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Shamohammadi H, Mehrabi S, Sadrizadeh S, Yaghoubi M, Abouali O. 3D numerical simulation of hot airflow in the human nasal cavity and trachea. Comput Biol Med 2022; 147:105702. [DOI: 10.1016/j.compbiomed.2022.105702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 05/17/2022] [Accepted: 06/04/2022] [Indexed: 11/30/2022]
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Nasal air conditioning following total inferior turbinectomy compared to inferior turbinoplasty - A computational fluid dynamics study. Clin Biomech (Bristol, Avon) 2021; 81:105237. [PMID: 33272646 DOI: 10.1016/j.clinbiomech.2020.105237] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 09/10/2020] [Accepted: 11/13/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND The aim of this study was to use computational fluid dynamics (CFD) to investigate the effects on nasal heat exchange and humidification of two different surgical techniques for reducing the inferior turbinate under different environmental conditions. METHODS Virtual surgery using two techniques of turbinate reduction was performed in eight nasal airway obstruction patients. Bilateral nasal airway models for each patient were compared: 1) Pre-operative 2) Post inferior turbinoplasty 3) Post total inferior turbinate resection (ITR). Two representative healthy models were included. Three different environmental conditions were investigated 1) ambient air 2) cold, dry air 3) hot, humid air. CFD modelling of airflow and conditioning was performed under steady-state, laminar, inspiratory conditions. FINDINGS Nasal conditioning is significantly altered following inferior turbinate reduction surgery, particularly with ITR under cold, dry inspired air (CDA). The degree of impairment is minor under the simulated range of environmental conditions (temperature = 12-40 °C; relative humidity = 13-80%). Streams of significantly colder air are found in the nasopharynx and more prevalent under CDA in ITR. These are related to high velocity flow streams, which remain cool in their centre throughout the widened inferior nasal cavity. INTERPRETATION Reduced air-mucosal heat exchange and moisture carrying capacity occurs under cooler temperatures in patients following inferior turbinate surgery. The clinical impact in extremely cold and dry conditions in groups with poor baseline respiratory function, respiratory illness, or endurance athletes is of special interest.
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Zimmerman K, Kearns F, Tzekov R. Natural protection of ocular surface from viral infections - A hypothesis. Med Hypotheses 2020; 143:110082. [PMID: 32679424 PMCID: PMC7346787 DOI: 10.1016/j.mehy.2020.110082] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 07/04/2020] [Indexed: 01/08/2023]
Abstract
A pandemic outbreak of a viral respiratory infection (COVID-19) caused by a coronavirus (SARS-CoV-2) prompted a multitude of research focused on various aspects of this disease. One of the interesting aspects of the clinical manifestation of the infection is an accompanying ocular surface viral infection, viral conjunctivitis. Although occasional reports of viral conjunctivitis caused by this and the related SARS-CoV virus (causing the SARS outbreak in the early 2000s) are available, the prevalence of this complication among infected people appears low (~1%). This is surprising, considering the recent discovery of the presence of viral receptors (ACE2 and TMPRSS2) in ocular surface tissue. The discrepancy between the theoretically expected high rate of concurrence of viral ocular surface inflammation and the observed relatively low occurrence can be explained by several factors. In this work, we discuss the significance of natural protective factors related to anatomical and physiological properties of the eyes and preventing the deposition of large number of virus-loaded particles on the ocular surface. Specifically, we advance the hypothesis that the standing potential of the eye plays an important role in repelling aerosol particles (microdroplets) from the surface of the eye and discuss factors associated with this hypothesis, possible ways to test it and its implications in terms of prevention of ocular infections.
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Affiliation(s)
- Keith Zimmerman
- Department of Ophthalmology, University of South Florida, Tampa, FL, USA
| | - Fiona Kearns
- Department of Chemistry, University of South Florida, Tampa, FL, USA
| | - Radouil Tzekov
- Department of Ophthalmology, University of South Florida, Tampa, FL, USA; Department of Pharmaceutical Sciences, University of South Florida, Tampa, FL, USA; Department of Medical Engineering, University of South Florida, Tampa, FL, USA.
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Tan MSA, Parekh HS, Pandey P, Siskind DJ, Falconer JR. Nose-to-brain delivery of antipsychotics using nanotechnology: a review. Expert Opin Drug Deliv 2020; 17:839-853. [PMID: 32343186 DOI: 10.1080/17425247.2020.1762563] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Orally-administered antipsychotics are effective in the management of psychosis-related disorders although generation-specific adverse drug reactions (ADRs) significantly hinder clinical outcomes, driven by issues such as patient non-compliance. Direct nose-to-brain (N2B) delivery of antipsychotics via the olfactory epithelium could avert peripheral ADRs by maximizing cerebral drug concentrations, and reducing drug levels in the periphery. However, there exist physicochemical challenges related to psychotropic drugs, alongside biochemical barriers associated with targeting the olfactory region. Nanotechnological approaches present a viable strategy for the development of intranasal antipsychotic formulations where drug stability, mucosal absorption and cerebrospinal fluid (CSF)-bioavailability can be optimized. AREAS COVERED This review explores the unique anatomical features of the nasal cavity as a pathway for antipsychotic drug delivery to the brain. Nanocarrier-based approaches to encapsulate antipsychotics, and enhance stability, absorption and bioavailability are explored. The aim of this review is to determine current knowledge gaps for direct N2B psychotropic drug delivery, and identify clinically acceptable strategies to overcome them. EXPERT OPINION The olfactory epithelium may be the most effective and direct administration route for antipsychotic delivery to the central nervous system (CNS). This research is novel and has the potential to revolutionize the mode of delivery of neurological medicines to the CNS in the future.
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Affiliation(s)
- Madeleine S A Tan
- School of Pharmacy, The University of Queensland , Brisbane, Australia
| | - Harendra S Parekh
- School of Pharmacy, The University of Queensland , Brisbane, Australia
| | - Preeti Pandey
- School of Pharmacy, The University of Queensland , Brisbane, Australia
| | - Dan J Siskind
- Mobile Intensive Rehabilitation Team, Princess Alexandra Hospital, Metro South Addiction and Mental Health Service , Woolloongabba, Qld, Australia.,Department of Psychiatry, School of Clinical Medicine, University of Queensland , Woolloongabba, Qld, Australia
| | - James R Falconer
- School of Pharmacy, The University of Queensland , Brisbane, Australia
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Numerical simulation of nasal airflows and thermal air modification in newborns. Med Biol Eng Comput 2019; 58:307-317. [PMID: 31848979 DOI: 10.1007/s11517-019-02092-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 11/27/2019] [Indexed: 12/23/2022]
Abstract
Warming, filtering, and humidification of inspired air are major functions of the upper airway, which can be negatively altered by local disorders or surgical interventions. These functions have not been described in neonates because of ethical and technical problems difficult to solve. Numerical simulations can get around these limitations. The objective of this study was to analyze physiological nasal airflow and thermal distribution using computational fluid dynamics (CFD) techniques in neonates. CT imaging of neonates was collected from the Pediatric Radiology Department of our center. CFD has been used to simulate nasal airflow numerically, with ambient air set at 19 °C, following the recommendations for a neonate's bedroom. Thermal distribution within the nasal cavity was analyzed and coupled with airflow patterns over complete respiratory cycles. Sixteen patients have been included in the study. During inspiration, important air warming is noticed in the first centimeter of the nasal cavity (+ 8 °C at the anterior end of the inferior turbinate). During the expiration phase, the temperature decreases slightly (- 3 °C) between the pharynx and the nostrils. A model with asymmetric nasal fossae showed that nasal obstruction leads to decreased airflow and abnormally high temperatures in the obstructed side (+ 2 °C at the nasal valve, + 4 °C at the choana). According to our results, the nasal valve area is of crucial importance in air warming in neonates, when ambient air is 19 °C, since about 70% of air warming is performed in this area. When needed, surgical interventions should respect the anatomy of this zone and restore normal airflows and warming. Graphical abstract .
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[Three-dimensional analysis of nasal physiology : Representation by means of computational fluid dynamics]. HNO 2019; 66:280-289. [PMID: 29222682 DOI: 10.1007/s00106-017-0443-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The human nose takes primary responsibility for preconditioning inhaled air. Numerous pathologies can affect the physiology of the nose. The beginnings of flow analyzes were carried out with three-dimensional casting models and differently colored liquids. Temperature and humidity could not be taken into account. Today, much more complex analyzes are possible using computational fluid dynamics (CFD), which are based on three-dimensional models generated from computed tomography (CT) or magnetic resonance imaging (MRI) datasets. Here, flow velocities, temperature, humidity, and pressure differences can be simulated and displayed in high-resolution videos as a function of multiple boundary conditions. The analysis of pathological changes or surgical interventions is thereby possible.
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Plotnikow GA, Accoce M, Navarro E, Tiribelli N. Humidification and heating of inhaled gas in patients with artificial airway. A narrative review. Rev Bras Ter Intensiva 2018; 30:86-97. [PMID: 29742220 PMCID: PMC5885236 DOI: 10.5935/0103-507x.20180015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 08/30/2017] [Indexed: 01/15/2023] Open
Abstract
Instrumentation of the airways in critical patients (endotracheal tube or
tracheostomy cannula) prevents them from performing their function of humidify
and heating the inhaled gas. In addition, the administration of cold and dry
medical gases and the high flows that patients experience during invasive and
non-invasive mechanical ventilation generate an even worse condition. For this
reason, a device for gas conditioning is needed, even in short-term treatments,
to avoid potential damage to the structure and function of the respiratory
epithelium. In the field of intensive therapy, the use of heat and moisture
exchangers is common for this purpose, as is the use of active humidification
systems. Acquiring knowledge about technical specifications and the advantages
and disadvantages of each device is needed for proper use since the conditioning
of inspired gases is a key intervention in patients with artificial airway and
has become routine care. Incorrect selection or inappropriate configuration of a
device can have a negative impact on clinical outcomes. The members of the
Capítulo de Kinesiología Intensivista of the
Sociedad Argentina de Terapia Intensiva conducted a
narrative review aiming to show the available evidence regarding conditioning of
inhaled gas in patients with artificial airways, going into detail on concepts
related to the working principles of each one.
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Affiliation(s)
- Gustavo Adrián Plotnikow
- Capítulo de Kinesiología Intensivista, Sociedad Argentina de Terapia Intensiva, Buenos Aires, Argentina
| | - Matias Accoce
- Capítulo de Kinesiología Intensivista, Sociedad Argentina de Terapia Intensiva, Buenos Aires, Argentina
| | - Emiliano Navarro
- Capítulo de Kinesiología Intensivista, Sociedad Argentina de Terapia Intensiva, Buenos Aires, Argentina
| | - Norberto Tiribelli
- Capítulo de Kinesiología Intensivista, Sociedad Argentina de Terapia Intensiva, Buenos Aires, Argentina
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Vainer BG. A Novel High-Resolution Method for the Respiration Rate and Breathing Waveforms Remote Monitoring. Ann Biomed Eng 2018; 46:960-971. [DOI: 10.1007/s10439-018-2018-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Accepted: 03/26/2018] [Indexed: 12/01/2022]
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Abstract
The nose forms the first 8 cm of the upper respiratory tract and is responsible for cleansing, humidification, and temperature control of the supplied air. This is also referred to as conditioning. The nasal valve region, formed by the head of the lower nasal concha, portions of the cartilaginous septum, and the upper lateral cartilage, is responsible for diffusing and accelerating the respiratory airflow. Prerequisite are regular mucociliary clearance and sufficient air passage. Hypertrophy of the lower nasal turbinate is one of the most common causes of symptomatic nasal congestion. In unclear cases, rhinometric procedures are available. In addition to conservative therapy of allergic or vasomotor rhinitis by specific immunotherapy or topical corticoids, numerous interventional procedures are available to reduce conchal tissue. All modern methods have a high degree of protection of the respiratory mucosa in common.
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Lindemann J, Reichert M, Kröger R, Schuler P, Hoffmann T, Sommer F. Numerical simulation of humidification and heating during inspiration in nose models with three different located septal perforations. Eur Arch Otorhinolaryngol 2015; 273:1795-800. [PMID: 26545380 DOI: 10.1007/s00405-015-3818-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 10/22/2015] [Indexed: 10/22/2022]
Abstract
Nasal septum perforations (SP) are characterized by nasal obstruction, bleeding and crusting. The disturbed heating and humidification of the inhaled air are important factors, which cause these symptoms due to a disturbed airflow. Numerical simulations offer a great potential to avoid these limitations and to provide valid data. The aim of the study was to simulate the humidification and heating of the inhaled air in digital nose models with three different SPs and without SP. Four realistic bilateral nose models based on a multi-slice CT scan were created. The SP were located anterior caudal, anterior cranial and posterior caudal. One model was without SP. A numerical simulation was performed. Boundary conditions were based on previous in vivo measurements. Heating and humidification of the inhaled air were displayed, analyzed in each model and compared to each other. Anterior caudal SPs cause a disturbed decrease of temperature and humidity of the inhaled air. The reduced temperature and humidity values can still be shown in the posterior nose. The anterior cranial and the posterior caudal perforation have only a minor influence on heating and humidification. A reduced humidification and heating of the air can be shown by numerical simulations due to SP depending on their localization. The anterior caudal SP representing a typical localization after previous surgery has the biggest influence on heating and humidification. The results explain the typical symptoms such as crusting by drying-out the nasal mucosa. The size and the localization of the SP are essential for the symptoms.
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Affiliation(s)
- Jörg Lindemann
- Department of ORL, Head and Neck Surgery, Ulm University Medical Center, Frauensteige 12, 89075, Ulm, Germany
| | - Michael Reichert
- Department of ORL, Head and Neck Surgery, Ulm University Medical Center, Frauensteige 12, 89075, Ulm, Germany.
| | | | - Patrick Schuler
- Department of ORL, Head and Neck Surgery, Ulm University Medical Center, Frauensteige 12, 89075, Ulm, Germany
| | - Thomas Hoffmann
- Department of ORL, Head and Neck Surgery, Ulm University Medical Center, Frauensteige 12, 89075, Ulm, Germany
| | - Fabian Sommer
- Department of ORL, Head and Neck Surgery, Ulm University Medical Center, Frauensteige 12, 89075, Ulm, Germany
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White DE, Bartley J, Nates RJ. Model demonstrates functional purpose of the nasal cycle. Biomed Eng Online 2015; 14:38. [PMID: 25907572 PMCID: PMC4416271 DOI: 10.1186/s12938-015-0034-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 04/08/2015] [Indexed: 11/18/2022] Open
Abstract
Background Despite the occurrence of the nasal cycle being well documented, the functional purpose of this phenomenon is not well understood. This investigation seeks to better understand the physiological objective of the nasal cycle in terms of airway health through the use of a computational nasal air-conditioning model. Method A new state-variable heat and water mass transfer model is developed to predict airway surface liquid (ASL) hydration status within each nasal airway. Nasal geometry, based on in-vivo magnetic resonance imaging (MRI) data is used to apportion inter-nasal air flow. Results The results demonstrate that the airway conducting the majority of the airflow also experiences a degree of ASL dehydration, as a consequence of undertaking the bulk of the heat and water mass transfer duties. In contrast, the reduced air conditioning demand within the other airway allows its ASL layer to remain sufficiently hydrated so as to support continuous mucociliary clearance. Conclusions It is quantitatively demonstrated in this work how the nasal cycle enables the upper airway to accommodate the contrasting roles of air conditioning and the removal of entrapped contaminants through fluctuation in airflow partitioning between each airway.
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Affiliation(s)
- David E White
- School of Engineering, Auckland University of Technology, Auckland, New Zealand.
| | - Jim Bartley
- Department of Surgery, University of Auckland, Auckland, New Zealand.
| | - Roy J Nates
- School of Engineering, Auckland University of Technology, Auckland, New Zealand.
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Mucoadhesive polymers in the design of nano-drug delivery systems for administration by non-parenteral routes: A review. Prog Polym Sci 2014. [DOI: 10.1016/j.progpolymsci.2014.07.010] [Citation(s) in RCA: 333] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Sukanesh R, Muthu Kumaran E. Spectral Estimation of Nasal Cyclic Rhythm by Nasal Airflow Temperature Measurement. APPLIED MECHANICS AND MATERIALS 2014; 573:848-855. [DOI: 10.4028/www.scientific.net/amm.573.848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
.The nasal cycle is referred to a cyclic fluctuation in congestion of the nasal mucosa that results in rhythmic and bilateral reciprocal alteration of nasal airway patency. The purpose of this study is to deal with statistical and power spectral analysis of nasal cycle by measuring the temperature difference between the airflow of both left and right nostrils. Five adult voluntary healthy subjects are enrolled for the study. Nasal temperature probe combined with amplifier are used for recording nasal airflow temperature on both nostrils. The highest nasal airflow temperature values are detected at the end of expiration and the lowest values are detected at the end of inspiration. Nasal cycle found in all the subjects and lasted to the minimum of 30 minutes to maximum of 6 hours. The difference in temperature of both nostrils is statistically significant (p<0.05) and spectral estimation is made using autoregressive modeling. The method is used to quantify nasal obstruction in pathological condition and also to correlate the related physiological phenomenon.
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Idelevich EA, von Eiff C, Friedrich AW, Iannelli D, Xia G, Peters G, Peschel A, Wanninger I, Becker K. In vitro activity against Staphylococcus aureus of a novel antimicrobial agent, PRF-119, a recombinant chimeric bacteriophage endolysin. Antimicrob Agents Chemother 2011; 55:4416-9. [PMID: 21746950 PMCID: PMC3165309 DOI: 10.1128/aac.00217-11] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 04/07/2011] [Accepted: 06/24/2011] [Indexed: 11/20/2022] Open
Abstract
Antistaphylococcal activity of the novel chimeric endolysin PRF-119 was evaluated with the microdilution method. The MIC(50) and MIC(90) of 398 methicillin-susceptible Staphylococcus aureus isolates were 0.098 μg/ml and 0.391 μg/ml, respectively (range, 0.024 to 0.780 μg/ml). Both the MIC(50) and MIC(90) values of 776 methicillin-resistant S. aureus isolates were 0.391 μg/ml (range, 0.024 to 1.563 μg/ml). All 192 clinical isolates of coagulase-negative staphylococci exhibited MIC values of >50 μg/ml. In conclusion, PRF-119 exhibited very good activity specifically against S. aureus.
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Affiliation(s)
- Evgeny A. Idelevich
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Christof von Eiff
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | | | | | - Guoqing Xia
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | - Georg Peters
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
| | - Andreas Peschel
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
| | | | - Karsten Becker
- Institute of Medical Microbiology, University Hospital Münster, Münster, Germany
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Abstract
The ability of the human nose to warm and humidify the respiratory air is important to maintaining the internal environment of the lungs, since ambient air is conditioned to nearly alveolar conditions (body temperature and fully saturated with water vapour) upon reaching the nasopharynx. Because of very short time of the inspiratory phase duration, as well as expiratory phase, only the rich vascularization of the nasal mucosa and specific organization of the submucosal vessels are not able to assure such effective physiological activity. Therefore the type of airflow during the respiration is essential to understanding the functional possibilities of the nasal mucosa. Most studies have investigated the airflow only in steady-flow conditions, where the laminar flow was observed. Anatomically accurate physical models of real nasal cavities and particle image velocimetry allow evaluation of the entire flow field in the nasal cavity. In these investigations a partially turbulent flow was observed even at low air velocities in most part of the nasal cavity. From a physiological perspective, a turbulent flow would seem sensible, since it enhances contact between air and the mucosal layer. By doing so, the nasal physiological functions - humidification, cleaning and warming are optimized.
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Affiliation(s)
- Stanisław Betlejewski
- Katedra Zdrowia Publicznego Collegium Medicum im. L. Rydygiera w Bydgoszczy, Uniwersytet Mikołaja Kopernika W Toruniu
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