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Modulation of intraocular pressure by unilateral and forced unilateral nostril breathing in young healthy human subjects

Mohan SM, Reddy SC, Wei LY

Int Ophthalmol, 2001;24(6):305-11.
PMID: 14750567

PURPOSE: To determine the effects of unilateral right/left nostril breathing (URNB/ULNB) and forced unilateral right/left nostril breathing (FURNB/FULNB) on intraocular pressure (IOP) and to examine the differences in the IOP during the various phases of nasal cycle.
METHODS: Young healthy volunteers of either sex aged between 19-24 years, participated in the sessions using URNB/ULNB (n = 52) and FURNB/FULNB (n = 28). The nostril dominance was calculated from signals recorded on the PowerLab equipment, representing pressure changes at the end of the nostrils during respiration. The IOP was measured with Tono-Pen. The subjects were divided into 4 groups viz. right nostril dominant (RND), left nostril dominant (LND), transitional right nostril dominant (TRND) and transitional left nostril dominant (TLND) groups. The IOP data 'before and after' URNB/ULNB or FURNB/FULNB were compared by using paired t-test. The baseline data of IOP between the groups were analysed by using independent samples t-test.
RESULTS: The URNB decreased the IOP in the LND and TLND (p < 0.01) and also in the RND (p < 0.05) groups but not significantly in the TRND group. The ULNB decreased the IOP in the RND group (p < 0.01) only. The FURNB significantly reduced the IOP (p < 0.05) only in the LND and RND groups. The FULNB decreased the IOP but not significantly. The baseline IOP did not differ significantly between the LND, RND, TLND and TRND groups.
CONCLUSION: The URNB/FURNB reduced the IOP, while ULNB/FULNB failed to increase the IOP significantly. It is suggested that the lowering of IOP by URNB indicated sympathetic stimulation.

Matched MeSH terms: Nasal Cavity/physiology*
Fulltext Hybrid mesh for nasal airflow studies

Zubair M, Abdullah MZ, Ahmad KA

Comput Math Methods Med, 2013;2013:727362.
PMID: 23983811 DOI: 10.1155/2013/727362

The accuracy of the numerical result is closely related to mesh density as well as its distribution. Mesh plays a very significant role in the outcome of numerical simulation. Many nasal airflow studies have employed unstructured mesh and more recently hybrid mesh scheme has been utilized considering the complexity of anatomical architecture. The objective of this study is to compare the results of hybrid mesh with unstructured mesh and study its effect on the flow parameters inside the nasal cavity. A three-dimensional nasal cavity model is reconstructed based on computed tomographic images of a healthy Malaysian adult nose. Navier-Stokes equation for steady airflow is solved numerically to examine inspiratory nasal flow. The pressure drop obtained using the unstructured computational grid is about 22.6 Pa for a flow rate of 20 L/min, whereas the hybrid mesh resulted in 17.8 Pa for the same flow rate. The maximum velocity obtained at the nasal valve using unstructured grid is 4.18 m/s and that with hybrid mesh is around 4.76 m/s. Hybrid mesh reported lower grid convergence index (GCI) than the unstructured mesh. Significant differences between unstructured mesh and hybrid mesh are determined highlighting the usefulness of hybrid mesh for nasal airflow studies.

Matched MeSH terms: Nasal Cavity/physiology*
Perceptual processing of Mandarin nasals by L1 and L2 Mandarin speakers

Lai YH

J Psycholinguist Res, 2012 Aug;41(4):237-52.
PMID: 22089521 DOI: 10.1007/s10936-011-9190-2

Nasals are cross-linguistically susceptible to change, especially in the syllable final position. Acoustic reports on Mandarin nasal production have recently shown that the syllable-final distinction is frequently dropped. Few studies, however, have addressed the issue of perceptual processing in Mandarin nasals for L1 and L2 speakers of Mandarin Chinese. The current paper addressed to what extent and in what directions L1 and L2 speakers of Mandarin differed in perceiving Mandarin nasals. Possible variables, including the linguistic backgrounds (i.e. L1 vs. L2 speakers of Mandarin Chinese), the vocalic contexts (i.e. [i, ə, a, y, ua, uə, ia]) and the phonetic settings (i.e. syllable-initial vs. syllable-final), were discussed. Asymmetrical findings in the current investigation indicated limitations of speech learning theories developed from European languages in the context of Mandarin nasals. A tri-dimensional model was thus suggested for interpreting the cognitive mechanism in Mandarin nasal perception.

Matched MeSH terms: Nasal Cavity/physiology
Fulltext Effects of alternate nostril breathing exercise on cardiorespiratory functions in healthy young adults

Jahan I, Begum M, Akhter S, Islam MZ, Jahan N, Samad N, et al.

Ann Afr Med, 2021 7 3;20(2):69-77.
PMID: 34213471 DOI: 10.4103/aam.aam_114_20

Introduction: Alternate nostril breathing (ANB) is an effective breathing exercise with therapeutic benefits on cardiorespiratory functions for healthy and diseased individuals. This study was conducted to assess the effects of ANB exercise on cardiorespiratory tasks in healthy adults.
Materials and Methods: This randomized experimental study was conducted in the Department of Physiology, Chittagong Medical College, Chattogram, from July 2017 to June 2018. A total of 100 1st-year students, aged between 18 and 20 years, were included by a random sampling method. Fifty participants (25 males and 25 females) were enrolled in the experimental group, while age- and body mass index-matched another 50 participants (25 males and 25 females) served as the control group. Experimental group participants performed ANB exercise for 4 weeks. Cardiorespiratory parameters (pulse rate, blood pressure, forced vital capacity, forced expiratory volume in 1st s [FEV1], and peak expiratory flow rate [PEFR] were measured. Data were taken at the start and after 4 weeks in both groups.
Results: Independent t-test showed no significant differences in the cardiorespiratory functions between the experimental and control groups among the male and female participants, except for the females' PEFR which showed small differences. On the other hand, repeated measure ANOVA shows significant improvement in the experimental groups among males (P < 0.001-0.028) and females (P < 0.001-0.001) in all the cardiorespiratory functions measured, except for the FEV1 and PEFR among males.
Conclusion: The results of this study suggest that cardiorespiratory functions were improved after breathing exercise, and therefore, ANB can be recommended for increasing cardiorespiratory efficiency.

Matched MeSH terms: Nasal Cavity/physiology*
Fulltext Effects of temperature changes on nasal patency

Yogeetha R, Raman R, Quek KF

Singapore Med J, 2007 Apr;48(4):304-6.
PMID: 17384876

This study aims to assess the difference in nasal patency and resistance to temperature changes objectively and subjectively.

Matched MeSH terms: Nasal Cavity/physiology
Fulltext Standardization of Malaysian adult female nasal cavity

Lee CF, Abdullah MZ, Ahmad KA, Lutfi Shuaib I

Comput Math Methods Med, 2013;2013:519071.
PMID: 23840279 DOI: 10.1155/2013/519071

This research focuses on creating a standardized nasal cavity model of adult Malaysian females. The methodology implemented in this research is a new approach compared to other methods used by previous researchers. This study involves 26 females who represent the test subjects for this preliminary study. Computational fluid dynamic (CFD) analysis was carried out to better understand the characteristics of the standardized model and to compare it to the available standardized Caucasian model. This comparison includes cross-sectional areas for both half-models as well as velocity contours along the nasal cavities. The Malaysian female standardized model is larger in cross-sectional area compared to the standardized Caucasian model thus leading to lower average velocity magnitudes. The standardized model was further evaluated with four more Malaysian female test subjects based on its cross-sectional areas and average velocity magnitudes along the nasal cavities. This evaluation shows that the generated model represents an averaged and standardized model of adult Malaysian females.

Matched MeSH terms: Nasal Cavity/physiology*