Flattened Form Research Articles

POTASSIUM CONCENTRATION IS REDUCED IN CULTURED RABBIT TRACHEAL SMOOTH MUSCLE CELLS AFTER WITHDRAWAL OF SERUM

Comparison of elemental concentrations in growth-arrested airway smooth muscle cells with those in their proliferating counterpart showed that potassium (K+) was significantly reduced, whereas concentrations of other elements sodium (Na+), magnesium (Mg2+), phosphorus (P), and chlorine (Cl−) remained unchanged. Reduced K+concentration was associated with a change in the cells from a spindle shape to a flattened form.

Progenitor endothelial cells on vascular grafts: an ultrastructural study.

The morphology of progenitor endothelial cells on vascular graft surfaces is addressed in this report. Such cells were seen to attach to intima-expressed CD34 and Flk-1 antigen and showed positive 5-bromo-2-deoxyuridine (BrdU) uptake. We examined CD34 and Flk-1 antigen-expressing endothelial progenitor cells three-dimensionally using confocal laser scanning microscopy (CLSM). Under detailed CLSM observation, through an ameboid-form cell, these progenitor endothelial cells changed from a globular to a flattened form. We also investigated these morphological changes using scanning electron microscopy. From these results, progenitor endothelial cells were observed not only near the advancing edge of endothelium, but also around the developing intimal site. Their form also changed from globular to flattened as observed in the CLSM results. These morphological changes were seen more frequently near the advancing edge and around the developing intimal site. They attached directly to vascular prosthesis fibers and likewise covered the graft luminal surface. Progenitor endothelial cells in any form had a common surface structure. We conclude from our results that progenitor endothelial cells can attach to graft fibers directly without clotting and directly cover the graft luminal surfaces.

A Mutation That Separates the RasG Signals That Regulate Development and Cytoskeletal Function inDictyostelium

The expression of an activatedRasG, RasG-G12T, in vegetative cells ofDictyostelium discoideiumproduced an alteration in cell morphology. Cells underwent a transition between an extensively flattened form that exhibited lateral membrane ruffling to a less flattened form that exhibited prominent dorsal membrane ruffling. TheserasG-G12T transformants exhibited a redistribution of F-actin at the cell periphery and did not undergo the rapid contraction upon refeeding that is characteristic of wild-type cells. These results suggest a role for RasG in regulating cytoskeletal rearrangement inD. discoideum.We had shown previously that expression ofrasG-G12T inhibited starvation induced aggregation (M. Khoslaet al.,1996,Mol. Cell. Biol.16, 4156–4162).rasG-G12T genes containing secondary mutations were transformed into cells to test whether the effects ofrasG-G12T were transmitted through a single downstream effector. Cells expressingrasG-G12T/T35S orrasG-G12T/Y40C (secondary mutations within the effector domain) exhibited normal morphology and underwent normal aggregation, suggesting that signaling through the effector domain was required for both the morphological and the development changes induced byrasG-G12T. In contrast, cells expressingrasG-G12T/T45Q (a secondary mutation in the effector distal flanking domain) exhibited normal aggregation but a morphology indistinguishable from that ofrasG-G12T transformants. This result suggests that RasG regulates developmental and cytoskeletal functions by direct interaction with more than one downstream effector.

The Computerised Weaving of Preforms for Composites. Part III: The Generation of a 3D Net-shaped Preform Weave Pattern and Weaving Instructions

The algorithms required for generating the weaving instructions (jacquard designs) for weaving truly 3D preforms in flattened form on conventional 2D looms are described. The basic approach is to divide the flattened structures into areas, each area into levels, and each level into fabric layers. Together with the chosen basic weave (plain, twill, satin, etc.) and the required number of shuttle paths, the number and size of these structural elements determine the size, in terms of numbers of ends and picks, of the over-all weave repeat of the whole structure. In principle, several repeats of the same structure can be woven side by side, but the structures chosen for analysis were too large for this purpose. In the warp direction, however, any desired number of repeats could be woven.

Transition crossing in proton synchrotrons using a flattened rf wave

The problems of beam loss and emittance growth during transition crossing in a proton synchrotron have been major issues for many years. Recently we have developed a scheme that resolves some of these problems by eliminating rf focusing during transition crossing. The technique uses a flattened (nonsinusoidal) rf wave form which delivers the correct acceleration to all particles in the beam. This scheme has been tested in the Fermilab Main Ring accelerator by the addition of 13% of a third harmonic rf voltage to the fundamental accelerating rf voltage during the nonadiabatic period near the transition energy. Beam loss was completely eliminated, and longitudinal emittance dilution after transition remained below 15%. Simulations of longitudinal beam dynamics reproduce the data well.

Morphological and immunohistochemical properties of primary long-term cultures of adult guinea-pig ventricular cardiomyocytes with peripheral cardiac neurons

Long-term (2–12 weeks) cultures of adult guinea-pig ventricular myocytes, cocultured with neurons derived from stellate or intrinsic cardiac ganglia, retain their functional properties (Horackova et al., 1993, 1994, 1995). The present study was designed to investigate the morphological and immunochemical properties of such neurons and their associated cardiomyocytes. Cultured myocytes studied by means of phalloidin-rhodamine (for F-actin) and an antibody raised against myomes revealed parallel myofibrils with striations typical of rod-shaped cardiomyocytes, even while myocytes changed from cylindrical to flattened form as they established intercellular contacts. Microtubular networks, identified by α-tubulin DM1A antibody, were arrayed longitudinally in myofibrils, being especially prominent during the formation of intercellular contacts between myocytes. Histochemically identified adult peripheral autonomic neurons cultured alone or with myocytes displayed a variety of shapes. α-Tubulin staining was associated with the somata and neurites of various-shaped neurons whether cultured alone or with myocytes. Cultured neurons derived from stellate and intrinsic cardiac ganglia also exhibited staining for the general neuronal marker PGP 9.5 (protein gene product 9.5), and for specific markers of the following neurochemicals: tyrosine hydroxylase, acetylcholinesterase, choline acetyltransferase, neuropeptide Y, vasoactive intestinal peptide, calcitonin gene-related peptide, bradykinin, oxytocin, and NADPH-diaphorase. These data indicate that: (a) adult ventricular myocytes cocultured with intrathoracic neurons retain the structural properties of adult myocytes found in vivo; (b) intrinsic cardiac and extrinsic intrathoracic neurons cultured alone or with cardiomyocytes display morphological characteristics similar to those of neurons studied in situ; (c) intrinsic cardiac and intrathoracic extracardiac neurons cultured alone or with cardiomyocytes display a variety of morphologies (unipolar, bipolar, and multipolar), larger and more multipolar neurons being present in cultures derived from stellate versus intrinsic cardiac ganglia; (d) such cultured neurons are associated with a number of neurochemicals, more than one chemical being associated with each neuron. This model presents an excellent opportunity to study the morphology of individual peripheral extracardiac and intracardiac neurons as well as their potential to produce various neurochemicals that are known to be involved in the neuromodulation of cardiomyocyte function.

Consequences of oocyte form modifications inEupolymnia nebulosa(Annelida; Polychaeta)

Summary The changes in form of intracoelomic oocytes during their developmental stages and the change from mature to the external fertilized (i.e., egg) phases during the spawning process were analyzed in Eupolymnia nebulosa with reference to the life-history strategy of the species. Accurate description of the real form of both oocytes and eggs was the objective of the study. All developmental stages of oocytes floating freely in the coelom (solitary oocytes) showed a flattened form. Increase in oocyte thickness was not reflected in a proportional increase in diameter. Therefore, by simply measuring diameters, a significant component of oocyte growth would not have been recorded. Different relationships between diameter and thickness of oocytes for the Mediterranean (slope=0.436, intercept=-4.507) and English Channel, (slope=0.321, intercepe-2.199) populations of E. nebulosa have been observed. The implications of this difference for the speciation problem of the “cosmopolitan” E. nebulosa are discussed....

Mutations and polymorphisms in the human peripherin-RDS gene and their involvement in inherited retinal degeneration.

The RDS gene codes for the protein peripherin-RDS, which is an integral membrane glycoprotein found in the outer segment of both rod and cone photoreceptor cells. It is thought to function as a structural protein involved in the maintenance of the flattened form of the disc lamellae. The RDS gene has been implicated in the mouse phenotype retinal degeneration slow, and mutations in the human homologue are now known to be associated with both central and peripheral retinal degenerations. In all, 43 sequence variants have been described in the human gene, including 30 missense mutations, two single base substitutions producing termination codons, 7 small in-frame deletions, and 4 insertion/ deletion events, which break the reading frame. Of these, 39 are associated with retinal phenotypes, which can be grouped into four broad categories: dominant retinitis pigmentosa, progressive macular degeneration, digenic RP, and pattern dystrophies. The mutations underlying dominant RP and severe macular degeneration are largely missense or small in-frame deletions in a large intradiscal loop between the third and fourth transmembrane domains. In contrast, those associated with the milder pattern phenotypes or with digenic RP are scattered more evenly through the gene and are often nonsense mutations. This observation correlates with the hypothesis that the large loop is an important site of interaction between RDS molecules and other protein components in the disc.

Unique Changes of Ganglion Cell Growth Cone Behavior Following Cell Adhesion Molecule Perturbations: A Time-Lapse Study of the Living Retina

In the mammalian retina, multiple mechanisms are responsible for guiding retinal ganglion cell axons to the optic fissure. In the present study we have used time-lapse videomicroscopy to show that, within the center of the retinal neuroepithelium, growth cones use a scaffold of previously formed axons as a substrate for guidance. High magnification time-lapse videomicroscopy of normal growth cones in the midretina have shown that they have the ability to alter their shape from long, streamlined forms that hug other axons to more flattened forms that move between axons or neuroepithelial endfeet. In studies on the role of specific cell interactions in these events, Fab fragments against L1 and NCAM, administered either alone or in combination, were found to have dramatic and distinct effects on retinal ganglion cell growth cones. Anti-L1 Fab fragments severely disrupted radial growth cone orientation and rate of outgrowth. The anti-L1-treated growth cones initially stalled for 2 h, then changed direction and, thereafter, resumed an elongation rate twice as fast as in control preparations. By contrast, anti-NCAM Fab did not affect growth cone direction, but caused subsets of growth cones to speed up initially, then to dramatically increase in size, stall, and eventually halt. These results imply that L1 and NCAM play different roles in the promotion and direction of axon growth and, along with repulsive molecules and physical channels, provide essential information for the unidirectional growth of retinal axons into the optic fissure.

Taphonomic and paleoecologic implications of flow‐induced forces on concavo‐convex articulate brachiopods: an experimental approach

The Orientation of benthic marine organisms may be disturbed by flow-induced forces (i.e. drag and lift) caused by wave and current activity. Drag and lift are partly a function of organism size and shape. Consequently, morphology may affect stability (defined as resistance to reorientation, flipping, or entrainment) both during the life of an organism and after its death. An understanding of drag-and-lift effects is therefore essential to the interpretation of paleoecology and biostratinomic processes. An experimental method for quantifying the relative effects of flow-induced forces is described. These forces are measured during flume experiments using transducers and plaster replicas of fossils. As an illustration of the method's potential for taphonomic research, results from experiments investigating the effects of concavo-convex morphologies of articulate brachiopods are presented. Concave-up and convex-up orientations are commonly used to infer paleohydraulic conditions. Two geniculate brachiopods (Rafinesquina alternata and Leptaena richrnondensis) and three flattened forms (a second morphotype of Rafinesquina altemata, Strophodonta demissa, and Tropidoleptus carinatus) were tested in convex-up and concave-up postures and in three azimuthal orientations (hingeline oriented upstream, hingeline downstream, and hingeline parallel to flow). Concave-up orientations consistently exhibit higher drag than convex-up orientations, and this supports the common observation that valved fossils are typically found convex up in paleoenvironments dominated by traction transport. The presence of geniculation significantly increases drag. Lift is relatively insignificant for all models in most orientations. □Taphonomy, paleoecology, brachiopods, flow-induced forces, transport.

A new Silurian retiolitid graptolite from Arctic Canada

Retiolitid graptolites are a very common component in Silurian graptolite faunas of the Canadian Arctic, both in flattened form on shale surfaces and in uncompressed form in limestone concretions found in the enclosing shales (Lenz and Melchin, 1987). Upper Wenlock and Ludlow rocks are particularly prolific, having yielded about 20 species of retiolitids to date. One of the collections made during the summer of 1991 was a single piece of talus-derived shale containing 10 complete and slightly fragmented retiolitids. These specimens are morphologically unique, and their description is the purpose of this note.

Effect of Maofeng tea processing on leaf trichomes of tea (Camellia sinensis L)

AbstractScanning electron microscopy was used to investigate the ultrastructure of trichomes on Maofeng, a special Chinese green tea. The trichomes were cylindrical in appearance with a length of 0.6–1 mm, wall thickness of 0.2–0.3 μm and a mid‐point diameter of 9–10 μm. The angles between the trichomes and the leaf under‐surface were below 30° in Maofeng tea though they were 45–75° in fresh green leaf. The trichome wall consisted mainly of fibre and its outer‐surface was unevenly covered with waxy substances and striped. The trichome joint, by which the trichome was attached to the leaf tower epidermis, was expanded and filled with essential oil droplets. The undeveloped trichomes assumed a flattened form because of the action of pressing during rolling and shrank during the tea drying process. During the Maofeng tea processing, trichome shedding was caused by disruption of its expanded joint structure and breakdown at the cylindrical wall above the expanded joint.

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Topography plays a major role in the morphology, geochemistry, and mineral inclusion profiles of placer gold from the East Fork of the San Gabriel River. These trends are consistent with a significant change in topographic gradient over a short distance, and coincident with the break in slope along the range-front of the San Gabriel Mountains. Placer gold from above this topographic transition is more rounded and 3-dimensional, with elevated silver in the alloy of the native gold, little evidence of gold enrichment rims, and abundant inclusions of brittle and reactive minerals. Below the topographic transition, placer gold assumes a distinctly flattened form, with lower silver alloy content, thin gold enrichment rims, and rare inclusions of relatively inert minerals. This relationship is observed for placer gold shed from two inferred lode sources within the river catchment, with placer gold from each of these sources being traceable as a unique population over at least 8 km of the river. Significantly, these placer gold properties are distinctive enough to fingerprint gold from specific portions of the placer deposit. These identifying characteristics, with virtually identical morphology and chemical trends, are observed in the large nuggets of the Mel Fisher collection of purported San Gabriel gold. These similarities appear to confirm the provenance of the collection, including identification of the specific locations where each nugget originated.

Acanthamoeba spp.: "Opportunistic Pathogens"

Acanthamoeba spp.: "Opportunistic Pathogens"

Approximate transformation of an arbitrary curved surface into a plane using dynamic programming

This paper is concerned with the approximate transformation of curved surfaces with arbitrary shape into a plane using dynamic programming. In designing for curved shapes, CAD systems have a prominent role; in particular, methods for the transformation of arbitrary regions on the curved surface into flattened forms are indispensable for manufacturing processes. Generally, until now, in the absence of a systematic scheme for obtaining flattened forms, manual methods have needed a great deal of work. A method to transform curved surfaces using the finite element method has already been proposed. In this paper, DP is introduced into the primal problem. That is, an objective curved surface is decomposed into regions of adjacent strips. Then, each region is developed in turn into a flattened shape. The whole shape is derived by solving multi-stage decision processes. Moreover, a two-step algorithm is proposed for obtaining a good initial shape. By way of illustration, the results are then applied to the problem of transforming duct and shoe models into flattened forms.

Polyelectrolyte induced aggregation of latex particles: Influence of the structural relaxation of adsorbed macromolecules on the colloid aggregation mode

An experimental procedure allowing reproducible mixing of colloids and polymers in dilute suspension was used to study perikinetic aggregation resulting from polymer adsorption onto colloids. Changes of the temporal variation of mean characteristics of the colloid suspension ( N 0 and N 2, zeroth and second moments of the aggregate size distribution) and of the shape of the colloid size distribution ( c n ( t) versus n, the number of elementary particles constituting an aggregate), were related to the slow structural relaxation of adsorbed macromolecules. At the time of initial contact of polymer and colloid, the adsorbed macromolecules had characteristics of solution macromolecules. Then, this coil-like conformation developed into a more flattened form. The parameter followed in the study was the relative polymer/latex concentration, which governed the initial surface coverage θ(0) and the rate of the temporal evolution of θ( t) toward equilibrium. At low polymer dosage, the destabilizing process at short times was interparticle bridging which developed with features of reaction-limited aggregation (RLA). After a given flocculation period depending on the polymer dosage, diffusion-limited aggregation (DLA) was found to describe the observed phenomenon. At higher polymer concentrations, “instantaneous” flocculation occurred when the polymer was continuously supplied to the stirred suspension. The aggregates formed during this RLA process thus became sterically protected against further agglomeration by the polymer layer on the surface and the suspension remained unchanged for days.

Ranikothalia sindensis Zone in Late Paleocene Biostratigraphy

Ranikothalia sindensis Zone in Late Paleocene Biostratigraphy

Development of any curved surface using dynamic programming.

This paper concerns the development of any curved surface using dynamic programming. In the case of designing curved transformation of any arbitrary region on the curved surface into flattened forms are indispensable to manufacturing processes. Generally speaking, until now, as there is no systematical sheme to get flattened forms, methods by man require a lot of effort. We have already proposed a method to transform any curved surface using the finite element method. In this paper, we introduce ideas of the dynamic programming to the primal problem. That is, an objective curved surface is decomposed into the regions in juxtaposed strips. Then each region is developed into a flattened shape. The whole shape is derived by means of solving multistage decision processes. To illustlate the results, we apply them to transform duct and shoe models into flattened forms.

Recovery of a curved surface using a finite element method.

This paper described a new scheme of 3D object modeling using a finite element method. When designing a curved surface, We need to consider the following processes. First, various regions on a curved surface are transformed into flattened forms. Second, a curved surface is recovered from the flattened form. Third, the corresponding curved surfaces have to be made based on modified flattened shapes. we have already proposed a method to develop any curved surface using the finite element method. In this paper, We deal with recovery of 3D shapes from flattened ones and some additional information. Examples about a body of axial symmetrical revolution and a shoes model are presented as typical and practical applications to illustrate the method that recovers 3D curved surface based on FEM.

Development of a curved surface using a finite element method. 2nd report. Consideration of design constraints.

Recently, 3-dimensional graphic technologies are topics of rapidly growing importance in the industrial fields such as those dealing with curved surfaces. When designing for a curved surface, methods for transformation of arbitrary regions on the curved surface into flattened forms are very important in manufacturing processes. The purpose of this paper is to describe a scheme for transformation of various regions on a curved surface subject to the following conditions. First, materials which constitute regions on a curved surface have different types of elasticity. Second, an objective curved surface has some regions whose shapes are fixed. Third, lengths of border lines between two regions need to be made equal to each other. As typical and practical applications, examples of shoe models corresponding to each case are presented to illustrate the method that transforms the various regions into flattened forms.