbishment actions. Also, available technical information about the building stock is often incomplete and the process of standardization and updating is expensive and time consuming. Some public owners are developing preliminary BIM models of their stock, but they are willing to limit the complexity of the models within the lowest amount of information required for management and maintenance, so as to make that process affordable. Indeed, administrations are challenged by their duty relative to planning regular maintenance and operation of buildings, because of the legislation in force, which requires monitoring of their facilities. For the reasons stated above, this paper presents a decision support tool that can help prioritize refurbishment actions on large building assets. To this purpose, many requirements must be jointly considered in this examination, each requirement being assessed by means of one or several indicators. Then the indicators are compared one another, according to a multi-criteria approach, that weighs the several criteria and rank the assets. In order to deal with the extensive and uncertain information that must be managed in this process, indicators are estimated by means of Bayesian Networks. This tool is used first to assess the technical indicators and rank the assets, while marking any facilities not complying with regulations. Then, additional Bayesian Networks are in charge of estimating the budget needed to upgrade non-compliant facilities with minimum legislation requirements. The outcomes of this research can be used even to assess the level of detail of the information that must be included in BIM models of the stock, in fact acting as guidelines for their development. Finally, the application of the decision tool on a real test case will be presented

    Analysis of the Relationship between Lifestyle and Coffee Consumption Habits, from the Myth Approach, in the Municipalities of Orizaba, Tehuipango, and Zongolica Veracruz.

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    Coffee consumption habits have evolved along with society for more than 300 years around the world. Social changes imply different lifestyles in each culture. Lifestyles influence the myths used by people in their consumption decisions. The objective of this research is to determine the relationship between lifestyle and coffee consumption habits, from the perspective of myth, in the inhabitants of the Mexican municipalities of Orizaba, Tehuipango, and Zongolica. A survey was conducted with a sample of inhabitants of the three municipalities studied. The statistical analyzes applied were the central limit theorem, Pearson, and Chi-square. The results show that the variables Consumption habits-Lifestyle-Myth, are highly dependent on the level of perception of people. It is concluded that the coffee myth corresponds to the "family union" in the study municipalities. This myth is not characterized in the evolutionary stages contemplated in the "waves of coffee"

    Clínica jurídica, una forma de aprendizaje-servicio para la protección de Derechos humanos

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    [spa] El artículo explica los primeros pasos dados en el desarrollo del proyecto "Clínica jurídica: una forma de aprendizaje-servicio para la protección de derechos humanos" en la Universidad de Valladolid, cuyo principal objetivo consiste en la formación de juristas socialmente comprometidos.[eng] The paper explains the first steps given on the development of the Project “Clínica jurídica: una forma de aprendizaje-servicio para la protección de derechos humanos“ at the University of Valladolid which main aim would be a social engaged lawyers training

    Validation of score in mna scale like nutritional risk factor in institutionalized geriatric patients with moderate and severe cognitive impairment

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    Introducción: La valoración geriátrica integral incluye el examen del apartado nutricional debido a la alta prevalencia de desnutrición en este tipo de pacientes; especialmente en los pacientes con deterioro cognitivo asociado. Las escalas de cribado del estado nutricional presentan preguntas de autopercepción subjetiva de difícil respuesta en pacientes mayores con demencia. Objetivo: Estudiar la especificidad, el valor predictivo positivo y la sensibilidad de la escala MNA para la detección de malnutrición en pacientes diagnosticados de enfermedad de Alzheimer con deterioro cognitivo avanzado. Material y métodos: Se diseñó un estudio descriptivo poblacional con una muestra de 52 pacientes mayores de 70 años, institucionalizados, con enfermedad de Alzheimer grado moderado y severo. Se estudió la sensibilidad, especificidad y valor predictivo positivo de la escala MNA respecto a los parámetros de malnutrición del American Institute of Nutrition (AIN). Resultados: Los valores de sensibilidad, especificidad y valor predictivo positivo son 60%, 94,7% y 93,8% respectivamente. Existe una correlación significativa (p < 0,001) ente la puntuación obtenida en la escala MNA y la escala de riesgo de caídas Tinneti (r = 0,577), de función Barthel (r = 0,742), de valoración cognitiva MEC (r = 0,651) y los niveles de creatinina (r = 0,402). Más del 50% de la muestra presentó al menos un parámetro de malnutrición AIN alterado. Conclusiones: La escala MNA presenta una menor sensibilidad y especificidad en estos pacientes. El diseño de una escala de valoración nutricional sin valoraciones subjetivas y sólo con parámetros objetivos podría mejorar la eficacia de la misma en ancianos institucionalizados con deterioro cognitivo moderado y severo.Introduction: comprehensive geriatric assessment includes examination of the nutritional status given the high prevalence of hyponutrition in this kind of patients, particularly in patients with associated cognitive impairment. Scales for screening the nutritional status include questions on self-perception difficult to answer by demented elder patients. Objective: To study the specificity, the positive predictive value, and the sensitivity of the MNA scale to detect malnutrition in patients diagnosed with Alzheimer’s disease with advanced cognitive impairment. Material and methods: a population-based descriptive study with a sample of 52 patients older than 70 years, institutionalized, and with moderate-severe Alzheimer’s disease was designed. The sensitivity, specificity, and positive predictive value of MNA scale were studied regarding the parameters on malnutrition of the American Institute of Nutrition (AIN). Results: the sensitivity, specificity, and positive predictive values were 60%, 94.7%, and 93.8%, respectively. There was a significant correlation (p < 0.001) between the score obtained with the MNA Scale and the Tinneti’s Risk of Fall Scale (r = 0.577), the Barthel’s function (r = 0.742), the MCT cognitive assessment (r = 0.651), and creatinine levels (r = 0.402). More than 50% of the sample presented at least one malnutrition parameter altered. Conclusions: the MNA Scale presents lower sensitivity and specificity in these patients. Designing a nutritional assessment scale without subjective evaluations and only with objective parameters might improve its efficiency in institutionalized elderly patients with moderate-severe cognitive impairment.Nutrición humana y dietétic

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum
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