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Respiratory Disease
Published in John S. Axford, Chris A. O'Callaghan, Medicine for Finals and Beyond, 2023
Ian Pavord, Nayia Petousi, Nick Talbot
An insidious onset of progressive breathlessness that may continue even after exposure to silica dust has ceased. Concomitant TB is common because silicosis predisposes to this infection. If there has been an acute and intense exposure to silicon dioxide, there may be a rapid onset of breathlessness, cough and sputum (acute silicosis).
Nutrients in Bamboo Shoots
Published in Nirmala Chongtham, Madho Singh Bisht, Bamboo Shoot, 2020
Nirmala Chongtham, Madho Singh Bisht
Silicon (Si) is a non-metallic element and the second most abundant element in the Earth’s crust with a great affinity for oxygen, forming 92% silica and silicates. It is also the most abundantly available trace element after iron and zinc. Chemically, silica is an oxide of silicon, viz. silicon dioxide and is generally colourless to white and insoluble in water. When associated with metals or minerals the family of silicates is formed. Humans are exposed to numerous sources of silica/silicon including dust, food, pharmaceuticals, cosmetics and medical implants and devices. As a metalloid, silicon has been used in many industrial applications including use as an additive in the food and beverage industry. As a result, humans are exposed to silicon through both environmental exposures and also as a dietary component. Bamboo extract is the richest known source of natural silica, containing over 70% organic silica. This is more than 10 times the level found in the widely used Horsetail plant (Equisetum) that contains 5% to 7% silica.
Organo-Modified Siloxane Polymers for Conditioning Skin and Hair
Published in Randy Schueller, Perry Romanowski, Conditioning Agents for Hair and Skin, 2020
The basic raw material from which silicones are formed is quartz, i.e., silica or silicon dioxide (SiCh). In the form of crystals or fine grains, quartz is the main constituent of white sand. In 1824, Jons-Jacob Berzelius, a Swedish chemist, was successful in liberating elemental silicon (Si) from quartz by reduction of potassium fluorosilicate with potassium. Alkylation of elemental silicon to prepare alkyl silanes was done initially by Friedel and Crafts (1863) using zinc compounds, by Kipping (1904) using organo-magnesium compounds (Grignard reaction), and independently in the 1930s by Hyde (Corning Glass Works) and Rochow (General Electric) using methyl chloride. These scientists synthesized the silicon-carbon bond—one of the most important steps in the history of organo-siloxane polymer development (1,2). The silicon-oxygen-silicon backbone was synthesized by Ladenburg in 1871 by hydrolyzing diethyldiethoxysilane in the presence of a dilute acid to form an oil (silicone). Between 1899 and 1944, Kipping published 54 papers on the subject of silicon chemistry, describing the first systematic study in the field. This work helped Hyde and Rochow develop a commercial process—"the direct process"— using elemental silicon and methyl chloride to produce organo-silicon compounds. Current reviews of the synthesis of organo-siloxane polymers have been written by Colas (3) and Rhone Poulenc (4).
Small interfering RNA-based nanotherapeutics for treating skin-related diseases
Published in Expert Opinion on Drug Delivery, 2023
Yen-Tzu Chang, Tse-Hung Huang, Ahmed Alalaiwe, Erica Hwang, Jia-You Fang
MSNs feature a porous network within the silicon oxide matrix. They have a broad range of applications, such as adsorbents, energy storage, sensors, and drug delivery vehicles [47]. It is practical to load the chemicals inside the mesopores with high loading efficiency, controlled delivery, and increased drug stability. The attractive characteristics of MSNs are the flexibility of surface functionalization and pore size control for improving drug incorporation and targeting [48]. A powerful tool of MSNs is their ability to carry siRNA molecules for passage through the cell membrane and release the cargo at their destination [49]. The native silicon oxide surface is anionic, repelling the interaction with nucleic acids. Surface functionalization with cationic materials is often needed to effectively load RNA-based agents [50]. The porous structure of MSNs enables the entrapment of two or more therapeutics to exhibit synergistic bioactivity [51]. MSN-based skin delivery has sparked some interest due to the high drug loading, enhancement in drug stability, absorption, and ease of functionalization. The functionalization of MSNs manifests a key capacity to facilitate the skin delivery of therapeutic agents in a highly sustained fashion [52].
Silicon dioxide nanoparticle exposure affects small intestine function in an in vitro model
Published in Nanotoxicology, 2018
Zhongyuan Guo, Nicole J. Martucci, Yizhong Liu, Eusoo Yoo, Elad Tako, Gretchen J. Mahler
Food-grade silicon dioxide (SiO2) or amorphous silica (coded E551) has been found to contain particles in the nano-size range (at least one dimension less than 100 nanometers) (Auffan et al. 2009; Dekkers et al. 2011; Peters et al. 2012; Yang et al. 2016). Similar to TiO2 NP, SiO2 nanoparticles (NP) are used to improve the taste and texture of rich foods without adding calories, preserve food color and durability, and carry fragrances or flavors (Dekkers et al. 2011; Contado et al. 2016). SiO2 NP also act as anti-caking agents to maintain flow properties of powdered mixes, seasonings, and coffee whiteners (Dekkers et al. 2011; Contado et al. 2016). The use of nanomaterials in food production and pharmaceutics, however, may have unknown health effects due to unexpected biological interactions (Dekkers et al. 2011).
Formation of organosilica nanoparticles with dual functional groups and simultaneous payload entrapment
Published in Journal of Microencapsulation, 2018
Ya-Ling Su, Chien-Yu Lin, Shih-Jiuan Chiu, Teh-Min Hu
Silicon is the second most abundant element in the Earth’s crust (Peng et al. 2014), and it is an indispensable element in the history of technological advance of mankind; i.e. from the early use of glass to the modern ‘Silicon Revolution’—associated first with computer chips and then with the recent development of solar panels (Rowlatt 2014). Silicon can be found in the human body in the form of silica (silicon dioxide, SiO2) through food intake (Sripanyakorn et al. 2004, 2009). Moreover, silica materials have been widely used in food and pharmaceutical industry (Dave 2008, Contado et al. 2013). In particular, silica nanomaterials have been extensively studied as drug carriers for improving drug delivery (Slowing et al. 2008, Cohen and Sukenik 2016). Currently, various silica nanoparticles (SiNPs), mesoporous or nanoporous, have been extensively studied for intelligent and precision delivery (i.e. targeted and responsive) of drugs or imaging agents, as well as various biomedical applications (Slowing et al. 2007, He and Shi 2011, Bitar et al. 2012, Colilla et al. 2013, Tang and Cheng 2013, Carpenter et al. 2014). Although it is not quite the beginning of a biomedical Silicon Revolution, the first human trials on the use of SiNPs for clinical imaging has been ongoing (Phillips et al. 2014).