Breathing Behavior Research Articles

Structural Insight of MOFs under Combined Mechanical and Adsorption Stimuli.

External control over the pore size of flexible metal-organic frameworks (MOFs) has recently emerged as an intriguing concept, with possible applications to gas storage and separation. In this work we present a new pressure cell capable for the first time of monitoring through in situ X-ray powder diffraction an adsorbent powder under combined uniaxial applied mechanical stress (up to 1 GPa) and gas pressure (up to 20 bar). The combined stress-pressure clamp (CSPC) cell was successfully exploited to follow the evolution of the CO2 breathing behaviour of the prototypical complex breathing MIL-53(Al) system under mechanical compression obtaining structural evidence that this MOF can be maintained in its closed pore state upon compression, precluding its re-opening at high gas pressure (>7 bar). This novel setup shows potential for the in-operando exploration of flexible systems, in equilibrium and flow configurations.

Structural Insight of MOFs under Combined Mechanical and Adsorption Stimuli

AbstractExternal control over the pore size of flexible metal–organic frameworks (MOFs) has recently emerged as an intriguing concept, with possible applications to gas storage and separation. In this work we present a new pressure cell capable for the first time of monitoring through in situ X‐ray powder diffraction an adsorbent powder under combined uniaxial applied mechanical stress (up to 1 GPa) and gas pressure (up to 20 bar). The combined stress–pressure clamp (CSPC) cell was successfully exploited to follow the evolution of the CO2 breathing behaviour of the prototypical complex breathing MIL‐53(Al) system under mechanical compression obtaining structural evidence that this MOF can be maintained in its closed pore state upon compression, precluding its re‐opening at high gas pressure (>7 bar). This novel setup shows potential for the in‐operando exploration of flexible systems, in equilibrium and flow configurations.

Active crack control approach applied to a horizontal rotating machine

The present contribution proposes an active vibration control technique devoted to shafts with cracks aiming to minimize their propagation. The existence of a crack in rotating shafts can be characterized by 2X and 3X super-harmonic amplitudes in the vibration responses of the rotor, which can increase as the crack propagates along the shaft’s cross-section. A proportional-integral-derivative control technique is applied to suppress the 2X and 3X vibration amplitudes of a cracked shaft, which is performed by using a bandpass filter applied to the vibration responses of the rotor. Numerical and experimental results are obtained through both a representative finite element model of a horizontal rotor and its corresponding test-rig. In this case, electromagnetic actuators are used to apply the control effort to the rotor. The Mayes model is applied for simulating the breathing behavior of the transverse crack. The linear fracture mechanics theory is considered to correlate the crack depth with the corresponding additional rotor flexibility. Both numerical and experimental results demonstrate the possibility of reducing the effects of a transverse crack through active control on the dynamic behavior of a rotating machine. Moreover, it is shown that the proposed control law is capable of controlling the crack effects with the rotor operating in different rotation speeds.

Associations of Sleep-Related Outcomes with Behavioral and Emotional Functioning in Children with Overweight/Obesity

To evaluate the associations of parent-reported sleep-disordered breathing (SDB) and device-assessed sleep behaviors with behavioral and emotional functioning in pediatric patients with overweight/obesity. A total of 109 children with overweight/obesity (mean age, 10.0±1.1years) were included in this cross-sectional study. We used the Spanish version of the Pediatric Sleep Questionnaire (PSQ) to assess SDB and its subscales (ie, snoring, daytime sleepiness, and inattention/hyperactivity). Device-assessed sleep behaviors (ie, wake time, sleep onset time, total time in bed, total sleep time, and waking after sleep onset) were estimated using wrist-worn accelerometers. We used the Behavior Assessment System for Children, second edition to assess behavioral and emotional functioning (ie, clinical scale: aggressiveness, hyperactivity, behavior problems, attention problems, atypicality, depression, anxiety, retreat, and somatization; adaptive scale: adaptability, social skills, and leadership). SDB was positively associated with all clinical scale variables (all β>0.197, P≤.041) and with lower adaptability and leadership (all β<-0.226, P<.021). Specifically, the PSQ subscale relating to daytime sleepiness was associated with higher attention problems, depression, anxiety, and retreat (all β>0.196, P≤.045) and lower adaptability (β=-0.246, P=.011). The inattention/hyperactivity subscale was significantly associated with the entire clinical and adaptive scales (all β>|0.192|, P≤.046) except for somatization. The snoring subscale and device-assessed sleep behaviors were not related to any behavioral or emotional functioning variables. Our study suggests that SDB symptoms, but not device-assessed sleep behaviors, are associated with behavioral and emotional functioning in children with overweight/obesity. Specifically, daytime sleepiness, a potential SDB symptom, was related to higher attention problems, depression, anxiety, and retreat and lower adaptability.

A Wearable Respiration Sensor for Real-Time Monitoring of Chronic Kidney Disease.

Human respiration is accompanied with abundant physiological and pathological information, such as the change in ammonia (NH3) content, which is related to chronic kidney disease (CKD); hence, monitoring the breathing behavior helps in health assessment and illness prediction. In this work, a wearable respiration sensor based on CeO2@polyaniline (CeO2@PANI) nanocomposites that underwent a hydrogen plasma treatment is developed. The results unambiguously show that the response of the corresponding nanocomposites is significantly enhanced from 165 to 670% to 100 ppm NH3 compared to the counterpart that did not undergo hydrogen plasma treatment and even reaches 24% to 50 ppb NH3, suggesting its fascinating capability of detecting the trace level of NH3 in human breathing. The superior response for NH3 is ascribed to the stable oxygen vacancies produced by the hydrogen plasma treatment. Furthermore, the clinical tests for patients with uremia suggest that the as-designed sensor has potential applications in clinical monitoring for CKD. Herein, this work offers a new strategy to obtain respiration sensors with high performance and provides a feasible approach for health evaluation and disease monitoring of patients with CKD.

Dissipative localized states and breathers in phase-mismatched singly resonant optical parametric oscillators: Bifurcation structure and stability

We study the emergence of dissipative localized states in phase mismatched singly resonant optical parametric oscillators. These states arise in two different bistable configurations due to the locking of front waves connecting the two coexisting states. In one of these configurations, the bistability is mediated by the coexistence of two uniform states. Here the localized states are organized in a collapsed snaking bifurcation structure. Moreover, these states undergo oscillatory instabilities which lead to a breathing behavior. When the bistability is related to the coexistence of a uniform state and a spatially periodic pattern, localized states are organized in a bifurcation structure similar to the standard homoclinic snaking. Performing an exhaustive bifurcation analysis, we characterize in detail the previous structures, their linear stability, and the modification of their dynamics as a function of the control parameters of the system.

An open-source tool for automated analysis of breathing behaviors in common marmosets and rodents.

The respiratory system maintains homeostatic levels of oxygen (O2) and carbon dioxide (CO2) in the body through rapid and efficient regulation of breathing frequency and depth (tidal volume). The commonly used methods of analyzing breathing data in behaving experimental animals are usually subjective, laborious, and time-consuming. To overcome these hurdles, we optimized an analysis toolkit for the unsupervised study of respiratory activities in animal subjects. Using this tool, we analyzed breathing behaviors of the common marmoset (Callithrix jacchus), a New World non-human primate model. Using whole-body plethysmography in room air as well as acute hypoxic (10% O2) and hypercapnic (6% CO2) conditions, we describe breathing behaviors in awake, freely behaving marmosets. Our data indicate that marmosets' exposure to acute hypoxia decreased metabolic rate and increased sigh rate. However, the hypoxic condition did not augment ventilation. Hypercapnia, on the other hand, increased both the frequency and depth (i.e., tidal volume) of breathing.

Chapter 15 - The phrenic neuromuscular system

The phrenic neuromuscular system consists of the phrenic motor nucleus in the mid-cervical spinal cord, the phrenic nerve, and the diaphragm muscle. This motor system helps sustain breathing throughout life, while also contributing to posture, coughing, swallowing, and speaking. The phrenic nerve contains primarily efferent phrenic axons and afferent axons from diaphragm sensory receptors but is also a conduit for autonomic fibers. On a breath-by-breath basis, rhythmic (inspiratory) depolarization of phrenic motoneurons occurs due to excitatory bulbospinal synaptic pathways. Further, a complex propriospinal network innervates phrenic motoneurons and may serve to coordinate postural, locomotor, and respiratory movements. The phrenic neuromuscular system is impacted in a wide range of neuromuscular diseases and injuries. Contemporary research is focused on understanding how neuromuscular plasticity occurs in the phrenic neuromuscular system and using this information to optimize treatments and rehabilitation strategies to improve breathing and related behaviors.

Modal Analysis of Cylinder-Induced Transitional Shock-Wave/Boundary-Layer Interaction Unsteadiness

Shock-wave/boundary-layer interactions (SWBLIs) are critical phenomena in the design of high-speed vehicles as they exhibit inherent unsteadiness that can damage airframes and lead to engine unstart. This paper presents a novel characterization of the unsteady dynamics of cylinder-induced SWBLIs at Reynolds numbers of and using proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD). Data sets analyzed in this paper were obtained from experiments conducted in the NASA Langley Research Center’s 20-Inch Mach 6 blowdown wind tunnel. The experiments used a cylinder protuberance model mounted on a 10° half-angle wedge to create the interaction. The lower-Reynolds-number case was observed to have a transitional incoming boundary layer, whereas a swept ramp array trip was used in the higher-Reynolds-number case to generate a turbulent incoming boundary layer. The POD analysis from both cases helped isolate spatial regions in the separation bubble that contained the highest percentage of energy for each case, which correlate to the dominant structures in the flow. A power spectral density analysis on the POD temporal components of the highest-energy POD mode (mode 1) revealed a frequency spectrum with a distinct peak at in the lower-Reynolds-number case and a band of high-energy peaks in the range of 0.05–0.2 for the tripped SWBLI case. Through the DMD analysis, an unsteadiness mode was isolated at and an asymmetric motion of the forward lambda shock was identified in the lower-Reynolds-number case. This dynamic asymmetry was not detected in the higher-Reynolds-number case, suggesting that the asymmetric effect may be unique to interactions in transitional incoming boundary layers. Additional spectral-kernel-based POD analysis identified primary unsteadiness frequencies that were in agreement with the DMD findings. A low-frequency mode at , exhibiting relatively high energy, was obtained for the lower-Reynolds-number (transitional) case, whereas a broadband “bump” with increased energy over a frequency range of was observed for the higher-Reynolds-number (tripped) case. Through these analysis techniques, a mode, likely connected to a shock-breathing mechanism, was identified at . In the assessment of the structural motion occurring in the shock-breathing mode, the phenomenon in the lower-Reynolds-number case was found to traverse a longer upstream distance and compress to a larger degree when compared with the breathing behavior in the higher-Reynolds-number case.

Spatio-spectral dynamics of soliton pulsation with breathing behavior in the anomalous dispersion fiber laser

We have numerically and experimentally observed the soliton pulsation with obvious breathing behavior in the anomalous fiber laser mode-locked by a nonlinear polarization rotation technique. The numerical study of the soliton pulsation with breathing behavior was analyzed through the split-step Fourier method at first, and it was found that the phase difference caused by the polarization controller would affect the breathing characteristics. Then, taking advantage of the dispersive Fourier transform technique, we confirmed the breathing characteristic of soliton pulsation in the same fiber laser as the simulation model experimentally. These results complement the research on the breathing characteristic of soliton pulsation.

Approach to Common Sleep Disorders

Sleep disorders are highly relevant in clinical practice given their prevalence as well as their impact on health outcomes and quality of life. The most common concerns are excessive daytime sleepiness, insomnia, disordered breathing, and abnormal movements or behaviors during sleep. A detailed but targeted history is vital, particularly from the sleep partner/witness. In-laboratory sleep testing (polysomnography and multiple sleep latency test) remains vital in the diagnosis of certain sleep disorders (such as sleep-disordered breathing and central hypersomnia) and in specific populations (such as in children and individuals with comorbid medical disorders). Advances in technology have allowed for a variety of methods in assessing a patient's sleep, from compact devices to evaluate for sleep apnea, wrist actigraphy, and mobile device-based applications. As the pathophysiology of various sleep disorders becomes better elucidated, disease-specific medications have been developed for these conditions. Nonetheless, a multidisciplinary approach to management is necessary, including improving sleep hygiene and cognitive behavioral therapy.

Effects of Speaking Rate on Breathing and Voice Behavior

The objective of this study was to investigate the effects of speaking rate (habitual and fast) and speech task (reading and spontaneous speech) on seven dependent variables: Breath group size (in syllables), Breath group duration (in seconds), Lung volume at breath group initiation, Lung volume at breath group termination, Lung volume excursion for each breath group (in % vital capacity), Lung volume excursion per syllable (in % vital capacity) and mean speaking Fundamental frequency (fO). Ten women and seven men were included as subjects. Lung volume and breathing behaviors were measured by respiratory inductance plethysmography and fO was measured from audio recordings by the Praat software. Statistical significance was tested by analysis of variance. For both reading and spontaneous speech, the group increased mean breath group size and breath group duration significantly in the fast speaking rate condition. The group significantly decreased lung volume excursion per syllable in fast speech. Females also showed a significant increase of fO in fast speech. The lung volume levels for initiation and termination of breath groups, as well as lung volume excursions in % vital capacity, showed great individual variations and no significant effects of rate. Significant effects of speech task were found for breath group size and lung volume excursion per syllable, where reading induced more syllables produced per breath group and less % VC spend per syllable as compared to spontaneous speech. Interaction effects showed that the increases in breath group size and breath group duration associated with fast rate were significantly larger in reading than in spontaneous speech. Our data from 17 vocally untrained, healthy subjects showed great individual variations but still significant group effects regarding increased speaking rate, where the subjects seemed to spend less air per syllable and inhaled less often as a consequence of greater breath group sizes in fast speech. Subjects showed greater changes in breath group patterns as a consequence of fast speech in reading than in spontaneous speech, indicating that effects of speaking rate are dependent on the speech task.

Multiscale Modeling of Solid Electrolyte Interphase Growth in Silicon Anodes

Solid electrolyte interphase (SEI) growth on silicon results in rapid calendar fade as well as thickness variations during cycling, termed as “SEI breathing”. This is primarily attributed to large volume expansion of the silicon anode resulting in SEI fracture and reformation. However, capacity fade and breathing characteristics are also exhibited in thin film/nano sized Si anodes obviating mechanics considerations and pointing to a chemical mechanism origin. In this work, we develop a multispecies, multiphase SEI model capable of capturing Si SEI characteristics via an electrochemical mechanism. Thermodynamic, reaction kinetics and transport property data for silicon and SEI species (Li+, EC, DMC, Li2EDC, Li2O, Li2CO3 etc.) in our model have been tabulated from atomistic calculations as well as experimental datasets for calendar and cycling are used for model validation. The model is used to investigate what contributes to the instability of Si SEI and better understand why Si SEI behaves distinctly different from SEI formed on graphite. Furthermore, reversibility of the electrolyte decomposition and solid phase conversion reactions can help unravel the SEI breathing behavior of silicon anodes. Figure 1

Numerical visualization of drop and opening process for parachute-payload system adopting fluid\u2013solid coupling simulation

In order to study the fluid–solid coupling dynamic characteristics of parachute-payload system during drop process and analyze the unsteady aerodynamic characteristics under finite mass opening conditions, an adaptive moving fluid mesh method is developed on the basis of the existing arbitrary Lagrangian–Eulerian (ALE) fluid–solid coupling method. The calculation results of open force and drop velocity on the C-9 parachute demonstrate the effectiveness of this method. On this basis, the effect of canopies with three different permeability on parachute-payload system motion characteristic including opening property, steady descent property and stability is studied. Comparative analysis is conducted for structures and characteristics of vortex with different canopy materials, and interference mechanism of unsteady flow for parachute-payload system in unsteady oscillation is revealed. The results show that the adaptive moving fluid mesh method can effectively eliminate restrictions of existing simulation methods for parachute-payload system and significantly reduce calculation time. For the lightweight parachute, permeability has significant effect on kinetic characteristic of parachute-payload system. Canopy with large permeability has small opening load and structural stress in opening stage. After opening, there are mainly small vortexes distributed evenly behind the canopy with good stability. However, canopy with small permeability has obvious breath behavior and oscillation in opening stage. The main vortexes periodically shed off after opening. With the change of permeability from small to large, Parachute-payload system eventually presents three steady descent modes: conical descent, gliding descent and stable vertical descent.Graphical abstract

A new generation of solid-phase microextraction based on breathing of metal organic framework nanorods MOF-508 for the determination of diazinon and chlorpyrifos in wheat samples

Flexible MOFs with reversible transformations between open- and closed-pore forms are a new generation of materials that have been applied for gas separation, catalysis, and molecular sensing. This article introduces smart SPME (SSPME) as a new generation of SPME based on the breathing behavior of flexible MOFs with nanorod structures. Stainless-steel (SS) wires were coated with zinc (II)-based MOF, namely MOF-508, with benzene dicarboxylic acid and 4,4-bipyridine. The prepared SSPMEs were investigated to determine some pesticides in wheat samples. The results showed a low limit of detection (4 and 20 µg Kg−1) and a wide linear dynamic range (20–4000 and 200–4000 µg Kg−1) for the determination of diazinon and chlorpyrifos analytes using the SSPME-GC-FID method. The acceptable relative standard deviation for one-fiber, fiber-to-fiber, intraday, and interday modes was obtained 5.6–15%. The use of SSPME during the extraction process led to the minimum desorption time and complete desorption of pesticides analytes from the SSPME fiber.

Resolving local and global kinematic signatures of satellite mergers with billion particle simulations

ABSTRACT In this work, we present two new ∼109 particle self-consistent simulations of the merger of a Sagittarius-like dwarf galaxy with a Milky Way (MW)-like disc galaxy. One model is a violent merger creating a thick disc, and a Gaia–Enceladus/Sausage-like remnant. The other is a highly stable disc which we use to illustrate how the improved phase space resolution allows us to better examine the formation and evolution of structures that have been observed in small, local volumes in the MW, such as the z−vz phase spiral and clustering in the vR−vϕ plane when compared to previous works. The local z−vz phase spirals are clearly linked to the global asymmetry across the disc: we find both 2-armed and 1-armed phase spirals, which are related to breathing and bending behaviours, respectively. Hercules-like moving groups are common, clustered in vR−vϕ in local data samples in the simulation. These groups migrate outwards from the inner galaxy, matching observed metallicity trends even in the absence of a galactic bar. We currently release the best-fitting ‘present-day’ merger snapshots along with the unperturbed galaxies for comparison.

Associations Between Hyperphagia, Symptoms of Sleep Breathing Disorder, Behaviour Difficulties and Caregiver Well-Being in Prader-Willi Syndrome: A Preliminary Study.

Prader-Willi syndrome (PWS) is a rare genetic disorder characterised by neurodevelopmental delays, hyperphagia, difficulties with social communication and challenging behaviours. Individuals require intensive supervision from caregivers which may negatively affect caregiver quality of life. This study used data collected in the Australasian PWS Registry (n = 50, mean age 11.2years) to evaluate associations between child behaviours and caregiver mental well-being. Symptoms of sleep-related breathing disorder, child depression and social difficulties were associated with poorer caregiver mental and physical well-being. Growth hormone therapy use was associated with better caregiver mental and physical well-being. Optimising management of problematic behaviours and sleep disturbances have the potential to support caregivers who are the most vital network of support for individuals affected by PWS.

Acceptability of capnography-assisted respiratory therapy: a new mind-body intervention for COPD.

Dyspnoea self-management is often suboptimal for patients with COPD. Many patients with COPD experience chronic dyspnoea as distressing and disabling, especially during physical activities. Breathing therapy is a behavioural intervention that targets reducing the distress and impact of dyspnoea on exertion in daily living.Using a qualitative design, we conducted interviews with 14 patients after they participated in a novel mind–body breathing therapy intervention adjunct, capnography-assisted respiratory therapy (CART), combined with outpatient pulmonary rehabilitation. Comprehensive CART consisted of patient-centred biofeedback, tailored breathing exercises, a home exercise programme and motivational interviewing counselling. We assessed participants’ perceptions and reported experiences to gauge the acceptability of CART and refine CART based on feedback. Constant comparative analysis was used to identify commonalities and themes.We identified three main themes relating to the acceptability and reported benefits of CART: (1) self-regulating breathing; (2) impact on health; and (3) patient satisfaction. Our findings were used to refine and optimise CART (i.e. its intensity, timing and format) for COPD.By addressing dysfunctional breathing behaviours and dysregulated interoception, CART offers a promising new paradigm for relieving dyspnoea and related anxiety in patients with COPD.

Chinese guideline for the diagnosis and treatment of childhood obstructive sleep apnea (2020).

Chinese guideline for the diagnosis and treatment of childhood obstructive sleep apnea (2020).

A novel geometric model of breathing crack and its influence on rotor dynamics

The present research focuses on performing the dynamic study of a cracked, internally damped, composite rotating shaft system with journal bearing end supports. A novel mathematical formulation is proposed to introduce a time-varying stiffness matrix for simulating the breathing behaviour of the crack. The random search algorithm is used as one of the metaheuristic processes to carry out the optimization and generate time-dependent geometric parameters of the cracked surface for one full rotation. The derived stiffness matrix is used in the composite shaft’s higher order motion equation obtained through equivalent modulus theory, whose internal damping properties are incorporated using operator-based viscoelastic model. Eigenanalysis is carried out to perform a thorough study of dynamic characteristics of cracked shaft considering the crack depth and crack position as two important parameters. The effect of crack on stacking sequence as well as mode shapes of the heterogeneous laminated shaft is also studied.