VAEs with structured image covariance applied to compressed sensing MRI.

Objective.This paper investigates how generative models, trained on ground-truth images, can be used as priors for inverse problems, penalizing reconstructions far from images the generator can produce. The aim is that learned regularization will provide complex data-driven priors to inverse problems while still retaining the control and insight of a variational regularization method. Moreover, unsupervised learning, without paired training data, allows the learned regularizer to remain flexible to changes in the forward problem such as noise level, sampling pattern or coil sensitivities in MRI.Approach.We utilize variational autoencoders that generate not only an image but also a covariance uncertainty matrix for each image. The covariance can model changing uncertainty dependencies caused by structure in the image, such as edges or objects, and provides a new distance metric from the manifold of learned images.Main results.We evaluate these novel generative regularizers on retrospectively sub-sampled real-valued MRI measurements from the fastMRI dataset. We compare our proposed learned regularization against other unlearned regularization approaches and unsupervised and supervised deep learning methods.Significance.Our results show that the proposed method is competitive with other state-of-the-art methods and behaves consistently with changing sampling patterns and noise levels.

Direct calculation of the temperature dependence of 2D-IR spectra: Urea in water.

A method for directly calculating the temperature derivative of two-dimensional infrared (2D-IR) spectra from simulations at a single temperature is presented. The approach is demonstrated by application to the OD stretching spectrum of isotopically dilute aqueous (HOD in H2O) solutions of urea as a function of concentration. Urea is an important osmolyte because of its ability to denature proteins, which has motivated significant interest in its effect on the structure and dynamics of water. The present results show that the temperature dependence of both the linear IR and 2D-IR spectra, which report on the underlying energetic driving forces, is more sensitive to urea concentration than the spectra themselves. Additional physical insight is provided by calculation of the contributions to the temperature derivative from different interactions, e.g., water-water, water-urea, and urea-urea, present in the system. Finally, it is demonstrated how 2D-IR spectra at other temperatures can be obtained from only room temperature simulations.

Cue polarization and representation in mouse home base behaviors.

The nature of the representation guiding spatial navigation has been investigated extensively; however, most of this work has used behavioral tasks that involved learning the location of food reward or an escape platform. In contrast, relatively few studies have focused on the spatial representation of a home base, a ubiquitous feature of open-field behavior, and its ability to be encoded relative to environmental cues. The current set of experiments investigated acquisition and retention of the location of home base establishment. In general, proximal cues anchored the position of the home base during acquisition sessions across all four experiments. Although mice established a home base during retention sessions, previous experience did not influence its position during retention sessions. These observations demonstrate that stimulus control of home base position depends on access to proximal cues. Further work is needed to determine the extent that home base establishment may provide a framework to encode goal-directed spatial behaviors.

Artificial intelligence (AI)-assisted exome reanalysis greatly aids in the identification of new positive cases and reduces analysis time in a clinical diagnostic laboratory.

PURPOSE: Artificial intelligence (AI) and variant prioritization tools for genomic variant analysis are being rapidly developed for use in clinical diagnostic testing. However, their clinical utility and reliability are currently limited. Therefore, we performed a validation of a commercial AI tool (Moon) and a comprehensive reanalysis of previously collected clinical exome sequencing cases using an open-source variant prioritization tool (Exomiser) and the now-validated AI tool to test their feasibility in clinical diagnostics. METHODS: A validation study of Moon was performed with 29 positive cases determined by previous manual analysis. After validation, reanalysis was performed on 80 previously manually analyzed nondiagnostic exome cases using Moon. Finally, a comparison between Moon and Exomiser was completed regarding their ability to identify previously completed positive cases and to identify new positive cases. RESULTS: Moon correctly selected the causal variant(s) in 97% of manually analyzed positive cases and identified 7 new positive cases. Exomiser correctly identified the causal gene in 85% of positive cases and agreed with Moon by ranking the new gene in its top 10 list 43% of the time. CONCLUSION: The use of AI in diagnostic laboratories greatly enhances exome sequencing analysis by reducing analysis time and increasing the diagnostic rate.

Dietary Sodium 'Controversy'-Issues and Potential Solutions.

PURPOSE OF REVIEW: High dietary sodium is estimated to be the leading dietary risk for death attributed to 1.8 million deaths in 2019. There are uniform recommendations to reduce sodium consumption based on evidence that increased dietary sodium is responsible for approximately a third of the prevalence of hypertension, and meta-analyses of randomized controlled trials show that sodium reduction lowers blood pressure, cardiovascular disease, and total mortality. Nevertheless, there is a perception that the beneficial effect of reducing dietary sodium is controversial. We provide experiential evidence relating to some sources of the controversy and propose potential solutions. RECENT FINDINGS: Inappropriate research methodology, lack of rigor in research, conflicts of interest and commercial bias, questions of professional conduct, and lack of policies to protect public interests are likely to contribute to the controversy about reducing dietary sodium. There is a failure to protect policies to reduce dietary sodium from nonscientific threats. Significant efforts need to be made to ensure the integrity of nutritional research and maintain public trust.

Building a national hernia registry in South Africa: initial ventral hernia repair results from a diverse healthcare sector.

PURPOSE: The purpose of this paper was to introduce a new registry in a developing country by describing the demographics, management and 30-day outcomes of patients undergoing ventral hernia repair in the public and private healthcare sectors of South Africa. METHODS: This study was a retrospective review of a prospectively maintained hernia registry from the 1st of February 2019 to 29th of February 2020. RESULTS: 353 ventral hernia repair cases were recorded of which 47% were incisional hernias and the remainder were primary hernias. The median age was 54 years with even distribution of males and females. Half of the patients were obese with a median BMI of 31 kg/m2. The private sector performed 190 cases (54%) and the public sector 163 cases (46%). The public sector had more current smokers undergoing elective repairs, 28% vs 15%, p = 0.01 and performed more emergency repair cases, 21% vs 8%, p < 0.01. The majority (89%) of hernias were repaired with mesh and one-third were repaired laparoscopically. 30 day follow up was obtained in 30% of cases, the private sector had better follow up rates (42% vs 14%). CONCLUSION: Participation in the HIG (SA) registry was low with poor follow up over the first year. Ongoing prospective data capture on the HIG (SA) hernia registry will continue to provide further insights into hernia repair practices in South Africa.

Controlling spin current polarization through non-collinear antiferromagnetism.

The interconversion of charge and spin currents via spin-Hall effect is essential for spintronics. Energy-efficient and deterministic switching of magnetization can be achieved when spin polarizations of these spin currents are collinear with the magnetization. However, symmetry conditions generally restrict spin polarizations to be orthogonal to both the charge and spin flows. Spin polarizations can deviate from such direction in nonmagnetic materials only when the crystalline symmetry is reduced. Here, we show control of the spin polarization direction by using a non-collinear antiferromagnet Mn3GaN, in which the triangular spin structure creates a low magnetic symmetry while maintaining a high crystalline symmetry. We demonstrate that epitaxial Mn3GaN/permalloy heterostructures can generate unconventional spin-orbit torques at room temperature corresponding to out-of-plane and Dresselhaus-like spin polarizations which are forbidden in any sample with two-fold rotational symmetry. Our results demonstrate an approach based on spin-structure design for controlling spin-orbit torque, enabling high-efficient antiferromagnetic spintronics.

Anisotropic spin-orbit torque generation in epitaxial SrIrO3 by symmetry design.

Spin-orbit coupling (SOC), the interaction between the electron spin and the orbital angular momentum, can unlock rich phenomena at interfaces, in particular interconverting spin and charge currents. Conventional heavy metals have been extensively explored due to their strong SOC of conduction electrons. However, spin-orbit effects in classes of materials such as epitaxial 5d-electron transition-metal complex oxides, which also host strong SOC, remain largely unreported. In addition to strong SOC, these complex oxides can also provide the additional tuning knob of epitaxy to control the electronic structure and the engineering of spin-to-charge conversion by crystalline symmetry. Here, we demonstrate room-temperature generation of spin-orbit torque on a ferromagnet with extremely high efficiency via the spin-Hall effect in epitaxial metastable perovskite SrIrO3 We first predict a large intrinsic spin-Hall conductivity in orthorhombic bulk SrIrO3 arising from the Berry curvature in the electronic band structure. By manipulating the intricate interplay between SOC and crystalline symmetry, we control the spin-Hall torque ratio by engineering the tilt of the corner-sharing oxygen octahedra in perovskite SrIrO3 through epitaxial strain. This allows the presence of an anisotropic spin-Hall effect due to a characteristic structural anisotropy in SrIrO3 with orthorhombic symmetry. Our experimental findings demonstrate the heteroepitaxial symmetry design approach to engineer spin-orbit effects. We therefore anticipate that these epitaxial 5d transition-metal oxide thin films can be an ideal building block for low-power spintronics.

Isostructural metal-insulator transition in VO2.

The metal-insulator transition in correlated materials is usually coupled to a symmetry-lowering structural phase transition. This coupling not only complicates the understanding of the basic mechanism of this phenomenon but also limits the speed and endurance of prospective electronic devices. We demonstrate an isostructural, purely electronically driven metal-insulator transition in epitaxial heterostructures of an archetypal correlated material, vanadium dioxide. A combination of thin-film synthesis, structural and electrical characterizations, and theoretical modeling reveals that an interface interaction suppresses the electronic correlations without changing the crystal structure in this otherwise correlated insulator. This interaction stabilizes a nonequilibrium metallic phase and leads to an isostructural metal-insulator transition. This discovery will provide insights into phase transitions of correlated materials and may aid the design of device functionalities.

A randomized controlled trial to prevent obesity among Latino paediatric patients.

BACKGROUND: Obesity disproportionately affects Latino youth. Community clinics are an important resource, yet there is little evidence for the efficacy of clinic-based approaches in this population. OBJECTIVE: The purpose of this study was to test the efficacy of a clinic-based intervention to lower body mass index (BMI) and improve body composition among overweight Latino children. METHODS: A randomized trial (2 group × 3 repeated measures) was conducted among 297 randomly sampled, overweight paediatric patients (5-10 years old) and their parents. The 12-month family-based culturally tailored behavioural intervention (Luces de Cambio) was based on the 'traffic light' concepts to address behaviour change and was delivered by clinic health educators and mid-level providers. The primary study outcome was child BMI (kg m-2 ) assessed at baseline, 6-month (n = 191) and 12-month (n = 201) post-baseline. A subsample of the children was examined for overall and site-specific adiposity using dual-energy X-ray absorptiometry (n = 79). RESULTS: There were no significant intervention effects on child BMI (p > 0.05); however, intervention children showed significantly (p < 0.05) lower total and trunk per cent fat compared with the usual care condition. CONCLUSIONS: The Luces intervention did not reduce child BMI, yet small but significant reductions were observed for child per cent body fat. Further research is needed to identify and reduce barriers to recruitment and participation among Latino families.

Encompassing new use cases - level 3.0 of the HUPO-PSI format for molecular interactions.

BACKGROUND: Systems biologists study interaction data to understand the behaviour of whole cell systems, and their environment, at a molecular level. In order to effectively achieve this goal, it is critical that researchers have high quality interaction datasets available to them, in a standard data format, and also a suite of tools with which to analyse such data and form experimentally testable hypotheses from them. The PSI-MI XML standard interchange format was initially published in 2004, and expanded in 2007 to enable the download and interchange of molecular interaction data. PSI-XML2.5 was designed to describe experimental data and to date has fulfilled this basic requirement. However, new use cases have arisen that the format cannot properly accommodate. These include data abstracted from more than one publication such as allosteric/cooperative interactions and protein complexes, dynamic interactions and the need to link kinetic and affinity data to specific mutational changes. RESULTS: The Molecular Interaction workgroup of the HUPO-PSI has extended the existing, well-used XML interchange format for molecular interaction data to meet new use cases and enable the capture of new data types, following extensive community consultation. PSI-MI XML3.0 expands the capabilities of the format beyond simple experimental data, with a concomitant update of the tool suite which serves this format. The format has been implemented by key data producers such as the International Molecular Exchange (IMEx) Consortium of protein interaction databases and the Complex Portal. CONCLUSIONS: PSI-MI XML3.0 has been developed by the data producers, data users, tool developers and database providers who constitute the PSI-MI workgroup. This group now actively supports PSI-MI XML2.5 as the main interchange format for experimental data, PSI-MI XML3.0 which additionally handles more complex data types, and the simpler, tab-delimited MITAB2.5, 2.6 and 2.7 for rapid parsing and download.

Direct observation of a two-dimensional hole gas at oxide interfaces.

The discovery of a two-dimensional electron gas (2DEG) at the LaAlO3/SrTiO3 interface 1 has resulted in the observation of many properties2-5 not present in conventional semiconductor heterostructures, and so become a focal point for device applications6-8. Its counterpart, the two-dimensional hole gas (2DHG), is expected to complement the 2DEG. However, although the 2DEG has been widely observed 9 , the 2DHG has proved elusive. Herein we demonstrate a highly mobile 2DHG in epitaxially grown SrTiO3/LaAlO3/SrTiO3 heterostructures. Using electrical transport measurements and in-line electron holography, we provide direct evidence of a 2DHG that coexists with a 2DEG at complementary heterointerfaces in the same structure. First-principles calculations, coherent Bragg rod analysis and depth-resolved cathodoluminescence spectroscopy consistently support our finding that to eliminate ionic point defects is key to realizing a 2DHG. The coexistence of a 2DEG and a 2DHG in a single oxide heterostructure provides a platform for the exciting physics of confined electron-hole systems and for developing applications.

Mining for pairs: shared clinic visit dates identify steady HIV-positive partnerships.

OBJECTIVES: Here we examined the hypothesis that some stable HIV-infected partnerships can be found in cohort studies, as the patients frequently attend the clinic visits together. METHODS: Using mathematical approximations and shuffling to derive the probabilities of sharing a given number of visits by chance, we identified and validated couples that may represent either transmission pairs or serosorting couples in a stable relationship. RESULTS: We analysed 434 432 visits for 16 139 Swiss HIV Cohort Study patients from 1990 to 2014. For 89 pairs, the number of shared visits exceeded the number expected. Of these, 33 transmission pairs were confirmed on the basis of three criteria: an extensive phylogenetic tree, a self-reported steady HIV-positive partnership, and risk group affiliation. Notably, 12 of the validated transmission pairs (36%; 12 of 33) were of a mixed ethnicity with a large median age gap [17.5 years; interquartile range (IQR) 11.8-22 years] and these patients harboured HIV-1 of predominantly non-B subtypes, suggesting imported infections. CONCLUSIONS: In the context of the surge in research interest in HIV transmission pairs, this simple method widens the horizons of research on within-pair quasi-species exchange, transmitted drug resistance and viral recombination at the biological level and targeted prevention at the public health level.

Feasibility and safety of lumbosacral epiduroscopy in the standing horse.

REASONS FOR PERFORMING STUDY: The large size of the adult horse prevents the use of advanced imaging modalities in most areas of the axial skeleton, including the lumbosacral vertebral column. Traditional imaging techniques are frequently unable to pinpoint the underlying pathology in horses with caudal back pain. In man, lumbosacral epiduroscopy is used to diagnose and treat subjects with chronic back and leg pain. This technique may close the diagnostic gap in horses with similar clinical signs. OBJECTIVES: To evaluate the safety and feasibility of lumbosacral epiduroscopy in the standing adult horse. STUDY DESIGN: Descriptive, experimental study. METHODS: Seven adult horses weighing 504-578 kg were sedated and restrained in stocks in preparation for aseptic surgery. Vascular dilators of increasing size were inserted cranial to the first moveable vertebra caudal to the sacrum to facilitate a minimally invasive approach into the epidural space. A flexible video-endoscope was introduced and advanced as far as its 60-cm working length permitted. Pre-, intra- and post-operative plasma cortisol samples were collected, and neurological and lameness examinations were performed prior to and during the 2 weeks following the procedure. Post-mortem examinations were conducted in 5 of the 7 horses. RESULTS: Standing lumbosacral epiduroscopy was well tolerated by all horses. The anatomic structures in the epidural space (dura mater, spinal nerve roots, fat and blood vessels) were followed as far cranial as the thoracolumbar region. No complications related to the procedure were noted in the 2-week monitoring period following epiduroscopy. Small, organised haematomas were identified in the sacral epidural space during necropsy in one horse. No abnormalities were seen in the other 4 animals. CONCLUSIONS: Lumbosacral epiduroscopy can be performed safely in sedated standing horses. The procedure may become a valuable diagnostic tool in horses with caudal back or hindlimb pain of unknown origin.

Cardiac rehabilitation delivery model for low-resource settings

"OBJECTIVE: Cardiovascular disease is a global epidemic, which is largely preventable. Cardiac rehabilitation (CR) is demonstrated to be cost-effective and efficacious in high-income countries. CR could represent an important approach to mitigate the epidemic of cardiovascular disease in lower-resource settings. The purpose of this consensus statement was to review low-cost approaches to delivering the core components of CR, to propose a testable model of CR which could feasibly be delivered in middle-income countries. METHODS: A literature review regarding delivery of each core CR component, namely: (1) lifestyle risk factor management (ie, physical activity, diet, tobacco and mental health), (2) medical risk factor management (eg, lipid control, blood pressure control), (3) education for self-management and (4) return to work, in low-resource settings was undertaken. Recommendations were developed based on identified articles, using a modified GRADE approach where evidence in a low-resource setting was available, or consensus where evidence was not. RESULTS: Available data on cost of CR delivery in low-resource settings suggests it is not feasible to deliver CR in low-resource settings as is delivered in high-resource ones. Strategies which can be implemented to deliver all of the core CR components in low-resource settings were summarised in practice recommendations, and approaches to patient assessment proffered. It is suggested that CR be adapted by delivery by non-physician healthcare workers, in non-clinical settings. CONCLUSIONS: Advocacy to achieve political commitment for broad delivery of adapted CR services in low-resource settings is needed."

Influence of unhealthy food and beverage marketing on children's dietary intake and preference: a systematic review and meta-analysis of randomized trials.

Marketing of foods and beverages high in fat, sugar and salt are suggested to contribute to poor dietary behaviours in children and diet-related diseases later in life. This systematic review and meta-analysis of randomized trials aimed to assess the effects of unhealthy food and beverage marketing on dietary intake (grams or kilocalories) and dietary preference (preference score or percentage of participants who selected specific foods/beverages) among children 2 to 18 years of age. We searched MEDLINE, EMBASE and PsycINFO up to January 2015 for terms related to advertising, unhealthy foods or beverages among children. Randomized trials that assessed the effects of unhealthy food and beverage marketing compared with non-dietary advertisement or no advertisement in children were considered eligible. Two authors independently extracted information on study characteristics and outcomes of interest and assessed risk of bias and the overall quality of evidence using grade methodology. Meta-analysis was conducted separately for dietary intake and preference using a random-effects model. We identified 29 eligible studies, of which 17 studies were included for meta-analysis of dietary preference and nine for meta-analysis of dietary intake. Almost half of the studies were at high risk of bias. Our meta-analysis showed that in children exposed to unhealthy dietary marketing, dietary intake significantly increased (mean difference [MD] = 30.4 kcal, 95% confidence interval [CI] 2.9 to 57.9, and MD = 4.8 g, 95%CI 0.8 to 8.8) during or shortly after exposure to advertisements. Similarly, children exposed to the unhealthy dietary marketing had a higher risk of selecting the advertised foods or beverages (relative risk = 1.1, 95%CI 1.0 to 1.2; P = 0.052). The evidence indicates that unhealthy food and beverage marketing increases dietary intake (moderate quality evidence) and preference (moderate to low quality evidence) for energy-dense, low-nutrition food and beverage. Unhealthy food and beverage marketing increased dietary intake and influenced dietary preference in children during or shortly after exposure to advertisements. © 2016 World Obesity.

Polar metals by geometric design.

Gauss's law dictates that the net electric field inside a conductor in electrostatic equilibrium is zero by effective charge screening; free carriers within a metal eliminate internal dipoles that may arise owing to asymmetric charge distributions. Quantum physics supports this view, demonstrating that delocalized electrons make a static macroscopic polarization, an ill-defined quantity in metals--it is exceedingly unusual to find a polar metal that exhibits long-range ordered dipoles owing to cooperative atomic displacements aligned from dipolar interactions as in insulating phases. Here we describe the quantum mechanical design and experimental realization of room-temperature polar metals in thin-film ANiO3 perovskite nickelates using a strategy based on atomic-scale control of inversion-preserving (centric) displacements. We predict with ab initio calculations that cooperative polar A cation displacements are geometrically stabilized with a non-equilibrium amplitude and tilt pattern of the corner-connected NiO6 octahedral--the structural signatures of perovskites--owing to geometric constraints imposed by the underlying substrate. Heteroepitaxial thin-films grown on LaAlO3 (111) substrates fulfil the design principles. We achieve both a conducting polar monoclinic oxide that is inaccessible in compositionally identical films grown on (001) substrates, and observe a hidden, previously unreported, non-equilibrium structure in thin-film geometries. We expect that the geometric stabilization approach will provide novel avenues for realizing new multifunctional materials with unusual coexisting properties.