scholarly journals Stabilizing immature breathing patterns of preterm infants using stochastic mechanosensory stimulation

2009 ◽  
Vol 107 (4) ◽  
pp. 1017-1027 ◽  
Author(s):  
Elisabeth Bloch-Salisbury ◽  
Premananda Indic ◽  
Frank Bednarek ◽  
David Paydarfar
Keyword(s):  
Preterm Infants ◽  
Respiratory Control ◽  
Behavioral State ◽  
Mean Square ◽  
Breathing Patterns ◽  
Nonlinear Properties ◽  
Improved Stability ◽  
Postconceptional Age ◽  
The Stability ◽  
Large Improvement

Breathing patterns in preterm infants consist of highly variable interbreath intervals (IBIs) that might originate from nonlinear properties of the respiratory oscillator and its input-output responses to peripheral and central signals. Here, we explore a property of nonlinear control, the potential for large improvement in the stability of breathing using low-level exogenous stochastic stimulation. Stimulation was administered to 10 preterm infants (postconceptional age: mean 33.3 wk, SD 1.7) using a mattress with embedded actuators that delivered small stochastic displacements (0.021 mm root mean square, 0.090 mm maximum, 30–60 Hz); this stimulus was subthreshold for causing arousal from sleep to wakefulness or other detectable changes in the behavioral state evaluated with polysomnography. We used a test-retest protocol with multiple 10-min intervals of stimulation, each paired with 10-min intervals of no stimulation. Stimulation induced an ∼50% reduction ( P = 0.003) in the variance of IBIs and an ∼50% reduction ( P = 0.002) in the incidence of IBIs > 5 s. The improved stability of eupneic breathing was associated with an ∼65% reduction ( P = 0.04) in the duration of O2 desaturation. Our findings suggest that nonlinear properties of the immature respiratory control system can be harnessed using afferent stimuli to stabilize eupneic breathing, thereby potentially reducing the incidence of apnea and hypoxia.

scholarly journals Improved Stability Criteria of Static Recurrent Neural Networks with a Time-Varying Delay

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Lei Ding ◽  
Hong-Bing Zeng ◽  
Wei Wang ◽  
Fei Yu
Keyword(s):  
Neural Networks ◽  
Recurrent Neural Networks ◽  
Linear Matrix ◽  
Time Varying ◽  
Time Varying Delay ◽  
Improved Stability ◽  
The Stability ◽  
Delay Dependent ◽  
Delay Dependent Stability ◽  
Varying Delay

This paper investigates the stability of static recurrent neural networks (SRNNs) with a time-varying delay. Based on the complete delay-decomposing approach and quadratic separation framework, a novel Lyapunov-Krasovskii functional is constructed. By employing a reciprocally convex technique to consider the relationship between the time-varying delay and its varying interval, some improved delay-dependent stability conditions are presented in terms of linear matrix inequalities (LMIs). Finally, a numerical example is provided to show the merits and the effectiveness of the proposed methods.

Periodic Breathing in Preterm Infants: Incidence and Characteristics

PEDIATRICS ◽  
1989 ◽  
Vol 84 (5) ◽  
pp. 785-792
Author(s):  
S. F. Glotzbach ◽  
R. B. Baldwin ◽  
N. E. Lederer ◽  
P. A. Tansey ◽  
R. L. Ariagno
Keyword(s):  
Preterm Infants ◽  
Age Groups ◽  
Periodic Breathing ◽  
Sudden Infant Death ◽  
Respiratory Pattern ◽  
Sudden Infant ◽  
Quiet Time ◽  
Term Infants ◽  
Respiratory Dysfunction ◽  
Postconceptional Age

The prevalence and characteristics of periodic breathing in preterm infants were measured by 24-hour impedance pneumograms in 66 preterm infants before discharge from the nursery. Four periodic breathing parameters (percentage of periodic breathing per quiet time, number of episodes of periodic breathing per 100 minutes of quiet time, mean duration of periodic breathing, and longest episode of periodic breathing) were compared to data available from healthy term infants and from term infants who subsequently died of sudden infant death syndrome (SIDS). Periodic breathing was found in all preterm infants studied and mean periodic breathing parameter values (12.0%, 8.6 episodes, 1.2 minutes, and 7.3 minutes, respectively) in our preterm population were substantially higher than values from healthy term infants and SIDS victims. Most periodic breathing parameters decreased significantly in infants studied at 39 to 41 weeks' postconceptional age compared with earlier postconceptional age groups. No relationship was found between central apneas of ≥15 seconds' duration and postconceptional age or any periodic breathing parameter. Periodic breathing is a common respiratory pattern in preterm infants that is usually not of pathologic significance. Associations between elevated levels of periodic breathing and respiratory dysfunction or SIDS should be made with caution.

Transcutaneous Oxygen Tension During Nonnutritive Sucking in Preterm Infants

PEDIATRICS ◽  
1984 ◽  
Vol 74 (4) ◽  
pp. 539-542
Author(s):  
Roberto Paludetto ◽  
Steven S. Robertson ◽  
Maureen Hack ◽  
Chandra R. Shivpuri ◽  
Richard J. Martin
Keyword(s):  
Heart Rate ◽  
Respiratory Rate ◽  
Preterm Infants ◽  
Oxygen Tension ◽  
Sleep State ◽  
Transcutaneous Oxygen Tension ◽  
Transcutaneous Oxygen ◽  
Beneficial Effects ◽  
Nonnutritive Sucking ◽  
Postconceptional Age

The effects of nonnutritive sucking on transcutaneous oxygen tension, heart rate, and respiratory rate were studied sequentially in 14 sleeping preterm infants breathing room air. Transcutaneous oxygen tension increased during nonnutritive sucking in infants between 32 and 35 weeks postconceptional age, but not in those between 36 and 39 weeks. This response was not associated with a change in respiratory rate or sleep state, although heart rate tended to increase. These data offer further support for the beneficial effects of nonnutritive sucking in preterm infants.

Dynamic gyroscope sensors fusion and calibration using Kalman filter

2018 ◽  
Vol 7 (2.3) ◽  
pp. 18
Author(s):  
Mishell D. Lawas ◽  
Sherwin A. Guirnaldo
Keyword(s):  
Kalman Filter ◽  
Unmanned Aerial Vehicle ◽  
Systems Design ◽  
Mean Square ◽  
Fusion Technique ◽  
System Experiment ◽  
Aerial Vehicle ◽  
Sensors Fusion ◽  
The Stability ◽  
Actual Test

The stability of an Unmanned Aerial Vehicle (UAV) during actual flight conditions is one parameter that is very important in systems design in Avionics. In this research, two sensors, the autopilot microcontroller and the smartphone gyroscope sensing mechanism, are fused together and calibrated to monitor the flying behavior of the UAV prior to actual test flights. The two fused sensors and installed inside the UAV for relatively increased sensing accuracy and best flight monitoring capabilities. A Kalman filter is used as fusion technique and a Stewart Motion tracker is also used to test the ruggedness and accuracy of the fused sensor system. Experiment results show that fused system can give an overall mean square error or 1.9729.

EXPONENTIAL MEAN SQUARE STABILITY OF STOCHASTICALLY FORCED INVARIANT MANIFOLDS FOR NONLINEAR SDEs

2007 ◽  
Vol 07 (03) ◽  
pp. 389-401 ◽  
Author(s):  
L. B. RYASHKO
Keyword(s):  
Linear Extension ◽  
Invariant Manifolds ◽  
Function Technique ◽  
Nonlinear Stochastic System ◽  
General Notion ◽  
Mean Square ◽  
Extension System ◽  
Mean Square Stability ◽  
The Stability ◽  
Exponential Mean Square Stability

An exponential mean square stability for the invariant manifold [Formula: see text] of a nonlinear stochastic system is considered. The stability analysis is based on the [Formula: see text]-quadratic Lyapunov function technique. The local dynamics of the nonlinear system near manifold is described by the stochastic linear extension system. We propose a general notion of the projective stability (P-stability) and prove the following theorem. The smooth compact manifold [Formula: see text] is exponentially mean square stable if and only if the corresponding stochastic linear extension system is P-stable.

scholarly journals Tailoring capping-layer composition for improved stability of mixed-halide perovskites

2022 ◽  
Author(s):  
Noor Titan Putri Hartono ◽  
Marie-Hélène Tremblay ◽  
Sarah Wieghold ◽  
Benjia Dou ◽  
Janak Thapa ◽  
...  
Keyword(s):  
Solar Cells ◽  
Perovskite Solar Cells ◽  
Capping Layer ◽  
Improved Stability ◽  
Halide Perovskites ◽  
The Stability ◽  
Low Dimensional ◽  
Layer Composition

Incorporating a low dimensional (LD) perovskite capping layer on top of perovskite absorber, improves the stability of perovskite solar cells (PSCs). However, in the case of mixed-halide perovskites, which can...

Improved stability of salvianolic acid B from Radix Salviae miltiorrhizae in deep eutectic solvents

2016 ◽  
Vol 8 (11) ◽  
pp. 2502-2509 ◽  
Author(s):  
Jue Chen ◽  
Shi-fei Li ◽  
Zhi-feng Yao ◽  
Da-wei Yang ◽  
Li-wei Zhang
Keyword(s):  
Environmentally Friendly ◽  
Deep Eutectic Solvents ◽  
Salvianolic Acid B ◽  
Radix Salviae Miltiorrhizae ◽  
Salvianolic Acid ◽  
Salviae Miltiorrhizae ◽  
Improved Stability ◽  
The Stability

Environmentally friendly deep eutectic solvents were developed for enhancing the stability of salvianolic acid B from Radix Salviae miltiorrhizae.

Biological Rhythmicity in Preterm Infants Prior to Discharge From Neonatal Intensive Care

PEDIATRICS ◽  
1995 ◽  
Vol 95 (2) ◽  
pp. 231-237
Author(s):  
Steven F. Glotzbach ◽  
Dale M. Edgar ◽  
Ronald L. Ariagno
Keyword(s):  
Heart Rate ◽  
Intensive Care ◽  
Preterm Infants ◽  
Rectal Temperature ◽  
Neonatal Intensive Care ◽  
Time Of Day ◽  
Circadian System ◽  
Physiological Variables ◽  
Postconceptional Age ◽  
The Impact

Objective. The study of biological rhythms and the influence of environmental factors in the timing and synchronization of different rhythmic events have important implications for neonatal health. Preterm infants in the neonatal intensive care unit (NICU) are deprived of the patterned influences of maternal sleep, temperature, heart rate, and hormonal cycles. The impact of the NICU and nursing interventions on the development of the circadian system was studied in 17 stable preterm infants in the Intermediate Intensive Care Nursery at Stanford University for three consecutive days at about 35 weeks postconceptional age. Outcome measurements. Rectal temperature, abdominal skin temperature, heart rate, and activity were simultaneously recorded at 2-minute intervals during each 3-day study by a small microcomputer (Vitalog). Results. Very low amplitude circadian rhythms were found for rectal and skin temperatures (maximum range 36.8 to 37.0°C); population mean values for heart rate (158 bpm) and activity (3.5 counts per 2-min bin) did not differ significantly as a function of time of day. Rectal temperature, averaged in 6-hour bins over the 24-hour day as a function of both postconceptional age and postnatal age, was significantly higher during the first part of the circadian cycle. In all infants, rhythmicity in each variable was dominated by ultradian periodicities that were coincident with feedings and related interventions; moreover, several physiological variables charted during feeding differed significantly from values obtained during periods in which caregiving interventions did not occur. Conclusion. Quantitative data on the preterm infant circadian system may facilitate evaluation of factors that improve therapeutic responses, recovery, and outcome of neonatal intensive care patients.

The Role of Internal Irreversibilities in the Performance and Stability of Power Plant Models Working at Maximum ϵ-Ecological Function

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Gabriel Valencia-Ortega ◽  
Sergio Levario-Medina ◽  
Marco Antonio Barranco-Jiménez
Keyword(s):  
Power Plants ◽  
Heat Engine ◽  
Combined Cycle ◽  
Ecological Function ◽  
Operating Conditions ◽  
Maximum Efficiency ◽  
Working Fluid ◽  
Engine Model ◽  
Improved Stability ◽  
The Stability

Abstract The proposal of models that account for the irreversibilities within the core engine has been the topic of interest to quantify the useful energy available during its conversion. In this work, we analyze the energetic optimization and stability (local and global) of three power plants, nuclear, combined-cycle, and simple-cycle ones, by means of the Curzon–Ahlborn heat engine model which considers a linear heat transfer law. The internal irreversibilities of the working fluid measured through the r-parameter are associated with the so-called “uncompensated Clausius heat.” In addition, the generalization of the ecological function is used to find operating conditions in three different zones, which allows to carry out a numerical analysis focused on the stability of power plants in each operation zone. We noted that not all power plants reveal stability in all the operation zones when irreversibilities are considered through the r-parameter on real-world power plants. However, an improved stability is shown in the zone limited by the maximum power output and maximum efficiency regimes.

Screening for Congenital Adrenal Hyperplasia: The Delfia Screening Test Overestimates Serum 17-Hydroxyprogesterone in Preterm Infants

PEDIATRICS ◽  
1996 ◽  
Vol 97 (1) ◽  
pp. 100-102 ◽  
Author(s):  
Saad Al Saedi ◽  
Heather Dean ◽  
William Dent ◽  
Elizabeth Stockl ◽  
Catherine Cronin
Keyword(s):  
Congenital Adrenal Hyperplasia ◽  
Preterm Infants ◽  
Gestational Age ◽  
Adrenal Hyperplasia ◽  
Blood Spots ◽  
Healthy Infants ◽  
Extraction Step ◽  
Postconceptional Age ◽  
17 Hydroxyprogesterone ◽  
Over Time

Objective. To compare 17-hydroxyprogesterone (17-OHP) levels measured by quantitative serum radioimmunoassay (RIA), including an extraction step, and by screening fluoroimmnoassay (FIA) on blood spots in preterm infants. Methods. Subjects were 39 healthy infants born at less than 31 weeks' gestational age. Each infant had weekly blood sampling, and RIA and FIA were performed on each sample. Results. Two hundred twenty-seven samples were taken at 28 to 41 weeks' postconceptional age. Mean ± SD 17-OHP measured by RIA was 11.4 ± 11.1 nmol/L (0.4 ± 0.4 µg/dL), and decreased over time. Mean ± SD 17-OHP measured by FIA was 38.96 ± 37.3 nmol/L, greater than 17-OHP (RIA). Log(δFIA-RIA) was inversely related to postconceptional age (R2 = .39). Conclusion. Screening FIA of blood spots overestimates levels of 17-OHP in preterm infants and should not be used to determine the likelthood of congenital adrenal hyperplasia in this population. We have abandoned FIA screening for congenital adrenal hyperplasia in infants weiging less than 1500 g.

Sign in / Sign up

Export Citation Format

Share Document