We demonstrate a reduction in the measured inner wall shear stress in moderately turbulent Taylor-Couette flows by depositing sprayable superhydrophobic microstructures on the inner rotor surface. ...The magnitude of reduction becomes progressively larger as the Reynolds number increases up to a value of 22% at Re=8.0×10(4). We show that the mean skin friction coefficient C(f) in the presence of the superhydrophobic coating can be fitted to a modified Prandtl-von Kármán-type relationship of the form (C(f)/2)(-1/2)=Mln (Re(C(f)/2)(1/2))+N+(b/Δr)Re(C(f)/2)(1/2) from which we extract an effective slip length of b≈19 μm. The dimensionless effective slip length b(+)=b/δ(ν), where δ(ν) is the viscous length scale, is the key parameter that governs the drag reduction and is shown to scale as b(+)∼Re(1/2) in the limit of high Re.
Using quantitative models to predict the biological interactions of nanoparticles will accelerate the translation of nanotechnology. Here, we characterized the serum protein corona ‘fingerprint’ ...formed around a library of 105 surface-modified gold nanoparticles. Applying a bioinformatics-inspired approach, we developed a multivariate model that uses the protein corona fingerprint to predict cell association 50% more accurately than a model that uses parameters describing nanoparticle size, aggregation state, and surface charge. Our model implicates a set of hyaluronan-binding proteins as mediators of nanoparticle–cell interactions. This study establishes a framework for developing a comprehensive database of protein corona fingerprints and biological responses for multiple nanoparticle types. Such a database can be used to develop quantitative relationships that predict the biological responses to nanoparticles and will aid in uncovering the fundamental mechanisms of nano–bio interactions.
Targeted delivery of drugs and imaging agents to inflamed tissues, as in the cases of cancer, Alzheimer's disease, Parkinson's disease, and arthritis, represents one of the major challenges in drug ...delivery. Monocytes possess a unique ability to target and penetrate into sites of inflammation. Here, we describe a broad approach to take advantage of the natural ability of monocytes to target and deliver flat polymeric particles (“Cellular Backpacks”) to inflamed tissues. Cellular backpacks attach strongly to the surface of monocytes but do not undergo phagocytosis due to backpack's size, disk-like shape and flexibility. Following attachment of backpacks, monocytes retain important cellular functions including transmigration through an endothelial monolayer and differentiation into macrophages. In two separate in vivo inflammation models, backpack-laden monocytes exhibit increased targeting to inflamed tissues. Cellular backpacks, and their abilities to attach to monocytes without impairing monocyte functions and ‘hitchhike’ to a variety of inflamed tissues, offer a new platform for both cell-mediated therapies and broad targeting of inflamed tissues.
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Recording transcriptional histories of a cell would enable deeper understanding of cellular developmental trajectories and responses to external perturbations. Here we describe an engineered protein ...fiber that incorporates diverse fluorescent marks during its growth to store a ticker tape-like history. An embedded HaloTag reporter incorporates user-supplied dyes, leading to colored stripes that map the growth of each individual fiber to wall clock time. A co-expressed eGFP tag driven by a promoter of interest records a history of transcriptional activation. High-resolution multi-spectral imaging on fixed samples reads the cellular histories, and interpolation of eGFP marks relative to HaloTag timestamps provides accurate absolute timing. We demonstrate recordings of doxycycline-induced transcription in HEK cells and cFos promoter activation in cultured neurons, with a single-cell absolute accuracy of 30-40 minutes over a 12-hour recording. The protein-based ticker tape design we present here could be generalized to achieve massively parallel single-cell recordings of diverse physiological modalities.
Summary Background Multidrug-resistant tuberculosis threatens to reverse recent reductions in global tuberculosis incidence. Although children younger than 15 years constitute more than 25% of the ...worldwide population, the global incidence of multidrug-resistant tuberculosis disease in children has never been quantified. We aimed to estimate the regional and global annual incidence of multidrug-resistant tuberculosis in children. Methods We developed two models: one to estimate the setting-specific risk of multidrug-resistant tuberculosis among child cases of tuberculosis, and a second to estimate the setting-specific incidence of tuberculosis disease in children. The model for risk of multidrug-resistant tuberculosis among children with tuberculosis needed a systematic literature review. We multiplied the setting-specific estimates of multidrug-resistant tuberculosis risk and tuberculosis incidence to estimate regional and global incidence of multidrug-resistant tuberculosis disease in children in 2010. Findings We identified 3403 papers, of which 97 studies met inclusion criteria for the systematic review of risk of multidrug-resistant tuberculosis. 31 studies reported the risk of multidrug-resistant tuberculosis in both children and treatment-naive adults with tuberculosis and were used for evaluation of the linear association between multidrug-resistant disease risk in these two patient groups. We identified that the setting-specific risk of multidrug-resistant tuberculosis was nearly identical in children and treatment-naive adults with tuberculosis, consistent with the assertion that multidrug-resistant disease in both groups reflects the local risk of transmitted multidrug-resistant tuberculosis. After application of these calculated risks, we estimated that around 999 792 (95% CI 937 877–1 055 414) children developed tuberculosis disease in 2010, of whom 31 948 (25 594–38 663) had multidrug-resistant disease. Interpretation Our estimates underscore that many cases of tuberculosis and multidrug-resistant tuberculosis disease are not being detected in children. Future estimates can be refined as more and better tuberculosis data and new diagnostic instruments become available. Funding US National Institutes of Health, the Helmut Wolfgang Schumann Fellowship in Preventive Medicine at Harvard Medical School, the Norman E Zinberg Fellowship at Harvard Medical School, and the Doris and Howard Hiatt Residency in Global Health Equity and Internal Medicine at the Brigham and Women's Hospital.
The response to the COVID-19 pandemic and the approach to patient safety share three important concepts: the challenges of preventing rare events, use of rules, and tolerance for uncertainty. We ...discuss how each of these ideas can be utilised in perioperative safety to create a high-reliability system.
Understanding factors that influence a species’ distribution and abundance across the annual cycle is required for range-wide conservation. Thousands of imperiled red knots (
Calidris cantus rufa
) ...stop on Virginia’s barrier islands each year to replenish fat during spring migration. We investigated the variation in red knot presence and flock size, the effects of prey on this variation, and factors influencing prey abundance on Virginia’s barrier islands. We counted red knots and collected potential prey samples at randomly selected sites from 2007–2018 during a two-week period during early and peak migration. Core samples contained crustaceans (Orders Amphipoda and Calanoida), blue mussels (
Mytilus edulis)
, coquina clams (
Donax variabilis
), and miscellaneous prey (horseshoe crab eggs (
Limulus polyphemus
), angel wing clams (
Cyrtopleura costata
), and other organisms (e.g., insect larvae, snails, worms)). Estimated red knot peak counts in Virginia during 21–27 May were highest in 2012 (11,959) and lowest in 2014 (2,857; 12-year peak migration
x
¯
= 7,175, SD = 2,869). Red knot and prey numbers varied across sampling periods and substrates (i.e., peat and sand). Red knots generally used sites with more prey. Miscellaneous prey (
x
¯
= 2401.00/m
2
, SE = 169.16) influenced red knot presence at a site early in migration, when we only sampled on peat banks. Coquina clams (
x
¯
= 1383.54/m
2
, SE = 125.32) and blue mussels (
x
¯
= 777.91/m
2
, SE = 259.31) affected red knot presence at a site during peak migration, when we sampled both substrates. Few relationships between prey and red knot flock size existed, suggesting that other unmeasured factors determined red knot numbers at occupied sites. Tide and mean daily water temperature affected prey abundance. Maximizing the diversity, availability, and abundance of prey for red knots on barrier islands requires management that encourages the presence of both sand and peat bank intertidal habitats.
X-ray photoelectron spectroscopy (XPS) depth profiling with C60 + sputtering was used to resolve the lithium-ion distribution in the nanometer-scale domain structures of block polymer electrolyte ...thin films. The electrolytes of interest are mixtures of lithium trifluoromethanesulfonate and lamellar-forming polystyrene–poly(oligo(oxyethylene)methacrylate) (PS–POEM) copolymer. XPS depth profiling results showed that the lithium-ion concentration was directly correlated with the POEM concentration. Furthermore, chemical state and atomic composition of the film were analyzed through the deconvolution of the C1s signal, indicating that the lithium ions appear to be uniformly distributed in the POEM domains. Overall, the unique capabilities of C60 + depth profiling XPS provide a powerful tool for the analysis of nanostructured polymer thin films in applications ranging from energy storage and generation to surface coatings and nanoscale templates.
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