Abstract
Analytical solutions are derived for the steady-state size distributions of precipitating rain and snow particles assuming growth via collection of suspended cloud particles. Application of ...the Liouville equation to the transfer of precipitating mass through size bins in a “cascade” yields a characteristic gamma distribution with a Marshall–Palmer exponential tail with respect to particle diameter. For rain, the principle parameters controlling size distribution shape are cloud droplet liquid water path and cloud updraft speed. Stronger updrafts lead to greater concentrations of large precipitating drops and a peak in the size distribution. The solutions provide a means for relating size distributions measured in the air or on the ground to cloud bulk microphysical and dynamic properties.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Phospholipid bilayers formed at solid–liquid interfaces have garnered interest as mimics of cell membranes to model association reactions of proteins with lipid bilayer-tethered ligands. Despite the ...importance of understanding how ligand density in a lipid bilayer impacts the protein–ligand association response, relating the ligand-modified lipid fraction to the absolute density of solution-accessible ligands in a lipid bilayer remains a challenge in interfacial quantitative analysis. In this work, confocal Raman microscopy is employed to quantify the association of anti-biotin IgG with a small fraction of biotinylated lipids dispersed in either gel-phase or liquid-crystalline supported lipid bilayers deposited on the interior surfaces of wide-pore silica surfaces. We examine the question of whether inter-leaflet lipid translocation contributes to the population of solution-accessible biotin ligands on the distal leaflet of a supported lipid bilayer by comparing their protein accumulation response with ligands dispersed in lipid monolayers on nitrile-derivatized silica surfaces. The binding of the antibody to biotin ligands dispersed in gel-phase bilayers exhibited an equivalent biotin coverage response as the accumulation of IgG onto gel-phase monolayers, indicating that gel-phase bilayer symmetry was preserved. This result contrasts with the ∼60% greater anti-biotin capture observed at fluid-phase bilayers compared to fluid-phase monolayers prepared at equivalent biotin fractions. This enhanced protein capture is attributed to biotin-capped lipids being transferred from the surface-associated proximal leaflet of the bilayer to the solution-exposed distal leaflet by the inter-leaflet exchange or lipid flip-flop, a facile process in fluid-phase supported lipid bilayers. The results suggest caution in interpreting the results of quantitative studies of protein binding to lipid-tethered ligands dispersed in fluid-phase phospholipid bilayers.
The snowflake microstructure determines the microwave scattering properties of individual snowflakes and has a strong impact on snowfall radar signatures. In this study, individual snowflakes are ...represented by collections of randomly distributed ice spheres where the size and number of the constituent ice spheres are specified by the snowflake mass and surface-area-to-volume ratio (SAV) and the bounding volume of each ice sphere collection is given by the snowflake maximum dimension. Radar backscatter cross sections for the ice sphere collections are calculated at X-, Ku-, Ka-, and W-band frequencies and then used to model triple-frequency radar signatures for exponential snowflake size distributions (SSDs). Additionally, snowflake complexity values obtained from high-resolution multi-view snowflake images are used as an indicator of snowflake SAV to derive snowfall triple-frequency radar signatures. The modeled snowfall triple-frequency radar signatures cover a wide range of triple-frequency signatures that were previously determined from radar reflectivity measurements and illustrate characteristic differences related to snow type, quantified through snowflake SAV, and snowflake size. The results show high sensitivity to snowflake SAV and SSD maximum size but are generally less affected by uncertainties in the parameterization of snowflake mass, indicating the importance of snowflake SAV for the interpretation of snowfall triple-frequency radar signatures.
Developmental ocular malformations, including anophthalmia-microphthalmia (AM), are heterogeneous disorders with frequent sporadic or non-Mendelian inheritance. Recurrent interstitial deletions of ...14q22-q23 have been associated with AM, sometimes with poly/syndactyly and hypopituitarism. We identify two further cases of AM (one with associated pituitary anomalies) with a 14q22-q23 deletion. Using a positional candidate gene approach, we analyzed the
BMP4 (Bone Morphogenetic Protein-4) gene and identified a frameshift mutation (c.226del2, p.S76fs104X) that segregated with AM, retinal dystrophy, myopia, brain anomalies, and polydactyly in a family and a nonconservative missense mutation (c.278A→G, p.E93G) in a highly conserved base in another family. MR imaging and tractography in the c.226del2 proband revealed a primary brain developmental disorder affecting thalamostriatal and callosal pathways, also present in the affected grandmother. Using in situ hybridization in human embryos, we demonstrate expression of
BMP4 in optic vesicle, developing retina and lens, pituitary region, and digits strongly supporting
BMP4 as a causative gene for AM, pituitary, and poly/syndactyly. Because
BMP4 interacts with
HH signaling genes in animals, we evaluated gene expression in human embryos and demonstrate cotemporal and cospatial expression of
BMP4 and
HH signaling genes. We also identified four cases, some of whom had retinal dystrophy, with “low-penetrant” mutations in both
BMP4 and
HH signaling genes:
SHH (
Sonic Hedgehog) or
PTCH1 (
Patched). We propose that
BMP4 is a major gene for AM and/or retinal dystrophy and brain anomalies and may be a candidate gene for myopia and poly/syndactyly. Our finding of low-penetrant variants in
BMP4 and
HH signaling partners is suggestive of an interaction between the two pathways in humans.
Several pathogens have been associated with increased cardiovascular disease (CVD) risk. Whether this occurs withMycobacterium tuberculosisinfection is unclear. We assessed if tuberculosis disease ...increased the risk of acute myocardial infarction (AMI). We identified patients with tuberculosis index claims from a large de-identified database of ∼15 million adults enrolled in a U.S. commercial insurance policy between 2008 and 2010. Tuberculosis patients were 1:1 matched to patients without tuberculosis claims using propensity scores. We compared the occurrence of index AMI claims between the tuberculosis and non-tuberculosis cohorts using Kaplan–Meier curves and Cox Proportional Hazard models. Data on 2026 patients with tuberculosis and 2026 propensity-matched patients without tuberculosis were included. AMI was more frequent in the tuberculosis cohort compared with the non-tuberculosis cohort, 67 (3·3%) vs. 32 (1·6%) AMI cases, respectively, 𝑃 < 0·01. Tuberculosis was associated with an increased risk of AMI (adjusted hazard ratio (HR) 1·98, 95% confidence intervals (CI) 1·3–3·0). The results were similar when the analysis was restricted to pulmonary tuberculosis (adjusted HR 2·43, 95% CI 1·5–4·1). Tuberculosis was associated with an increased risk of AMI. CVD risk assessment should be considered in tuberculosis patients. Mechanistic studies of tuberculosis and CVD are warranted.
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Exaggerated Janus kinase-signal transducer and activator of transcription (JAK-STAT) signalling is key to the pathogenesis of pro-inflammatory disorders, such as rheumatoid arthritis ...and cardiovascular diseases. Mutational activation of JAKs is also responsible for several haematological malignancies, including myeloproliferative neoplasms and acute lymphoblastic leukaemia. Accumulating evidence links adenosine 5′-monophosphate (AMP)-activated protein kinase (AMPK), an energy sensor and regulator of organismal and cellular metabolism, with the suppression of immune and inflammatory processes. Recent studies have shown that activation of AMPK can limit JAK-STAT-dependent signalling pathways via several mechanisms. These novel findings support AMPK activation as a strategy for management of an array of disorders characterised by hyper-activation of the JAK-STAT pathway. This review discusses the pivotal role of JAK-STAT signalling in a range of disorders and how both established clinically used and novel AMPK activators might be used to treat these conditions.
Chemical looping is a promising combustion technology utilizing the cyclic oxidation and reduction of a metal oxide to transport oxygen for a variety of applications related to carbon capture and ...storage (CCS). The scalable manufacture of a suitable oxygen carrier is a pivotal aspect of this research field. This work surveys the experimental preparation of CuO and CuO/NiO on SiC and SiO2 substrates for chemical looping with oxygen uncoupling (CLOU) applications. A novel impregnation method that enhances the metal–support interaction to increase dispersion and reduce CuO sintering has been developed in this work. Particles prepared using this method, termed “selective adsorption wet coimpregnation”, exhibited agglomeration resistance and high reactivity over many regeneration cycles. CuO/NiO@SiO2 oxygen carrier (33 wt % CuO, 1 mol of Ni/99 mol of Cu) showed no signs of agglomeration up to 975 °C in fluidized bed testing, cycling between CuO and Cu2O. Thermogravimetric analysis showed no loss in oxygen transport capacity or decrease in kinetics over 100 cycles.
A single nanoparticle (NP) mass spectrometry method was used to measure sublimation rates as a function of nanoparticle temperature (TNP) for sets of individual graphite and graphene NPs. Initially, ...the NP sublimation rates were ∼400 times faster than those for bulk graphite, and there were large NP-to-NP variations. Over time, the rates slowed substantially, though they remained well above the bulk rate. The initial activation energies (E a values) were correspondingly low and doubled, as a few monolayers worth of material was sublimed from the surfaces. The high initial rates and low E a values are attributed to large numbers of edge, defect, and other low coordination sites on the NP surfaces, and the changes are attributed to atomic-scale “smoothing” of the surface by preferential sublimation of the less stable sites. The emissivity of the NPs also changed after heating, more frequently increasing. The emissivity and sublimation rates were anticorrelated, leading to the conclusion that high densities of low-coordination sites on the NP surfaces enhance sublimation but suppress emissivity
In addition to the well-characterized role of AMPK in the regulation of nutrient metabolism, it is increasingly clear that AMPK activation has multiple actions on inflammatory signalling. Here we ...describe methods to identify effects of AMPK activity on pro-inflammatory signalling, specifically (1) the nuclear localization of the key inflammatory mediators nuclear factor-κB (NFκB) and phosphorylated c-Jun N-terminal kinase (JNK), (2) preparation of conditioned medium to analyze the secretion of cytokines/chemokines, and (3) the pro-inflammatory adhesion of leukocytes to cultured cells.
We introduce a novel interactive framework for visualizing and exploring high‐dimensional datasets based on subspace analysis and dynamic projections. We assume the high‐dimensional dataset can be ...represented by a mixture of low‐dimensional linear subspaces with mixed dimensions, and provide a method to reliably estimate the intrinsic dimension and linear basis of each subspace extracted from the subspace clustering. Subsequently, we use these bases to define unique 2D linear projections as viewpoints from which to visualize the data. To understand the relationships among the different projections and to discover hidden patterns, we connect these projections through dynamic projections that create smooth animated transitions between pairs of projections. We introduce the view transition graph, which provides flexible navigation among these projections to facilitate an intuitive exploration. Finally, we provide detailed comparisons with related systems, and use real‐world examples to demonstrate the novelty and usability of our proposed framework.
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