Thermodynamic aspects in the adsorption of polynuclear aromatic hydrocarbons on chrysotile and silica – possible relation to synergistic effects in lung toxicity

1989 ◽  
Vol 67 (2) ◽  
pp. 289-296 ◽  
Author(s):  
Jeanine Fournier ◽  
Bice Fubini ◽  
Vera Bolis ◽  
Henri Pezerat
Keyword(s):  
Adsorption Mechanism ◽  
Organic Molecules ◽  
Synergistic Effects ◽  
Polynuclear Aromatic Hydrocarbons ◽  
Cigarette Smoke Exposure ◽  
Multilayer Adsorption ◽  
Lung Cancers ◽  
Adsorption Of Water ◽  
Ionic Solid ◽  
Covalent Solid

This study is to compare the adsorption of phenanthrene — a polynuclear aromatic hydrocarbon — (apolar molecule) and water (polar molecule) on chrysotile, a mainly ionic solid and on one silica (Aerosil), a covalent solid. The adsorption of water shows that the adsorption capacity and the interaction energies are much higher for chrysotile than for silica. With phenanthrene, the adsorption mechanism on these two materials is very different: on chrysotile — a solid with a surface having a basic character — there is a multilayer adsorption, with lateral interactions between PAH molecules vertically oriented with regard to solid surface, whereas on silica (acidic solid), the PAH molecules are adsorbed flat and form only one layer. Chrysotile turns out to be a much more powerful adsorbent than silica towards both polar molecules and apolar molecules. The calorimetric data concerning the adsorption of phenanthrene on chrysotile in xylene reveal three thermal stages, showing the influence of preadsorbed water and solvent and permit to propose a model of adsorption mechanism. The formation of multilayers of phenanthrene on chrysotile converts its marked hydrophilic surface into a hydrophobic one which may act as a carrier of organic molecules and slowly release them into the biological medium. These phenomena may provide a possible interpretation for some synergistic effects concerning lung cancers observed after asbestos and cigarette-smoke exposure. Keywords: adsorption, phenanthrene, chrysotile, silica, water.

scholarly journals Signal Transduction Involving the Dmp1 Transcription Factor and its Alteration in Human Cancer

2008 ◽  
Vol 2 ◽  
pp. CMO.S548 ◽  
Author(s):  
Takayuki Sugiyama ◽  
Donna P. Frazier ◽  
Pankaj Taneja ◽  
Robert D. Kendig ◽  
Rachel L. Morgan ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Human Cancer ◽  
Synergistic Effects ◽  
Tumor Formation ◽  
Binding Property ◽  
Lung Cancers ◽  
Myc Oncogene ◽  
Oncogenic Ras ◽  
Cycle Arrest ◽  
Dependent Cell

Summary Dmp1 (cyclin D-interacting myb-like protein 1; also called Dmtf1) is a transcription factor that has been isolated in a yeast two-hybrid screen through its binding property to cyclin D2. Dmp1 directly binds to and activates the Arf promoter and induces Arf-p53-dependent cell cycle arrest in primary cells. D-type cyclins usually inhibit Dmp1-mediated transcription in a Cdk-independent fashion; however, Dmp1 shows synergistic effects with D-cyclins on the Arf promoter. Ras or Myc oncogene-induced tumor formation is accelerated in both Dmp1+/- and Dmp1-/- mice with no significant differences between Dmp1+/- and Dmp1-/-. Thus, Dmp1 is haplo-insufficient for tumor suppression. Tumors from Dmp1-/- or Dmp1+/- mice often retain wild-type Arf and p53, suggesting that Dmp1 is a physiological regulator of the Arf-p53 pathway. The Dmp1 promoter is activated by oncogenic Ras-Raf signaling, while it is repressed by physiological mitogenic stimuli, overexpression of E2F proteins, and genotoxic stimuli mediated by NF-κB. The human DMP1 gene (h DMP1) is located on chromosome 7q21 and is hemizygously deleted in approximately 40% of human lung cancers, especially those that retain normal INK4a/ARF and P53 loci. Thus, h DMP1 is clearly involved in human carcinogenesis, and tumors with h DMP1 deletion may constitute a discrete disease entity.

scholarly journals Pickett Equation for the Description of Adsorption on Arbitrary Surfaces

2020 ◽  
Vol 4 (2) ◽  
pp. 17
Author(s):  
Volodymyr V. Kutarov ◽  
Eva Schieferstein ◽  
Shanath A. A. Jayaweera
Keyword(s):  
Fractal Dimension ◽  
Water Vapor ◽  
Coal Sample ◽  
Lunar Regolith ◽  
Theoretical Models ◽  
Multilayer Adsorption ◽  
Topological Approach ◽  
Adsorption Of Water ◽  
Adsorption Of Gases ◽  
Adsorption Of Water Vapor

The theory of multilayer adsorption of gases, namely the Pickett equation, has been developed to the case of adsorption on arbitrary surfaces in a molecular and a topological approach. We present the prediction of the fractal dimension for the surface of an adsorbent and for the set of interfaces generated by the growing of layers. The theoretical models correctly predict quantities and qualitative features of the experiment for two systems: adsorption of water vapor (T = 298 K) on the sample of lunar regolith and of nitrogen (T = 77 K) on a coal sample.

Monolayer and multilayer adsorption of water on Ru(001)

1981 ◽  
Vol 75 (11) ◽  
pp. 5556-5572 ◽  
Author(s):  
P. A. Thiel ◽  
F. M. Hoffmann ◽  
W. H. Weinberg
Keyword(s):  
Multilayer Adsorption ◽  
Adsorption Of Water

Synthesis of Magnetic Ni0.3Mg0.3Zn0.4Fe2O4 Nanoparticles and Their Adsorption Performances of Congo Red

2020 ◽  
Vol 20 (5) ◽  
pp. 2878-2886
Author(s):  
Jia Liu ◽  
Guo-Dong Su ◽  
Zhou Wang
Keyword(s):  
Congo Red ◽  
Room Temperature ◽  
Adsorption Mechanism ◽  
Combustion Method ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Multilayer Adsorption ◽  
X Ray ◽  
Pseudo Second Order ◽  
Solvent Volume

Magnetic Ni0.3Mg0.3Zn0.4Fe2O4 nanoparticles were synthesized by the absolute alcohol combustion method. The morphology, microstructure, and composition of as-prepared Ni0.3Mg0.3Zn0.4Fe2O4 nanoparticles were characterized by several techniques: the vibrating sample magnetometer (VSM), the scanning electron microscopy (SEM), the X-ray diffraction (XRD), and the energy dispersive spectroscopy (EDS). The experimental results showed that the calcination temperature and the solvent volume were the crucial factors for the synthesis of the magnetic Ni0.3Mg0.3Zn0.4Fe2O4 nanoparticles. The adsorption performance of Ni0.3Mg0.3Zn0.4Fe2O4 nanoparticles for congo red (CR) was investigated. The model of pseudo-second-order kinetic was optimal matching for obtaining the parameters of adsorption CR in the initial range of 100–400 mg/L−1, while, the isotherm data of CR onto Ni0.3Mg0.3Zn0.4Fe2O4 nanoparticles could conform to the Temkin model owing to the values of the square deviations, which revealed that the adsorption of CR onto Ni0.3Mg0.3Zn0.4Fe2O4 nanoparticles at room temperature was the monolayer and multilayer adsorption mechanism.

Adsorption mechanism of acid orange 7 on photocatalytic materials based on TiO2

MRS Advances ◽  
2019 ◽  
Vol 4 (61-62) ◽  
pp. 3399-3405
Author(s):  
A. Arteaga-Jiménez ◽  
A. I. Caudana-Campos ◽  
A. L. García-García ◽  
E. Hernández-Zapata ◽  
M. A. Vidales-Hurtado
Keyword(s):  
Chemical Composition ◽  
Organic Compound ◽  
Titanium Tetrachloride ◽  
Adsorption Mechanism ◽  
Organic Molecules ◽  
Heterogeneous Photocatalysis ◽  
Acid Orange 7 ◽  
No Adsorption ◽  
Acid Orange ◽  
Catalytic Material

ABSTRACTThe degradation of organic molecules in an aqueous medium using heterogeneous photocatalysis depends on the chemical composition and concentration of the organic compound, the crystalline and morphological nature of the photocatalyst, the pH of the dye dilution, and the reaction temperature. Since photocatalytic degradation is a process that occurs on the surface of the catalytic material, it is desirable to induce maximum adsorption of the organic compound. One strategy to achieve this is to functionalize the surface of the catalyst to retain the molecule of interest. In this work, we studied the interaction of acid orange 7 (AO7) with commercial TiO2-anatase powder catalyst, and with a catalyst synthesized in house using titanium tetrachloride and ethanolamine (TiO2-et). Our results indicate that there is no adsorption of the AO7 dye on the TiO2-et particles. The infrared spectrum of the TiO2-et particles is presented.

Multilayer adsorption of water at a rutile TiO2(110) surface: Towards a realistic modeling by molecular dynamics

2004 ◽  
Vol 121 (8) ◽  
pp. 3722-3726 ◽  
Author(s):  
Andreas Kornherr ◽  
Doris Vogtenhuber ◽  
Matthias Ruckenbauer ◽  
Raimund Podloucky ◽  
Gerhard Zifferer
Keyword(s):  
Molecular Dynamics ◽  
Multilayer Adsorption ◽  
Rutile Tio2 ◽  
Realistic Modeling ◽  
Adsorption Of Water
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