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Biological Systems and Biomimetics
Published in Efstathios E. Michaelides, Clayton T. Crowe, John D. Schwarzkopf, Multiphase Flow Handbook, 2016
Efstathios E. Michaelides, Clayton T. Crowe, John D. Schwarzkopf
e human respiratory system consists of upper airways, including nasal and oral cavity, pharynx, and larynx, and lower airways, including trachea, bronchi, bronchioles, and pulmonary alveoli as shown schematically in Figure 16.1. Air enters from nose or mouth and passes into the pharynx and then ows through the larynx into the trachea and then to the primary bronchi. e bronchioles successively bifurcate about 23 times until they reach the alveoli. In the alveolar cavities, gas exchange with the cardiovascular system occurs. Figure 16.2 shows a schematic of the nasal cavity that extends from the naris (nostril) to the entrance of nasopharynx. e nostril is the external opening of the nasal passage through which air is inhaled and exhaled. e funnel region following the nostril is the vestibule that extends to the nasal valve region. e nasal passage has its minimum cross-sectional area at the nasal valve region; therefore, the axial component of air ow velocity is the highest in this region. e nasal valve region is connected to the main airway region that has a complex geometry and includes turbinate regions. At the end of the main airway and the beginning of nasopharynx, the le and right nasal cavities merge together and form one passage. Figure 16.2 also shows the inferior, middle, and superior turbinates. One of the functions of the turbinates is to help humidify and thermally condition the inhaled air. In addition, they remove particulate pollutant form the air. e thin wall that is dividing the nose in the center is called the septum. e regions between turbinates and the lateral side of the passage are the inferior meatus, middle meatus, and superior meatus regions.
Natural Biopolymeric Nanoformulations for Brain Drug Delivery
Published in Raj K. Keservani, Anil K. Sharma, Rajesh K. Kesharwani, Nanocarriers for Brain Targeting, 2019
Josef Jampílek, Katarina Král’ová
Phospholipids were found to play an essential role in memory and learning abilities and act as a source of choline in acetylcholine synthesis. The effect of CS/phospholipid/β-CD microspheres on the improvement of cognitive impairment was studied by Shan et al. (2016). Formation of hydrogen bonds between phospholipids and the amide group of CS as well as with OH group of β-CD was estimated, and the treatment with the above-mentioned microspheres notably increased the learning and memory abilities of rats compared to the control group, attenuated the expression of protein kinase C-ô and inhibited the activation of microglia, indicating that they would be suitable for treatment of AD. Glycol CS/sulfobutylether-β-CD based NPs were tested for intranasal delivery of dopamine to the striatum by Di Gioia et al. (2015). An inclusion complex was formed between sulfobutylether-β-CD and dopamine, whereby the drug was situated on the external surface of NPs, and the acute administration of this nanoformulation into the right nostril of rats did not modify the levels of the neurotransmitter in both right and left striatum, while its repeated intranasal administration into the right nostril resulted in a considerable increase of drug concentration in the ipsilateral striatum. Following the acute administration of glycol CS/sulfobutylether-β-CD NPs incorporating dopamine into the right nostril, the presence of NPs was estimated only in the right olfactory bulb and no morphological tissue damage was observed, indicating that this preparation could be applied for nose-to-brain delivery of dopamine for the PD treatment. Anand et al. (2012) performed a spectroscopic and photophysical study of the NPs consisting of the association of DOX and artemisinin to β-CD-epichlorohydrin cross-linked polymers (ca. 15 nm) and found that the complexes evidenced an alcohol-like environment for artemisinin and improved inherent emission ability for DOX in the nanoparticle frame.
Endoscopic Approach in Maxillary Tumours
Published in Cut Adeya Adella, Stem Cell Oncology, 2018
A 49-year-old man presented to our centre with a persistent unilateral nose blockage with a protruding mass in the left nostril. He was then further assessed using computer tomography. The mass was noted to occupy his entire unilateral sinuses; however, there was no evidence of orbital and intracranial involvement. He was then scheduled for endoscopic excision of the tumour.
Airflow patterns and particle deposition in a pediatric nasal upper airway following a rapid maxillary expansion: Computational fluid dynamics study
Published in Cogent Engineering, 2023
John Valerian Corda, Jeny Emmanuel, Supriya Nambiar, Prakashini K, Mohammad Zuber
In equation 9, a1, a2, and a3 reflect the constants that apply to smooth spherical particles throughout a wide range of (Karakosta et al., 2015). The microparticles with an aerodynamic diameter ranging from 1 micron to 60 µm are considered in this study. It is assumed that the particles are spherical having a density of 1100 kg/m3 (Islam et al., 2021). The particles are injected into the nasal cavity through the nostril with the same velocity as that of inlet air velocity at the nostrils. The particles are assumed to be inert without any interaction between them. The injection type considered is the surface injection where the particles are released from each facet of the surface. It is assumed that the particles are deposited as they hit the wall. The forces involved in rotational and thermophoretic actions are assumed to be negligible. An ensemble of around 60,000 micro-sized particles ranging from 2 to 60 µm was uniformly injected from the nostrils. The particle number 60,000 is finalized based on the particle independence test as shown in Figure 2, which is carried out for 5 µm sized particles at 5 LPM.
Numerical analysis of enhanced nano-drug delivery to the olfactory bulb
Published in Aerosol Science and Technology, 2021
Shantanu Vachhani, Clement Kleinstreuer
As an alternative to drug particle size change or using different forces, exhalation delivery systems (EDS) have also been employed for olfactory drug targeting. Djupesland et al. (2004) developed an bi-directional nasal delivery system. that results more deposition in the upper parts of the body. This system has been implemented in the form of an EDS device (Djupesland 2013). It consists of a mouthpiece to which person exhales and this air goes to the connected nosepiece which is inserted into one of the nostrils. During exhalation, the soft palate closes off the nasal cavity from the oral cavity due to positive air pressure. As a result, the air and drug particles from the nostril travels through the nasal cavity behind the septum and exits from the other nostril. This creates more airflow within the upper parts of the nasal cavity. Ofactory drug targeting of microparticles through this bi-directional airflow system was numerically investigated by Yarragudi et al. (2020). They found that for a bi-directional flowrate of 6 lpm, a peak olfactory deposition of ∼16% was observed for a particle size of 17 µm as opposed to ∼9% for 10 µm under uni-directional flow. Although a high deposition is observed, the size of the particle poses a hindrance for travel through the BBB and hence after reaching the nasal mucosa, the drug delivery can only take place through the process of diffusion.
Validating 3D face morphing towards improving pre-operative planning in facial reconstruction surgery
Published in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2021
Z. Fishman, Jerry Liu, Joshua Pope, J.A. Fialkov, C.M. Whyne
To measure the accuracy of the 3D facial estimates, the modelled 3D face and true 3D face surfaces were first aligned at the nose tip and then rigidly registered using the iterative closest point (ICP) technique. The error between them was measured by the per-vertex Euclidean distance from the model to the scan surface. A symmetry analysis of 3D faces to their own mirror image determined that 2.16 mm is the average minimum distance measurable, below which is measurement noise from two coinciding face shapes (see Appendix/Supplemental Materials). An accuracy of 2.5 mm was defined in this work as a clinically marginal error at the limits of facial perception (Hohman et al. 2014). The regional error is defined according to the facial sections illustrated in Figure 1(e): forehead, temples, eyes, nose, cheeks, mouth, and chin. On the nose region, the deeper nostril surfaces are not included since the BU-3DFE scans have sealed nostril surfaces. The model chin region is also cropped along the jawline to better match the boundary of the true scan shape.