The Fine Structure of Different Types of Experimental Edemas for Testing the Effect of Vasoactive Drugs Demonstrated with a Flavonoid

1972 ◽  
Vol 9 (3-6) ◽  
pp. 326-354 ◽  
Author(s):  
F. Hammersen
Keyword(s):  
Fine Structure ◽  
Vasoactive Drugs ◽  
Different Types

scholarly journals DAFNE-Light DXR1 Soft X-Ray Synchrotron Radiation Beamline: Characteristics and XAFS Applications

2019 ◽  
Vol 4 (1) ◽  
pp. 7 ◽  
Author(s):  
Antonella Balerna
Keyword(s):  
Fine Structure ◽  
Synchrotron Radiation ◽  
Disordered Systems ◽  
Beam Line ◽  
Long Range Order ◽  
X Ray ◽  
Xafs Spectroscopy ◽  
Insertion Device ◽  
Different Types ◽  
X Ray Absorption

X-ray Absorption Fine Structure Spectroscopy (XAFS) is a powerful technique to investigate the local atomic geometry and the chemical state of atoms in different types of materials, especially if lacking a long-range order, such as nanomaterials, liquids, amorphous and highly disordered systems, and polymers containing metallic atoms. The INFN-LNF DAΦNE-Light DXR1 beam line is mainly dedicated to soft X-ray absorption spectroscopy; it collects the radiation of a wiggler insertion device and covers the energy range from 0.9 to 3.0 keV or the range going from the K-edge of Na through to the K-edge of Cl. The characteristics of the beamline are reported here together with the XAFS spectra of reference compounds, in order to show some of the information achievable with this X-ray spectroscopy. Additionally, some examples of XAFS spectroscopy applications are also reported.

scholarly journals Stellar Archaeology: Using Metal-Poor Stars to Test Theories of the Early Universe

2008 ◽  
Vol 4 (S255) ◽  
pp. 336-340
Author(s):  
Anna Frebel ◽  
Jarrett L. Johnson ◽  
Volker Bromm
Keyword(s):  
Fine Structure ◽  
Low Mass Stars ◽  
First Stars ◽  
Abundance Patterns ◽  
Cosmological Context ◽  
Different Types ◽  
The Galaxy ◽  
Structure Line ◽  
History Of ◽  
Low Mass

AbstractConstraints on the chemical yields of the first stars and supernova can be derived by examining the abundance patterns of different types of metal-poor stars. We show how metal-poor stars are employed to derive constraints of the formation of the first low-mass stars by testing a fine-structure line cooling theory. The concept of stellar archaeology, that stellar abundances truly reflect the chemical composition of the earliest times, is then addressed. The accretion history of a sample of metal-poor stars is examined in detail in a cosmological context, and found to have no impact on the observed abundances. Predictions are made for the lowest possible Fe and Mg abundances observable in the Galaxy, [Fe/H]min = −7.5 and [Mg/H]min = −5.5. The absence of stars below these values is so far consistent with a top-heavy IMF. These predictions are directly relevant for future surveys and the next generation of telescopes.

scholarly journals FINE STRUCTURE OF SMOOTH MUSCLE CELLS GROWN IN TISSUE CULTURE

1971 ◽  
Vol 49 (1) ◽  
pp. 21-34 ◽  
Author(s):  
Gordon R. Campbell ◽  
Yasuo Uehara ◽  
Gerda Mark ◽  
Geoffrey Burnstock
Keyword(s):  
Electron Microscopy ◽  
Smooth Muscle ◽  
Fine Structure ◽  
Cell Membrane ◽  
Smooth Muscle Cells ◽  
Phase Contrast ◽  
Muscle Cells ◽  
Different Types ◽  
Membrane Infoldings

The fine structure of smooth muscle cells of the embryo chicken gizzard cultured in monolayer was studied by phase-contrast optics and electron microscopy. The smooth muscle cells were irregular in shape, but tended to be elongate. The nucleus usually contained prominent nucleoli and was large in relation to the cell body. When fixed with glutaraldehyde, three different types of filaments were noted in the cytoplasm: thick (150–250 A in diameter) and thin (30–80 A in diameter) myofilaments, many of which were arranged in small bundles throughout the cytoplasm and which were usually associated with dark bodies; and filaments with a diameter of 80–110 A which were randomly orientated and are not regarded as myofilaments. Some of the aggregated ribosomes were helically arranged. Mitochondria, Golgi apparatus, and dilated rough endoplasmic reticulum were prominent. In contrast to in vivo muscle cells, micropinocytotic vesicles along the cell membrane were rare and dense areas were usually confined to cell membrane infoldings. These cells are compared to in vivo embryonic smooth muscle and adult muscle after treatment with estrogen. Monolayers of cultured smooth muscle will be of particular value in relating ultrastructural features to functional observations on the same cells.

Exafs Evidence For Atom Location In Icosahedral TiZrNi And Hydrogenated TiZrNi Quasicrystals

1998 ◽  
Vol 553 ◽  
Author(s):  
A. Sadoc ◽  
J. K. Kim ◽  
K.F. Kelton
Keyword(s):  
Fine Structure ◽  
Metal Atom ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Absorption Fine ◽  
Different Types ◽  
X Ray Absorption ◽  
Absorption Edges

AbstractWe present results from the first extended X-ray absorption fine-structure studies in a Ti/Zrbased quasicrystal. The icosahedral Ti53Zr27Ni20 phase and an icosahedral Ti45Zr38Ni17 phase that also contains 1.7 hydrogen atoms for each metal atom were investigated. Experiments performed above the Ti, Ni and Zr K absorption edges have allowed to identify different types of atomic subshells around the Ti, Ni and Zr atoms. Significant differences are observed between these two quasicrystalline alloys, suggesting preferential sites for the hydrogen atoms.

The fine structure of uniporous and nonporous pegs on the distal antennal segment of the diving beetle Graphoderus occidentalis Horn (Coleoptera: Dytiscidae)

1991 ◽  
Vol 69 (2) ◽  
pp. 334-352 ◽  
Author(s):  
J. C. Jensen ◽  
R. Y. Zacharuk
Keyword(s):  
Fine Structure ◽  
Antennal Segment ◽  
Terminal Segment ◽  
Sheath Cell ◽  
Terrestrial Habitat ◽  
Insect Sensilla ◽  
Virus Like Particles ◽  
Accessory Cells ◽  
Different Types ◽  
Diving Beetle

The terminal segment of the antenna of the predaceous diving beetle Graphoderus occidentalis Horn bears approximately 50 sensilla of nine different types. There are six types of uniporous chemosensilla, one type of nonporous mechanosensitive peg, and two types of multiporous pegs. Two types of uniporous pegs, which occur only at the antennal tip, have features of both contact chemosensilla and thermo- and hygro-sensilla. Three other types that occur only on the terminal segment below the apex also exhibit some features of chemosensilla and thermo- and hygro-sensilla. The sensilla are innervated by one to four neurons and most are ensheathed by two accessory cells. Four types of sensilla exhibit elaborate sheath cell configurations and secretions associated with their sinus that may reflect an adaptation to an aquatic or a dual aquatic–terrestrial habitat. All are atypical of generalized insect sensilla in having portions of the proximal dendrites and axons as well as the entire neuronal perikarya unsheathed and exposed to the hemocoel. The neuronal perikarya of two sensillar types contain virus-like particles.

Movement, Fine Structure, and Fusion of Pseudopods of an Enclosed Amoeba, Difflugiella Sp

1972 ◽  
Vol 10 (2) ◽  
pp. 563-583
Author(s):  
J. L. GRIFFIN
Keyword(s):  
Fine Structure ◽  
Cell Body ◽  
Activity Cycle ◽  
Different Types ◽  
Anterior Extension

In Difflugiella sp., strain F-20, a small amoeba enclosed in a flexible mantle, pseudopods extended through a mouth or aperture and seemed to function only for movement and feeding. Pseudopods from different cells fused on contact and cell clumps shared common pseudopods and moved in a co-ordinated way. During locomotion, pseudopods or pseudopod complexes usually exhibited an activity cycle of 3 phases: anterior extension with the tip firmly adhering; stable hold as other pseudopods advanced; and flaccid posterior retraction. While distal adhesive tips advanced, proximal unattached parts of pseudopods simultaneously shortened as the cell body advanced. Microtubules were numerous in pseudopods within the mouth but extended for only 1-2 µm into pseudopods up to 20-30 µm long. Microfilaments were present where pseudopods adhered to the substratum, to the mantle, or to bacteria and were also associated with pinocytotic invaginations. Pseudopod ground plasm was either reticulate or amorphous; no axial rods or aligned filaments related to pseudopod rigidity were seen. Simultaneous pseudopod adhesion, extension, and proximal shortening apparently account for locomotion or cell body translation of Difflugiella. While some similarities to other amoeboid systems were noted, the need for detailed studies on different types of organisms or cells is emphasized.

scholarly journals The fine structure of phloem fibres I. Untreated and swollen hemp

1940 ◽  
Vol 128 (851) ◽  
pp. 214-231 ◽  
Keyword(s):  
Optical Properties ◽  
Fine Structure ◽  
Natural Condition ◽  
Anatomical Study ◽  
Longitudinal Axis ◽  
Cellulose Chain ◽  
X Ray ◽  
Different Types

During an anatomical study of the jute and hemp plants carried out by one of us (B. C. K.), the opportunity was taken of reinvestigating in these plants the structure of the walls of the fibres, using the term “fibre” in its botanical sense. The so-called “bast” fibres are of particular interest in wall studies since it was apparently on the basis of their investigation that the “crossed fibrillar” conception was first introduction. Thus we find Reimers (1922) stating that in a number of plants, including hemp, the walls of these fibres are composed of two or more layers differing considerably in cellulose-Chain direction. Since that time numerous other statement of this kind have been made for different types of cell (Freudenberg and Dürr 1932; Ritter 1930; Ritter and Chidester 1928; Bailey and Kerr 1935); v. Iterson 1937; Wuhrmann-Meyer 1939). It seems rather a common feature of the evidence quoted in support of such a structure that it is derived from material swollen considerably either in acid or alkali. Certainly the optical properties of the wall have been used in support (Freudenberg and Durr 1932; Bailey and Kerr 1935 v. Iterson 1937; Wuhrmann-Meyer 1939). It seems rather a common feature of the evidence quoted in support of such a structure that it is derived from material swollen considerably either in acid or alkali. Certainly the optical properties of the wall have been used in support (Freudenberg and Durr 1932; Bailey and Kerr 1935 v. Iterson 1937; Wuhrmann-Meyer 1939). It seems rather a common feature of the evidence quoted in support of such a structure that it is derived from material swollen considerably either in acid or alkali. Certainly the optical properties of the wall have been used in support (Freudenberg and Durr 1932; Bailey and Kerr 1935; v. Iterson 1937; Wuhrmann-Meyer 1939). It seems rather a common feature of the evidence quoted in support of such a structure that it is derived from material swollen considerably either in acid or alkali. Certainly the optical properties of the wall have been used in support (Freudenberg and Dürr 1932; Bailey and Kerr 1935) but the implication of such work have already been discussed elsewhere (Preston 1939 a ). We are here concerned chiefly with the swelling technique. While it is not to be suggested that treatment with swelling reagents totally invalidates all observations of this type, it is quite clear that in some cases at least observation of swollen material can give an entirely erroneous conception of the wall in its natural condition. This is perhaps particularly clear in the case of jute, for which Osborne (1935, quoted also by Barker 1938) refers to the fibres as being composed of a series of chains lying at a considerable angle to the longitudinal axis of the cell, in spite of contrary X-ray evidence.

The fine structure of coelomocytes of the sea urchin, Strongylocentrotus dröbachiensis (Müllier O.F.)

1972 ◽  
Vol 50 (1) ◽  
pp. 77-81 ◽  
Author(s):  
V. G. Vethamany ◽  
M. Fung
Keyword(s):  
Stem Cells ◽  
Fine Structure ◽  
Sea Urchin ◽  
Plasma Membranes ◽  
Cell Aggregation ◽  
Structural Components ◽  
Physiological Conditions ◽  
Different Types ◽  
Spherical Cells

The fine structure of six different types of coelomocytes from Strongylocentrotus dröbachiensis (Müller), a sea urchin, is described. (1) Phagocytic leukocytes have either phagosomes of different sizes or large bladder-like, as well as veils of, cytoplasmic extensions. Syncytia are not observed under normal physiological conditions, although cell aggregation occurs without fusing of the plasma membranes. (2) Vibra-tile cells have a conventional flagellum and numerous mucopolysaccharide granules fill their cytoplasm. (3) The amoeboid red spherule cells contain typical echinochrome granules showing three structural components. (4) Colorless spherule cells contain numerous vacuole-like structures. (5) Small spherical cells are probably stem cells. (6) The granulocytes are few in number.

Cytoplasmic Structures in Insect Granular Hemocytes

1971 ◽  
Vol 29 ◽  
pp. 528-529
Author(s):  
M. Hagopian
Keyword(s):  
Electron Microscopy ◽  
Wound Healing ◽  
Fine Structure ◽  
Circulatory System ◽  
Cellular Function ◽  
Large Nucleus ◽  
Cytoplasmic Granules ◽  
Leucophaea Maderae ◽  
Different Types ◽  
Cytoplasmic Structures

Femoral segments from the metathoracic leg of the freshly molted cockroach nymph, Leucophaea maderae, were removed and were prepared for electron microscopy. The femoral cuticle with underlying epidermal cells encloses muscle, nerves, tracheae, tracheoles, and the hemocoel. In the insect open circulatory system the hemocoel contains hemolymph and hemocytes. Some of the known functions of insect hemocytes are phagocytosis, encapsulation, melanization, Wound healing, coagulation and possible transformation into other tissues. Previous studies of the agranular and granular hemocytes however lack the fine structure that is helpful in determining cellular function.The several different types of granular hemocytes have a general elliptical appearance, large nucleus, and prominent cytoplasmic granules. The most abundant type of granules are the membrane-bounded, roughly spherical, opaque inclusions which average about 1 to 2μ in diameter. These dense inclusions resemble vertebrate melanosomes. Other granules with an organized substructure are reminiscent of the vertebrate premelanosomes (Figs. 1, 2). In certain planes of section the premelanosome-like granules reveal that the internal configurations are microtubules which measure about 250A in diameter.

FINE STRUCTURE IN CORE LEVEL PHOTOEMISSION INTENSITIES — A STUDY OF THE Si(111)−(7×7) SURFACE

1994 ◽  
Vol 08 (30) ◽  
pp. 1889-1903
Author(s):  
J.A. CARLISLE ◽  
M.T. SIEGER ◽  
T. MILLER ◽  
T.-C. CHIANG
Keyword(s):  
Fine Structure ◽  
Structural Information ◽  
Structural Features ◽  
Core Level ◽  
Ratio Analysis ◽  
Intensity Analysis ◽  
Ongoing Debate ◽  
Attenuation Model ◽  
Different Types ◽  
The Individual

Photoemission intensities from core levels derived from surface and bulk atoms of a solid exhibit oscillations as a function of the excitation photon energy. These oscillations cannot be described by the classical layer attenuation model, which has been the basis for intensity analysis and quantitative structural modeling in a number of studies. The physics responsible for these oscillations is the extended photoemission fine structure (EPFS) above the core level absorption edge, which contains structural information in regard to surface bond lengths. The present paper examines in detail this phenomenon for the Si 2p core level of the Si (111)−(7×7) surface. The EPFS is found to modulate the surface-to-bulk Si 2p core level intensity ratios up to ~50%; thus, structural models based on a surface-to-bulk intensity ratio analysis using the classical layer attenuation model at a few photon energies may suffer large errors. This EPFS may be responsible for the ongoing debate in the literature over the assignment of the surface core levels to structural features on both the (111) and (100) surfaces of Si and Ge. This dilemma is resolved for the (7×7) surface. Using the usual three-component fit of the Si 2p core level (a bulk component and two surface components, S1 and S2), the EPFS signals from the individual components are separately analyzed. The results show the S2 component to be derived from adatom emission. The S1 component is unresolved, and represents emission from several different types of atoms in the top double layer of the (7×7) reconstruction.

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