We report the first evidence of the potential of new amphiphilic ABA-triblock copolymers as gelling agents for lamellar liquid crystalline LR phases. Recently, we described a new type of lamellar hydrogels which are not based on a polymer network swollen in water but are obtained by the addition of small amounts of a nonionic polymer surfactant to the fluid lamellar LR phase of the dimyristoylp...

It is shown in rat that antiserum alpha 12B/18 specifically labels a new lamellar organelle that is exclusively located in dendritic appendages. These dendritic lamellar bodies occur in a restricted number of brain regions, which include areas like the inferior olive, area CA1 and CA3 of the hippocampus, dentate gyrus, olfactory bulb, and cerebral cortex. In these regions the neurons with lamel...

Calcium ion is thought to play a role in the structure and function of pulmonary surfactant after secretion into the alveolar space. Since fetal lung liquid calcium concentration is inadequate for this hypothesized role, at a time when optimal surfactant function is necessary for survival, we speculated that the necessary calcium is secreted with the surfactant material, i.e., in the lamellar b...

We used a modified lamellar body phospholipid (LB-PL) assay to evaluate the effect of sample processing and to evaluate the clinical efficacy of LB-PL determinations. Within-run and between-run CVs for the modified LB-PL assay respectively ranged from 2.9 to 6.7% and from 3.4 to 14.3%. Freezing and storage at -20 degrees C did not affect results for LB-PL (n = 12). Statistically significant amo...

The ABC lamellar phase of a triblock copolymer in the strong segregation region is studied on periodic and bounded intervals. In the periodic case we find a family of local minimizers of the free energy functional all with a fine lamellar structure. Among these local minimizers we identify the one most favored by the free energy, and hence determine the thickness of lamellar microdomains. In th...

The dilute lamellar phase of the nonionic surfactant C 12EO 5 was doped with goethite (iron oxide) nanorods up to a fraction of 5 vol %. The interaction between the inclusions and the host phase was studied by polarized optical microscopy (with or without an applied magnetic field) and by small-angle X-ray scattering. We find that, when the orientation of the nanorods is modified using the magn...

In his investigation of the fine structure of the nervous system, Fernf indez-Mor~n observed lamellar structures in the Purkinje cells of the ra t cerebel lum (1). ~Ihe use of newer methods of prepara t ion fail to demonst ra te these bodies in the cytoplasm of neurons (6, 3). Dur ing the course of a study of the normal Purkinje cell in rats (3), we observed lamellar bodies in two of the ten an...

We consider the phase behavior of a symmetric AB diblock, blended with corresponding A and B homopolymers, all of equal chain length. Evaluating the phase diagram in mean-field theory at all compositions of the ternary blend, we find no hexagonal and cubic phases. However, up to three distinct lamellar phases can coexist, one being symmetric and the other two being asymmetric. For strong incomp...

Phase behavior of distearoylphosphatidylethanolamine dispersed in excess glycerol has been examined by differential scanning calorimetry. Transformation from lamellar-gel to lamellar crystalline phase was found to take place at temperatures near 74.9 degrees C upon cooling and near 76.3 degrees C during heating scans. The transition can also be observed under isothermal conditions at temperatur...

In order to address the selection mechanism that is responsible for the unique lamellar orientation observed in block copolymers under oscillatory shears, we use a constitutive law for the dissipative part of the stress tensor that respects the uniaxial symmetry of a lamellar phase. An interface separating two domains oriented parallel and perpendicular to the shear is shown to be hydrodynamica...