China
Africa
Explore chapters and articles related to this topic
Terahertz Propagation in Tissues and Its Thickness Limitation
Published in Lingyan Shi, Robert R. Alfano, Deep Imaging in Tissue and Biomedical Materials, 2017
Dental caries, a serious prevalent disease, is the main underlying cause of tooth losses and the potential for diagnosis of such diseases without the harmful side effects of such technologies that use x-rays continue to drive the research in this field. This disease both destructs tooth structure and affects ultimately surrounding tissues and pulp. Its formation is a dynamic process and the detection of lesions is difficult at early stages due to deficiency of methods to identify the presence of tooth decay precisely on the entire tooth structure. Therefore, there is a requirement for new methods to monitor whole structure and characterize defects. Transverse microradiography (TMR) is one of the methods to investigate mineral content of lesions [69]. However, this technique requires a destructive sample preparation phase since tooth samples have to be cut into thin slices before microradiography. X-ray microtomography (XMT) is an alternative method to TMR [70]. Because this method uses ionizing radiation, detrimental effects of this method on human health can be significant [71], [72]. On the other hand, TPI is by far one of the more successful applications of THz biomedical applications and so far has been extensively employed due to its non-destructive and non-ionizing nature. There have also been some studies on the identification of natural dental caries [73] and artificial lesions [74] and detection of remineralization of artificially induced lesions [75] using TPI. These investigations and others sustain the usability of TPI in studies on identification of demineralization.
Bioresponsive Hydrogels for Controlled Drug Delivery
Published in Deepa H. Patel, Bioresponsive Polymers, 2020
Tamgue Serges William, Dipali Talele, Deepa H. Patel
It is somehow difficult to evaluate the porosity of hydrogel due to some inconvenient parameters such as temperature change, mathematical manipulation, and postulation required. Porosity is an important parameter that needs to be controlled in many devices for various applications such as optimal cell migration in hydrogel-based scaffolds or tunable lode/release of macromolecules [17]. Porosity % = Vpore/Vbulk + Vpore ×100 Many techniques have been employed in the past decades for porosity investigation studies. First of all, porosity can be estimated by theoretic procedures like unit cube analysis, mass technique, Archimedes method, liquid displacement method, these evaluations are generally coupled with optical and electronic microscopy. Other methods include the mercury porosimetry based on Washburn’s equation, gas pycnometry, gas adsorption (small quantity adsorption, monolayer, and multilayer adsorption), liquid extrusion porosity, and capillary flow porosity. Moreover, an alternate assay is the Micro-CT also called X-ray Microtomography, a relative new imaging technology expressed as nondestructive high-resolution radiography, qualified for qualitative and quantitative assays on samples and estimation of their pore interconnections. Micro-CT can provide information on average pore size, pore size distribution, and pore interconnection which are essential factors of a hydrogel matrix that are often difficult to calculate. Micro-CT provides also information about wall thickness and anisotropy/isotropy of the sample [19].
Thyme essential oil loaded microspheres for fish fungal infection: microstructure, in vitro dynamic release and antifungal activity
Published in Journal of Microencapsulation, 2021
Sergio Benavides, María Salomé Mariotti-Celis, Maria Jose Carolina Paredes, Javier A. Parada, Wendy V. Franco
The X-ray microtomography showed the formation of a wall around the TEO-MS (Figure 1(b–d)). This structure also responds to the drying process which generates a kind of surface crust, given the rapid evaporation of water (Benavides et al.2012, Wang et al.2015). In a previous work (Benavides et al.2016) we determined that the dispersed phase droplet size (TEO) was a critical parameter to improve the encapsulation efficiency of TEO (The amount of TEO effectively encapsulated from the original emulsion) and loading capacity (The mass of TEO that is capable of containing a microsphere). In that study we achieved encapsulation efficiencies of 67, 74, and 85% for droplet sizes obtained at 10 000 (big size); 14 000 (medium size), and 18 000 rpm (small size) respectively. On the other hand, the LC% were of 43, 46 and 51% (w/w) for big, medium and small droplet size, respectively. We concluded that both the encapsulation efficiency and the loading capacity were significantly favoured by a smaller dispersed phase droplet size. This is because a smaller droplet size allows a better distribution of TEO within the microsphere (Benavides et al.2016).
Quantification of porosity in composite resins delivered by injectable syringes using X-ray microtomography
Published in Biomaterial Investigations in Dentistry, 2020
Bo Wold Nilsen, Mathieu Mouhat, Asbjørn Jokstad
A non-destructive technique to identify pores in samples, which also enables estimating the pore size distribution, also known as differential pore volume distribution or porosity spectrum, is the use of x-ray microtomography, referred to as micro-CT in this article. The method is non-invasive, three-dimensional and can be used to appraise the amount of porosity both in polymerised and in unpolymerised specimens. While many studies have measured the amount of porosity in polymerised CPRs [10–13], nobody has – to the knowledge of the authors – undertaken studies of whether the unpolymerised material within CPR compules may include pores. Quantifying and characterising such pores can provide knowledge about potential sources of pores in dental restorations. With this background, the study objectives were to assess whether composite polymer resin delivered in compules include pores and the possible effect on the amount of porosity in dental restorations.
X-ray microtomography assessment of Carisolv and Papacarie effect on dentin mineral density and amount of removed tissue
Published in Acta Odontologica Scandinavica, 2018
Jehan AlHumaid, Fahad Al-Harbi, Maha El Tantawi, Abeer Elembaby
Our study fills a gap in knowledge about chemomechanical caries removal where the effect of the two commercially available agents, Carisolv and Papacarie, was directly compared in the same study regarding both RT and DMD thus building on previous studies that focused on only one agent or parameter. We used X-ray microtomography with a scanning and visualization method that was different from that used by others [19,21,22,24] and obtained comparable results. Although not proven statistically, Papacarie excavation was associated with 17% increase in cases with sound dentin and 23% reduction in RT showing its potential advantage over Carisolv. This needs further confirmation in future studies including cavities with various sizes in addition to quantifying the volume of remaining carious tissue after excavation as well as the amount of sound dentin removed so that better decisions can be made about which agent to select.