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Yttria Stabilised Zirconia (YSZ) is a tough, phase-transforming ceramic that finds use in a wide range of commercial applications from dental prostheses to thermal barrier coatings. Micromechanical modelling of phase transformation can deliver reliable predictions in terms of the influence of temperature and stress. However, models must rely on the accurate knowledge of single crystal elastic stiffness constants. Some techniques for elastic stiffness determination are well-established. The most popular of these involve exploiting frequency shifts and phase velocities of acoustic waves. However, the application of these techniques to YSZ can be problematic due to the micro-twinning observed in larger crystals. Here, we propose an alternative approach based on selective elastic strain sampling (e.g., by diffraction) of grain ensembles sharing certain orientation, and the prediction of the same quantities by polycrystalline modelling, for example, the Reuss or Voigt average. The inverse problem arises consisting of adjusting the single crystal stiffness matrix to match the polycrystal predictions to observations. In the present model-matching study, we sought to determine the single crystal stiffness matrix of tetragonal YSZ using the results of timeof- flight neutron diffraction obtained from an in situ compression experiment and Finite Element modelling of the deformation of polycrystalline tetragonal YSZ. The best match between the model predictions and observations was obtained for the optimized stiffness values of C11=451, C33=302, C44=39, C66=82, C12=240, and C13=50 (units: GPa). Considering the significant amount of scatter in the published literature data, our result appears reasonably consistent. [ABSTRACT FROM AUTHOR]

We present a comprehensive study of free-charge carrier and structural properties of two sets of InN films grown by molecular beam epitaxy and systematically doped with Mg from 1.0×1018 cm-3 to 3.9×1021 cm-3. The free electron and hole concentration, mobility, and plasmon broadening parameters are determined by infrared spectroscopic ellipsometry. The lattice parameters, microstructure, and surface morphology are determined by high-resolution X-ray diffraction and atomic force microscopy. Consistent results on the free-charge carrier type are found in the two sets of InN films and it is inferred that p-type conductivity could be achieved for 1.0×1018 cm-3≲[Mg]≲9.0×1019 cm-3. The systematic change of free-charge carrier properties with Mg concentration is discussed in relation to the evolution of extended defect density and growth mode. A comparison between the structural characteristics and free electron concentrations in the films provides insights in the role of extended and point defects for the n-type conductivity in InN. It further allows to suggest pathways for achieving compensated InN material with relatively high electron mobility and low defect densities. The critical values of Mg concentration for which polarity inversion and formation of zinc-blende InN occurred are determined. Finally, the effect of Mg doping on the lattice parameters is established and different contributions to the strain in the films are discussed. [ABSTRACT FROM AUTHOR]

We have studied hydrogen impurities and related structural properties in state-of-the-art wurtzite InN films with polar, nonpolar, and semipolar surface orientations. The effects of thermal annealing and chemical treatment on the incorporation and stability of H are also discussed. The near-surface and bulk hydrogen concentrations in the as-grown films increase when changing the surface orientation from (0001) to ([formula]) to ([formula]) and to ([formula]), which may be associated with a decrease in the grain size and change of the growth mode from 2D to 3D. Thermal annealing at 350oC in N2 leads to a reduction of H concentrations and the intrinsic levels of bulk H are found to correlate with the structural quality and defects in the annealed films. [ABSTRACT FROM AUTHOR]

We present a detailed study of the structural characteristics of molecular beam epitaxy grown nonpolar InN films with a- and m-plane surface orientations on r-plane sapphire and (100) γ-LiAlO2, respectively, and semipolar (1011) InN grown on r-plane sapphire. The on-axis rocking curve (RC) widths were found to exhibit anisotropic dependence on the azimuth angle with minima at InN [0001] for the a-plane films, and maxima at InN [0001] for the m-plane and semipolar films. The different contributions to the RC broadening are analyzed and discussed. The finite size of the crystallites and extended defects are suggested to be the dominant factors determining the RC anisotropy in a-plane InN, while surface roughness and curvature could not play a major role. Furthermore, strategy to reduce the anisotropy and magnitude of the tilt and minimize defect densities in a-plane InN films is suggested. In contrast to the nonpolar films, the semipolar InN was found to contain two domains nucleating on zinc-blende InN(111)A and InN(111)B faces. These two wurtzite domains develop with different growth rates, which was suggested to be a consequence of their different polarity. Both, a- and m-plane InN films have basal stacking fault densities similar or even lower compared to nonpolar InN grown on free-standing GaN substrates, indicating good prospects of heteroepitaxy on foreign substrates for the growth of InN-based devices. [ABSTRACT FROM AUTHOR]

The lattice parameters and strain evolution in Al1-xInxN films with 0.07≤x≤0.22 grown on GaN-buffered sapphire substrates by metal organic vapor phase epitaxy have been studied by reciprocal space mapping. Decoupling of compositional effects on the strain determination was accomplished by measuring the In contents in the films both by Rutherford backscattering spectrometry (RBS) and x-ray diffraction (XRD). Differences between XRD and RBS In contents are discussed in terms of compositions and biaxial strain in the films. It is suggested that strain plays an important role for the observed deviation from Vegard’s rule in the case of pseudomorphic films. On the other hand, a good agreement between the In contents determined by XRD and RBS is found for Al1-xInxN films with low degree of strain or partially relaxed, suggesting applicability of Vegard’s rule in the narrow compositional range around the lattice matching to GaN. [ABSTRACT FROM AUTHOR]

Only double-outlet right ventricle and pulmonary artery stenosis were diagnosed on prenatal ultrasound. Double-outlet right ventricle and pulmonary artery stenosis were diagnosed on prenatal ultrasound. Congenital heart disease (CHD) is the most common birth defect in newborns, with an incidence of 4.0-6.0% in China. [Extracted from the article]

OBJECTIVE: To discover the impact of the various degrees of coronary artery stenosis (CAD) on the left ventricular systolic dysfunction in steady state with quantitative analysis of the regional systolic myocardium in longitudinal, radial and circumferential direction in patients with coronary artery disease by two-dimensional speckle tracking imaging (STI). PATIENTS AND METHODS: Forty-three normal wall motion-multi vessel coronary artery disease (NWM-MVD) patients labeled as the experimental groups and forty-two subjects with little risk of CAD marked as the control group were enrolled in this study. The two-dimensional STI was obtained in the apical long axis and three levels of the short axis of the left ventricle. The left ventricular wall was divided into 18 segments. The affected myocardia were divided into three groups: group B (coronary stenosis degree ≤50%), group C (coronary stenosis degree 50%-99%)and group D (coronary stenosis degree ≥99%). Using the Q-analysis software, the longitudinal, radial and circumferential systolic strain (SL, SR, SC) and strain ratio (SrL, SrR, SrC) of the myocardium were analyzed. RESULTS: The bradycardia in the NWM-MVD group is greater than that in the control group (16/43 vs. 7/42, p <0.05). Compared with the control group, the SL and SR of group B, group C and group D decreased significantly (p <0.05). Compared with group C, the SL of group D also decreased significantly (p <0.05). However, there was no SC difference among the four groups. Meanwhile, compared with group A, the SrL, SrR and SrC of group B, group C and group D decreased significantly (p <0.05). Compared with group A, group B and group C, the SrL and SrC of group D also decreased (p <0.05). Compared with group A and group C, the SrR of group D decreased. The SrL was equal to 1.085 for the cut-off value, and the sum (1.348) of sensitivity (0.673) and specificity (0.675) were the greatest. Bland-Altman analysis showed that there was myocardium conformity of in both the multi-vessel CAD patients and the control subjects. CONCLUSIONS: Myocardial systolic function was impaired in the MVD patients of group B (coronary stenosis degree ≤50%), group C (coronary stenosis degree 50%-99%)and group D (coronary stenosis degree ≥99%), especially the longitudinal and radial systolic function, even though they had normal wall motion. The SrL equaled 1.085 for the cut-off value, and the sums (1.348) of sensitivity (0.673) and specificity (0.675) were the greatest. Bradycardia might be a compensatory mechanism in NWM-MVD patients. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To evaluate the clinical value of two-dimensional speckle tracking echocardiography for analyzing the left ventricular systolic function in patients with multivessel coronary artery disease with normal wall motion (NWM-MVD). PATIENTS AND METHODS: Forty-five NWMMVD patients and thirty-six subjects with low risk of coronary artery disease (control group) were enrolled in this study. Echocardiogram images of the short axis of the left ventricle and apical long axis were obtained. The Q-analysis software was used to analyze the peak systolic strain of the left ventricular segments and the global longitudinal strain (GLS). We calculated the left ventricular global circumferential strain (GCS) and the radial strain (GRS), as well as the longitudinal, radial and circumferential strain of the basal (Bas-GLS, Bas-GCS, Bas-GRS), middle (Mid-GLS, Mid-GCS, Mid-GRS) and apical segments (Ap-GLS, Ap-GCS, Ap-GRS). RESULTS: (1) The coronary occlusion or subtotal occlusion were visible in 85.71% of the NWM-MVD patients. (2) The heart rate of the NWM-MVD patients was lower than that of the control group [(61.78 ± 6.76) beats/min vs. (66.13 ± 6.24) beats/min, p < 0.05]. The conventional ultrasonic measurement indices are similar between the NWM-MVD group and the control group (p > 0.05). (3) Compared with the control group, the GLS, Bas-GLS, Mid-GLS, Bas- GCS, Mid-GCS, GRS and Bas-GRS were lower in the NWM-MVD group (p < 0.05). CONCLUSIONS: The longitudinal, circumferential and radial systolic functions of the NWMMVD patients were impaired at different degrees. [ABSTRACT FROM AUTHOR]

We present a theoretical analysis on the applicability of Vegard's linear rule in InxAl-xN alloys in relation to strain related elastic and piezoelectric properties. We derive the elastic stiffness constants and biaxial coefficients, as well as the respective deviations from linearity (Vegard's rule) by using ab initio calculations. The stress-strain relationships to extract composition from the lattice parameters are derived in different coordinate systems for InxAl1-xN with an arbitrary surface orientation. The error made in the composition extracted from the lattice parameters if the deviations from linearity are not taken into account is discussed for different surface orientations, compositions and degrees of strain in the InxAl-xN films. The strain induced piezoelectric polarization is analyzed for InxAl1-xN alloys grown pseudomorphically on GaN. The polarization values are compared with those obtained from our experimental data for the lattice parameters. We establish the importance of the deviation from linearity to correctly determine the piezoelectric polarization and also a smooth, not particular piezoelectric response at GaN lattice matched conditions. [ABSTRACT FROM AUTHOR]

The lattice parameters of InxAl1-xN in the whole compositional range are studied using first-principle calculations. Deviations from Vegard’s rule are obtained via the bowing parameters, δa=0.0412±0.0039 Å and δc=-0.060±0.010 Å, which largely differ from previously reported values. Implications of the observed deviations from Vegard’s rule on the In content extracted from x-ray diffraction are discussed. We also combine these results with x-ray diffraction and Raman scattering studies on InxAl1-xN nanocolumns with 0.627<=x<=1 and determine the E2 phonon frequencies versus In composition in the scarcely studied In-rich compositional range. [ABSTRACT FROM AUTHOR]

Objective: To establish a three-dimensional model of middle ear-eustachian tube based on Chinese digital visual human dataset, and the deformation and pressure changes of the middle ear-eustachian tube system after eustachian tube opening are simulated by computer numerical simulation. Methods: The first female Chinese Digital Visual Human data was adopted. The images were imported by Amira image processing software, and the images were segmented by Geomagic software to form a three-dimensional model of middle ear-eustachian tube system, including eustachian tube, tympanum, tympanic membrane, auditory ossicles, and mastoid air cells system. The 3D model was imported into Hypermesh software for meshing and analysis. The structural mechanics calculation was carried out by Abaqus, and gas flow was simulated by Xflow. The tissue deformation and middle ear pressure changes during eustachian tube opening were numerically simulated by fluid-solid coupling algorithm. Several pressure monitoring points including tympanum, mastoid, tympanic isthmus, and external auditory canal were set up in the model, and the pressure changes of each monitoring point were recorded and compared. Results: In this study, a three-dimensional model of middle ear-eustachian tube and a numerical simulation model of middle ear ventilation were established, including eustachian tube, tympanum, mastoid air cells, tympanic membrane, and auditory ossicles. The dynamic changes of the model after ventilation could be divided into five stages according to the pressure. In addition, the pressure changes of tympanum and tympanic isthmus were basically synchronous, and the pressure changes of mastoid air cells system were later than that of tympanum and tympanic isthmus, which verified the pressure buffering effect of mastoid. The extracted pressure curve of the external auditory canal was basically consistent with that of tympanometry in terms of value and trend, which verified the effectiveness of the model. Conclusions: The numerical simulation model of middle ear-eustachian tube ventilation established in this paper can simulate the tissue deformation and middle ear pressure changes after eustachian tube opening, and its accuracy and effectiveness are also verified. This not only lays a foundation for further research, but also provides a new research method for the study of middle ear ventilation.

Background: Orexin A, a small-molecule peptide, can regulate female hormones, but limited evidence for its mechanism of activity exists in ovine., Aims: The objective of this study was to investigate the effect of orexin A on progesterone (P4) secretion in cultured granulosa of sheep follicles., Methods: Sheep ovarian granulosa were isolated and identified, pre-incubated with luteinizing hormone (LH) (2.5 IU/ml), follicle-stimulating hormone (FSH) (2.5 IU/ml), or oestrogen (1 µg/ml); and cultured in vitro . The pretreated sheep ovarian granulosa were subsequently cultured with different concentrations (1 nM, 10 nM, 58 nM, 100 nM, and 145 nM) of orexin A for varying amounts of time (0 h, 24 h, 48 h, and 72 h). Then, the expression levels of P4, steroidogenic acute regulatory protein (StAR), 3β-Hydroxysteroid dehydrogenase (3β-HSD) and cytochrome P450 (CYP11) were determined., Results: The results showed that the sheep ovarian granulosa were correctly identified. The different concentrations of orexin A promoted the secretion of P4 from granulosa in the ovine ovary compared with that in the control. The expression of StAR, 3β-HSD and P450 (CYP11) gradually increased, and then decreased with increasing concentrations of orexin A, but the expression of P450 (CYP11) decreased with the increase of time., Conclusion: These results revealed that orexin A promotes the secretion of P4 by regulating the expression of StAR, 3β-HSD, and P450 (CYP11). Understanding the mechanism underlying the promotion of P4 by orexin A could open new therapeutic possibilities in the treatment of hormone homeostasis.