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The structural, elastic, and basic thermodynamic properties of hexagonal ScxAl1−xN crystals are calculated and discussed over the whole range of possible random alloys, including the transition from wurtzite to the layered hexagonal structure. Based on a review of lattice and internal parameters in combination with complete datasets of stiffness coefficients published in the literature, differing in the considered alloying intervals and the predicted structural transitions, changes in the crystal lattices caused by the substitution of aluminum by scandium atoms are discussed and illustrated. Crystal properties like the mass densities, average bond angles, and bond lengths are calculated, and the compliance coefficients, Young's modulus, shear modulus, Poisson's ratio, compressibility, and sound velocities are determined depending on the alloy composition and in relation to the orientation of crystal planes and axes. Particular attention is paid to the occurring directional anisotropies and the changes in structural and elastic properties in the alloy region of the structural transition between wurtzite and layered hexagonal ScxAl1−xN crystals. The acoustic velocities determined are used to calculate basic thermodynamic properties such as the Debye temperature, heat capacity, and minimum heat conduction, as well as to evaluate both the influence of the alloying and the structural transition on these properties. [ABSTRACT FROM AUTHOR]

In this work, surface acoustic wave (SAW) modes and their dependence on propagation directions in epitaxial Al 0.68 Sc 0.32 N(0001) films on Al 2 O 3 (0001) substrates were studied using numerical and experimental methods. In order to find optimal propagation directions for higher-order SAW modes, phase velocity dispersion branches of Al 0.68 Sc 0.32 N on Al 2 O 3 with Pt mass loading were computed for the propagation directions <11 2 ¯ 0> and <1 1 ¯ 00> with respect to the substrate. Experimental investigations of phase velocities and electromechanical coupling were performed for comparison with the numerical results. Simulations carried out with the finite element method and a Green function approach allowed identification of each wave type, including Rayleigh, Sezawa, and shear-horizontal wave modes. For the propagation direction <1 1 ¯ 00>, significantly increased wave guidance of the Sezawa mode compared to other directions was observed, resulting in enhanced electromechanical coupling (k eff 2 = 1.6 %) and phase velocity (v phase = 6 km / s). We demonstrated that selecting wave propagation in <1 1 ¯ 00> with high mass density electrodes results in increased electromechanical coupling without significant reduction in phase velocities for the Sezawa wave mode. An improved combination of metallization, Sc concentration x , and SAW propagation direction is suggested that exhibits both high electromechanical coupling (k eff 2 > --> 6 %) and high velocity (v phase = 5.5 km / s) for the Sezawa mode. [ABSTRACT FROM AUTHOR]

We present detailed investigations of the structural, elastic, dielectric, and piezoelectric properties of scandium aluminum nitride (ScxAl1−xN) with the wurtzite crystal structure by means of first-principles calculations based on density functional theory in order to enable a detailed comparison to the corresponding physical properties of GaAlN and InAlN. The goal of our approach is to use atomistic simulations to extract the novel solid state characteristics of ScxAl1−xN crystals by the determination of complete sets of coefficients for the elastic, compliance, and piezoelectric tensor and to confirm the theoretical predictions by experimental measurements of selected tensor coefficients. The calculation of the tensor components is accompanied by a detailed analysis of the crystal structures, e.g., average bond length, bond angles, lattice parameters, and mass density in dependence on alloy composition of ScxAl1−xN. If an increasing number of Al atoms of up to x = 0.5 are replaced by Sc atoms, we observe a nonlinear change of the ratio of lattice parameter c (x) a (x) and average bond angles of about 10% and 5%, respectively, which give an indication of an increasing deviation of the crystal structure of ScxAl1−xN from an ideal hexagonal lattice. As a consequence of the deformed crystal structure and the iconicity of the Sc–N bond, we predict a change in value of the elastic coefficient C 33 S c A l N (x) , the piezoelectric coefficient e 33 S c A l N (x) , and the value of spontaneous polarization P S P S c A l N (x) of up to 65%, 150%, and 230%, respectively. Based, on these simulation results, physical features of practical use are derived, like the average bulk, shear, and the Young modulus as well as the reciprocal Young's modulus and Poisson ratio. Furthermore, the spontaneous polarization of ScxAl1−xN is approximated, taking nonlinear effects into account as well as the piezoelectric polarization caused by uniaxial, biaxial, and hydrostatic stresses in dependency on alloy composition and strain. A detailed comparison of the structural and polarization related properties of GaAlN and InAlN allows us to point out the peculiarity of wurtzite ScAlN crystals within the group III-nitrides. [ABSTRACT FROM AUTHOR]

This work reports on the growth of 1 µm nonpolar a-plane Al0.7Sc0.3N(11 2 ¯ 0) thin films on an r-plane sapphire Al2O3(1 1 ¯ 02) via magnetron sputter epitaxy. The electro-acoustic properties of the film structures were characterized using surface acoustic wave (SAW) resonators. Measured electrical responses were found to be strongly anisotropic in terms of the wave propagation direction. We identified a sagittal polarized Rayleigh wave mode with large coupling ( k eff 2 = 3.7%), increased phase velocity (v = 4825 m/s), as well as high quality factor (Q > 1000) for SAW propagation along the c-axis [0001] and normalized thicknesses h / λ = 0.2. Finite element method simulations using electro-acoustic properties of Al0.7Sc0.3N obtained from the density functional theory reproduce our experimental results. [ABSTRACT FROM AUTHOR]

In accordance but more pronounced in comparison to the minimum thermal conductivity, which results from heat propagation by phonons, the diffusive thermal conductivity of I wz- i Sc I SB x sb i Al SB 1- I x i sb N decreases linearly with increasing I x i . Also, for I hl- i ScN ( HT ht ) the minimum thermal conductivity increases significantly with increasing temperature. Within the accuracy of our calculation, the minimum thermal conductivity of layered hexagonal crystals ( HT ht ) stays constant. [Extracted from the article]

Discussing plant-based diets and substitutions for animal-based foods in food-based dietary guidelines (FBDGs) can be a key step in making dietary recommendations more sustainable and healthy as well as more inclusive. The existing large-scale evaluations of FBDGs do not assess whether and to what extent countries cover the broad spectrum of plant-based diets and have policy positions on vegetarian diets, including vegan diets, and whether they mention specific plant-based alternatives to milk, dairy products, and meat. The main aim of this state-of-the-art review was to determine whether and how FBDGs provide such information. An overall 95 guidelines and 100 corresponding countries were assessed via an exploratory sequential mixed method. This involved qualitative explorative content analysis of the guidelines, followed by hierarchical cluster analysis. Furthermore, the Balanced Food Choice Index (BFCI) was constructed, which measures the extent to which FBDGs provide recommendations that cover the broad spectrum of plant-based diets, with some or no animal-based products. To explore the correlations between FBDGs' recommendations and ecological and economic country characteristics, ordinary least squares regression was used. It was found that most countries do not provide information to their citizens that cover the broad spectrum of plant-based diets, as indicated by the mean score of the BFCI (33.58 of 100 points). A total of 38 guidelines (40%) contain a position on vegetarian diets. Nearly half (45%) of all FBDGs already mention plant-based alternatives to meat or animal milk. The regressions showed that the BFCI correlates positively with countries' ecological efforts and negatively with the importance of animal-based products in their economies. This study demonstrates considerable information insufficiency in current FBDGs worldwide. FBDGs should provide recommendations for the broad spectrum of plant-based diets and balance the ethical, ecological, religious, and economic aspects that play a role in people's food choice., (© The Author(s) 2022. Published by Oxford University Press on behalf of the American Society for Nutrition.)

This is a case report of a ureteral obstruction from inguinal hernia entrapment with an ipsilateral cryptorchid testis in a 45-year-old male with an ectopic pelvic kidney. Ureteral herniation is unusual and to our knowledge has not been described in the setting of a patient with an ectopic pelvic kidney and undescended testis. The patient initially presented at an outside hospital with mild right lower quadrant abdominal pain and scrotal fullness, and initial computed tomography (CT) imaging demonstrated a pelvic right kidney with an indirect right inguinal hernia containing an entrapped ureter resulting in severe hydronephrosis. The CT also revealed an undescended testis on the patient's right side. A nephrostomy tube was then placed in the right kidney under interventional radiological (IR) guidance and subsequent CT urography showed resolution of hydronephrosis. Surgical hernia repair was followed up on a later date. The discussion addresses the unique pathological features of this case while highlighting the relevant complications of a ureteral herniation., Topics: Pelvic kidney, renal ectopia, ureteral obstruction, cryptorchidism, undescended testis., (© 2022 Feil, et al.)

Background and Objectives: One of the challenges in developing effective hair loss therapies is the lack of reliable methods to monitor treatment response or alopecia progression. In this study, we propose the use of optical coherence tomography (OCT) and automated deep learning to non-invasively evaluate hair and follicle counts that may be used to monitor the success of hair growth therapy more accurately and efficiently., Study Design/materials and Methods: We collected 70 OCT scans from 14 patients with alopecia and trained a convolutional neural network (CNN) to automatically count all follicles present in the scans. The model is based on a dual approach of both detecting hair follicles and estimating the local hair density in order to give accurate counts even for cases where two or more adjacent hairs are in close proximity to each other., Results: We evaluate our system on 70 OCT manually labeled scans taken at different scalp locations from 14 patients, with 20 of those redundantly labeled by two human expert OCT operators. When comparing the individual human predictions and considering the exact locations of hair and follicle predictions, we find that the two human raters disagree with each other on approximately 22% of hairs and follicles. Overall, the deep learning (DL) system predicts the number of follicles with an error rate of 11.8% and the number of hairs with an error rate of 18.7% on average on the 70 scans. The OCT system can capture one scalp location in three seconds, and the DL model can make all predictions in less than a second after processing the scan, which takes half a minute using an unoptimized implementation., Conclusion: This approach is well-positioned to become the standard for non-invasive evaluation of hair growth treatment progress in patients, saving significant amounts of time and effort compared with manual evaluation. Lasers Surg. Med. © 2020 Wiley Periodicals, Inc., (© 2020 Wiley Periodicals LLC.)