scholarly journals Surfaces of a Colloidal Iron Nanoparticle in Its Chemical Environment: A DFT Description

Langmuir ◽  
2014 ◽  
Vol 30 (39) ◽  
pp. 11670-11680 ◽  
Author(s):  
Guntram Fischer ◽  
Romuald Poteau ◽  
Sébastien Lachaize ◽  
Iann C. Gerber
Author(s):  
P. Hernández-Jáuregui ◽  
A. Sosa ◽  
A. González Angulo

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.


Author(s):  
John R. Rowley

The morphology of the exine of many pollen grains, at the time of flowering, is such that one can suppose that transport of substances through the exine occurred during pollen development. Holes or channels, microscopic to submicroscopic, are described for a large number of grains. An inner part of the exine of Epilobium angustifolium L. and E. montanum L., which may be referred to as the endexine, has irregularly shaped channels early in pollen development although by microspore mitosis there is no indication of such channeling in chemically fixed material. The nucleus in microspores used in the experiment reported here was in prophase of microspore mitosis and the endexine, while lamellated in untreated grains, did not contain irregularly shaped channels. Untreated material from the same part of the inflorescence as iron treated stamens was examined following fixation with 0.1M glutaraldehyde in cacodylate-HCl buffer at pH 6.9 (315 milliosmoles) for 24 hrs, 4% formaldehyde in phosphate buffer at pH 7.2 (1,300 milliosmoles) for 12 hrs, 1% glutaraldehyde mixed with 0.1% osmium tetroxide for 20 min, osmium tetroxide in deionized water for 2 hrs and 1% glutaraldehyde mixed with 4% formaldehyde in 0.1M cacodylate-HCl buffer at pH 6.9 for two hrs.


1969 ◽  
Vol 22 (03) ◽  
pp. 508-512
Author(s):  
L Pechet ◽  
Giselle S. Pechet ◽  
R. A MacDonald

SummaryIntravascular coagulation and its possible effect on carbon clearance was studied in rats following the injection of commercial india ink containing shellac; a shellac-free carbon preparation; gelatin; heat denatured albumin; colloidal iron; and heparin. No relationship was found between activation of coagulation and RES function as measured by clearance of intravenously injected carbon.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Lindsay E. Anderson ◽  
Benjamin F. Trueman ◽  
Dewey W. Dunnington ◽  
Graham A. Gagnon

AbstractDissolved organic matter (DOM) concentrations have been increasing in parts of the northern hemisphere for several decades. This process—brownification—often accompanies increasing iron and aluminum, but the metal–DOM interactions these concurrent trends imply are poorly described. Here we used field-flow fractionation with UV and ICP-MS detection to measure the size distribution of colloidal iron, aluminum, manganese, copper, uranium, and chromophoric DOM in six lakes over six months. Five of these lakes have browned to some degree in the past three decades, with linear increases in organic carbon and color ranging from 0.01 to 0.13 mg C L−1 yr−1 and 0.13–1.94 PtCo yr−1. Browning trends were more pronounced and colloids more abundant in lakes with wetlands in their catchments. Iron and aluminum were present in two primary fractions, sized nominally at 1 and 1000 kDa. The 1 kDa fraction included the primary DOM signal, while the 1000 kDa fraction absorbed minimally at 254 nm and likely represents iron-rich (oxyhydr)oxides. Colloidal manganese was sized at 1000+ kDa, whereas colloidal copper and uranium occurred primarily at 1 kDa. These associations fit with a pattern of increasing DOC, iron, aluminum, and color in the region’s lakes. They represent a significant challenge for drinking water treatment systems, especially those in remote communities. Given that browning trends are expected to continue, monitoring plans would better inform treatment process design and operation by characterizing DOM and iron-rich, primarily inorganic colloids that contribute to adverse water quality outcomes.


Nanoscale ◽  
2021 ◽  
Author(s):  
Ning Gao ◽  
Kang Zhou ◽  
Kai Feng ◽  
Wanlin Zhang ◽  
Jiecheng Cui ◽  
...  

Micellar and vesicular structures capable of sensing and reporting the chemical environment as well as facilely introducing user-defined functions make a vital contribution to constructing versatile compartmentalized systems. Herein, combing...


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