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Supercrystalline nanocomposites (SCNCs) are inorganic-organic hybrid materials with a unique periodic nanostructure, and thus they have been gaining growing attention for their intriguing functional properties and parallelisms with hierarchical biomaterials. Their mechanical behavior remains, however, poorly understood, even though its understanding and control are important to allow SCNCs’ implementation into devices. An important aspect that has not been tackled yet is their time-dependent deformation behavior, which is nevertheless expected to play an important role in materials containing such a distribution of organic phase. Hereby, we report on the creep of ceramic-organic SCNCs with varying degrees of organic crosslinking, as assessed via nanoindentation. Creep strains and their partial recoverability are observed, hinting at the co-presence of viscoelasticity and viscoplasticity, and a clear effect of crosslinking in decreasing the overall material deformability emerges. We rationalize our experimental observations with the analysis of stress exponent and activation volume, resulting in a power-law breakdown behavior and governing deformation mechanisms occurring at the organic sub-nm interfaces scale, as rearrangement of organic ligands. The set of results is reinforced by the evaluation of the strain rate sensitivity via strain rate jump tests, and the assessment of the effect of oscillations during continuous stiffness measurement mode.

Background: SARS-CoV-2 viral load decreases over time after illness onset. However, immunocompromised patients may take longer for viral load decrease or have a more erratic viral-load trajectory. We used strand-specific assay data from admitted patients to evaluate viral-load trajectories after illness onset. Methods: We reviewed records of hospitalized patients with a positive SARS-CoV-2 PCR and tested using the strand-specific SARS-CoV-2 PCR during July 2020–April 2022. At Stanford Healthcare, we use a 2-step reverse real-time polymerase chain reaction (rRT-PCR) assay specific to the minus strand of the SARS-CoV-2 envelope gene to assess infectivity. Restricting our analysis to each patient’s first strand-specific assay, we used logistic regression models to compare patients with single versus multiple assays. Among patients with multiple tests, we compared those who had an upward trajectory in cycle threshold (Ct) values (a surrogate of decreasing viral load) versus those who did not. We analyzed presence of symptoms, immunocompromised state, immunosuppression reason, and severe COVID-19 leading to ICU care in univariate and multivariate models that further adjust for additional covariates. Significant differences were assessed using logistic regression odds ratios and an α level of 0.05. Results: In total, 848 inpatients were included. Among them, 703 were tested only once and 145 were tested 2–6 times. The longest duration of minus-strand detection was 163 days. In univariate analyses, patients with a single minus-strand assay had lower odds of being symptomatic (OR, 0.55), of being immunocompromised (OR, 0.58), and of being admitted to the ICU with severe COVID-19 (OR, 0.49). In the multivariate analysis, being admitted to the ICU with severe COVID-19 was the only significant variable associated with having >1 test (OR, 2.44). Among patients who had multiple strand-specific SARS-CoV-2 assays, 119 had upward minus-strand trends of Ct values (as expected) and 26 did not. Being immunocompromised was associated with nonrising minus-strand CT values (OR, 33.3) when holding all other covariates in the model constant. Conclusions: Immunocompromised patients with COVID-19 tend to actively replicate for longer and have unexpected viral trajectories compared to immunocompetent patients. Among immunocompromised patients, suspension of transmission-based precautions may require a case-by-case evaluation.

Background: Many hospitals have implemented admission SARS-CoV-2 testing to evaluate for the need for transmission-based precautions. However, a positive test in an asymptomatic patient may represent (1) active infection, signifying infectiousness; (2) false positivity; or (3) past infection with prolonged viral shedding. We used a strand-specific SARS-CoV-2 reverse real-time polymerase chain reaction (rRT-PCR) assay to assess infectivity among asymptomatic patients with a positive SARS-CoV-2 PCR admission test. Methods: We used a 2-step rRT-PCR specific to the minus strand of the SARS-CoV-2 envelope gene. We reviewed records of patients with a positive SARS-CoV-2 PCR who were also tested for the strand-specific SARS-CoV-2 PCR within 2 days of admission at Stanford Health Care during July 2020–April 2022. We restricted our analysis to each patient’s first test. We calculated the percentage of detectable minus strand-specific tests among asymptomatic patients over time and gathered descriptive statistics for age, sex, and immunocompromised state. Results: In total, 848 admitted patients had strand-specific SARS-CoV-2 assays performed. Of 532 patients with a strand-specific assay done within 2 days of admission, 242 (45%) were asymp tomatic. Among asymptomatic patients, the mean age was 56 years (range, 19–99), 133 (55%) were male, 50 (21%) had immunocompromising conditions, and 30 (12%) were admitted for a surgical procedure. In total, 21 (9%; range, 4%–25% per quarter) had detectable minus strand-specific assays (Fig. 1). Conclusions: Most asymptomatic patients tested for SARS-CoV-2 on admission were not infectious. Hospitals using SARS-CoV-2 PCR admission testing may need to re-evaluate the continued use of this practice.

Bioinspired ceramics with micron-scale ceramic "bricks" bonded by a metallic "mortar" are projected to result in higher strength and toughness ceramics, but their processing is challenging as metals do not typically wet ceramics. To resolve this issue, we made alumina structures using rapid pressureless infiltration of a zirconium-based bulk-metallic glass mortar that reactively wets the surface of freeze-cast alumina preforms. The mechanical properties of the resulting Al2O3 with a glass-forming compliant-phase change with infiltration temperature and ceramic content, leading to a trade-off between flexural strength (varying from 89 to 800 MPa) and fracture toughness (varying from 4 to more than 9 MPa·m½). The high toughness levels are attributed to brick pull-out and crack deflection along the ceramic/metal interfaces. Since these mechanisms are enabled by interfacial failure rather than failure within the metallic mortar, the potential for optimizing these bioinspired materials for damage tolerance has still not been fully realized.

In ceramic thin films, choosing an appropriate sample preparation method for transmission electron microscopy (TEM) analyses is of paramount importance to avoid preparation-induced damage and retain nanoscale features that require investigation. Here we compare two methods of TEM thin film sample preparation, namely conventional wedge polishing and focused ion beam (FIB) based lift out preparation applied to ferroelectric barium titanate (BaTiO3, BT) thin films made by chemical solution deposition (CSD). The aim of the work is to determine the pros and cons of each method considering not only the quality of the TEM specimen, but also aspects such as availability, ease of use, and affordability. Besides some limitations on the selection of visualized area due to thickness constraints on the FIB-made sample, both methods offer the capability to prepare samples with very comparable quality, as indicated by achieving the same thickness, a largely agreeing microstructure, no secondary phases on the diffraction pattern, and good atomic resolution. This last observation is especially important in the current context of material science, where more nanoscale phenomena are becoming the subject of study. The wedge polishing method, however, is deemed more affordable in terms of instrumentation, as it only requires a tripod polisher, a polishing wheel, and a precision ion polishing system, whereas the lift out method requires a scanning electron microscope (SEM) equipped with an FIB system. We believe that this work serves groups working on ferroelectric thin films in preparing TEM samples in a more effective and uncomplicated manner, facilitating progress in understanding this fascinating class of materials.

Abstract Background Autoimmune disease following COVID-19 has been studied intensely since the beginning of the pandemic. Growing evidence indicates that SARS-CoV-2 infection, by virtue of molecular mimicry can lead to an antigen-mediated cross-reaction promoting the development of a plethora of autoimmune spectrum diseases involving lungs and extrapulmonary tissues alike. In both COVID-19 and autoimmune disease, the immune self-tolerance breaks, leading to an overreaction of the immune system with production of a variety of autoantibodies, sharing similarities in clinical manifestation, laboratory, imaging, and pathology findings. Anti-Melanoma Differentiation-Associated gene 5 dermatomyositis (anti-MDA5 DM) comprises a rare subtype of systemic inflammatory myopathies associated with characteristic cutaneous features and life-threatening rapidly progressive interstitial lung disease (RP-ILD). The production of anti-MDA5 autoantibodies was proposed to be triggered by viral infections. Case presentation A 20-year-old male patient with polyarthritis, fatigue and exertional dyspnea was referred to our department. An elevated anti-MDA5 autoantibody titer, myositis on MRI, ground glass opacifications on lung CT and histological features of Wong-type dermatomyositis were confirmed, suggesting the diagnosis of an anti-MDA5 DM. Amid further diagnostic procedures, a serologic proof of a recent SARS-CoV-2 infection emerged. Subsequently, the patient deteriorated into a fulminant respiratory failure and an urgent lung transplantation was performed, leading to remission ever since (i.e. 12 months as of now). Conclusions We report a unique case of a patient with a new-onset anti-MDA5 DM with fulminant ARDS emerging in a post-infectious stage of COVID-19, who underwent a successful lung transplantation and achieved remission. Given the high mortality of anti-MDA5 DM associated RP-ILD, we would like to highlight that the timely recognition of this condition and urgent therapy initiation are of utmost importance.

Objective To characterise associations between individual nailfold capillary aberrations with autoantibodies in a cross-sectional study on children and adults with Raynaud’s phenomenon (RP).Methods Consecutive children and adults with RP and without previously known connective tissue disease (CTD) systemically underwent nailfold capillaroscopy and laboratory tests for the presence of antinuclear antibodies (ANA). The prevalence of individual nailfold capillary aberrations and ANA was assessed, and the associations between individual nailfold capillary aberrations and ANA were analysed separately in children and adolescents.Results In total, 113 children (median age 15 years) and 2858 adults (median age 48 years) with RP and without previously known CTD were assessed. At least one nailfold capillary aberration was detected in 72 (64%) of included children and in 2154 (75%) of included adults with RP (children vs adults p

This document is an editorial for a special issue of the journal Advanced Engineering Materials dedicated to Reinhard Pippan, a retired vice director and group leader at the Erich Schmid Institute. It highlights Pippan's contributions to material science, particularly in the areas of plastic deformation, fatigue and fracture, and micro- and nanomechanics. The editorial discusses his impact on young researchers and provides an overview of the manuscripts included in the special issue, covering topics such as high-pressure torsion, nanocrystalline materials, and fracture and fatigue. The document serves as a compilation of research articles celebrating Pippan's 70th birthday, showcasing his innovative thinking and commitment to scientific excellence in the field of materials science. [Extracted from the article]

FeTi–Cu composites with varying Cu contents are subjected to high‐pressure torsion, and their deformation behavior is explored systematically using scanning electron microscopy, microhardness, and nanoindentation. The study identifies the limiting factors influencing the refinement during severe plastic deformation. The pronounced strength differences between phases lead to fragmentation primarily through hard–hard (FeTi–FeTi) contact points, promoted by homogeneous, i.e., nonlocalized, and possibly turbulent material flow. These conditions are prevalent in Cu‐rich composites and during high‐temperature deformation. Conversely, Cu‐lean composites exhibit deformation localization, hindering the fragmentation process. Abrasion becomes an efficient refinement mechanism at the submicron‐/nanoscale, particularly for composites containing higher concentrations of nanocrystalline FeTi and exhibiting homogeneous plastic deformation. Consequently, deformation localization in Cu‐lean composites inhibits both refinement mechanisms, while Cu‐rich compositions and higher temperatures result in efficient refinement but at the risk of coarsening at the nanoscale. Refinement is localization‐limited in the former case and abrasion‐limited in the latter. Optimized processing conditions can overcome these constraints, yielding a uniform nanocomposite. This study sheds light on the intricate interplay of the mechanical properties of the respective phases in a composite, emphasizing the importance of tailored compositions and deformation conditions to optimize nanocomposites, particularly when dealing with challenging material pairings. [ABSTRACT FROM AUTHOR]