Impact of Supplemental Oxygen on Obstructive Sleep Apnea of Infants

Abstract: Treatment options may be limited for infants with obstructive sleep apnea when there is no surgically correctable upper airway lesion. We therefore evaluated, retrospectively, the efficacy of low-flow oxygen as a therapeutic option for infant obstructive sleep apnea. We reviewed the medical charts of 23 infants who had undergone a therapeutic trial of low-flow oxygen during polysomnography. Split-night polysomnography was used in 21/23 subjects while 2/23 had undergone two separate, full-night polysomnography sleep architecture and respiratory findings on the baseline polysomnogram segment that was obtained in room air were compared with the segment on low-flow oxygen (0.25–1 L/min). Wilcoxon signed rank or McNemar’s test were used as indicated for comparing apnea hypopnea index and measures of sleep architecture at baseline and with oxygen therapy. The mean (plus/minus SD) age of subjects was 4.8 (plus/minus 2.7) months, with 52% being males. The median apnea hypopnea index fell from a baseline of 18 (range 7–43) to 3 (range 1–19; p = 0.001) on oxygen. The baseline median obstructive/mixed apnea index decreased from 2 (range 1–16) to 1 during oxygen therapy (range 0–1; p = 0.003). Additionally, a significant decrease in central apnea index (median interquartile range (IQR) 1 (0–2) vs. 0 (0–1), p = 0.002) was noted. Sleep efficiency remained unaffected, while O2 saturation (SaO2) average and SaO2 nadir improved on oxygen. We were able to confirm the utility of low-flow oxygen in reducing central, obstructive, and mixed apneas and improving average oxygen saturation in infants with obstructive sleep apnea (OSA)

Studies of electrical conductivity and magnetic properties of Bi1-xGdxFeO3 multiferroics

The polycrystalline samples of Bi1-xGdxFeO3 (x = 0, 0.1, and 0.2) multiferroic oxides have been synthesized by a solid-state reaction/mixed oxide technique. The preliminary X-ray structural analysis with room temperature diffraction data confirmed the formation of single-phase systems. Study of room temperature scanning electron micrograph (SEM) of the surface of the above samples exhibits a uniform distribution of plate- and rod-shaped grains throughout the sample surface with less porosity. The dielectric behavior of the materials was studied in a wide range of frequency (1 kHz–1 MHz) and temperature (30–400°C). The nature of temperature dependence of dc conductivity confirms the Arrhenius behavior of the materials. The frequency–temperature dependence of ac conductivity suggests that the material obeys Jonscher's universal power law. An increase in Gd-content results in the enhancement of spontaneous magnetization BiFeO3 (BFO) due to the collapse of spin cycloid structure. The magnetoelectric coupling coefficient of BFO has been enhanced on Gd-substitution

Effect of KNbO3 modification on structural, electrical and magnetic properties of BiFeO3

The polycrystalline samples of (Bi1-x K (x) ) (Fe1-x Nb (x) ) O-3 (BKFN) for x = 0.0, 0.1, 0.2 and 0.3 were synthesized by a solid-state reaction method. The X-ray diffraction patterns of BKFN exhibit that the addition of KNbO3 in BiFeO3 gradually changes its structure from rhombohedral to pseudocubic. The analysis of scanning electron micrograph clearly showed that the sintered samples have well-defined and uniformly distributed grains. Addition of KNbO3 to BiFeO3 enhances the dielectric, ferroelectric and ferromagnetic properties of BiFeO3. Detailed studies of impedance and related parameters of BKFN using the complex impedance spectroscopic technique exhibit the significant contributions of grain and grain boundaries in the resistive and transport properties of the materials. Some oxygen vacancies created in the ceramic samples during high-temperature processing play an important role in the conduction mechanism. The leakage current or tangent loss of BiFeO3 is greatly reduced on addition of KNbO3 to the parent compound BiFeO3. Preliminary studies of ferroelectric and magnetic characteristics of the samples reveal the existence of ferroelectric, and weak ferromagnetic ordered ceramics

Half-lives of proton emitters I, Cs, La, Eu and Ha nuclei using E-RMF densities

643-645We have studied the nuclear properties and life-time of few proton emitters in their ground state using spherical densities obtained from effective field theory motivated relativistic mean field formalism (E-RMF) for two recent parameter sets G3 and IOPB-I. We have found that these emitters have binding energy per nucleon near the iron peak but due to the inadequate number of neutrons, the Coulomb force cannot be compensated completely hence, the nucleus breaks down. Experimental Q-value is used for the calculate of proton emission half-life using WKB approximation. It is noticed that for suitable l-values our results meet the experimental half-lives. This study enhances our understanding on the nuclear force and shell structure in the drip line region

Structural, dielectric, and multiferroic properties of (Bi0.5K0.5)(Fe0.5Nb0.5)O-3

A polycrystalline sample of (Bi0.5K0.5)(Fe0.5Nb0.5)O-3 was prepared using a mixed oxide at 1000 degrees C. The preliminary structural analysis using X-ray diffraction data of the compound indicates the formation of a single-phase rhombohedral structure similar to that of parent BiFeO3. Microstructural and elemental analysis using a scanning electron micrograph and energy-dispersive X-ray spectroscopy, respectively, were carried out at room temperature with higher magnification exhibiting a uniform distribution of grains and stoichiometry. The appearance of hysteresis loops (P-E) confirms the existence of ferroelectricity of the sample with a high remnant polarization of (2P(r)) 17.76 mu Ccm(-2). Using impedance spectroscopy, the electrical properties of the material were investigated at a wide range of temperature (25-500 degrees C) and frequencies (1 kHz - 1 MHz) suggesting dielectric non-Debye-type relaxation in the material. The nature of the Nyquist plot (Z' similar to Z '') shows the dominance of the grain contribution in the impedance. The bulk resistance of the compound decreases with increasing temperature, like that of a semiconductor, which shows a negative temperature coefficient of resistance (NTCR) behavior. The frequency dependence of AC conductivity suggests that that the material obeys Jonscher's power law. Magnetic hysteresis (M-H) loop shows very weak ferromagnetic behavior at room temperature

Dielectric response and pyroelectric properties of lead-free ferroelectric Ba3(VO4)2

The current paper presents results of dielectric response, pyroelectric behavior and conductivity study of lead-free ferroelectric barium orthovanadate (Ba3(VO4)2 or Ba3V2O8) ceramic, for a wide range of temperature and frequency. An X-ray diffraction study suggests the formation of a single-phase compound in trigonal crystal system. The SEM micrograph of gold-coated pellet sample shows well-defined and homogeneous morphology. Detailed studies of dielectric parameters (εr and tan δ) of the compound as a function of temperature and frequency reveal their independence over a wide range of temperature and frequency. The nature of Polarization versus electric field (P–E) hysteresis loop of Ba3V2O8 at room temperature suggests its ferroelectric nature. The temperature dependence of pyroelectric coefficient and figure of merits of the sample support its dielectric response. The nature of variation of dc conductivity with temperature confirms the Arrhenius and negative temperature coefficient of resistance (NTCR) behavior of the material

Ferroelectric Properties of Na2Pb2R2W2Ti4V4O30(R = Dy, Pr) Ceramics

The polycrystalline samples of Na2Pb2R2W2Ti4V4O30 (R = Dy, Pr) were prepared by low-temperature, (i.e., at 650∘C) solid-state reaction technique. The preparation conditions have been optimized using thermogravimetry analysis (TGA) technique. X-ray diffraction (XRD) studies of the compounds showed the formation of a single-phase orthorhombic crystal structure at room temperature. Studies of dielectric properties (ɛr and tan δ) of the compounds at frequencies 10, 100, and 1000 kHz in a wide temperature range (room temperature–500∘C) exhibit ferroelectric phase transitions at 132∘C for NPDWTV and at 122∘C for NPPWTV of diffuse type. Ferroelectric properties of the materials are confirmed by polarization study