Functional composites by programming entropy-driven nanosheet growth.

Nanomaterials must be systematically designed to be technologically viable1-5. Driven by optimizing intermolecular interactions, current designs are too rigid to plug in new chemical functionalities and cannot mitigate condition differences during integration6,7. Despite extensive optimization of building blocks and treatments, accessing nanostructures with the required feature sizes and chemistries is difficult. Programming their growth across the nano-to-macro hierarchy also remains challenging, if not impossible8-13. To address these limitations, we should shift to entropy-driven assemblies to gain design flexibility, as seen in high-entropy alloys, and program nanomaterial growth to kinetically match target feature sizes to the mobility of the system during processing14-17. Here, following a micro-then-nano growth sequence in ternary composite blends composed of block-copolymer-based supramolecules, small molecules and nanoparticles, we successfully fabricate high-performance barrier materials composed of more than 200 stacked nanosheets (125 nm sheet thickness) with a defect density less than 0.056 µm-2 and about 98% efficiency in controlling the defect type. Contrary to common perception, polymer-chain entanglements are advantageous to realize long-range order, accelerate the fabrication process (<30 min) and satisfy specific requirements to advance multilayered film technology3,4,18. This study showcases the feasibility, necessity and unlimited opportunities to transform laboratory nanoscience into nanotechnology through systems engineering of self-assembly.

Studying the high-rate deformation of soft materials via laser-induced membrane expansion.

Cavitation is a phenomenon that occurs when the internal pressure of a material exceeds the resistance to deformation provided by the surrounding medium. Several measurements, such as the blister test, bubble inflation, and cavitation rheology, take advantage of this phenomenon to measure the local mechanical properties of soft materials at relatively low deformation rates. Here, we introduce a new measurement called laser-induced membrane expansion (LIME) that measures the shear modulus of a thin membrane at high strain rates (≈106 s-1 to 108 s-1) by using laser ablation to rapidly expand a thin (tens of microns) elastomeric membrane. To demonstrate the capabilities of this measurement, we use LIME to study the mechanical properties of poly(dimethylsiloxane) (PDMS) membranes at several thicknesses (from 10 µm to 60 µm) and crosslink densities. We find that the shear modulus of the PDMS measured by LIME was weakly dependent on the crosslink density, but was strongly strain rate dependent with values ranging from 106 Pa to 108 Pa. This measurement platform presents a new approach to studying the mechanical properties of soft but thin materials over a range of deformation rates.

Relative effects of polymer composition and sample preparation on glass dynamics.

Modern design of common adhesives, composites and polymeric parts makes use of polymer glasses that are stiff enough to maintain their shape under a high stress while still having a ductile behavior after the yield point. Typically, material compositions are tuned with co-monomers, polymer blends, plasticizers, or other additives to arrive at a tradeoff between the elastic modulus and toughness. In contrast, strong changes to the mechanics of a glass are possible by changing only the molecular packing during vitrification or even deep in the glassy state. For example, physical aging or processing techniques such as physical vapor deposition increase the density, embrittle the material, and increase elastic modulus. Here, we use molecular simulations, validated by positron annihilation lifetime spectroscopy (PALS) and quasi-elastic neutron scattering, to understand the free volume distribution and the resulting dynamics of glassy co-polymers where the composition is systemically varied between polar 5-norbornene-2-methanol (NBOH) and non-polar ethylidene norbornene (ENB) monomers. In these polymer glasses, we analyze the structural features of the unoccupied volume using clustering analysis, where the clustering is parameterized to reproduce experimental measurements of the same features from PALS. Further, we analyze the dynamics, quantified by the Debye-Waller factor, and compare the results with softer, lower density states. Our findings indicate that faster structural relaxations and potentially improved ductility are possible through changes to the geometric structure and fraction of the free volume, and that the resulting changes to the glass dynamics are comparable to large changes in the monomer composition.

The characteristics and practice proficiency of nurse practitioners who care for older adults.

Roughly 54 million Americans are 65 years of age or older. Given the number of comorbid diseases reported in older adults, healthcare tailored to the specific needs of this population is imperative. Nurse practitioners (NPs) are uniquely positioned to provide care to older adults; yet little is known about the geriatric-oriented NP workforce. In this study, four professional organizations distributed a survey link to their members who were queried on their demographic, employment, and practice characteristics; one organization's members responded to a previous survey, providing two time points for comparison. Compared with 2016 respondents, there was minimal growth in diversity, fewer who practice in suburban or rural areas, and restrictions on clinical education related to the ongoing pandemic. The findings from this study should alert policymakers of the need to address the development of an adequate workforce of clinicians who specialize in geriatrics.

Factors influencing intention to apply spatial approaches to on-farm experimentation: insights from the Australian winegrape sector.

Grape growers are often constrained by available time and labor to conduct trials that deliver informative results. Spatially distributed trial designs coupled with data collection using sensing technologies can introduce efficiencies and also account for the impact of land variability on trial results. Various spatial approaches have been proposed, yet how farmers perceive them is largely unknown. We collaborated with four wine businesses in Australia to explore how grape growers and viticultural consultants perceive a simplified spatial approach to experimentation involving one or more vineyard rows or "strips." In each case, the simplified strip approach was applied alongside growers' or consultants' own methods to compare the perceived value of different methods. The Theory of Planned Behavior was used as an analytical framework to identify factors influencing participants' intentions towards adopting the strip approach. Our findings show that growers and consultants perceived several advantages of the strip approach over their own methods. Key factors impeding uptake were resource constraints for collecting trial data and lack of skills and knowledge to use and analyze spatial data to position the trial and interpret results. These constraints highlight the need to support growers and consultants who see value in this approach by developing automated and affordable measurements for viticultural variables beyond yield, and by providing training on how to analyze and interpret spatial and response data. This study provides novel insights for private and public sectors on where to focus efforts to facilitate adoption of spatial approaches to On-Farm Experimentation by specific target audiences.

Effect of Exercise Interventions on Health-Related Quality of Life After Stroke and Transient Ischemic Attack: A Systematic Review and Meta-Analysis.

Exercise interventions have been shown to help physical fitness, walking, and balance after stroke, but data are lacking on whether such interventions lead to improvements in health-related quality of life (HRQoL). In this systematic review and meta-analysis, 30 randomized controlled trials (n=1836 patients) were found from PubMed, OVID MEDLINE, Web of Science, CINAHL, SCOPUS, The Cochrane Library, and TRIP databases when searched from 1966 to February 2020 that examine the effects of exercise interventions on HRQoL after stroke or transient ischemic attack. Exercise interventions resulted in small to moderate beneficial effects on HRQoL at intervention end (standardized mean difference, -0.23 [95% CI, -0.40 to -0.07]) that appeared to diminish at longer-term follow-up (standardized mean difference, -0.11 [95% CI, -0.26 to 0.04]). Exercise was associated with moderate improvements in physical health (standardized mean difference, -0.33 [95% CI, -0.61 to -0.04]) and mental health (standardized mean difference, -0.29 [95% CI, -0.49 to -0.09]) domains of HRQoL while effects on social or cognitive composites showed little difference. Interventions that were initiated within 6 months, lasted at least 12 weeks in duration, involved at least 150 minutes per week, and included resistance training appeared most effective. Exercise can lead to moderate beneficial effects on HRQoL and should be considered an integral part of stroke rehabilitation.

Pathogen Incursions - Integrating Technical Expertise in a Socio-Political Context.

The incursion of a plant pathogen into a new geographic area initiates a series of decisions about appropriate control or eradication efforts. Incomplete, erroneous, and/or selective information may be used by diverse stakeholders to support individual goals and positions on how an incursion should be managed. We discuss the complex social, political, and technical factors that shape a biosecurity response prior to reviewing information needs and common stakeholder misunderstandings. Selected examples focus on the rust fungi (order Pucciniales). We then explore how plant pathologists, as technical experts, can interact with biosecurity stakeholders to build empathy and understanding that in turn allows a shift from being a distant subject matter expert to an active participant helping to structure problems and shape knowledge flows for better outcomes.

Ethical Decision Making in Autonomous Vehicles: The AV Ethics Project.

The ethics of autonomous vehicles (AV) has received a great amount of attention in recent years, specifically in regard to their decisional policies in accident situations in which human harm is a likely consequence. Starting from the assumption that human harm is unavoidable, many authors have developed differing accounts of what morality requires in these situations. In this article, a strategy for AV decision-making is proposed, the Ethical Valence Theory, which paints AV decision-making as a type of claim mitigation: different road users hold different moral claims on the vehicle's behavior, and the vehicle must mitigate these claims as it makes decisions about its environment. Using the context of autonomous vehicles, the harm produced by an action and the uncertainties connected to it are quantified and accounted for through deliberation, resulting in an ethical implementation coherent with reality. The goal of this approach is not to define how moral theory requires vehicles to behave, but rather to provide a computational approach that is flexible enough to accommodate a number of 'moral positions' concerning what morality demands and what road users may expect, offering an evaluation tool for the social acceptability of an autonomous vehicle's ethical decision making.

Automated Analysis of Aggregated Datasets to Identify Climatic Predictors of Botrytis Bunch Rot in Wine Grapes.

Botrytis bunch rot (BBR), caused by Botrytis cinerea, results in serious losses to wine-grape production in some seasons during the preharvest period. In order to predict seasons that are at risk from BBR, datasets consisting of 25 disease, weather and vine phenology variables were aggregated from 101 SiteYears across seven regions and nine growing seasons. Automated analyses were used to compare a range of statistical methods for their ability to predict BBR epidemics, including the Kruskal-Wallis test, logistic regression, receiver operating characteristic analysis, and skill-scores. Variables based on relative humidity and surface-wetness duration were significant and consistent predictors of BBR epidemics across the range of analyses applied. Variables integrating temperature and wetness duration, including the Bacchus and Broome models, also demonstrated high predictive ability; however, they did not outperform their constituent components in all analyses. Automation of data analyses was an effective way to compare a wide range of statistical methods and a large number of variables with minimal user input, following initial code development. Significant time was needed to check input data and software code, but a greater return on investment would occur should the analytical process be applied to new datasets, including those from other pathosystems.

Grape Sour Rot: A Four-Way Interaction Involving the Host, Yeast, Acetic Acid Bacteria, and Insects.

Sour rot, a disease affecting berries of cultivated Vitis spp. worldwide, has not been clearly defined. Reported symptoms of the disease include browning of the berry skin, oozing of disintegrated berry pulp, and the smell of acetic acid, all in the presence of fruit flies (Drosophila spp.). We determined acetic acid concentrations in multiple collections of symptomatic berries, isolated and identified microbes from them, and inoculated commonly isolated organisms into healthy berries with and without concurrent exposure to wild-type or axenic Drosophila melanogaster. Coinoculations combining one of several yeasts (Metschnikowia spp., Pichia spp., and a Saccharomyces sp.) plus an acetic acid bacterium (an Acetobacter sp. and Gluconobacter spp.) reproduced sour rot symptoms, defined here as decaying berries with a loss of turgor and containing acetic acid at a minimum of 0.83 g/liter, based on observed field levels. Symptoms developed only in the presence of D. melanogaster, either wild type or axenic, indicating a nonmicrobial contribution of these insects in addition to a previously suggested microbial role. We conclude that sour rot is the culmination of coinfection by various yeasts, which convert grape sugars to ethanol, and bacteria that oxidize the ethanol to acetic acid, and that this process is mediated by Drosophila spp.

"No wash" albumin-dextran dilution for double-unit cord blood transplantation is safe with high rates of sustained donor engraftment.

Washing cord blood (CB) grafts involves product manipulation and may result in cell loss. We investigated double-unit CB transplantation (CBT) using red blood cell (RBC)-depleted units diluted with albumin-dextran in patients with hematologic malignancies. One-hundred thirty-six patients (median age, 43 years; range, 4 to 71; median weight, 69 kilograms (kg); range, 24 to 111) underwent transplantation with a 4/6 to 6/6 HLA-matched graft. Patients ≤ 20 kg were excluded, as they only received washed units. Units were diluted a median of 8 fold to a median volume of 200 mL/unit. The median infused total nucleated cell doses were 2.7 (larger unit) and 2.0 (smaller unit) x 10(7)/kg, respectively, and the median post-thaw recovery was 86%. Units were infused consecutively (median, 45 minutes/unit). While only 17 patients (13%) had no infusion reactions, reactions in the remaining 119 patients were almost exclusively mild-moderate (by CTCAE v4 criteria 12 grade 1, 43 grade 2, 63 grade 3) with only 1 patient (< 1%) having a severe (grade 4) reaction. Moreover, most were easily treated. Grade 2 to 3 hypertension was the most common in 101 (74%) patients. The cumulative incidence of sustained donor-derived neutrophil engraftment was high: 95% in myeloablative and 94% in nonmyeloablative CBT recipients. With appropriate supportive care, double-unit CBT with RBC-depleted grafts infused after albumin-dextran dilution is safe with high rates of engraftment in patients > 20 kg.

Improvement in peripheral blood disease burden in patients with Sézary syndrome and leukemic mycosis fungoides after total skin electron beam therapy.

BACKGROUND: There is a paucity of effective therapies for patients with Sézary syndrome and advanced mycosis fungoides with peripheral blood involvement. Total skin electron beam (TSEB) radiation therapy is an extremely effective skin-directed therapy for these patients, but, until recently, it was thought not to signifcantly affect the peripheral blood malignant T-cell population. OBJECTIVE: We conducted this study to determine if TSEB has therapeutic effect on the peripheral blood in patients with advanced mycosis fungoides and Sézary syndrome. METHODS: All patients on stable medication regimens seen in our photopheresis facility who received TSEB therapy between January 2008 and October 2011 at Temple University Hospital, Philadelphia, PA, were analyzed retrospectively for improvement in the peripheral blood, as documented by flow cytometry. RESULTS: Six of 11 patients achieved 50% or greater decrease in their peripheral blood malignant T-cell population after TSEB therapy, for an overall response rate of 55%. Within the group of patients who had a response in the skin, 67% also had a response in the peripheral blood. LIMITATIONS: This analysis is limited in 3 ways. First, the sample described is small. Second, the results may be confounded by the fact that each patient was on other systemic therapies in addition to TSEB, albeit stable pre-existing regimens. The time interval between completion of TSEB therapy and repetition of flow cytometry was not standardized among patients, which may result in an underestimation of the overall response to TSEB therapy. CONCLUSION: In patients with advanced mycosis fungoides and Sézary syndrome, the peripheral blood tumor burden may improve after treatment with TSEB.

Paraneoplastic subacute cutaneous lupus erythematosus: an underrecognized entity.

Subacute cutaneous lupus erythematosus (SCLE) is a form of cutaneous lupus erythematosus that most often presents as scaly, erythematous, papulosquamous, or annular papules and plaques in a photodistributed pattern. Subacute cutaneous lupus erythematosus is classically considered to be either idiopathic or drug induced. There have been few reports of SCLE arising in the setting of malignancy, raising the possibility that paraneoplastic SCLE may be a rare distinct subset of lupus. We report a case of SCLE arising as a paraneoplastic phenomenon in the setting of small cell lung cancer. Given the close temporal proximity of the detection of malignancy and the development of the rash in our patient, we believe this report presents a case of paraneoplastic SCLE. The presentation of new-onset idiopathic SCLE should prompt a careful review of systems and age-appropriate cancer screening, as SCLE may be a sign of an occult malignancy.

The Projectile Perforation Resistance of Materials: Scaling the Impact Resistance of Thin Films to Macroscale Materials.

From drug delivery to ballistic impact, the ability to control or mitigate the puncture of a fast-moving projectile through a material is critical. While puncture is a common occurrence, which can span many orders of magnitude in the size, speed, and energy of the projectile, there remains a need to connect our understanding of the perforation resistance of materials at the nano- and microscale to the actual behavior at the macroscale that is relevant for engineering applications. In this article, we address this challenge by combining a new dimensional analysis scheme with experimental data from micro- and macroscale impact tests to develop a relationship that connects the size-scale effects and materials properties during high-speed puncture events. By relating the minimum perforation velocity to fundamental material properties and geometric test conditions, we provide new insights and establish an alternative methodology for evaluating the performance of materials that is independent of the impact energy or the specific projectile puncture experiment type. Finally, we demonstrate the utility of this approach by assessing the relevance of novel materials, such as nanocomposites and graphene for real-world impact applications.

Development of a dense SNP-based linkage map of an apple rootstock progeny using the Malus Infinium whole genome genotyping array.

BACKGROUND: A whole-genome genotyping array has previously been developed for Malus using SNP data from 28 Malus genotypes. This array offers the prospect of high throughput genotyping and linkage map development for any given Malus progeny. To test the applicability of the array for mapping in diverse Malus genotypes, we applied the array to the construction of a SNP-based linkage map of an apple rootstock progeny. RESULTS: Of the 7,867 Malus SNP markers on the array, 1,823 (23.2%) were heterozygous in one of the two parents of the progeny, 1,007 (12.8%) were heterozygous in both parental genotypes, whilst just 2.8% of the 921 Pyrus SNPs were heterozygous. A linkage map spanning 1,282.2 cM was produced comprising 2,272 SNP markers, 306 SSR markers and the S-locus. The length of the M432 linkage map was increased by 52.7 cM with the addition of the SNP markers, whilst marker density increased from 3.8 cM/marker to 0.5 cM/marker. Just three regions in excess of 10 cM remain where no markers were mapped. We compared the positions of the mapped SNP markers on the M432 map with their predicted positions on the 'Golden Delicious' genome sequence. A total of 311 markers (13.7% of all mapped markers) mapped to positions that conflicted with their predicted positions on the 'Golden Delicious' pseudo-chromosomes, indicating the presence of paralogous genomic regions or mis-assignments of genome sequence contigs during the assembly and anchoring of the genome sequence. CONCLUSIONS: We incorporated data for the 2,272 SNP markers onto the map of the M432 progeny and have presented the most complete and saturated map of the full 17 linkage groups of M. pumila to date. The data were generated rapidly in a high-throughput semi-automated pipeline, permitting significant savings in time and cost over linkage map construction using microsatellites. The application of the array will permit linkage maps to be developed for QTL analyses in a cost-effective manner, and the identification of SNPs that have been assigned erroneous positions on the 'Golden Delicious' reference sequence will assist in the continued improvement of the genome sequence assembly for that variety.

Surfactant protein-A inhibits mycoplasma-induced dendritic cell maturation through regulation of HMGB-1 cytokine activity.

During pulmonary infections, a careful balance between activation of protective host defense mechanisms and potentially injurious inflammatory processes must be maintained. Surfactant protein A (SP-A) is an immune modulator that increases pathogen uptake and clearance by phagocytes while minimizing lung inflammation by limiting dendritic cell (DC) and T cell activation. Recent publications have shown that SP-A binds to and is bacteriostatic for Mycoplasma pneumoniae in vitro. In vivo, SP-A aids in maintenance of airway homeostasis during M. pneumoniae pulmonary infection by preventing an overzealous proinflammatory response mediated by TNF-α. Although SP-A was shown to inhibit maturation of DCs in vitro, the consequence of DC/SP-A interactions in vivo has not been elucidated. In this article, we show that the absence of SP-A during M. pneumoniae infection leads to increased numbers of mature DCs in the lung and draining lymph nodes during the acute phase of infection and, consequently, increased numbers of activated T and B cells during the course of infection. The findings that glycyrrhizin, a specific inhibitor of extracellular high-mobility group box-1 (HMGB-1) abrogated this effect and that SP-A inhibits HMGB-1 release from immune cells suggest that SP-A inhibits M. pneumoniae-induced DC maturation by regulating HMGB-1 cytokine activity.

Chronic fusiform extracranial vertebral artery aneurysm with recurrent posterior circulation emboli: Case report and review of the literature.

We report a case of a 64-year-old man with a fusiform right extracranial vertebral artery aneurysm, spanning over half the extra-cranial V2 (foraminal) segment, presenting with recurrent multi-focal posterior circulation embolic ischaemic stroke. The patient was treated with endovascular embolisation of the right vertebral artery to prevent further thrombo-embolic events. Distal and proximal occlusion of the aneurysmal vertebral artery was performed with a micro-vascular plug with partial aneurysm sack embolisation to aid thrombosis and reduce the risk of recanalisation. Two months post procedure MR angiography confirmed successful aneurysm occlusion with no post-procedural complication. The patient returned to his normal independent life. Endovascular treatment with vessel sacrifice is an effective treatment with low morbidity and we believe the MVP device to be a efficacious option in the vertebral artery.

Using Machine Learning to Predict and Understand Complex Self-Assembly Behaviors of a Multicomponent Nanocomposite.

Blends of nanoparticles, polymers, and small molecules can self-assemble into optical, magnetic, and electronic devices with structure-dependent properties. However, the relationship between a multicomponent nanocomposite's formulation and its assembled structure is complex and cannot be predicted by theory. The blends can be strongly influenced by processing conditions, which can introduce non-equilibrium states. Currently, nanocomposite devices are designed through cycles of experimental trial and error. Machine learning (ML) methods are a compelling alternative because they can use existing datasets to map high-dimensional spaces. These methods do not rely on known relationships between parameters, so they are suited to complex systems without a solid theoretical foundation. Here, a dataset of 595 microscopy images of nanocomposite thin films is used to train a series of ML models. Correlations between the input and output parameters are examined, providing new insights into the system. Finally, the most successful ML model is used to predict the structures of new nanocomposite compositions. The results confirm that ML techniques can be used to improve the efficiency of nanocomposite device design. More broadly, the current study suggests some of the advantages and challenges associated with applying ML to complex systems.

Survival-Larval Density Relationships in the Field and Their Implications for Control of Container-Dwelling Aedes Mosquitoes.

Population density can affect survival, growth, development time, and adult size and fecundity, which are collectively known as density-dependent effects. Container Aedes larvae often attain high densities in nature, and those densities may be reduced when larval control is applied. We tested the hypothesis that density-dependent effects on survival are common and strong in nature and could result in maximal adult production at intermediate densities for Aedes aegypti, Aedes albopictus, and Aedes triseriatus. We surveyed naturally occurring densities in field containers, then introduced larvae at a similar range of densities, and censused the containers for survivors. We analyzed the survival-density relationships by nonlinear regressions, which showed that survival-density relationships vary among seasons, sites, and species. For each Aedes species, some sites and times yielded predictions that larval density reduction would yield the same (compensation), or more (overcompensation), adults than no larval density reduction. Thus, larval control targeting these Aedes species cannot always be assumed to yield a reduction in the number of adult mosquitoes. We suggest that mosquito control targeting larvae may be made more effective by: Imposing maximum mortality; targeting populations when larval abundances are low; and knowing the shape of the survival-density response of the target population.

Thermal Percolation in Well-Defined Nanocomposite Thin Films.

Thermal percolation in polymer nanocomposites─the rapid increase in thermal transport due to the formation of networks among fillers─is the subject of great interest in thermal management ranging from general utility in multifunctional nanocomposites to high-conductivity applications such as thermal interface materials. However, It remains a challenging subject encompassing both experimental and modeling hurdles. Successful reports of thermal percolation are exclusively found in high-aspect-ratio, conductive fillers such as graphene, albeit at filler loadings significantly higher than the electrical percolation threshold. This anomaly was attributed to the lower filler-matrix thermal conductivity contrast ratio kf/km ∼104 compared to electrical conductivity ∼1012-1016. In a randomly dispersed composite, the effect of a low contrast ratio is further accentuated by uncertainties in the morphology of the percolating network and presence of other phases such as disconnected aggregates and colloidal dispersions. Thus, the general properties of percolating networks are convoluted as they lack a defined structure. In contrast, a prototypical system with controllable nanofiller placement enables the elucidation of structure-property relations such as filler size, loading, and assembly. Using self-assembled nanocomposites with a controlled 1,2,3-dimension nanoparticle (NP) arrangement, we demonstrate that thermal percolation can be achieved in spite of using spherical, nonconductive fillers (kf/km ∼60) at a low volume fraction (9 vol %). We observe that the effects of volume fraction, interfacial thermal resistance, and filler conductivity on thermal conductivity depart from effective medium approximations. Most notably, contrast ratio plays a minor role in thermal percolation above kf/km ∼60─a common range for semiconducting nanoparticles/polymer ratios. Our findings bring new perspectives and insights to thermal percolation in nanocomposites, where the limits in contrast ratio, interfacial thermal conductance, and filler size are established.