Breathing Process Research Articles

The Contribution of Adsorbent Materials (Silica Gel and Sawdust) in Removing Water Vapor; Iraq as a Study Case

This research aims to remove the moisture (latent load) generated by the occupants of the space due to the addition of water vapor resulting from the natural breathing process, the perspiration that evaporates in the air of the space. In sum, the dehumidification system (DS) reduces the amount of latent load or removes it completely to reduce the load on the air conditioner. In this study, adsorbent materials, such as silica gel-Blue and sawdust were used and their effectiveness was compared when used in dehumidification. The results of these experiments for June showed that the adsorption rate and temperature of the blue silica gel - Blue were 20% and 34°C, while the humidity and temperature increased to 52% and 36°C when using sawdust (when rotating the dehumidifying system hourly). Moreover, for July, the adsorption percentages of silica gel-Blue were 8%, while the moisture content of sawdust increased to 49%, while the adsorption percentage in August when using silica gel - Blue was 10% and the relative humidity increased until it reached 39% when using sawdust. While the temperatures in July and August reached their maximum value when using silica gel - Blue and sawdust at 35°C and 36°C, respectively. The water vapor absorption rate in June, July, and August is 83.39 g, 70.82 g, and 65 g, respectively. While the drying process increased during these months due to the increase in solar radiation. Therefore, silica gel - Blue has proven its effectiveness by absorbing moisture more efficiently than sawdust. However, when drying sawdust, it was more effective and faster drying than silica gel - Blue.

Influence of Morphological Parameters on the Flow Development within Human Airways

Anatomical airways parameters, such as length, diameter and angles, have a strong effect on the flow dynamics. Aiming to explore the effect of variations of the bifurcation angle (BA) and carina rounding radius (CRR) of lower human airways on respiratory processes, numerical simulations of airflow during inhalation and exhalation were performed using synthetic bifurcation models. Geometries for the airways models were parameterized based on a set of different BA’s and several CRR’s. A range of Reynolds numbers (Re), relevant to the human breathing process, were selected to analyze airflow behavior. The numerical results showed a significant influence of BA and the CRR on the development of the airflow within the airways, and, therefore, affecting the following relevant features of the flow: the deformation of velocity profiles, alterations of pressure drop, flow patterns, and, finally, enhancement or attenuation of wall shear stresses (WSS) appearing during the regular respiratory process. The numerical results showed that increases in the bifurcation angle value were accompanied by pressure increases of about 20%, especially in the regions close to the bifurcation. Similarly, increases in the BA value led to a reduction in peak shear stresses of up to 70%. For the ranges of angles and radii explored, an increase in pressure of about 20% and a reduction in wall shear stress of more than 400% were obtained by increasing the carina rounding radius. Analysis of the coherent structures and secondary flow patterns also revealed a direct relationship between the location of the vortical structures, the local maxima of the velocity profiles and the local vorticity minima. This relationship was observed for all branches analyzed, for both the inhalation and exhalation processes of the respiratory cycle.

Constant Force-Tracking Control Based on Deep Reinforcement Learning in Dynamic Auscultation Environment.

Intelligent medical robots can effectively help doctors carry out a series of medical diagnoses and auxiliary treatments and alleviate the current shortage of social personnel. Therefore, this paper investigates how to use deep reinforcement learning to solve dynamic medical auscultation tasks. We propose a constant force-tracking control method for dynamic environments and a modeling method that satisfies physical characteristics to simulate the dynamic breathing process and design an optimal reward function for the task of achieving efficient learning of the control strategy. We have carried out a large number of simulation experiments, and the error between the tracking of normal force and expected force is basically within ±0.5 N. The control strategy is tested in a real environment. The preliminary results show that the control strategy performs well in the constant force-tracking of medical auscultation tasks. The contact force is always within a safe and stable range, and the average contact force is about 5.2 N.

Application of the human organism adaptation model to extreme environmental conditions for scientific support of the health protection system of military servants

The NATO Medical Doctrine emphasizes the need to use scientific support to create a modern system of medical support for the health of military personnel. When considering various aspects of joint operations, it is emphasized that extreme environmental conditions are taken into account, as well the features of the complex technical conditions of life of the military contingent. The issue of professional selection is also important. To solve these problems, it is proposed to use mathematical modeling, in particular mathematical models of transport and mass exchange of respiratory gases, self-organization of the respiratory system and blood circulation, and urgent adaptation of the human body to extreme environmental conditions. A mathematical model of the functional breathing system of continuous interaction system operators is provided, which can include pilots and drivers of land, water and underwater transport. To study the influence of environmental temperature factors, the given model is proposed to be used in interaction with the thermoregulation model. In these models, the breathing process is considered as a controlled dynamic system, in which the executive organs of self-regulation direct their efforts to maintaining a state of equilibrium with oxygen and carbon dioxide tensions at a given level of disturbing influences on the body. Analysis of these models allows establishing the main regularities of the course of the breathing process, the role of regulatory mechanisms in providing and maintaining the main function of the respiratory system under the most diverse conditions of human life, to establish the most important properties of the studied process. Mathematical models of adaptation make it possible to predict the stationary state of the organism at a given level of disturbing influences and thus manage the process of training and preparation of military personnel and contingent selection for carrying out certain operations.

Rapid Preparation of Novel Ionic Polymer-Metal Composite for Improving Humidity Sensing Effect.

Ionic polymer-metal composites (IPMCs) have attracted attention in recent years due to their integration of actuation and sensing functions. As one of the main sensing functions of IPMCs, humidity sensing has been of consistent interest in wearable health monitors and artificial skin. However, there are still some technical challenges in that classical IPMCs have poor humidity sensing performance due to their dense surface electrode, and IPMCs are damaged easily due to an electrode/membrane mismatch. In this work, through the spraying and electrodepositing process, we developed an efficient method to rapidly prepare a Au-shell-Ag-NW (silver nanowire)-based IPMC with high strength, low surface resistance and excellent humidity sensing performance. Meanwhile, we optimized the preparation method by clarifying the influence of solvent type and electrodepositing time on the performance of the Au-shell-Ag-NW-based IPMC, thus effectively improving the humidity sensing effect and strength of the IPMC. Compared with previous research, the humidity electrical response (~9.6 mV) of the Au-shell-Ag-NW-based IPMC is at least two orders of magnitude higher than that of the classical IPMC (~0.41 mV), which is mainly attributed to the sparse gap structure for promoting the exchange of water molecules in the environment and Nafion membrane, a low surface resistance (~3.4 Ohm/sq) for transmitting the signal, and a seamless connection between the electrode and Nafion membrane for fully collecting the ion charges in the Nafion membrane. Additionally, the Au-shell-Ag-NW-based IPMC could effectively monitor the human breathing process, and the humidity sensing performance did not change after being exposed to the air for 4 weeks, which further indicates that the Au-shell-Ag-NW-based IPMC has good application potential due to its efficient preparation technology, high stability and good reproducibility.

A novel method for conformity assessment testing of mechanical ventilators for post-market surveillance purposes.

Mechanical ventilators are medical devices used in intensive care units when patients are in need of mechanical aid to facilitate the process of breathing. As the function of breathing is the exchange of gases, the mechanical ventilator takes over that function while the patient is incapable to spontaneous breathing. As these devices are used to maintain the life of patents, their performance must be ensured and there cannot be significant deviations in the volumes and pressure of gases they introduce to the patient. The new Medical Device Regulation (MDR) defines medical device post-market surveillance (PMS) as performed by independent, third-party, notified bodies more strategically in hope to improve traceability of device performance. However, there is still an apparent gap in terms of standardised conformity assessment testing methods. This paper proposes a novel method for conformity assessment testing of mechanical ventilators for post-market surveillance purposes. The method was developed on the basis of metrology characteristics of mechanical ventilators and evaluation of their vital safety and performance parameters. In addition to the evaluation of essential safety and visual integrity of mechanical ventilators, their performance in terms of volume of oxygen delivered to the patient as well as the flow and pressure of the delivered gas is evaluated. The developed method was validated between 2018 and 2021 in healthcare institutions of all levels. The results obtained during validation suggest that conformity assessment testing of mechanical ventilators as a method used during PMS contributes to significant improvement in devices' accuracy and reliability. A standardized approach in conformity assessment testing of mechanical ventilators during PMS, besides increasing reliability of the devices, is the first step in digital transformation of management of these devices in healthcare institutions opening possibility for use of artificial intelligence.

In-Fiber Breathing Monitoring Sensor by Micro-Tapered Long-Period Grating Structure

A simple in-fiber breathing monitoring sensor based on a micro-tapered long-period fiber grating (MT-LPFG) structure was proposed and demonstrated. The MT-LPFG structure was manufactured through the periodical tapering of an optical fiber utilizing a CO2 laser fusion splicer. Without the use of a humidity sensitive film, the MT-LPFG structure can directly and dynamically monitoring relative humidity with a fast response, based on which, the breathing process can be monitored in real time through the monitoring of its transmission affected by the humidity. Experiments show that breathing rate and breathing status during respiration were successfully monitored by placing the sensor structure nearby the nose in a breathing mask. A rise time of 0.237 s and a fall time of 0.299 s were realized in the breathing process monitoring. For its advantages of simple fabrication, miniature size, and fast response, the proposed sensor may found applications in visual observation of the patient’s breathing condition.

Accelerometer based system for unobtrusive sleep apnea detection

Sleep is an essential part of human existence, as we are in this state for approximately a third of our lives. Sleep disorders are common conditions that can affect many aspects of life. Sleep disorders are diagnosed in special laboratories with a polysomnography system, a costly procedure requiring much effort for the patient. Several systems have been proposed to address this situation, including performing the examination and analysis at the patient's home, using sensors to detect physiological signals automatically analysed by algorithms. This work aims to evaluate the use of a contactless respiratory recording system based on an accelerometer sensor in sleep apnea detection. For this purpose, an installation mounted under the bed mattress records the oscillations caused by the chest movements during the breathing process. The presented processing algorithm performs filtering of the obtained signals and determines the apnea events presence. The performance of the developed system and algorithm of apnea event detection (average values of accuracy, specificity and sensitivity are 94.6%, 95.3%, and 93.7% respectively) confirms the suitability of the proposed method and system for further ambulatory and in-home use.

OPTIMAL DETECTION OF SIGNALS SEQUENTIALLY MODULATED BY PSEUDO NOISE IN RADAR FOR RESCUERS

Searching for living people under the rubble of buildings collapsed due to man-made or natural disasters, special radars play an important role, which allow you to see a living person behind optically opaque obstacles. The information sign of a living person in the reflected signal is the Doppler modulation of the signal phase, due to the processes of breathing and heartbeats. This phase modulation has an ultralow frequency and can be effectively detected using long pseudo-noise probing signals, for example, based on Mersenne codes. To reduce inter-symbol interference in the code sequence, a linear correlation receiver is built. Its signal processing algorithm is based on all received patterns observed during a fixed interval. The decision in favor of the first character in the chosen code combination is made under the assumption of ideal feedback, which provides almost the maximum error probability characteristics in systems with a serial Mersenne code.

Design of a multilayer lung chip with multigenerational alveolar ducts to investigate the inhaled particle deposition.

We present the development and application of a multilayer microfluidic lung chip designed to accurately replicate the human respiratory bronchi, providing an innovative platform for controlled particle deposition in the lung. By employing a quantitative control method of fluid velocity through the deformation of an elastic PDMS membrane, this platform mimics the passive breathing process in humans and allows for precise simulation of the respiration cycle. We utilized time-lapse photography of fluorescent particles in a water/glycerol solution to qualitatively observe fluid morphology in the channel, while a chip-aerosol exposure device combined with microscopy imaging was employed to visualise aerosol deposition. Both experimental and numerical simulation results showed that particle concentration decreased towards the distal generations of the lung, and that changes in breathing pattern significantly affected particle deposition trends. Furthermore, we found that increasing the residence time of particles in the channel facilitated deeper particle deposition, achievable by adjusting parameters such as breath-hold time, exhalation time, respiration cycle length, and tidal volume. The proposed microfluidic lung chip device has significant potential for future research in respiratory health and inhaled drug delivery, providing an efficient, cost-effective, and ethical alternative to traditional in vivo studies.

Transformer Internal and Inrush Current Fault Detection Using Machine Learning

Preventive maintenance in the transformer is performed through a differential relay protection system, and it protects the transformer from internal and external faults. However, the Current Transformer (CT) in the differential protection system mal-operates during inrush currents. CT saturates due to magnetizing inrush currents and causes false tripping of the differential relays. Moreover, identification of tripping in protection relay either due to inrush current or internal faults needs to be diagnosed. For the above problem, continuous monitoring of transformer breather and CT terminals with thermal camera helps detect the tripping in relay due to inrush or internal fault. The transformer’s internal fault leads to high breathing process in the transformer breather, never for inrush currents. During inrush currents, CT temperature is increased. Continuous monitoring of breather and CT of the transformer through thermal imaging and radiometric pixels detect the causes of CT saturation and differentiates maloperation. Hybrid wavelet threshold image analytics (HWT-IA) based radiometric pixels analysis of the transformer breather and CT after de-noising provides an accurate result of about 95% for identification of the false tripping of differential protection system of transformer.

Numerical simulation of social distancing of preventing airborne transmission in open space with lateral wind direction, taking into account temperature of human body and floor surface.

This paper presents the numerical results of particle propagation in open space, taking into account the temperature of the human body and the surface of the ground. And also, the settling of particles or droplets under the action of gravitational force and transport in the open air is taken into account, taking into account the temperature during the process of breathing and sneezing or coughing. The temperature of the body and the surface of the ground, different rates of particle emission from the mouth, such as breathing and coughing or sneezing, are numerically investigated. The effect of temperature, cross-inlet wind, and the velocity of particle ejection from a person's mouth on social distancing is being investigated using a numerical calculation. The variable temperature of the human body forms a thermal plume, which affects the increase in the trajectory of the particle propagation, taking into account the lateral air flow. The thermal plume affects the particles in the breathing zone and spreads the particles over long distances in the direction of the airflow. The result of this work shows that in open space, taking into account the temperature of the body and the surface of the ground, a 2-m social distance may be insufficient for the process of sneezing and social distance must be observed depending on the breathing mode.

Physicochemical evaluation of the acellular tracheal graft for tissue remodeling

In a biological system, the airway system upper respiratory tract, or trachea connects the nostrils and lungs, to help in breathing process and trapping dust and pathogen particles. Clinically, to overcome the tracheal defects and dsyfunctioning different type of artificial prosthetics, stents, and grafts are used to reconstruct tracheal tissue at the injured tissue. Decellularized tissue fabricated from xenogeneic and allogeneic tissue are Extracellular matrix (ECM) protein rich, biocompatible, 3D biomimetic grafts having potential mechanical stability for better tissue regeneration. Acellular tracheal graft fabricated from the cadaver goat-tracheal tissue have 3D interconnected porous structure with good mechanical stability upto 18 MPa measured by UTM, stability and control degradability rate. Biochemical analysis by the FTIR spectra analysis and assays confirmed the presence of stable collagenous protein triple helix structure with retained majority of the ECM (extra cellular matrix) molecules (collagen, proteoglycans, elastin and GAGs) without any significant loss, bio-degradability, and physiochemical stability.

A CASE REPORT ON: MANAGEMENT AND COMPLICATION OF HANGING

Background: The process of breathing, or the exchange of air between the atmosphere and the lungs' alveoli, is impaired in cases of hanging by a neck rope, which results in asphyxia and death. Main symptoms and important findings: A 27-year-old male was admitted to a rural hospital with complaints of hanging from a fan at home after a fight with his wife, with unconscious state, and one episode of seizure associated with up rolling off the eyeball, frothing from the mouth, and tonic-clonic movement. There was previous deliberate self-harm. Given low GCS, the patient was immediately intubated with ET TUBE 7.5 and taken on mechanical ventilation on volume control mode with peep 5, RR 16, Spo2 100%, TV 360 ml. rapid antigen test was done which came out to be negative and ECG done and show sign of tachycardia. Chest and spine X-RAY was done. CT brain done and the finding was normal. EEG was done and show the finding was beta activity and no epileptiform changes. An orthopedic physician's opinion was taken and to continue Philadelphia collar for 4 weeks was advised. The main diagnosis, therapeutic interventions, and outcomes: After a physical examination and investigations doctor diagnosed a case of hanging with depression. Medical management was provided with Inj. Ceftriaxone 1 gm intravenous twice a day for 9 days, Inj. Pan 40 mg intravenous once a day, Inj. Emset 4 mg three times a day, Inj. Levipril 500 mg twice a day, Inj. Dexa 6 mg once a day for 5 days, Nebulization With Duolin And Budecort three times a day, intravenous fluids given. Now his outcomes were good. His complications were reduced. Conclusion: Hanging is a complicated case and produces more complications but early diagnosis management can secure the life of a patient and reduce the complication of hanging.

Nonlinear vibration analysis of beam-like bridges with multiple breathing cracks under moving vehicle load

The beam-like bridges with small and medium spans are designed to mainly sustain the moving vehicle. Hence, the dynamic behavior of bridges under vehicular loading can provide important information for the bridge design, assessment, and maintenance. Cracks, as one of the most common damage in the bridge structures, alter the bridge dynamic characteristics and therefore responses to the moving vehicle. This paper proposes a novel semi-analytical approach for nonlinear vibration analysis of the beam-like bridges with breathing cracks subjected to vehicular loading, taking into account the dynamic interactions between the vehicle and cracked bridge. The Dirac’s delta function is utilized to represent the local stiffness change at the crack location, leading to closed-form solutions of mode shapes of the cracked beam. The breathing process of the crack, causing eigenproperties of the beam to change over time, is characterized by the time-varying curvature of the bridge. Subsequently, the nonlinear dynamic equation of the vehicle-cracked bridge interaction system is established, which is solved through a formulated double-iterative numerical scheme. Eigenvalues and dynamic responses of the bridge with open crack presented in the literature are compared with those obtained from the proposed approach for purposes of validation. The effects of various crack parameters, vehicle speed, and bridge surface irregularity are investigated through a parametric study. In addition, the detection of breathing cracks is also discussed. The results show that the proposed approach can be used to effectively obtain the nonlinear vibration characteristics and dynamic responses of the beam-like bridge with general boundary conditions and different crack numbers, locations, depths, and initial status under moving vehicle. Moreover, the approach has the potential to be incorporated into the vibration-based bridge damage detection.

Role of physical therapy in post-coronavirus syndrome

The aim of this study was to describe the current official guidelines issued by the World Federation of Physiotherapy and Physiotherapy Societies in various countries. It was also aimed to define the recommended procedures for respiratory rehabilitation and physical therapy for Coronavirus Disease 2019 patients (COVID-19). A pilot study was carried out for certain cases that were infected with the Corona virus within the city of Waleed -Libya in the period between October 2020 to March 2021. A physiotherapy treatment was carried involving 15 cases over a 7-day period. During the first several days of treatment, there was no much difference in the readings. However, within a few days, cases began to improve, indicating a positive response to physical therapy. On the last day of the tasks, the respiratory rate was recorded on a device (Spirometer) at the beginning of the session with 92.6 and at the end of the session with 94.6, and the numbers increased significantly, and there was a noticeable improvement in the breathing process and the almost complete removal of cough and congestion.

Application of whole body plethysmography for assessment of pulmonary function in patients with asthma and obesity

The incidence of asthma and obesity is constantly increasing. It is commonly acknowledged that obesity can make asthma more severe and poorly controlled. Conventional spirometry, despite of being a “gold standard” in diagnostics of lung diseases, cannot provide information on residual lung volume and bronchial resistance, which can be a key to understanding the mechanics of spirometric deviations found in asthma-obesity phenotype.The aim. To evaluate pulmonary function in patients with asthma and obesity by non-invasive and safe clinical method – body plethysmography.Methods. 46 women with asthma were enrolled into the study, of which 21 were obese and 25 had normal body weight. 18 women with obesity and 20 women with normal body weight were selected as controls. All the patients were postmenopausal. Body plethysmography was performed with MasterScreen Body device, CareFusion, Germany.Results. Asthma is associated with a decrease in forced vital lung capacity and an increase in residual volume. Also, Gensler index and peak expiration flows at 25, 50, and 75% expiration were decreased. Interestingly, specific effective resistance in patients with asthma without obesity was 30 – 40% higher than in the control group. In patients with asthma and obesity, specific effective resistance was 2,5 times higher than in the control group. Residual volume and bronchial resistance were found to have a strong positive correlation.Conclusion. despite of similar spirometric changes, only asthma in obesity was marked by an increase of specific bronchial resistance. This finding can be related to higher energy load of breathing process in obese asthma.

Effect of the Buteyko breathing technique on asthma severity control among school age children

BackgroundAsthma is a complex condition that can impair not only the child’s physical growth but also his optimal functional capacity and performance. Buteyko breathing technique is an exercise designed to regulate the breathing process. This study aimed to evaluate the effect of the Buteyko breathing technique on asthma severity control among school-age children. In Egypt, this technique was applied through five studies, four among adult patients and only one among children. In Mansoura University, only one study conducted among adult patients and no studies conducted among children. Therefore, to fulfill this gap of knowledge, it was necessary to study the effect of this technique on asthma severity control among school age children.ResultsThe mean childhood asthma control pretest was significantly improved in the posttest with high mean percent change of posttest than pretest (p = 0.0001), which was clinically and statically high significant. There was a statistical significant increase in the mean of peak expiratory flow rate and control pause test at the fourth week than the first one (p = 0.0001), with a high significant mean percent of change. There was a significant decrease in the heart rate over the 4 weeks of follow-up with high mean percent changes at fourth week than the first one (p = 0.003).ConclusionsThis study supports the effectiveness of the Buteyko breathing technique in improving respiratory outcome and promoting asthma control among school-age children with bronchial asthma.Trial registrationClinicalTrials.gov, NCT05390554, registered on May 24 2022, retrospectively registered.

Detecting Respiratory Rate Using Flexible Multimaterial Fiber Electrodes Designed for a Wearable Garment

Smart sensors embedded into wearables and capable of monitoring vital signs have become an important research topic and the technology of interest for numerous commercial ventures. Monitoring respiratory rate is challenging due to the complexity and uniqueness of the musculoskeletal movements involved in the breathing process. At the same time, it is a critical factor in assessing patient health. Multi-material fibers exhibit the potential to be inter-woven into a textile and used in a wearable garment to measure respiration rate. This study compares the effectiveness of two types of flexible multi-material fibers, namely the polyethylene-co-vinyl acetate (PEVA) fiber and the polydimethylsiloxane elastomer (PDMS) fiber, in detecting respiratory rate using two principles, the Fiber Strain method and the Bioimpedance method. The study involved five experiments where ten volunteers’ respiratory rate was measured under different conditions: deep breathing, holding breath, deep breathing with exercise, relaxed breathing, and deep breathing with the fibers mounted onto a wearable. Overall, the PDMS fiber outperformed the PEVA fiber in detecting the breathing rate by providing better accuracy, greater signal to noise ratio (SNR), and more versatility. Although some studies have previously described the successful use of multi-material fibers in monitoring vital signs, e.g., electromyography, no reported research could be identified that examined the use of these multi-material fibers for respiratory rate measurement.

Characterization and size distribution of initial droplet concentration discharged from human breathing and speaking

A study of the aerodynamic characteristics of aerosol expiration is important for understanding the size distribution of droplet concentration in COVID-19 disease transmission. This study measured the initial concentration and size distribution of droplets released during four breathing processes: nose breathing, mouth breathing, reading alphabets and counting numbers. Influencing factors on droplet generation were studied by statistical analyses. Significant differences in droplet concentration among the four breathing activities in pairs were found ( p < 0.001), except for reading alphabets and numbers ( p = 1). The droplet concentration during nose breathing ( p < 0.05), but not mouth breathing ( p = 0.136), of male subjects, was found significantly higher than that of female subjects. The droplet concentration generated by speaking during letters reading with special phonemes, for example, /i:/, was significantly ( p < 0.05) higher than reading letters without phonemes. The discharged droplet sizes from four breathing activities were dominated by small droplets ( dp < 1.037 μm of over 50% and dp < 2.642 μm of over 80%). Basically, no particles larger than 8 μm were detected by the aerodynamic particle sizer. The inference indicates a possible aerosol transmission of disease during non-symptomatic aerosol-producing activities such as breathing or speaking and may elucidate the disease transmission pathway of COVID-19.