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Material Properties for Biomedical Applications
Published in Savaş Kaya, Sasikumar Yesudass, Srinivasan Arthanari, Sivakumar Bose, Goncagül Serdaroğlu, Materials Development and Processing for Biomedical Applications, 2022
D. Ajith, K.G. Ashok, K. Aravind
The market potential of biomaterial is ever increasing in the last few decades. For example, materials used in eye lenses or those used as biosensors require suitable optical properties. Materials such as contrast mediums (iodine-based material, barium-sulfate, or gadolinium) are intended for short-duration imaging applications. Cardiac biomaterials have various applications, such as heart valves, endovascular stents, vascular grafts, catheters, heart assist devices, and hemodialyzers. These biomaterials are predominantly blood contacting and hence they must necessarily be blood compatible, not induce thrombosis, have appropriate physical and mechanical properties including tensile strength, friction and wear resistance, as well as flow resistance among others [4]. Materials used for drug delivery and tissue engineering applications usually require to be biodegradable, with the degraded products being non-toxic to the body and easily excreted out. While the property of biodegradation is desirable for scaffolds used for tissue engineering, their rate of degradation must match the rate of regeneration. Also, it must be noted that the physical and mechanical properties of these degradable materials deteriorate with progress in biodegradation. Hence, wherever required, appropriate modification of the scaffolds may be done either by adding functional groups (surface modification), creating blends (two or more polymers), cross-linking, and composites.
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Published in Valerio Voliani, Nanomaterials and Neoplasms, 2021
Nohyun Lee, Seung Hong Choi, Taeghwan Hyeon
Barium sulfate suspensions and water-soluble aromatic iodinated compounds are currently used as CT contrast agents [5]. Owing to the inherent toxicity of Ba2+ ions, the use of barium sulfate is restricted only to gastrointestinal (GI) tract imaging. Currently available injectable CT contrast agents are composed of iodinated compounds. However, the short circulation time of iodinated contrast agents prevents wider application. In addition, although iodinated agents are generally safe [6], a severe adverse reaction sometimes occurs owing to their high osmolality and viscosity [7]. Despite the demand for new safer CT contrast agents and more sensitive imaging, to date, little progress has been made due to the low sensitivity of CT. For example, while MRI can detect micromolar concentrations of contrast agents, millimolar concentrations are required for successful CT imaging [8]. The strong magnetic field generated by magnetic nanoparticles allows MR imaging of objects smaller than voxel size [9], and even single cells (c.a. 10 µm) are readily revealed [10]. However, such an amplification effect is almost impossible for CT because CT contrast is related to the interaction between heavy atoms and X-rays. In addition, materials that are effective for X-ray attenuation have high atomic weights, and most of them are very toxic.
Membrane Fouling and Scaling in Reverse Osmosis
Published in Andreas Sapalidis, Membrane Desalination, 2020
Nirajan Dhakal, Almotasembellah Abushaban, Nasir Mangal, Mohanad Abunada, Jan C. Schippers, Maria D Kennedy
Barium sulphate precipitation results in very hard deposits on the membrane surface (Boerlage et al. 2000b). The solubility of the barium sulphate is very low (1×10-5 mol/L or 2.33 mg/L in pure water) (Van der Leeden 1991). Therefore, concentrate water at very low recoveries can be supersaturated with respect to barium sulphate. It is worth mentioning that precipitation is not only governed by the supersaturation, but also depends on the precipitation kinetics that involve the formation of nuclei and further crystal growth. Boerlage et al. (2002a) reported that BaSO4 has a long stable phase prior to nucleation in the supersaturated state. Consequently substantial supersaturation is allowable.
Evaluation of radiation dose reduction by barium composite shielding in an angiography system
Published in Radiation Effects and Defects in Solids, 2021
Jong-Woong Lee, Dae Cheol Kweon
Barium sulfate has long been used for in-vivo testing to contrast the density of soft tissues for radiology, and is one of the most economical and environmentally friendly shielding materials. Although harmless to the human body, previous studies have reported some limitations of barium sulfate as an independent shielding material due to its high density (4.5 g/cm3) and low compatibility with other materials. Previous studies have mixed barium sulfate with cerium, antimony, tungsten, gadolinium, boron and bismuth (18). Barium sulfate is relatively inert, non-toxic, environmentally friendly, harmless to humans, easy to mix with other compounds, and importantly, has a high radiation absorption coefficient, making it suitable for use in X-ray and γ-ray shielding (18). Barium sulfate shields are not classified as hazardous and are much less toxic than lead (13).
Surfactant mediated synthesis of barium sulfate, strontium sulfate and barium-strontium sulfate nanoparticles
Published in Inorganic and Nano-Metal Chemistry, 2019
Prutviraj K., Thimmasandra Narayan Ramesh
Barium sulfate known as barite is technically used as base material for all the barium compounds and barium metal. Barium sulfate is extensively used in oil and natural gas production to obtain high-density drilling fluids for flotation which keeps the boreholes free of rock.[1] Barium sulfate increases the plasticity and weight of plastic materials, car mats, carpet coatings/plastic sewage pipes that are used for sound insulation. Barium sulfate is used in friction and brake linings, clutches due to its inertness and high temperature resistance. Barium sulfate has been used in paint and varnishes as filler to increase volume, viscosity and as additive for glossy papers and photographic papers.[2,3] In textile industries, it is used as an agent for rayon matting during etching and printing. Due to its high coefficient of absorption for γ and X-radiation, barium sulfate is used in concrete as screening medium in nuclear reactors and in radio-opaque substances.[4] The synthesis of nanoparticles is of increasing scientific and technical interest. The small size of these particles endows them with unusual structural, electronic, magnetic and chemical properties, leading to many important applications in catalysis, electro-optical devices and precursor phases to prepare ceramics.