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A nanostructure is a structure of intermediate size between microscopic and molecular structures. Nanostructural detail is microstructure at nanoscale . In describing nanostructures, it is necessary to differentiate between the number of dimensions in the volume of an object which are on the nanoscale. Nanotextured surfaces have one dimension ...
Bottom–up and top–down design. Bottom–up and top–down are both strategies of information processing and ordering knowledge, used in a variety of fields including software, humanistic and scientific theories (see systemics ), and management and organization. In practice they can be seen as a style of thinking, teaching, or leadership.
Naomi Osaka ( Japanese: 大坂 なおみ, Hepburn: Ōsaka Naomi, Japanese pronunciation: [oːsaka naomi], born October 16, 1997) is a Japanese professional tennis player. She has been ranked world No. 1 in singles by the Women's Tennis Association (WTA) and is the first Asian player to hold the top ranking in singles.
Naomi Ellen Watts (born 28 September 1968) is a British actress. [1] . After her family moved to Australia, she made her film debut there in the drama For Love Alone (1986) and then appeared in three television series, Hey Dad..! (1990), Brides of Christ (1991), and Home and Away (1991), and the film Flirting (1991).
- Background
- Properties That Affect Toxicity
- Routes of Administration
- Biodistribution
- Mechanisms of Toxicity
- Methods and Standards
- Policy and Regulatory Aspects
- External Links
Nanomaterials have at least one primary dimension of less than 100 nanometers, and often have properties different from those of their bulk components that are technologically useful. Because nanotechnology is a recent development, the health and safety effects of exposures to nanomaterials, and what levels of exposure may be acceptable, is not yet...
Size is a key factor in determining the potential toxicity of a particle. However it is not the only important factor. Other properties of nanomaterials that influence toxicity include: chemical composition, shape, surface structure, surface charge, aggregation and solubility, and the presence or absence of functional groupsof other chemicals. The ...
Respiratory
Inhalation exposure is the most common route of exposure to airborne particles in the workplace. The deposition of nanoparticles in the respiratory tract is determined by the shape and size of particles or their agglomerates, and they are deposited in the lungs to a greater extent than larger respirable particles. Based on animal studies, nanoparticles may enter the bloodstream from the lungs and translocate to other organs, including the brain. The inhalation risk is affected by the dustines...
Dermal
Some studies suggest that nanomaterials could potentially enter the body through intact skin during occupational exposure. Studies have shown that particles smaller than 1 μm in diameter may penetrate into mechanically flexed skin samples, and that nanoparticles with varying physicochemical properties were able to penetrate the intact skin of pigs. Factors such as size, shape, water solubility, and surface coating directly affect a nanoparticle's potential to penetrate the skin. At this time,...
Gastrointestinal
Ingestion can occur from unintentional hand-to-mouth transfer of materials; this has been found to happen with traditional materials, and it is scientifically reasonable to assume that it also could happen during handling of nanomaterials. Ingestion may also accompany inhalation exposure because particles that are cleared from the respiratory tract via the mucociliary escalatormay be swallowed.
The extremely small size of nanomaterials also means that they much more readily gain entry into the human body than larger sized particles. How these nanoparticles behave inside the body is still a major question that needs to be resolved. The behavior of nanoparticles is a function of their size, shape and surface reactivity with the surrounding ...
Oxidative stress
For some types of particles, the smaller they are, the greater their surface area to volume ratio and the higher their chemical reactivity and biological activity. The greater chemical reactivity of nanomaterials can result in increased production of reactive oxygen species (ROS), including free radicals. ROS production has been found in a diverse range of nanomaterials including carbon fullerenes, carbon nanotubes and nanoparticle metal oxides. ROS and free radical production is one of the p...
Cytotoxicity
A primary marker for the damaging effects of NPs has been cell viability as determined by state and exposed surface area of the cell membrane. Cells exposed to metallic NPs have, in the case of copper oxide, had up to 60% of their cells rendered unviable. When diluted, the positively charged metal ions often experience an electrostatic attraction to the cell membrane of nearby cells, covering the membrane and preventing it from permeating the necessary fuels and wastes.With less exposed membr...
Genotoxicity
Metal and metal oxide NPs such as silver, zinc, copper oxide, uraninite, and cobalt oxide have also been found to cause DNA damage. The damage done to the DNA will often result in mutated cells and colonies as found with the HPRTgene test.
Characterization of a nanomaterial's physical and chemical properties is important for ensuring the reproducibility of toxicology studies, and is also vital for studying how the properties of nanomaterials determine their biological effects. The properties of a nanomaterial such as size distribution and agglomeration statecan change as a material i...
Toxicology studies of nanomaterials are a key input into determining occupational exposure limits. The Royal Society identifies the potential for nanoparticles to penetrate the skin, and recommends that the use of nanoparticles in cosmetics be conditional upon a favorable assessment by the relevant European Commissionsafety advisory committee. The ...
Berger, Michael (2007-02-02). "Toxicology - from coal mines to nanotechnology". Nanowerk LLC. Retrieved 2007-05-15.Internet of Living Things. International Space Station mission. References. External links. Oxford Nanopore Technologies plc is a UK-based company which develops and sells nanopore sequencing products (including the portable DNA sequencer, MinION) for the direct, electronic analysis of single molecules. [2] [3] [4] History.
Scott Francis McTominay (born 8 December 1996) is a professional footballer who plays as a midfielder for Premier League club Manchester United and the Scotland national team . McTominay is a graduate of Manchester United's youth academy and made his senior debut for the club in May 2017. He has gone on to make more than 200 appearances for the ...
