Dopamine, norepinephrine, and vasopressin accelerate particle transport velocity in murine tracheal epithelium via substance-specific receptor pathways: dependency on intra- and extracellular Ca2+ sources.

Background: The unique ability of the respiratory tract to protect the integrity of the airways by removing potentially harmful substances is defined as mucociliary clearance. This complex physiological mechanism protects the lower airways by ridding them of pollutants and pathogens. This study aimed to evaluate the potential influence of clinically relevant vasopressors on mucociliary clearance. Material and methods: The particle transport velocity (PTV) of isolated murine tracheae was measured as a surrogate for mucociliary clearance under the influence of dopamine, norepinephrine, and vasopressin. Inhibitory substances were applied to elucidate relevant signal transduction cascades and the value and origin of calcium ions. Reverse-transcription polymerase chain reactions (RT-PCR) were performed to identify the expression of vasopressin receptor subtypes. Results: Dopamine, norepinephrine, and vasopressin significantly increased the PTV in a dose-dependent manner with half maximal effective concentrations of 0.58 µM, 1.21 µM, and 0.10 µM, respectively. Each substance increased the PTV via separate receptor pathways. While dopamine acted on D1-like receptors to increase the PTV, norepinephrine acted on ß-adrenergic receptors, and vasopressin acted on V1a receptors. RT-PCR revealed the expression of V1a in the murine whole trachea and tracheal epithelium. PTV increased when protein kinase A was inhibited and norepinephrine or vasopressin were applied, but not when dopamine was applied. Phospholipase C inhibition decreased the PTV when vasopressin was applied. In general, maximum PTV was significantly reduced when extracellular calcium entry was inhibited. When intracellular calcium stores were depleted, no increase in PTV was observed after administering all three substances. Inositol trisphosphate receptor activation was found to be pivotal in the increase in murine PTV after applying dopamine and vasopressin. Discussion: Dopamine, norepinephrine, and vasopressin accelerate the murine PTV via substance-specific receptor pathways. Further investigations should assess the value and interaction of these substances on mucociliary clearance in clinical practice.

Evaluation of Open-Source Ciliary Analysis Software in Primary Ciliary Dyskinesia: A Comparative Assessment.

Primary Ciliary Dyskinesia (PCD) is a rare genetic disorder characterized by alterations in motile cilia function. The diagnosis of PCD is challenging due to the lack of standardized methods in clinical practice. High-speed video microscopy analysis (HSVA) directly evaluates ciliary beat frequency (CBF) in PCD. Recently, open-source ciliary analysis software applications have shown promise in measuring CBF accurately. However, there is limited knowledge about the performance of different software applications, creating a gap in understanding their comparative effectiveness in measuring CBF in PCD. We compared two open-source software applications, CiliarMove (v219) and Cilialyzer (v1.2.1-b3098cb), against the manual count method. We used high-speed videos of nasal ciliary brush samples from PCD RSPH4A-positive (PCD (RSPH4A)) patients and healthy controls. All three methods showed lower median CBF values for patients with PCD (RSPH4A) than in healthy controls. CiliarMove and Cilialyzer identified lower CBF in patients with PCD (RSPH4A), similarly to the manual count. Cilialyzer, CiliarMove, and manual count methods demonstrated statistical significance (p-value < 0.0001) in the difference of median CBF values between patients with PCD (RSPH4A) and healthy controls. Correlation coefficients between the manual count values against both software methods demonstrated positive linear relationships. These findings support the utility of open-source software-based analysis tools. Further studies are needed to validate these findings with other genetic variants and identify the optimal software for accurate CBF measurement in patients with PCD.

The Increase in the Frequency and Amplitude of the Beating of Isolated Mouse Tracheal Cilia Reactivated by ATP and cAMP with Elevation in pH.

Single cilia, 100 nm in diameter and 10 µm in length, were isolated from mouse tracheae with Triton X-100 (0.02%) treatment, and the effects of pH on ciliary beating were examined by measuring the ciliary beat frequency (CBF) and the ciliary bend distance (CBD-an index of amplitude) using a high-speed video microscope (250 fps). ATP (2.5 mM) plus 8Br-cAMP (10 µM) reactivated the CBF and CBD in the isolated cilia, similar to the cilia of in vivo tracheae. In the reactivated isolated cilia, an elevation in pH from 7.0 to 8.0 increased the CBF from 3 to 15 Hz and the CBD from 0.6 to 1.5 µm. The pH elevation also increased the velocity of the effective stroke; however, it did not increase the recovery stroke, and, moreover, it decreased the intervals between beats. This indicates that H+ (pHi) directly acts on the axonemal machinery to regulate CBF and CBD. In isolated cilia priorly treated with 1 µM PKI-amide (a PKA inhibitor), 8Br-cAMP did not increase the CBF or CBD in the ATP-stimulated isolated cilia. pH modulates the PKA signal, which enhances the axonemal beating generated by the ATP-activated inner and outer dyneins.

Comparing region of interest selection and whole-field analysis for measurement of ciliary beat frequency in high-speed video analysis.

BACKGROUND: Ciliary beat frequency (CBF) is crucial in mucociliary clearance. High-speed video analysis (HSVA) is commonly used to measure CBF but lacks standardization. We compared visual observation and computer-assisted calculation using fast Fourier transformation (FFT) in freshly collected bronchial ciliary epithelial cells and cultured cells. METHODS: Bronchial epithelial cells were obtained from 12 patients who required bronchoscopic examination. Eighty-five videos of ciliary movement of freshly collected and cultured cells were recorded and used to calculate CBF using manual observation, region of interest (ROI) selection, and whole-field analysis. RESULTS: CBF measured by the ROI selection method strongly correlated with that measured using manual observation, especially in freshly collected cells. However, 27.8% of the manual observation method values were doubled in the ROI selection method, probably because a round trip of cilia was calculated as two cycles and needed to be corrected to 1/2 value. Upon increasing the number of ROIs, the results of the ROI selection method came closer to that of WFA. CONCLUSIONS: Computer-assisted calculation using FFT can aid in measuring CBF; however, current methods require visual confirmation. Further automated evaluation techniques are needed to establish more standardized and generalized CBF measurement methods using HSVA.

Pervasive mimicry in flight behavior among aposematic butterflies.

Flight was a key innovation in the adaptive radiation of insects. However, it is a complex trait influenced by a large number of interacting biotic and abiotic factors, making it difficult to unravel the evolutionary drivers. We investigate flight patterns in neotropical heliconiine butterflies, well known for mimicry of their aposematic wing color patterns. We quantify the flight patterns (wing beat frequency and wing angles) of 351 individuals representing 29 heliconiine and 9 ithomiine species belonging to ten color pattern mimicry groupings. For wing beat frequency and up wing angles, we show that heliconiine species group by color pattern mimicry affiliation. Convergence of down wing angles to mimicry groupings is less pronounced, indicating that distinct components of flight are under different selection pressures and constraints. The flight characteristics of the Tiger mimicry group are particularly divergent due to convergence with distantly related ithomiine species. Predator-driven selection for mimicry also explained variation in flight among subspecies, indicating that this convergence can occur over relatively short evolutionary timescales. Our results suggest that the flight convergence is driven by aposematic signaling rather than shared habitat between comimics. We demonstrate that behavioral mimicry can occur between lineages that have separated over evolutionary timescales ranging from <0.5 to 70 My.

Lianhua Qingke Preserves Mucociliary Clearance in Rat with Acute Exacerbation of Chronic Obstructive Pulmonary Disease by Maintaining Ciliated Cells Proportion and Protecting Structural Integrity and Beat Function of Cilia.

Purpose: Acute Exacerbation of Chronic Obstructive Pulmonary Disease (AECOPD) is a sudden worsening of symptoms in patients with Chronic Obstructive Pulmonary Disease (COPD), such as cough, increased sputum volume, and sputum purulence. COPD and AECOPD are characterized by damage to cilia and increased mucus secretion. Mucociliary clearance (MCC) functions as part of the primary innate system of the lung to remove harmful particles and pathogens together with airway mucus and is therefore crucial for patients with COPD. Methods: AECOPD was induced by cigarette smoke exposure (80 cigarettes/day, 5 days/week for 12 weeks) and lipopolysaccharide (LPS) instillation (200 µg, on days 1, 14, and 84). Rats administered Lianhua Qingke (LHQK) (0.367, 0.732, and 1.465 g/kg/d) or Eucalyptol, Limonene, and Pinene Enteric Soft Capsules (ELP, 0.3 g/kg/d) intragastrically. Pulmonary pathology, Muc5ac+ goblet cell and ß-tubulin IV+ ciliated cells, and mRNA levels of forkhead box J1 (Foxj1) and multiciliate differentiation and DNA synthesis associated cell cycle protein (MCIDAS) were assessed by hematoxylin and eosin staining, immunofluorescence staining, and RT-qPCR, respectively. Ciliary morphology and ultrastructure were examined through scanning electron microscopy and transmission electron microscopy. Ciliary beat frequency (CBF) was recorded using a high-speed camera. Results: Compared to the model group, LHQK treatment groups showed a reduction in inflammatory cell infiltration, significantly reduced goblet cell and increased ciliated cell proportion. LHQK significantly upregulated mRNA levels of MCIDAS and Foxj1, indicating promoted ciliated cell differentiation. LHQK protected ciliary structure and maintained ciliary function via increasing the ciliary length and density, reducing ciliary ultrastructure damage, and ameliorating random ciliary oscillations, consequently enhancing CBF. Conclusion: LHQK enhances the MCC capability of ciliated cells in rat with AECOPD by preserving the structural integrity and beating function of cilia, indicating its therapeutic potential on promoting sputum expulsion in patients with AECOPD.

Nasal polyps show decreased mucociliary transport despite vigorous ciliary beating.

OBJECTIVE: Mucociliary transport function in the airway mucosa is essential for maintaining a clean mucosal surface. This function is impaired in upper and lower airway diseases. Nasal polyps are a noticeable pathological feature that develop in some of the patients with chronic rhinosinusitis. Like ordinary nasal mucosae, nasal polyps have a ciliated pseudostratified epithelium with vigorous ciliary beating. We measured ex vivo Mucociliary Transport Velocity (MCTV) and Ciliary Beat Frequency (CBF) and explored the expressions of Planar Cell Polarity (PCP) proteins in nasal polyps in comparison with turbinate mucosae. METHODS: Inferior turbinates and nasal polyps were surgically collected from patients with chronic rhinosinusitis. Ex vivo MCTV and CBF were measured using a high-speed digital imaging system. Expressions of PCP proteins were explored by fluorescence immunohistochemistry and quantitative RT-PCR. RESULTS: The MCTV of nasal polyps was significantly lower than that of the turbinates (7.43 ±â€¯2.01 vs. 14.56 ±â€¯2.09 µm/s; p = 0.0361), whereas CBF did not differ between the two tissues. The MCTV vector was pointed to the posteroinferior direction in all turbinates with an average inclination angle of 41.0 degrees. Immunohistochemical expressions of Dishevelled-1, Dishevelled-3, Frizzled3, Frizzled6, Prickle2 and Vangl2 were lower in the nasal polyps than in the turbinates. Confocal laser scanning microscopy showed that Frizzled3 was localized along the cell junction on the apical surface. The expression levels of mRNAs for Dishevelled-1, Dishevelled-3 and Frizzled3 in the nasal polyps were also decreased in comparison with the turbinates. CONCLUSION: These results indicate that muco ciliary transport in nasal polyps is impaired although vigorous ciliary beating is maintained, and that the impairment may be caused by a decrease in Dishevelled/Frizzled proteins and resultant PCP disarrangement. LEVEL OF EVIDENCE: Level 3.

Nasal polyps show decreased mucociliary transport despite vigorous ciliary beating

Abstract Objective Mucociliary transport function in the airway mucosa is essential for maintaining a clean mucosal surface. This function is impaired in upper and lower airway diseases. Nasal polyps are a noticeable pathological feature that develop in some of the patients with chronic rhinosinusitis. Like ordinary nasal mucosae, nasal polyps have a ciliated pseudostratified epithelium with vigorous ciliary beating. We measured ex vivo Mucociliary Transport Velocity (MCTV) and Ciliary Beat Frequency (CBF) and explored the expressions of Planar Cell Polarity (PCP) proteins in nasal polyps in comparison with turbinate mucosae. Methods Inferior turbinates and nasal polyps were surgically collected from patients with chronic rhinosinusitis. Ex vivo MCTV and CBF were measured using a high-speed digital imaging system. Expressions of PCP proteins were explored by fluorescence immunohistochemistry and quantitative RT-PCR. Results The MCTV of nasal polyps was significantly lower than that of the turbinates (7.43 ± 2.01 vs. 14.56 ± 2.09 μm/s; p= 0.0361), whereas CBF did not differ between the two tissues. The MCTV vector was pointed to the posteroinferior direction in all turbinates with an average inclination angle of 41.0 degrees. Immunohistochemical expressions of Dishevelled-1, Dishevelled-3, Frizzled3, Frizzled6, Prickle2 and Vangl2 were lower in the nasal polyps than in the turbinates. Confocal laser scanning microscopy showed that Frizzled3 was localized along the cell junction on the apical surface. The expression levels of mRNAs for Dishevelled-1, Dishevelled-3 and Frizzled3 in the nasal polyps were also decreased in comparison with the turbinates. Conclusion These results indicate that muco ciliary transport in nasal polyps is impaired although vigorous ciliary beating is maintained, and that the impairment may be caused by a decrease in Dishevelled/Frizzled proteins and resultant PCP disarrangement. Level of evidence: Level 3.

Glutathione and bicarbonate nanoparticles improve mucociliary transport in cystic fibrosis epithelia.

INTRODUCTION: Cystic fibrosis (CF) airway disease is characterized by thick mucus and impaired mucociliary transport (MCT). Loss of functional cystic fibrosis transmembrane receptor (CFTR) leads to acidification and oxidation of airway surface mucus. Replacing bicarbonate (HCO3 - ) topically fails due to rapid reabsorption and neutralization, while the scavenging antioxidant, glutathione sulfhydryl (GSH), is also rapidly degraded. The objective of this study is to investigate GSH/NaHCO3 nanoparticles as novel strategy for CF airway disease. METHODS: GSH/NaHCO3 poly (lactic-co-glycolic acid) nanoparticles were tested on primary CF (F508del/F508del) epithelial cultures to evaluate dose-release curves, surface pH, toxicity, and MCT indices using micro-optical coherence tomography. In vivo tests were performed in three rabbits to assess safety and toxicity. After 1 week of daily injections, histopathology, computed tomography (CT), and blood chemistries were performed and compared to three controls. Fluorescent nanoparticles were injected into a rabbit with maxillary sinusitis and explants visualized with confocal microscopy. RESULTS: Sustained release of GSH and HCO3 - with no cellular toxicity was observed over 2 weeks. Apical surface pH gradually increased from 6.54 ± 0.13 (baseline) to 7.07 ± 0.10 (24 h) (p < 0.001) and 6.87 ± 0.05 at 14 days (p < 0.001). MCT, ciliary beat frequency, and periciliary liquid were significantly increased. When injected into the maxillary sinuses of rabbits, there were no changes to histology, CT, or blood chemistries. Nanoparticles penetrated rabbit sinusitis mucus on confocal microscopy. CONCLUSION: Findings suggest that GSH/NaHCO3 - nanoparticles are a promising treatment option for viscous mucus in CF and other respiratory diseases of mucus obstruction such as chronic rhinosinusitis.

Novel nasal formulation of xylometazoline with hyaluronic acid: In vitro ciliary beat frequency study.

Acute viral rhinosinusitis (viral ARS), or commonly referred to as the "common cold", is caused by respiratory viruses that cause disruption of the airway epithelial barrier and mucociliary dysfunction. Treatment of ARS is mainly symptomatic, with xylometazoline, a direct-acting α-adrenoceptor agonist, commonly used as a nasal decongestant. Unfortunately, this treatment does not resolve the epithelial dysfunction observed in ARS, and its use might negatively impact the nasal mucosa causing issues such as dryness, stinging, burning, rebound congestion, as well as atrophy. In light of this, a novel nasal spray formulation containing both xylometazoline and hyaluronic acid (HA) was developed to provide a more effective and safer treatment for viral ARS. HA is a natural polysaccharide known to hydrate and moisturise the upper respiratory tract, maintain the integrity of the nasal mucosa, and promote mucociliary clearance and wound healing. To investigate the potential of this combination, this study was conducted using the nasal MucilAirTMin vitro model and high-speed phase-contrast microscopy to examine the effect of xylometazoline and HA on ciliary function by measuring ciliary beat frequency and their cytotoxicity by morphological, histological and ultrastructural analysis. This research is the first to assess the effects of a specific dose and molecular weight of HA as an active pharmaceutical ingredient in nasal spray formulations. The combination of a fast-acting decongestant and an additional active agent targeting nasal epithelial dysfunction has the potential to provide an improved, reliable and safe treatment for viral ARS, and may serve as the basis for future clinical studies.

A 20:1 synergetic mixture of cafedrine/theodrenaline accelerates particle transport velocity in murine tracheal epithelium via IP3 receptor-associated calcium release.

Background: Mucociliary clearance is a pivotal physiological mechanism that protects the lung by ridding the lower airways of pollution and colonization by pathogens, thereby preventing infections. The fixed 20:1 combination of cafedrine and theodrenaline has been used to treat perioperative hypotension or hypotensive states due to emergency situations since the 1960s. Because mucociliary clearance is impaired during mechanical ventilation and critical illness, the present study aimed to evaluate the influence of cafedrine/theodrenaline on mucociliary clearance. Material and Methods: The particle transport velocity (PTV) of murine trachea preparations was measured as a surrogate for mucociliary clearance under the influence of cafedrine/theodrenaline, cafedrine alone, and theodrenaline alone. Inhibitory substances were applied to elucidate relevant signal transduction cascades. Results: All three applications of the combination of cafedrine/theodrenaline, cafedrine alone, or theodrenaline alone induced a sharp increase in PTV in a concentration-dependent manner with median effective concentrations of 0.46 µM (consisting of 9.6 µM cafedrine and 0.46 µM theodrenaline), 408 and 4 µM, respectively. The signal transduction cascades were similar for the effects of both cafedrine and theodrenaline at the murine respiratory epithelium. While PTV remained at its baseline value after non-selective inhibition of ß-adrenergic receptors and selective inhibition of ß1 receptors, cafedrine/theodrenaline, cafedrine alone, or theodrenaline alone increased PTV despite the inhibition of the protein kinase A. However, IP3 receptor activation was found to be the pivotal mechanism leading to the increase in murine PTV, which was abolished when IP3 receptors were inhibited. Depleting intracellular calcium stores with caffeine confirmed calcium as another crucial messenger altering the PTV after the application of cafedrine/theodrenaline. Discussion: Cafedrine/theodrenaline, cafedrine alone, and theodrenaline alone exert their effects via IP3 receptor-associated calcium release that is ultimately triggered by ß1-adrenergic receptor stimulation. Synergistic effects at the ß1-adrenergic receptor are highly relevant to alter the PTV of the respiratory epithelium at clinically relevant concentrations. Further investigations are needed to assess the value of cafedrine/theodrenaline-mediated alterations in mucociliary function in clinical practice.

Assessing motile cilia coverage and beat frequency in mammalian in vitro cell culture tissues.

Cilia density, distribution and beating frequency are important properties of airway epithelial tissues. These parameters are critical in diagnosing primary ciliary dyskinesia and examining in vitro models, including those derived from induced pluripotent stem cells. Video microscopy can be used to characterize these parameters, but most tools available at the moment are limited in the type of information they can provide, usually only describing the ciliary beat frequency of very small areas, while requiring human intervention and training for their use. We propose a novel and open-source method to fully characterize cilia beating frequency and motile cilia coverage in an automated fashion without user intervention. We demonstrate the ability to differentiate between different coverage densities, identifying even small patches of cilia in a larger field of view, and to fully characterize the cilia beating frequency of all moving areas. We also show that the method can be used to combine multiple fields of view to better describe a sample without relying on small pre-selected regions of interest. This is released with a simple graphical user interface for file handling, enabling a full analysis of individual fields of view in a few minutes on a typical personal computer.

The Cilialyzer - A freely available open-source software for the analysis of mucociliary activity in respiratory cells.

BACKGROUND AND OBJECTIVE: Primary ciliary dyskinesia (PCD) is a rare genetic disorder causing a defective ciliary structure, which predominantly leads to an impaired mucociliary clearance and associated airway disease. As there is currently no single diagnostic gold standard test, PCD is diagnosed by a combination of several methods comprising genetic testing and the examination of the ciliary structure and function. Among the approved diagnostic methods, only high-speed video microscopy (HSVM) allows to directly observe the ciliary motion and therefore, to directly assess ciliary function. In the present work, we present our recently developed freely available open-source software - termed "Cilialyzer", which has been specifically designed to support and facilitate the analysis of the mucociliary activity in respiratory epithelial cells captured by high-speed video microscopy. METHODS: In its current state, the Cilialyzer software enables clinical PCD analysts to load, preprocess and replay recorded image sequences as well as videos with a feature-rich replaying module facilitating the commonly performed qualitative visual assessment of ciliary function (including the assessment of the ciliary beat pattern). The image processing methods made accessible through an intuitive user interface allow clinical specialists to comfortably compute the ciliary beating frequency (CBF), the activity map and the "frequency correlation length" - an observable getting newly introduced. Furthermore, the Cilialyzer contains a simple-to-use particle tracking interface to determine the mucociliary transport speed. RESULTS: Cilialyzer is fully written in the Python programming language and freely available under the terms of the MIT license. The proper functioning of the computational analysis methods constituting the Cilialyzer software is demonstrated by using simulated and representative sample data from clinical practice. Additionally, the software was used to analyze high-speed videos showing samples obtained from healthy controls and genetically confirmed PCD cases (DNAI1 and DNAH11 mutations) to show its clinical applicability. CONCLUSIONS: Cilialyzer serves as a useful clinical tool for PCD analysts and provides new quantitative information awaiting to be clinically evaluated using cohorts of PCD. As Cilialyzer is freely available under the terms of a permissive open-source license, it serves as a ground frame for further development of computational methods aiming at the quantification and automation of the analysis of mucociliary activity captured by HSVM.

Does the Sound of a Singing Bowl Synchronize Meditational Brainwaves in the Listeners?

This study aims to verify if the beating sound of a singing bowl synchronizes and activates brain waves during listening. The singing bowl used in this experiment produce beats at a frequency of 6.68 Hz, while it decays exponentially and lasts for about 50 s. Brain waves were measured for 5 min in the F3 and F4 regions of seventeen participants (eight males and nine females, average age 25.2) who heard the beating singing bowl sounds. The experimental results showed that the increases (up to ~251%) in the spectral magnitudes of the brain waves were dominant at the beat frequency compared to those of any other clinical brain wave frequency bands. The observed synchronized activation of the brain waves at the beating sound frequency supports that the singing bowl sound may effectively facilitate meditation and relaxation, considering that the beat frequency belongs to the theta wave region which increases in the relaxed meditation state.

Comparing Cytology Brushes for Optimal Human Nasal Epithelial Cell Collection: Implications for Airway Disease Diagnosis and Research.

Primary nasal epithelial cells and culture models are used as important diagnostic, research and drug development tools for several airway diseases. Various instruments have been used for the collection of human nasal epithelial (HNE) cells but no global consensus yet exists regarding the optimal tool. This study compares the efficiency of two cytology brushes (Olympus (2 mm diameter) and Endoscan (8 mm diameter)) in collecting HNE cells. The study involved two phases, with phase one comparing the yield, morphology and cilia beat frequency (CBF) of cells collected from paediatric participants using each of the two brushes. Phase two compared nasal brushing under general anaesthetic and in the awake state, across a wide age range, via the retrospective audit of the use of the Endoscan brush in 145 participants. Results indicated no significant difference in CBF measurements between the two brushes, suggesting that the choice of brush does not compromise diagnostic accuracy. However, the Endoscan brush collected significantly more total and live cells than the Olympus brush, making it a more efficient option. Importantly, the Endoscan brush is more cost-effective, with a notable price difference between the two brushes.

Resource Allocation in the Noise-Free Striatal Beat Frequency Model of Interval Timing.

The Striatal Beat Frequency (SBF) model of interval timing uses many neural oscillators, presumably located in the frontal cortex (FC), to produce beats at a specific criterion time Tc. The coincidence detection produces the beats in the basal ganglia spiny neurons by comparing the current state of the FC neural oscillators against the long-term memory values stored at reinforcement time Tc. The neurobiologically realistic SBF model has been previously used for producing precise and scalar timing in the presence of noise. Here we simplified the SBF model to gain insight into the problem of resource allocation in interval timing networks. Specifically, we used a noise-free SBF model to explore the lower limits of the number of neural oscillators required for producing accurate timing. Using abstract sine-wave neural oscillators in the SBF-sin model, we found that the lower limit of the number of oscillators needed is proportional to the criterion time Tc and the frequency span (fmax - fmin) of the FC neural oscillators. Using biophysically realistic Morris-Lecar model neurons in the SBF-ML model, the lower bound increased by one to two orders of magnitude compared to the SBF-sin model.

Multiplexed optical fiber cell temperature sensing system with high sensitivity and accuracy.

Significance: A multiplexed fiber laser sensing system for cell temperature is proposed. To the best of the authors' knowledge, this is the first multilongitudinal mode (MLM) optical fiber laser sensor array designed for cell temperature sensing. Aim: A two-channel cell temperature sensing system with high sensitivity and real-time sensing capability is achieved. The temperature change of human hepatoellular carcinomas (HepG2) cells under the influence of exogenous chemical aflatoxin B1 (AFB1) can be monitored in real time. Approach: A fiber laser cavity consists of a pair of fiber Bragg gratings (FBGs) with matched central wavelengths and a piece of erbium-doped fiber (EDF). The static FBG is utilized for design of fiber laser cavity and laser modes selection. In comparison, the sensing FBG is used for cell temperature sensing. The sensing FBG has a length of 10 mm and a diameter of 200 µ m . Beat frequency signals (BFS) are generated by MLM lasers after optical-to-electrical conversion at a photodetector. Frequency change of a BFS is closely related to the reflected wavelength change of the sensing FBG. Through frequency division multiplexing, two fiber laser cavities are designed in the sensing system for two-channel temperature sensing. Frequency shift of a BFS that represents temperature change of cells can be automatically recorded in seconds. Results: A two-channel cell temperature sensing system is designed with high sensitivities of 101.62 and 119.82 kHz / ° C , respectively. The temperature change of HepG2 cells under the influence of exogenous chemical AFB1 is monitored in real time. Conclusions: The proposed system has the advantages of simple structure, high sensitivity, and two-channel sensing capability. Our study provides a simple and effective method to design a fiber laser sensor system without complex demodulation techniques and expensive optical components.

Impact of Bepanthen® and dexpanthenol on human nasal ciliary beat frequency in vitro.

BACKGROUND: Dexpanthenol-containing ointments/fluids are recommended to restore impaired nasal mucosa. To date, there are no data about the influence of dexpanthenol or formulations including dexpanthenol on ciliary beat frequency (CBF) of nasal epithelial cells. METHODS: We tested the ciliary beat frequency of human nasal epithelial cells in RPMI 1640 cell solution using in vitro high-frequency video microscopy every 60 s over a period of 15 min (min). Bepanthen® solution and dexpanthenol in two clinically relevant concentrations (1.67% and 3.33%) were added to the cells. Addition of sterile water served as control group. To get a better overview, the measurements after 1 min, 5 min and 15 min were combined. RESULTS: The CBF in the control group (n = 17) after 15 min was 7.3 ± 2.6 Hz. In comparison, the CBF after 15 min was 1.8 ± 1.0 Hz in the 3.33% Bepanthen® group (n = 17) and 3.2 ± 1.2 Hz in the 1.67% group, which was statistically significantly lower in both groups (p < 0.001). With regard to the dexpanthenol group (n = 17) a CBF of 6.0 ± 2.6 Hz with 3.33% and 6.1 ± 2.4 Hz with 1.67% dexpanthenol, was detected, which was again statistically significantly lower (p = 0.06) compared to the control group except CBF at 15 min with 1.57% (n = 17; p = 0.04). In general, the effect on CBF was less pronounced with dexpanthenol compared with Bepanthen® with a statistically significant difference between the two formulations. The results were verified by calculating an analysis of variance (ANOVA). CONCLUSIONS: Bepanthen® as an ointment, solution or inhalation is commonly used in ENT for mucosal care. Our results have shown that both substances reduce CBF in clinically relevant concentrations, although the effect was more pronounced with Bepanthen® compared to dexpanthenol solution, which could be related to additives or change of physical properties in the solution. Further research is needed to assess potential clinical relevance.

Femtosecond Time-Resolved Observation of Relaxation and Wave Packet Dynamics of the S1 State in Electronically Excited o-Fluoroaniline.

Quantum beat frequency is the basis for understanding interference effects and vibrational wave packet dynamics and has important applications. Using femtosecond time-resolved mass spectrometry and femtosecond time-resolved photoelectron image combined with theoretical calculations, we study the electronic excited-state relaxation of o-fluoraniline molecule and the time-dependent evolution of vibrational wave packets between different eigenstates. After the molecule absorbs a photon of 288.3 nm and is excited to the S1 state, intramolecular vibrational redistribution first occurs on the time scale τ1 = 349 fs, and then the transition to the triplet state occurs through the intersystem crossing on the time scale τ2 = 583 ps, and finally, the triplet state occurs decays slowly through the time scale τ3 = 2074 ps. We find the intramolecular vibrational redistribution is caused by the 00, 10b1 and 16a1 vibrational modes of the Sl state origin. That is, the 288.3 nm femtosecond laser excites the molecule to the S1 state, and the continuous flow of the vibrational wave packet prepares a coherent superposition state of three vibrational modes. Through extracting the oscillation of different peak intensities in the photoelectron spectrum, we observe reversible changes caused by mutual interference of the S1 00, S1 10b1 and S1 16a1 states when the wave packets flow. When the pump pulse is 280 nm, the beat frequency disappears completely. This is explained in terms of increases in the vibrational field density and characteristic period of oscillation, and statistical averaging makes the quantum effect smooth and indistinguishable. In addition, the Rydberg component of the S1 state is more clearly resolved by combining experiment and theory.

Ciliated epithelia are key elements in the recruitment of bacterial partners in the squid-vibrio symbiosis.

The Hawaiian bobtail squid, Euprymna scolopes, harvests its luminous symbiont, Vibrio fischeri, from the surrounding seawater within hours of hatching. During embryogenesis, the host animal develops a nascent light organ with ciliated fields on each lateral surface. We hypothesized that these fields function to increase the efficiency of symbiont colonization of host tissues. Within minutes of hatching from the egg, the host's ciliated fields shed copious amounts of mucus in a non-specific response to bacterial surface molecules, specifically peptidoglycan (PGN), from the bacterioplankton in the surrounding seawater. Experimental manipulation of the system provided evidence that nitric oxide in the mucus drives an increase in ciliary beat frequency (CBF), and exposure to even small numbers of V. fischeri cells for short periods resulted in an additional increase in CBF. These results indicate that the light-organ ciliated fields respond specifically, sensitively, and rapidly, to the presence of nonspecific PGN as well as symbiont cells in the ambient seawater. Notably, the study provides the first evidence that this induction of an increase in CBF occurs as part of a thus far undiscovered initial phase in colonization of the squid host by its symbiont, i.e., host recognition of V. fischeri cues in the environment within minutes. Using a biophysics-based mathematical analysis, we showed that this rapid induction of increased CBF, while accelerating bacterial advection, is unlikely to be signaled by V. fischeri cells interacting directly with the organ surface. These overall changes in CBF were shown to significantly impact the efficiency of V. fischeri colonization of the host organ. Further, once V. fischeri has fully colonized the host tissues, i.e., about 12-24 h after initial host-symbiont interactions, the symbionts drove an attenuation of mucus shedding from the ciliated fields, concomitant with an attenuation of the CBF. Taken together, these findings offer a window into the very first interactions of ciliated surfaces with their coevolved microbial partners.