Observations on Cellular Structures of Porphyridium cruentum

The cellular structure of Porphyridium cruentum was studied with both light and electron microscope. The photosynthetic plastid in this red alga was found to be structurally similar to that in the Chlorophyceae and higher green plants. The phycobilins, as well as the chlorophyll, seem to be associated with the lamellae of the plastid. The pyrenoid, a region of low lamellar density, contains no tubules, and does not appear to function in synthesis or storage of reserve material. Grains of floridean starch are located in the cytoplasm, outside the plastid. Typical mitochondrial organelles were not observed. The nucleus is eccentric, and contains a nucleolus located on the inner face of the nucleus, nearest the plastid. The schedule for staining the nucleus is given in detail. Other cell structures (sheath, dictyosomes, etc.) are described. Growing cells in light of intensity leads to disruption of the parallel arrangement of the lamellar characteristic of cells grown in moderate light.

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Viscoelastic Properties of Cell Structures Manufactured Using a Photo-Curable Additive Technology—PJM

Polymers ◽

10.3390/polym13111895 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1895

Author(s):

Tomasz Kozior ◽

Czesław Kundera

Keyword(s):

Viscoelastic Properties ◽

Cellular Structure ◽

Material Selection ◽

Cellular Structures ◽

Test Results ◽

Additive Technology ◽

Polymer Resin ◽

Cell Structures ◽

Relaxation Curves ◽

The Impact

This research paper reviews the test results involving viscoelastic properties of cellular structure models made with the PolyJet Matrix—PJM additive technology. The designed test specimens were of complex cellular structure and made of three various photo-curable polymer resin types. Materials were selected taking into account the so-called “soft” and “tough” material groups. Compressive stress relaxation tests were conducted in accordance with the recommendations of standard ISO 3384, and the impact of the geometric structure shape and material selection on viscoelastic properties, as well as the most favorable geometric variants of the tested cellular structure models were determined. Mathematica and Origin software was used to conduct a statistical analysis of the test results and determine five-parameter functions approximating relaxation curves. The most favorable rheological was adopted and its mean parameters determined, which enables to match both printed model materials and their geometry in the future, to make a component with a specific rheological response. Furthermore, the test results indicated that there was a possibility of modelling cellular structures within the PJM technology, using support material as well.

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CHROMATOPHORE DEVELOPMENT, PITS, AND OTHER FINE STRUCTURE IN THE RED ALGA, LOMENTARIA BAILEYANA (HARV.) FARLOW

The Journal of Cell Biology ◽

10.1083/jcb.12.3.553 ◽

1962 ◽

Vol 12 (3) ◽

pp. 553-569 ◽

Cited By ~ 91

Author(s):

G. Benjamin Bouck

Keyword(s):

Endoplasmic Reticulum ◽

Plasma Membrane ◽

Fine Structure ◽

Higher Plants ◽

Red Alga ◽

Cellular Structures ◽

Secretory Function ◽

Thin Sections ◽

Floridean Starch ◽

Oriented Parallel

Thin sections of the red alga, Lomentaria baileyana, a tubular member of the Rhodymeniales, were examined after permanganate fixation and Araldite embedding. Many of the cellular structures in Lomentaria were found to be similar to analogous structures in animals and higher plants. However, in the walls between cells are modified areas generally known as pits which are unique to the higher orders of red algae (Florideae). In this study the pits were found to consist of a plug-like structure surrounded by an uninterrupted membrane apparently continuous with the plasma membrane. Examination of the chromatophore revealed a characteristic limiting membrane, a relatively sparse distribution of plates, no grana, and a single disc apparently oriented parallel to the limiting membrane. In addition to their origin from non-lamellate proplastids, chromatophores were found capable of division by simple constriction. Floridean starch grains were observed outside the chromatophore and the possibility of an association of the first formed grains with portions of the endoplasmic reticulum is considered. Gland cells seem to have a high proportion of Golgi components (dictyosomes), and are believed to have some kind of secretory function. Many of the Golgi vesicles seem to open on the wall and presumably discharge their contents.

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Preparatory Procedures for Electron Microscopic Analysis at the Molecular Level of Resolution

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100070230 ◽

1978 ◽

Vol 36 (3) ◽

pp. 516-520

Author(s):

F.J. Sjostrand

Keyword(s):

Electron Microscope ◽

Molecular Level ◽

Microscopic Analysis ◽

Resolving Power ◽

Cellular Structures ◽

Electron Microscopic ◽

Systematic Analysis ◽

Technical Developments ◽

Thin Sectioning ◽

Obvious Reason

In the 1940's and 1950's electron microscopy conferences were attended with everybody interested in learning about the latest technical developments for one very obvious reason. There was the electron microscope with its outstanding performance but nobody could make very much use of it because we were lacking proper techniques to prepare biological specimens. The development of the thin sectioning technique with its perfectioning in 1952 changed the situation and systematic analysis of the structure of cells could now be pursued. Since then electron microscopists have in general become satisfied with the level of resolution at which cellular structures can be analyzed when applying this technique. There has been little interest in trying to push the limit of resolution closer to that determined by the resolving power of the electron microscope.

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Preparation and properties of silicone rubber materials with foam/solid alternating multilayered structures

Polymer Journal ◽

10.1038/s41428-020-00439-x ◽

2021 ◽

Author(s):

Wenhuan Zhang ◽

Zhaoping Deng ◽

Hongwei Yuan ◽

Shikai Luo ◽

Huayin Wen ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Silicone Rubber ◽

Cellular Structure ◽

Cellular Structures ◽

Compressive Property ◽

Solid Layer ◽

Multilayered Structures ◽

Element Analysis ◽

Morphology And Mechanical Properties

AbstractIn this paper, silicone rubber materials with foam/solid alternating multilayered structures were successfully constructed by combining the two methods of multilayered hot-pressing and supercritical carbon dioxide (SCCO2) foaming. The cellular morphology and mechanical properties of the foam/solid alternating multilayered silicone rubber materials were systematically studied. The results show that the growth of the cell was restrained by the solid layer, resulting in a decrease in the cell size. In addition, the introduction of the solid layer effectively improved the mechanical properties of the microcellular silicone rubber foam. The tensile strength and compressive strength of the foam/solid alternating multilayered silicone rubber materials reached 5.39 and 1.08 MPa, which are 46.1% and 237.5% of the pure silicone rubber foam, respectively. Finite element analysis (FEA) was applied and the results indicate that the strength and proportion of the solid layer played important roles in the tensile strength of the foam/solid alternating multilayered silicone rubber materials. Moreover, the small cellular structures in silicone rubber foam can provided a high supporting counterforce during compression, meaning that the microcellular structure of silicone rubber foam improved the compressive property compared to that for the large cellular structure of silicone rubber foam.

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Control of Hierarchically Ordered Positive and Negative Replicas of Wood Cellular Structures by Surfactant-Directed Sol-Gel Mineralization

MRS Proceedings ◽

10.1557/proc-726-q5.4 ◽

2002 ◽

Vol 726 ◽

Author(s):

Yongsoon Shin ◽

Jun Liu ◽

Li-Qiong Wang ◽

Jeong Ho Chang ◽

William D. Samuels ◽

...

Keyword(s):

Silicic Acid ◽

Cell Walls ◽

Cellular Structure ◽

Sol Gel ◽

Ceramic Materials ◽

Silica Particles ◽

Low Ph ◽

Cellular Structures ◽

Inner Surface

AbstractWe here report the synthesis of ordered ceramic materials with hierarchy produced by an in-situ mineralization of ordered wood cellular structures with surfactant-templated sol-gel at different pH. At low pH, a silicic acid is coated onto inner surface of wood cellular structure and it penetrates into pores left, where degraded lignin and hemicellulose are leached out, to form a positive replica, while at high pH the precipitating silica particles due to fast condensation clog the cells and pit structures to form a negative replica of wood. The calcined monoliths produced in different pHs contain ordered wood cellular structures, multi-layered cell walls, pits, vessels well-preserved with positive or negative contrasts, respectively. The surfactant-templated mineralization produces ordered hexagonal nanopores with 20Å in the cell walls after calcination.

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The complete amino acid sequence of R-phycocyanin-I alpha and beta subunits from the red alga Porphyridium cruentum. Structural and phylogenetic relationships of the phycocyanins within the phycobiliprotein families

European Journal of Biochemistry ◽

10.1111/j.1432-1033.1994.tb18769.x ◽

1994 ◽

Vol 221 (1) ◽

pp. 563-580 ◽

Cited By ~ 30

Author(s):

Axel DUCRET ◽

Walter SIDLER ◽

Gerhard FRANK ◽

Herbert ZUBER

Keyword(s):

Amino Acid ◽

Amino Acid Sequence ◽

Phylogenetic Relationships ◽

Red Alga ◽

Porphyridium Cruentum ◽

Beta Subunits ◽

Complete Amino Acid Sequence

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ELECTRON MICROSCOPY OF CENTRIFUGED HYPHAE OF NEUROSPORA

The Journal of Cell Biology ◽

10.1083/jcb.9.3.609 ◽

1961 ◽

Vol 9 (3) ◽

pp. 609-617 ◽

Cited By ~ 14

Author(s):

M. Zalokar

Keyword(s):

Electron Microscopy ◽

Endoplasmic Reticulum ◽

Electron Microscope ◽

Optical Microscope ◽

Granular Structure ◽

Cell Physiology ◽

Cell Structures ◽

Light Area ◽

Fat Bodies

Normal and centrifuged hyphae of Neurospora were studied with the electron microscope. The following cell structures could be identified: nuclei with nucleoli, mitochondria, endoplasmic reticulum, ribosomes, glycogen, fat bodies, vacuoles, and vesicles with an inner canalicular system, of unknown nature. In centrifuged hyphae, the glycogen layer appeared as a light area, with a slight indication of granular structure. The ribosome layer consisted of densely packed ribosomes without any membranes. The mitochondrial layer contained spaces filled with ribosomes. The nuclei were loosely packed, with endoplasmic reticulum between them. The "enchylema" layer was composed of vesicles belonging to the endoplasmic reticulum. The vacuolar layer was poorly preserved and consisted of double-walled vesicles. Fat appeared as stellate osmiophilic droplets. These observations were compared with previous observations under the optical microscope and their meaning for cell physiology was discussed.

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Computational and Experimental Studies of Cellular Samples Manufactured Using Additive Methods for Use in Advanced Lightweight Designs of Engine Parts

Volume 10B: Structures and Dynamics ◽

10.1115/gt2020-15158 ◽

2020 ◽

Author(s):

Liubov Magerramova ◽

Michael Volkov ◽

Oleg Volgin ◽

Pavel Kolos

Keyword(s):

Fatigue Testing ◽

Low Cycle Fatigue ◽

Cell Structure ◽

Experimental Studies ◽

Cellular Structures ◽

Uniaxial Tensile ◽

Porous Structures ◽

Lattice Cell ◽

Cell Structures ◽

Homogeneous Materials

Abstract The use of cellular structures is one way to reduce the weight of engine parts. Cellular structures are used to provide rigidity and strength for parts subject to compression, bending, and shock loads. Failure of the individual elements of a lattice/cell structure does not result in the destruction of the entire part; this stands in contrast to the structure of a conventional homogeneous metal object, in which cracks will continue to increase with increasing load, causing the destruction of the entire part. Lattice/cell structures have relatively high characteristics of rigidity and strength, excellent thermal insulation properties, energy absorption characteristics, and high fatigue resistance. The use of this type of structure in engine part construction opens up new opportunities for advanced aviation applications. However, the deformation behavior of porous and metallic structures differs significantly from that of conventional homogeneous materials. Samples with cellular and porous structures are themselves designs. Therefore, procedures for strength testing and interpretation of experimental results for cellular and porous structures differ from those for samples derived from homogeneous materials. The criteria for determining the properties of cellular structures include density, stiffness, ability to accumulate energy, etc. These parameters depend on the configuration of the cells, the size of each cell, and the thickness of the connecting elements. Mechanical properties of cellular structures can be established experimentally and confirmed numerically. Special cellular specimens have been designed for uniaxial tensile, bending, compression, shear, and low-cycle fatigue testing. Several variants of cell structures with relative densities ranging from 13 to 45% were considered. Specifically, the present study examined the stress-strain states of cell structures from brands “CobaltChrome MP1” powder compositions obtained by laser synthesis on an industrial 3D printer Concept Laser M2 Cusing Single Laser 400W. Numerical simulations of the tests were carried out by the finite element method. Then, the most rational cellular structures in terms of mass and strength were established on the basis of both real and numerical experiments.

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