Search results for "NODAL"
showing 10 items of 264 documents
Spinodal decomposition of a two-dimensional model alloy with mobile vacancies
1991
Abstract Monte Carlo simulations are performed for the initial stages of phase separation in a model binary alloy (AB), where unmixing is caused by a repulsive energy between atoms of different kind ( e AA = e BB = e ), and a small fraction c v of mobile vacancies is present (typically c v = 0.04.) Unlike previous work, where interdiffusion was modelled in an unrealistic way by direct interchange of A and B atoms for c v = 0, were use the vacancy mechanism of diffusion: A-atoms may jump to vacant sites with a rate Γ A and B-atoms may jump to vacant sites with a rate Γ B , no direct A–B interchange being permitted. It is shown that the overall time-scale on which phase separation proceeds ty…
Phase separation of an asymmetric binary fluid mixture confined in a nanoscopic slit pore: Molecular-dynamics simulations
2008
As a generic model system of an asymmetric binary fluid mixture, hexadecane dissolved in carbon dioxide is considered, using a coarse-grained bead-spring model for the short polymer, and a simple spherical particle with Lennard-Jones interactions for the carbon dioxide molecules. In previous work, it has been shown that this model reproduces the real phase diagram reasonable well, and also the initial stages of spinodal decomposition in the bulk following a sudden expansion of the system could be studied. Using the parallelized simulation package ESPResSo on a multiprocessor supercomputer, phase separation of thin fluid films confined between parallel walls that are repulsive for both types…
Spinodal lines and Flory-Huggins free-energies for solutions of human hemoglobins HbS and HbA
1991
Gelation of deoxygenated solutions of sickle-cell human Hemoglobin (HbS) is of high theoretical interest and it has serious pathological consequences. For this reason HbS is probably the most studied protein capable of self-organization. This notwithstanding, the location in the T, c plane of the region of thermodynamic instability of solutions of deoxy-HbS (as bounded by the spinodal line and as distinct from the gelation region) has remained unknown, along with related values of Flory-Huggins enthalpies and entropies. In the present work this information is derived from experiments for the two cases of (deoxy) HbS and of human adult hemoglobin (HbA). Experiments also show critical exponen…
Crystallization of hard spheres revisited. II. Thermodynamic modeling, nucleation work, and the surface of tension
2018
Combining three numerical methods (forward flux sampling, seeding of droplets, and finite-size droplets), we probe the crystallization of hard spheres over the full range from close to coexistence to the spinodal regime. We show that all three methods allow us to sample different regimes and agree perfectly in the ranges where they overlap. By combining the nucleation work calculated from forward flux sampling of small droplets and the nucleation theorem, we show how to compute the nucleation work spanning three orders of magnitude. Using a variation of the nucleation theorem, we show how to extract the pressure difference between the solid droplet and ambient liquid. Moreover, combining th…
Über die möglichkeiten zur bestimmung von mischungsenthalpien und -volumina aus der molekulargewichtsabhängigkeit der kritischen entmischungstemperat…
1977
Cloud-point curves and critical curves (Tc = f(p)) have been measured for the system trans-decahydronaphthalene/polystyrene and three different molecular weights of the polystyrene component (2,5 · 106; 3,9 · 105; 1,1 · 105). It turned out that by variation of the pressure the metastable region can be investigated up to the spinodal curve. A comparison of the theta-temperatures and the enthalpy contributions χH (to the Flory-Huggins interaction parameter χ) resulting from the measured critical temperatures according to Shultz-Flory, with the corresponding directly obtained literature data, demonstrates that, although the extrapolation of Tc to infinite molecular weight is feasible, χH obtai…
L'intensité nodale, une évaluation de la performance de l'intermodalité dans les pôles d'échanges
2011
National audience; L'aménagement de pôles d'échanges vise à faciliter les pratiques intermodales et à limiter les contraintes liées à la rupture de charge. Plusieurs leviers doivent être activés pour valoriser l'intermodalité : l'information multimodale, la tarification intégrée, l'aménagement fonctionnel et l'insertion urbaine sont autant d'éléments indispensables au bon fonctionnement des pôles d'échanges. Sans minimiser l'importance de ces différents aspects, cet article porte plus spécifiquement sur un autre levier tout aussi décisif pour la pratique intermodale : l'ajustement des offres de services horaires des différents opérateurs de transport public. Nous développons un indicateur é…
Intraflagellar transport protein 172 is essential for primary cilia formation and plays a vital role in patterning the mammalian brain
2008
AbstractIFT172, also known as Selective Lim-domain Binding protein (SLB), is a component of the intraflagellar transport (IFT) complex. In order to evaluate the biological role of the Ift172 gene, we generated a loss-of-function mutation in the mouse. The resulting Slb mutant embryos die between E12.5 and 13.0, and exhibit severe cranio-facial malformations, failure to close the cranial neural tube, holoprosencephaly, heart edema and extensive hemorrhages. Cilia outgrowth in cells of the neuroepithelium is initiated but the axonemes are severely truncated and do not contain visible microtubules. Morphological and molecular analyses revealed a global brain-patterning defect along the dorsal–…
Reading changes in children and adolescents with dyslexia after transcranial direct current stimulation.
2016
Noninvasive brain stimulation offers the possibility to induce changes in cortical excitability and it is an interesting option as a remediation tool for the treatment of developmental disorders. This study aimed to investigate the effect of transcranial direct current stimulation (tDCS) on reading and reading-related skills of children and adolescents with dyslexia. Nineteen children and adolescents with dyslexia performed different reading and reading-related tasks (word, nonword, and text reading; lexical decision; phonemic blending; verbal working memory; rapid automatized naming) in a baseline condition without tDCS and after 20 min of exposure to three different tDCS conditions: left …
Saukas ezera fitoplanktona raksturojums
2022
Bakalaura darbs tika veikts saskaņā ar projekta “Latvijas upju baseinu apsaimniekošanas plānu ieviešana laba virszemes ūdens stāvokļa sasniegšanai” (LIFE GoodWater IP, 23 Nr. LIFE18IPE/LV/000014) ietvaros. Pētījuma mērķis bija izvērtēt Saukas ezera ekoloģisko stāvokli 2020. un 2021. gada vasarā pēc fitoplanktona kvantitatīvajiem un kvalitatīvajiem rādītājiem. 2020. gada fitoplanktona paraugos Saukas ezerā tika konstatētās 84 fitoplanktona sugas no septiņiem aļģu nodalījumiem. Jūlijā konstatētas augstākās fitoplanktona biomasas pateicoties kramaļģēm un zilaļģēm. 2021. gadā tika konstatētas 63 fitoplanktona sugas no astoņiem fitoplanktona nodalījumiem. Apsekotajās paraugošanas stacijās dominē…
Aportación al conocimiento clínico y prosnóstico de los Linfomas de Cabeza y Cuello
2015
Los linfomas son neoplasias del sistema linforreticular que asientan preferentemente en los ganglios linfáticos. Representan aproximadamente el 5% de todas las neoplasias malignas que se pueden desarrollar en la región anatómica de la cabeza y cuello. En general los Linfomas no Hodgkin son más frecuentes que los Hodgkin y suponen el 88% de todos los linfomas. En términos generales el modo de presentación más frecuente y común de estos tumores en esta región anatómica es la aparición de adenopatías cervicales Las manifestaciones extranodales aparecen en un 23-30% de los pacientes en los Linfomas no Hodgkin, siendo el anillo de Waldeyer la localización más frecuente. Por el contrario el Linfo…