scholarly journals Physicochemical Properties of Nanomaterials: Implication in Associated Toxic Manifestations

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Manzoor Ahmad Gatoo ◽  
Sufia Naseem ◽  
Mir Yasir Arfat ◽  
Ayaz Mahmood Dar ◽  
Khusro Qasim ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Surface Roughness ◽  
Chemical Composition ◽  
Physicochemical Properties ◽  
Physicochemical Characteristics ◽  
Consumer Products ◽  
Engineered Nanomaterials ◽  
Structure Surface ◽  
Living Organisms

Nanotechnology has emerged as one of the leading fields of the science having tremendous application in diverse disciplines. As nanomaterials are increasingly becoming part of everyday consumer products, it is imperative to assess their impact on living organisms and on the environment. Physicochemical characteristics of nanoparticles and engineered nanomaterials including size, shape, chemical composition, physiochemical stability, crystal structure, surface area, surface energy, and surface roughness generally influence the toxic manifestations of these nanomaterials. This compels the research fraternity to evaluate the role of these properties in determining associated toxicity issues. Reckoning with this fact, in this paper, issues pertaining to the physicochemical properties of nanomaterials as it relates to the toxicity of the nanomaterials are discussed.

Sb-V-Ox catalysts—Role of chemical composition of MCM-41 supports in physicochemical properties

2009 ◽  
Vol 142 (3-4) ◽  
pp. 175-180 ◽  
Author(s):  
H. Golinska ◽  
P. Decyk ◽  
M. Ziolek ◽  
J. Kujawa ◽  
E. Filipek
Keyword(s):  
Chemical Composition ◽  
Physicochemical Properties ◽  
Mcm 41

Negevite, the pyrite-type NiP2, a new terrestrial phosphide

2020 ◽  
Vol 105 (3) ◽  
pp. 422-427 ◽  
Author(s):  
Sergey N. Britvin ◽  
Michail N. Murashko ◽  
Yevgeny Vapnik ◽  
Yury S. Polekhovsky ◽  
Sergey V. Krivovichev ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Chemical Composition ◽  
Empirical Formula ◽  
Structural Analog ◽  
Structure Type ◽  
P System ◽  
Southern Levant ◽  
Holotype Specimen ◽  
Reflected Light

Abstract Negevite, ideally NiP2, is a new phosphide mineral from pyrometamorphic complex of the Hatrurim Formation (the Mottled Zone), Southern Levant. It is found in phosphide assemblages of the Hatrurim Basin, south Negev Desert, Israel, and Daba-Siwaqa complex, Jordan. The mineral occurs as tiny isometric grains reaching 15 μm in size and forms intimate intergrowths with other phosphides related to the Fe-Ni-P system. In reflected light, negevite is white with yellowish tint and isotropic. Reflectance values for COM recommended wavelengths [R (%), λ (nm)] are as follows: 54.6 (470), 55.0 (546), 55.3 (589), 55.6 (650). Chemical composition of the holotype specimen (electron micro-probe, wt%): Ni 42.57, Co 3.40, Fe 2.87, P 42.93, S 8.33, total 100.10, corresponding to the empirical formula (Ni0.88Co0.07Fe0.06)Σ1.01(P1.68S0.31)Σ1.99. The crystal structure of negevite was solved and refined to R1 = 1.73% based on 52 independent observed [I >2σ(I)] reflections. The mineral is cubic, space group Pa3, a = 5.4816(5) Å, V = 164.71(3) Å3, and Z = 4. Dx = 4.881(1) g/cm3 calculated on the basis of the empirical formula. Negevite is a first natural phosphide belonging to the pyrite structure type. It is a chemical and structural analog of vaesite, NiS2, krutovite, NiAs2, and penroseite, NiSe2. The well-explored catalytic and photocatalytic properties of a synthetic counterpart of negevite could provide new insights into the possible role of higher phosphides as a source of low-valent phosphorus in prebiotic phosphorylation processes.

scholarly journals Effect of Surface Roughness on Aggregation of Polypeptide Chains: A Monte Carlo Study

Biomolecules ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 596
Author(s):  
Nguyen Truong Co ◽  
Mai Suan Li
Keyword(s):  
Surface Roughness ◽  
Self Assembly ◽  
Molecular Mechanisms ◽  
Monte Carlo Study ◽  
The Self ◽  
Living Organisms ◽  
Polypeptide Chains ◽  
The Impact ◽  
Kinetics Of

The self-assembly of amyloidogenic peptides and proteins into fibrillar structures has been intensively studied for several decades, because it seems to be associated with a number of neurodegenerative diseases, such as Alzheimer’s and Parkinson’s disease. Therefore, understanding the molecular mechanisms of this phenomenon is important for identifying an effective therapy for the corresponding diseases. Protein aggregation in living organisms very often takes place on surfaces like membranes and the impact of a surface on this process depends not only on the surface chemistry but also on its topology. Our goal was to develop a simple lattice model for studying the role of surface roughness in the aggregation kinetics of polypeptide chains and the morphology of aggregates. We showed that, consistent with the experiment, an increase in roughness slows down the fibril formation, and this process becomes inhibited at a very highly level of roughness. We predicted a subtle catalytic effect that a slightly rough surface promotes the self-assembly of polypeptide chains but does not delay it. This effect occurs when the interaction between the surface and polypeptide chains is moderate and can be explained by taking into account the competition between energy and entropy factors.

scholarly journals Radiopharmaceuticals for sentinel node detection

2002 ◽  
Vol 45 (spe) ◽  
pp. 83-86 ◽  
Author(s):  
Malcolm Frier
Keyword(s):  
Particle Size ◽  
Chemical Composition ◽  
Particle Size Distribution ◽  
Physicochemical Properties ◽  
Sentinel Node Detection ◽  
Sentinel Nodes ◽  
Similar Chemical ◽  
The Relationship

Imaging of sentinel nodes is a valuable technique in the management of some types of cancer. Several different radiopharmaceuticals have been successfully employed in the technique, but there have been few systematic studies to examine the relationship between physicochemical properties of the radiopharmaceuticals used and in-vivo performance. The present study describes the preparation and characterisation of radiocolloids of similar chemical composition but differing in particle size distribution in an attempt to identify the role of variations in the single parameter of size.

Toxicity of engineered nanomaterials with different physicochemical properties and the role of protein corona on cellular uptake and intrinsic ROS production

Toxicology ◽  
2020 ◽  
Vol 442 ◽  
pp. 152545
Author(s):  
Alejandro Déciga-Alcaraz ◽  
Estefany I. Medina-Reyes ◽  
Norma L. Delgado-Buenrostro ◽  
Carolina Rodríguez-Ibarra ◽  
Adriana Ganem-Rondero ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Cellular Uptake ◽  
Protein Corona ◽  
Engineered Nanomaterials ◽  
Ros Production

Design and Science Instrumentation of an Unmanned Vehicle for Sample Return from the Asteroid Eros

1971 ◽  
Vol 12 ◽  
pp. 543-560 ◽  
Author(s):  
H. F. Meissinger ◽  
E. W. Greenstadt
Keyword(s):  
Crystal Structure ◽  
Chemical Composition ◽  
Solar System ◽  
Surface Texture ◽  
Magnetic Characteristics ◽  
Sample Return ◽  
Surface Sample ◽  
System A ◽  
Structure Surface ◽  
Fragmentation Processes

Unmanned missions to the asteroids have been proposed and investigated as part of the overall plan of exploration of the solar system. A principal incentive for landing on an asteroid and retrieving a surface sample for return to Earth is the expectation that detailed laboratory analysis of the sample material’s chemical composition, crystal structure, surface texture, magnetic characteristics, radioactive state, and age can provide essential clues, not available by other means, to the origin of asteroids and possibly the history and formative processes of the solar system (Alfvén and Arrhenius, 1910a,b; Bratenahl; Friedlander and Vickers, 1964; IIT Research Institute, 1964; Öhman, 1963). The results may indicate, for example, to what extent accretion or fragmentation processes have been involved in the formation of asteroids.

scholarly journals Critical physicochemical properties of lubricating oils for aviation applications and their significance in terms of flight safety

2018 ◽  
Vol 48 (1) ◽  
pp. 223-251
Author(s):  
Marta Skolniak ◽  
Anna Turlej
Keyword(s):  
Chemical Composition ◽  
Physicochemical Properties ◽  
Operational Reliability ◽  
Operating Conditions ◽  
Flight Safety ◽  
Lubricating Oils ◽  
Transmission Gear

Abstract The article presents the role of lubricating oils for aviation applications, along with their classification, and discusses the key physicochemical properties. It characterises engine, transmission gear, hydraulic and instrumentation oils and their impact on a device operational reliability. It also points out the requirements for these products in relation to the operating conditions and the chemical composition of a product.

Characteristics Of The Structure Formation Of Gypsum Binder Modified With Zinc Hydrosilicates

2020 ◽  
pp. 40-46
Keyword(s):  
Synergistic Effect ◽  
Physicochemical Properties ◽  
Structure Formation ◽  
Silicic Acid ◽  
Chemical Properties ◽  
Crystal Formation ◽  
Ability To Act ◽  
Chemical Factors ◽  
Sorption Characteristics

The authors' methodic for assessing the role of chemical and physic-chemical factors during the structure formation of gypsum stone is presented in the article. The methodic is also makes it possible to reveal the synergistic effect and to determine the ranges of variation of controls factors that ensure maximum values of such effect. The effect of a micro-sized modifier based on zinc hydro-silicates on the structure formation of building gypsum is analyzed and corresponding dependencies are found. It is shown that effects of influence of modifier on the properties of gypsum compositions are determined by chemical properties of modifier. Among the mentioned properties are sorption characteristics (which depend on the amount of silicic acid and its state) and physicochemical properties - the ability to act as a substrate during crystal formation. The proposed method can also be extended to other binding substances and materials. This article contributes to the understanding of the processes that occur during the structure formation of composites, which will make it possible to control the structure formation in the future, obtaining materials with a given set of properties.

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