Search Results (7)

Background/Objectives: Small airway disease/dysfunction (SAD) is crucial in obstructive airway diseases but is less investigated in interstitial lung disease (ILD). There are only a few physiological studies investigating SAD in the context of pulmonary fibrosis. Oscillometry is a simple technique that assesses SAD with minimal patient effort. In this study, we investigated the role of oscillometry in patients with mild pulmonary fibrosis without evident obstructive disorder, focusing on small airways. Methods: Oscillometry and pulmonary function test (PFT) data of consecutive patients newly diagnosed with pulmonary fibrosis of unknown etiology in a university hospital ILD clinic were collected and analyzed. Results: Data from 34 patients with mild pulmonary fibrosis were collected in 6 months. Disease severity, as evaluated by FVC, presented strong correlations with the oscillometry parameters: resistance (R5: r = −0.588, p < 0.001), reactance (X5: r = 0.671, p < 0.001), resonant frequency (Fres: r = −0.562, p = 0.001), and the area of reactance (AX: r = −0.515, p = 0.002). The oscillometry parameter R5-19-expressing was abnormal in 27% of patients, correlated with FEF25-75% (r = −0.370, p = 0.021) and was a predictor of a FEF25-75% < 60% pred. with AUC 0.738 (95%Cl 0.519–0.956). R5-19 correlated with FVC (r = −0.481, p = 0.004) and was the only SAD parameter that correlated with the composite physiologic index (CPI, r = 0.338, p = 0.04), while FEF 25-75% and RV/TLC% did not. Conclusions: Oscillometry is an easy to perform technique that may reveal early mechanical alterations caused by pulmonary fibrosis. Peripheral resistance, as expressed by R5-19, which identifies small airway dysfunction as a marker of peripheral lung pathology, may be complementary to pulmonary function testing and may also have prognostic implications for ILD patients. Full article

A typical body-centered cubic (BCC) CoFe(110) peak was discovered at approximately 2θ = 44.7°. At 2θ = 46°, 46.3°, 47.7°, 55.4°, 54.6°, and 56.4°, the Yb₂O₃ and Co₂O₃ oxide peaks were visible in all samples. However, with a heat treatment temperature of 300 °C, there was no typical peak of CoFe(110). Electrical characteristics demonstrated that resistivity and sheet resistance reduced dramatically as film thickness and annealing temperatures increased. At various heat treatments, the maximum hardness was 10 nm. The average hardness decreased as the thickness increased, and the hardness trend decreased slightly as the annealing temperature was higher. The highest low-frequency alternative-current magnetic susceptibility (χ_ac) value was discovered after being annealed at 200 °C with 50 nm, and the optimal resonance frequency (f_res) was discovered to be within the low-frequency range, indicating that the Co₄₀Fe₄₀Yb₂₀ film can be used in low-frequency applications. The maximum saturation magnetization (Ms) was annealed at 200 °C for 50 nm. Thermal disturbance caused the Ms to decrease as the temperature reached to 300 °C. The results show that when the oxidation influence of as-deposited and thinner films is stronger than annealing treatments and thicker thickness, the magnetic and electrical properties can be enhanced by the weakening peak of the oxide, which can also reduce interference. Full article

In this paper, a Co₆₀Fe₂₀Y₂₀ film was sputtered onto Si (100) substrates with thicknesses ranging from 10 to 50 nm under four conditions to investigate the structure, magnetic properties, and surface energy. Under four conditions, the crystal structure of the CoFeY films was found to be amorphous by an X-ray diffraction analyzer (XRD), suggesting that yttrium (Y) added into CoFe films and can be refined in grain size and insufficient annealing temperatures do not induce enough thermal driving force to support grain growth. The saturation magnetization (M_S) and low-frequency alternate-current magnetic susceptibility (χ_ac) increased with the increase of the thicknesses and annealing temperatures, indicating the thickness effect and Y can be refined grain size and improved ferromagnetic spin exchange coupling. The highest Ms and χ_ac values of the Co₆₀Fe₂₀Y₂₀ films were 883 emu/cm³ and 0.26 when the annealed temperature was 300 °C and the thickness was 50 nm. The optimal resonance frequency (f_res) was 50 Hz with the maximum χ_ac value, indicating it could be used at a low frequency range. Moreover, the surface energy increased with the increase of the thickness and annealing temperature. The maximum surface energy of the annealed 300 °C film was 30.02 mJ/mm² at 50 nm. Based on the magnetic and surface energy results, the optimal thickness was 50 nm annealed at 300 °C, which has the highest Ms, χ_ac, and a strong adhesion, which can be as a free or pinned layer that could be combined with the magnetic tunneling layer and applied in magnetic fields. Full article

When B and V are added to CoFe material, the mechanical strength and spin tunneling polarization of a CoFe alloy can be improved and enhanced by the high tunneling magnetoresistance (TMR) ratio. Based on these reasons, it is worthwhile investigating Co₄₀Fe₄₀V₁₀B₁₀ films. In this work, X-ray diffraction (XRD) showed that Co₄₀Fe₄₀V₁₀B₁₀ thin films have some distinct phases including CoFe (110), CoFe (200), FeB (130), and V (110) diffracted peaks with the strongest diffracted peak for 30 nm. The lowest low-frequency alternate-current magnetic susceptibility (χ_ac) was detected at 30 nm because the large grain distribution inducing that high coercivity (H_c) enhances the spin coupling strength and low χ_ac. The external field (H_ext) had difficulty rotating in the spin state, hence, the spin sensitivity was reduced and the χ_ac value decreased due to increased surface roughness. The 20 mm thickness had the highest χ_ac 1.96 × 10⁻² value at 50 Hz of an optimal resonance frequency (f_res). The surface energy increased from 34.2 mJ/mm² to 51.5 mJ/mm² for Co₄₀Fe₄₀V₁₀B₁₀ films. High surface energy had corresponding strong adhesive performance. According to the magnetic and surface energy results, the optimal thickness is 20 nm due as it had the highest χ_ac and strong adhesion. Full article

Airways obstruction is frequent in patients with pulmonary hypertension (PH). Small airway disease (SAD) was identified as a major contributor to resistance and symptoms. However, it is easily missed using current diagnostic approaches. We aimed to evaluate more elaborate diagnostic tests such as impulse oscillometry (IOS) and SF₆-multiple-breath-washout (MBW) for the assessment of SAD in PH. Twenty-five PH patients undergoing body-plethysmography, IOS and MBW testing were prospectively included and equally matched to pulmonary healthy and non-healthy controls. Lung clearance index (LCI) and acinar ventilation heterogeneity (S_acin) differed significantly between PH, healthy and non-healthy controls. Likewise, differences were found for all IOS parameters between PH and healthy, but not non-healthy controls. Transfer factor corrected for ventilated alveolar volume (TLCO/VA), frequency dependency of resistance (D5-20), resonance frequency (F_res) and S_acin allowed complete differentiation between PH and healthy controls (AUC (area under the curve) = 1.0). Likewise, PH patients were separated from non-healthy controls (AUC 0.762) by D5-20, LCI and conductive ventilation heterogeneity (S_cond). Maximal expiratory flow (MEF) values were not associated with additional diagnostic values. MBW and IOS are feasible in PH patients both providing additional information. This can be used to discriminate PH from healthy and non-healthy controls. Therefore, further research targeting SAD in PH and evaluation of therapeutic implications is justified. Full article

In this investigation, the low-frequency alternate-current (AC) magnetic susceptibility (χ_ac) and hysteresis loop of various MgO thickness in CoFeB/MgO/CoFeB magnetic tunneling junction (MTJ) determined coercivity (H_c) and magnetization (M_s) and correlated that with χ_ac maxima. The multilayer films were sputtered onto glass substrates and the thickness of intermediate barrier MgO layer was varied from 6 to 15 Å. An experiment was also performed to examine the variation of the highest χ_ac and maximum phase angle (θ_max) at the optimal resonance frequency (f_res), at which the spin sensitivity is maximal. The results reveal that χ_ac falls as the frequency increases due to the relationship between magnetization and thickness of the barrier layer. The maximum χ_ac is at 10 Hz that is related to the maximal spin sensitivity and that this corresponds to a MgO layer of 11 Å. This result also suggests that the spin sensitivity is related to both highest χ_ac and maximum phase angle. The corresponding maximum of χ_ac is related to high exchange coupling. High coercivity and saturation magnetization contribute to high exchange-coupling χ_ac strength. Full article

This investigation studies CoFeB/AlO_x/Co magnetic tunneling junction (MTJ) in the magnetic field of a low-frequency alternating current, for various thicknesses of the barrier layer AlO_x. The low-frequency alternate-current magnetic susceptibility (χ_ac) and phase angle (θ) of the CoFeB/AlO_x/Co MTJ are determined using an c_ac analyzer. The driving frequency ranges from 10 to 25,000 Hz. These multilayered MTJs are deposited on a silicon substrate using a DC and RF magnetron sputtering system. Barrier layer thicknesses are 22, 26, and 30 Å. The X-ray diffraction patterns (XRD) include a main peak at 2θ = 44.7° from hexagonal close-packed (HCP) Co with a highly (0002) textured structure, with AlO_x and CoFeB as amorphous phases. The full width at half maximum (FWHM) of the Co(0002) peak, decreases as the AlO_x thickness increases; revealing that the Co layer becomes more crystalline with increasing thickness. χ_ac result demonstrates that the optimal resonance frequency (f_res) that maximizes the χ_ac value is 500 Hz. As the frequency increases to 1000 Hz, the susceptibility decreases rapidly. However, when the frequency increases over 1000 Hz, the susceptibility sharply declines, and almost closes to zero. The experimental results reveal that the mean optimal susceptibility is 1.87 at an AlO_x barrier layer thickness of 30 Å because the Co(0002) texture induces magneto-anisotropy, which improves the indirect CoFeB and Co spin exchange-coupling strength and the χ_ac value. The results concerning magnetism indicate that the magnetic characteristics are related to the crystallinity of Co. Full article