Alkali-regulated Fe6 and Fe18 molecular clusters and their structural transformation

2021 ◽  
Author(s):  
Xiao-Yu Li ◽  
Ying Zou ◽  
Song-De Han ◽  
Guo-Ming Wang
Keyword(s):  
Structural Transformation ◽  
Iron Hydroxide ◽  
Molecular Clusters ◽  
Synthesis Condition ◽  
Iron Ions

As a kind of metastable aggregation between the iron ions and iron hydroxide precipitates, Fe clusters only can be isolated in the narrow synthesis condition. Here, two Fe clusters with...

Molecular Clusters of 3D and Lower Magnetic Dimensionality

1990 ◽  
Vol 206 ◽  
Author(s):  
G. C. Papaefthymiou
Keyword(s):  
Magnetic Properties ◽  
Solid State ◽  
Molecular Clusters ◽  
Magnetic Interactions ◽  
Iron Ions ◽  
Controlled Polymerization ◽  
Magnetic Correlations

ABSTRACTControlled polymerization of iron leads to the synthesis of molecular clusters of ever-increasing size, tending to extended structures. Polymerization of oxo-bridged octahedrally coordinated iron leads to clusters with 3D magnetic interactions between iron ions, while sulfide- and selenide-bridged tetrahedrally coordinated iron ions produce clusters of lower magnetic dimensionality. The magnetic properties of the resulting large molecular clusters with N ≥ 17 (where N = the number of iron ions in the cluster) are being investigated for the presence of collective magnetic correlations associated with the solid state.

Enhanced removal of antimony by acid birnessite with doped iron ions: Companied by the structural transformation

Chemosphere ◽  
2019 ◽  
Vol 226 ◽  
pp. 834-840 ◽  
Author(s):  
Hongbo Lu ◽  
Weifang Zhang ◽  
Le Tao ◽  
Feng Liu ◽  
Jing Zhang
Keyword(s):  
Structural Transformation ◽  
Iron Ions

The Supply of Iron to Diatoms

1937 ◽  
Vol 22 (1) ◽  
pp. 205-219 ◽  
Author(s):  
H. W. Harvey
Keyword(s):  
Sea Water ◽  
Iron Hydroxide ◽  
Ferric Hydroxide ◽  
Iron Ions ◽  
Surrounding Water ◽  
Nitzschia Closterium ◽  
Open Sea ◽  
Subsequent Passage

The nature of iron occurring in sea water, and its utilization by diatoms, is discussed.Diatoms in the sea obtain many thousand times more iron than calculation shows they can obtain by diffusion of iron ions from the surrounding water.Evidence is presented that ferric hydroxide is readily adsorbed on the surface of diatoms.It is shown that colloidal and larger particles of ferric hydroxide or phosphate can be utilized by, and support the growth of diatoms.Experiments show that the diatoms Nitzschia closterium and Lauderia borealis require, for continued growth, a very small quantity of iron compared with that found on, and in, diatoms taken from the open sea.It is contended that iron hydroxide adsorbed on diatoms is in contact with an interface where its solution, and subsequent passage into the cell, is probable.

The Fine Structure of Glycocalyx in Human Spermatozoa. A High Resolution Cytochemical Study

1973 ◽  
Vol 31 ◽  
pp. 640-641
Author(s):  
P. Hernández-Jáuregui ◽  
A. Sosa ◽  
A. González Angulo
Keyword(s):  
Negative Charge ◽  
Iron Hydroxide ◽  
Human Spermatozoa ◽  
Surface Coat ◽  
Cell Surfaces ◽  
Colloidal Iron ◽  
Cytochemical Study ◽  
Specific Permeability ◽  
Extracellular Glycoprotein ◽  
Mammalian Spermatozoa

Glycocalyx is the name given by Bennett to the extracellular glycoprotein coat present in some cell surfaces. It appears to play an important role in cell properties such as antigenicity, cell adhesivity, specific permeability, and ATP ase activity. In the sperm this coat can be directly related to such important phenomena as capacitation and fertilization. The presence of glycocalyx in invertebrate spermatozoa has already been demonstrated. Recently Yanagimachi et al. has determined the negative charges on sperm surfaces of mammalian spermatozoa including man, using colloidal iron hydroxide. No mention was made however of the outer surface coat as composed of substances other than those confering a negative charge. The purpose of this work was therefore to determine the presence of a glycocalyx in human spermatozoa using alcian blue and lanthanum staining.

The structure of pre-mRNA and mRNA from erythroid cells

1978 ◽  
Vol 36 (2) ◽  
pp. 234-235
Author(s):  
A.-M. Ladhoff ◽  
B.J. Thiele ◽  
Ch. Coutelle ◽  
S. Rosenthal
Keyword(s):  
Bone Marrow ◽  
Structural Transformation ◽  
Electron Micrographs ◽  
Ammonium Acetate ◽  
Bone Marrow Cells ◽  
Erythroid Cells ◽  
Globin Mrna ◽  
Ordered Structures ◽  
Rabbit Bone ◽  
Rabbit Reticulocytes

The suggested precursor-product relationship between the nuclear pre-mRNA and the cytoplasmic mRNA has created increased interest also in the structure of these RNA species. Previously we have been published electron micrographs of individual pre-mRNA molecules from erythroid cells. An intersting observation was the appearance of a contour, probably corresponding to higher ordered structures, on one end of 10 % of the pre-mRNA molecules from erythroid rabbit bone marrow cells (Fig. 1A). A virtual similar contour was observed in molecules of 9S globin mRNA from rabbit reticulocytes (Fig. 1B). A structural transformation in a linear contour occurs if the RNA is heated for 10 min to 90°C in the presence of 80 % formamide. This structural transformation is reversible when the denatured RNA is precipitated and redissolved in 0.2 M ammonium acetate.

Structural Transformation of a Germanium Σ=13 (510) [001] Tilt Grain Boundary under the Electron Beam

1990 ◽  
Vol 48 (1) ◽  
pp. 52-53 ◽  
Author(s):  
Jean-Luc Rouvière ◽  
Alain Bourret
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Grain Boundary ◽  
Structural Transformation ◽  
Mirror Symmetry ◽  
High Resolution Electron Microscopy ◽  
Structural Transformations ◽  
Covalent Bonds ◽  
Resolution Electron ◽  
Tilt Grain Boundary

The possible structural transformations during the sample preparations and the sample observations are important issues in electron microscopy. Several publications of High Resolution Electron Microscopy (HREM) have reported that structural transformations and evaporation of the thin parts of a specimen could happen in the microscope. Diffusion and preferential etchings could also occur during the sample preparation.Here we report a structural transformation of a germanium Σ=13 (510) [001] tilt grain boundary that occurred in a medium-voltage electron microscopy (JEOL 400KV).Among the different (001) tilt grain boundaries whose atomic structures were entirely determined by High Resolution Electron Microscopy (Σ = 5(310), Σ = 13 (320), Σ = 13 (510), Σ = 65 (1130), Σ = 25 (710) and Σ = 41 (910), the Σ = 13 (510) interface is the most interesting. It exhibits two kinds of structures. One of them, the M-structure, has tetracoordinated covalent bonds and is periodic (fig. 1). The other, the U-structure, is also tetracoordinated but is not strictly periodic (fig. 2). It is composed of a periodically repeated constant part that separates variable cores where some atoms can have several stable positions. The M-structure has a mirror glide symmetry. At Scherzer defocus, its HREM images have characteristic groups of three big white dots that are distributed on alternatively facing right and left arcs (fig. 1). The (001) projection of the U-structure has an apparent mirror symmetry, the portions of good coincidence zones (“perfect crystal structure”) regularly separate the variable cores regions (fig. 2).

Highly sensitive NADH detection by utilising an aluminium hydroxide/iron hydroxide/MWCNTs nanocomposite film-modified electrode

2020 ◽  
Vol 15 (14) ◽  
pp. 997-1002
Author(s):  
Yu Wang ◽  
Lingling Yin ◽  
Xia Li ◽  
Ran Shang ◽  
Xiangli Yang ◽  
...  
Keyword(s):  
Modified Electrode ◽  
Aluminium Hydroxide ◽  
Nanocomposite Film ◽  
Iron Hydroxide ◽  
Highly Sensitive

STRUCTURAL TRANSFORMATION STUDIED BY THERMAL EXPANSION ON SINGLE CRYSTALS V3Si IN NORMAL AND SUPERCONDUCTING STATES

1978 ◽  
Vol 39 (C6) ◽  
pp. C6-406-C6-407 ◽  
Author(s):  
T. Fukase ◽  
T. Kobayashi ◽  
M. Isino ◽  
N. Toyota ◽  
Y. Muto
Keyword(s):  
Thermal Expansion ◽  
Single Crystals ◽  
Structural Transformation
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