Search results for "Filament"
showing 10 items of 405 documents
Serum Response Factor-Mediated Gene Regulation in a Drosophila Visual Working Memory
2013
Summary Background Navigation through the environment requires a working memory for the chosen target and path integration facilitating an approach when the target becomes temporarily hidden. We have previously shown that this visual orientation memory resides in the ellipsoid body, which is part of the central complex in the Drosophila brain. Former analysis of foraging and ignorant mutants have revealed that a hierarchical PKG and RSKII kinase signaling cascade in a subset of the ellipsoid-body ring neurons is required for this type of working memory in flies. Results Here we show that mutants in the ellipsoid body open ( ebo ) gene, which encodes the actin-binding protein Exportin 6, e…
OPLA scaffold, collagen I, and horse serum induce a higher degree of myogenic differentiation of adult rat cardiac stem cells
2009
In the last few years, a major goal of cardiac research has been to drive stem cell differentiation to replace damaged myocardium. Several research groups have attempted to differentiate potential cardiac stem cells (CSCs) using bi- or three-dimensional systems supplemented with growth factors or molecules acting as differentiating substances. We hypothesize that these systems failed to induce a complete differentiation because they lacked an architectural space. In the present study, we isolated a pool of small proliferating and fibroblast-like cells from adult rat myocardium. The phenotype of these cells was assessed and the characterized cells were cultured in a collagen I/OPLA scaffold …
Temperature and density structure of hot and cool loops derived from the analysis of TRACE data
2002
We address the plasma structuring both across and along the magnetic field in two sets of solar coronal loops, observed with TRACE in the 17lÅ and 195Å passbands. We derive, after proper background removal, the density stratification and the thermal structure of the plasma in the fibrils forming the loops with two techniques: a) filter ratio diagnostic (195 Å/171 Å) and b) modeling intensity profiles along the fibrils with hydrostatic models. We find evidence of a hot fibril (T ∼ 5·106 K), with temperature and density stratification well-described with a typical non-isothermal hydrostatic loop model, and evidence of rather cold fibrils (T ∼ 2 · 105 K), isothermal and probably in dynamic con…
Flow and mass transfer in spacer-filled channels for reverse electrodialysis: a CFD parametrical study
2016
Abstract In reverse electrodialysis (RED) concentration polarization phenomena and pressure drop affect strongly the power output obtainable; therefore the channel geometry has a crucial impact on the system optimization. Both overlapped and woven spacers are commonly commercialised and adopted for RED experiments; the latter exhibit some potential advantages, such as better mixing and lower shadow effect, but they have been poorly investigated in the literature so far. In this work, computational fluid dynamics was used to predict fluid flow and mass transfer in spacer-filled channels for RED applications. A parametric analysis for different spacer geometries was carried out: woven (w) and…
Flexible magnetic filaments in a shear flow
2006
By flexible magnetic filament model its behavior under the simultaneous action of the shear flow and the magnetic field is investigated. It is found that for magnetoelastic numbers larger as the critical value, which depends on the shear rate, the periodic regime is established. For the values of the magnetoelastic number close to the critical the periodical regime is characterized by a rather slow development of the buckling instability due to the action of magnetic torques with the subsequent stage of the fast straightening of the filament. For the magnetoelastic numbers below the critical slightly bent shape of the filament orientated along the flow is established. The application of the…
SiRNA-mediated selective inhibition of mutant keratin mRNAs responsible for the skin disorder pachyonychia congenita.
2006
RNA interference offers a novel approach for treating genetic disorders including the rare monogenic skin disorder pachyonychia congenita (PC). PC is caused by mutations in keratin 6a (K6a), K6b, K16, and K17 genes, including small deletions and single nucleotide changes. Transfection experiments of a fusion gene consisting of K6a and a yellow fluorescent reporter (YFP) resulted in normal keratin filament formation in transfected cells as assayed by fluorescence microscopy. Similar constructs containing a single nucleotide change (N171K) or a three-nucleotide deletion (N171del) showed keratin aggregate formation. Mutant-specific small inhibitory RNAs (siRNAs) effectively targeted these site…
An experimental study for the characterization of fluid dynamics and heat transport within the spacer-filled channels of membrane distillation modules
2018
Abstract The thermo-fluid dynamic behavior of spacer-filled channels for membrane distillation was investigated experimentally. Several different geometry were investigated thanks to customized reference spacers manufactured using a 3D printer. In particular, two sets of experiments were conducted: in the first set, cylindrical filaments were orthogonally arranged and the flow attack angle was made to vary from 0o to 90o; in the second set, the flow attack angle was kept symmetrical and the filament angle was made to vary from 30° to 150°. Each spacer was tested for Reynolds numbers between 200 and 900 in the hot channel, while maintaining a constant temperature difference of 13 °C between …
Observations on a new species of Unicapsula (Myxosporida) in the fish Maena smaris (L.) by conventional and electronmicroscopy
1975
A myxosporidian parasite believed to be congeneric with Unicapsula muscularis Davis (1924), type (and only) species of this genus, was found in the dorsal muscles of the fish Maena smaris (L.) at Banyuls-sur-Mer, France. The spores were tripartite, with corresponding components of the three parts differentially developed. One part consisted of a small shell valve overlying no more than a trace of sporoplasm but covering a polar apparatus with well-developed polar capsule. Each of the other two parts consisted of a long shell valve covering a large sporoplasm and a polar apparatus with only the rudiment of a polar capsule. Electron microscope pictures of the trophozoite showed evidence of pi…
An Extended Filament Based Lamellipodium Model Produces Various Moving Cell Shapes in the Presence of Chemotactic Signals
2015
The Filament Based Lamellipodium Model (FBLM) is a two-phase two-dimensional continuum model, describing the dynamcis of two interacting families of locally parallel actin filaments (C.Schmeiser and D.Oelz, How do cells move? Mathematical modeling of cytoskeleton dynamics and cell migration. Cell mechanics: from single scale-based models to multiscale modeling. Chapman and Hall, 2010). It contains accounts of the filaments' bending stiffness, of adhesion to the substrate, and of cross-links connecting the two families. An extension of the model is presented with contributions from nucleation of filaments by branching, from capping, from contraction by actin-myosin interaction, and from a pr…
The mathematical modeling of the single and ensemble dynamics of magnetic filaments
2016
Biomimētisku sistēmu izmantošana mikrodzinēju un šķidrumu maisītāju izveidei ir aktuāls izpētes objekts mīksto materiālu nozarē. Šiem mērķiem iespējams izmantot magnētiskas stīgas, ko ir viegli kontrolēt mainot ārēja magnētiskā lauka parametrus. Šajā darbā ir izveidots magnētisku stīgu matemātisks modelis, kas ietver gan vērp es, gan hidrodinamisko mijiedarbību ietekmi dažādos tuvinājumos un izveidota praktiska implementācija divu programmatūras bibliotēku formā. Ar izveidotā modeļa palīdzību iegūti rezultāti, kas raksturo individuālu stīgu un stīgu ansambļu dinamika plašā kustību kontrolējošo parametru diapazonā un iegūti jauni rezultāti, kas raksturo feromagnētisku un superparamagnētisku …