Characterization of the pigment from homogentisic acid and urine and tissue from an alkaptonuria patient

1991 ◽  
Vol 69 (4) ◽  
pp. 269-273 ◽  
Author(s):  
I. Aravind Menon ◽  
Suruj D. Persad ◽  
Herbert F. Haberman ◽  
Prasanta K. Basu ◽  
Joseph F. Norfray ◽  
...  
Keyword(s):  
Superoxide Dismutase ◽  
Electron Spin Resonance ◽  
Electron Spin ◽  
Ehrlich Ascites Carcinoma ◽  
Homogentisic Acid ◽  
Carcinoma Cells ◽  
Ehrlich Ascites ◽  
Spin Resonance

When urine samples from alkaptonuria patients are allowed to stand, they turn black, presumably owing to the oxidation of homogentisic acid to a melanin-like substance. We report the characterization of the pigments formed by polymerization of (a) the components in the urine from a patient with alkaptonuria and (b) homogentisic acid. The absorption spectra and electron spin resonance signals of these pigments are similar to those of eumelanins. Irradiation of the pigments with nitroblue tetrazolium caused reduction of the tetrazolium; this was partially inhibited by superoxide dismutase. Irradiation of Ehrlich ascites carcinoma cells with the pigments from homogentisic acid or urine caused cell lysis. Since this lysis was inhibited by catalase, we have concluded that it was mediated by H2O2. A similar pigment was also extracted from the tissue from an alkaptonuria patient. It is suggested that the degeneration of tissue in vivo may be due to the deposition of melanin-like pigments in the tissues, probably in combination with metal ions.Key words: alkaptonuria, homogentisic acid, pigmentation, melanin, photosensitization.

Trichosanthes dioica seed lectin inhibits Ehrlich ascites carcinoma cells growth in vivo in mice by inducing G 0 /G 1 cell cycle arrest

2021 ◽  
Author(s):  
Shaikh Shohidul Islam ◽  
Md. Rezaul Karim ◽  
A. K. M. Asaduzzaman ◽  
A. H. M. Khurshid Alam ◽  
Zahid Hayat Mahmud ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Ehrlich Ascites Carcinoma ◽  
Carcinoma Cells ◽  
Cycle Arrest ◽  
Ehrlich Ascites ◽  
Trichosanthes Dioica

Electron Spin Resonance Characterization of Defects at Interfaces in Stacks of Ultrathin High-κ Dielectric Layers on Silicon

2003 ◽  
Vol 786 ◽  
Author(s):  
A. L. Stesmans ◽  
V.V. Afanas'ev
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Dielectric Layers ◽  
Growth Standard ◽  
Spin Resonance ◽  
Dielectric Interfaces ◽  
Standard Quality

ABSTRACTElectron spin resonance (ESR) analysis of (100)Si/SiOx/ZrO2, (100)Si/Al2O3 and Si/HfO2 structures with nm-thin dielectric layers deposited by different chemical vapor deposition procedures reveals, after hydrogen detachment, the presence of the trivalent Si dangling-bond-type centers Pb0, Pb1 as prominent defects in all entities. This Pb0, Pb1 fingerprint, generally unique for the thermal (100)Si/SiO2 interface, indicates that the as-deposited (100)Si/metal oxides interface is basically Si/SiO2-like. Though sensitive to the deposition process, the Pb0 density is found to be substantially larger than in standard (100)Si/SiO2. As probed by the Pb- type center properties, the Si/dielectric interfaces of all structures are under enhanced (unrelaxed) stress, typical for low temperature Si/SiO2 growth. Standard quality thermal Si/SiO2 properties in terms of Pb signature may be approached by appropriate annealing (≥ 650°C) in vacuum in the case of (100)Si/SiOx/ZrO2. Yet, O2 ambient appears required for Si/Al2O3 and Si/HfO2. It appears that Si/high-κ metal oxide structures with device grade quality interfaces can be realized with sub-nm thin SiOx interlayers. The density of fast interface states closely matches the Pb0 density variations, suggesting the center as the dominant fast interface trap. They may be efficiently passivated in H2 at 400 °C.

scholarly journals Characterization of manganese in coal by electron spin resonance.

1985 ◽  
Vol 34 (5) ◽  
pp. 243-247 ◽  
Author(s):  
Junichi SHIDA ◽  
Mamoru ITOH ◽  
Tateaki OGATA ◽  
Hitoshi KAMADA
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Spin Resonance

scholarly journals Two-dimensional pulsed electron spin resonance characterization of 15 N-labeled archaeal Rieske-type ferredoxin

FEBS Letters ◽  
2009 ◽  
Vol 583 (21) ◽  
pp. 3467-3472 ◽  
Author(s):  
Toshio Iwasaki ◽  
Rimma I. Samoilova ◽  
Asako Kounosu ◽  
Sergei A. Dikanov
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Two Dimensional ◽  
Spin Resonance
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