Objective To accurately estimate liver PDFF from chemical shift-encoded (CSE) MRI using a deep learning (DL)-based MultiDecoder Water-Fat separation Network (MDWF-Net), that operates over complex-valued CSE-MR images with only 3 echoes. Methods The proposed MDWF-Net and a U-Net model were independently trained using the frst 3 echoes of MRI data from 134 subjects, acquired with conventional 6-echoes abdomen protocol at 1.5 T. Resulting models were then evaluated using unseen CSE-MR images obtained from 14 subjects that were acquired with a 3-echoes CSE-MR pulse sequence with a shorter duration compared to the standard protocol. Resulting PDFF maps were qualitatively assessed by two radiologists, and quantitatively assessed at two corresponding liver ROIs, using Bland Altman and regression analysis for mean values, and ANOVA testing for standard deviation (STD) (signifcance level: .05). A 6-echo graph cut was considered ground truth. Results Assessment of radiologists demonstrated that, unlike U-Net, MDWF-Net had a similar quality to the ground truth, despite it considered half of the information. Regarding PDFF mean values at ROIs, MDWF-Net showed a better agreement with ground truth (regression slope=0.94, R2=0.97) than U-Net (regression slope=0.86, R2=0.93). Moreover, ANOVA post hoc analysis of STDs showed a statistical diference between graph cuts and U-Net (p<.05), unlike MDWF-Net (p=.53). Conclusion MDWF-Net showed a liver PDFF accuracy comparable to the reference graph cut method, using only 3 echoes and thus allowing a reduction in the acquisition times. Clinical relevance statement We have prospectively validated that the use of a multi-decoder convolutional neural network to estimate liver proton density fat fraction allows a signifcant reduction in MR scan time by reducing the number of echoes required by 50%. Key Points • Novel water-fat separation neural network allows for liver PDFF estimation by using multi-echo MR images with a reduced number of echoes. • Prospective single-center validation demonstrated that echo reduction leads to a signifcant shortening of the scan time, compared to standard 6-echo acquisition. • Qualitative and quantitative performance of the proposed method showed no signifcant diferences in PDFF estimation with respect to the reference technique.

The crystal growth of boric acid from an aqueous solution in the absence and presence of sodium and lithium sulfate was studied by real-time monitoring. For this purpose, atomic force microscopy in situ has been used. The results show that the growth mechanism of boric acid from its pure and impure solutions is spiral growth driven by screw dislocation and that the velocity of advancement of steps on the crystal surface, and the relative growth rate (ratio of the growth rate in presence and absence of a salt) is reduced in the presence of salts. The reduction of the relative growth rate could be explained by the inhibition of advancement of steps of the (001) face mainly in the growth direction [100] caused by the adsorption of salts on the actives sites and the inhibition of the formation of sources of steps such as dislocations. The adsorption of the salts on the crystal surface is anisotropic and independent of the supersaturation and preferentially on the active sites of the (100) edge. Moreover, this information is of significance for the improvement of the quality of boric acid recovered from brines and minerals and the synthesis of nanostructures and microstructures of boron-based materials.

Student ratings are now an accepted orthodoxy in global higher education environments. They form an increasingly important metric that has been assimilated as a robust proxy measure of quality for evaluating individual, institutional and even system-level performativity. Although the technical design aspects of student ratings have received extensive attention, the broad sociocultural contexts of their use in higher education settings have had considerably less attention. In this study, a meta-synthesis framed by a critical sociocultural perspective was used to investigate the social evolution of student ratings over the last four decades. The outcomes suggest that student ratings have developed through three primary motives: an originating democratic improvement imperative; a dominating quality assurance assimilation and the emerging drive of satisfying the student-as-consumer. This analysis suggests that student ratings cannot be understood only in their benign technical form but must also be considered as performing significant functions in supporting the changing social imperatives of evolving higher education policy.