We report on the rheology of a lyotropic lamellar surfactant solution (SDS/dodecane/pentanol/ water), and identify a discontinuous transition between two shear thinning regimes which correspond to the low-stress lamellar phase and the more viscous shear-induced multilamellar vesicle, or "onion" phase. We study in detail the flow curve, stress as a function of shear rate, during the transition r...

Injecting vitally stained blood cells into the ventral aorta of unrestrained, cannulated fish, and rapid freezing in liquid nitrogen, permitted the examination of the effects of oxygen supply, epinephrine and acetylcholine on branchial lamellar perfusion. Compared to the conditions in resting fish in air-saturated water, hypoxia and injection of epinephrine significantly increased the proportio...

The retina of the pearl mutant mouse, C57BL/6J pe/pe, exhibits reduced light sensitivity in the dark-adapted condition (Balkema and Pinto, J Neurophysiol 48:968, 1982). The authors searched for an anatomic correlate in the retina which could relate to the functional deficit. Electron microscopic mosaics of the outer plexiform layer of light- and dark-adapted pearl and wild-type mice were analyz...

Chlorophyll in green plants is thought to reside in the internal membranes or lamellae of chloroplasts (1). These membranes are observable by electron microscopy and can be roughly grouped, on the basis of size and arrangement , into grana lamellae and stroma lamellae which exist as closed, flattened sacs, or thylakoids (2). Al though the chlorophyll molecule is not yet demonstrable by electron...

Monochromatic light microscopy at 435 mmicro shows in Euglena gracilis, the distribution of chlorophyll and the general orientation and geometry of chloroplasts in vivo. In addition it discloses, in swelling chloroplasts, a lamellar pigmented structure. Changes in this structure are observed in extruded swollen chloroplasts treated with lipolytic or proteolytic enzymes. Lipolytic enzymes produc...

The dictyosome (Golgi body) in the secondary spermatocyte of the cricket appears in electron micrographs as a duplex structure composed of (a) a group of parallel double-membraned lamellae and (b) a group of associated vacuoles arranged along the compact lamellae in a chain-like fashion. This arrangement of ultramicroscopic structure for the dictyosomes is strikingly comparable to that describe...

The galactolipid, phospholipid, and fatty acid composition of chloroplast envelope membrane fractions isolated from leaves of Vicia faba L. has been determined. The major lipids in this fraction are: monogalactosyldiglyceride, 29%; digalactosyldiglyceride, 32%; phosphatidylcholine, 30%; and phosphatidylglycerol 9%. The lipid composition of the chloroplast envelope membranes is qualitatively sim...

The equine radius is a useful subject for examining the adaptation of bone histology to loading because in life the anterior cortex is loaded almost entirely in tension, the posterior cortex in compression. The histology of the two cortices is correspondingly different, the osteones and the interstitial lamellae in the posterior cortex having a more transversely oriented fibre arrangement than ...

Piauçus (Leporinus macrocephalus), were raised in 300 m2 ponds (density of 10 fish/m2) presenting asphyxia signals and daily mortality of 27 fishes. Specimens with 8-cm total body length, were collected for necropsy. Mucus of body surface and pieces of organs were collected and examined microscopically, in wet mounts, stained or in histological sections. The smears examination showed the presen...

Understanding the microstructural evolution in metallic alloys helps to control their properties and improve their performance in industrial applications. The emphasis of our study is the coarsening mechanisms of lamellar structures. Coarsening of lamellar structure is modeled numerically using Monte Carlo Potts method. The initial microstructure consists of alternating lamellae of phase A and ...