Motion of nanodroplets near edges and wedges

Nanodroplets residing near wedges or edges of solid substrates exhibit a disjoining pressure induced dynamics. Our nanoscale hydrodynamic calculations reveal that non-volatile droplets are attracted or repelled from edges or wedges depending on details of the corresponding laterally varying disjoining pressure generated, e.g., by a possible surface coating.Comment: 12 pages, 7 figure

Numerical Experiments on Extreme Waves Through Oblique–Soliton Interactions

Extreme water-wave motion is investigated analytically and numerically by considering two-soliton and three-soliton interactions on a horizontal plane. We successfully determine numerically that soliton solutions of the unidirectional Kadomtsev–Petviashvili equation (KPE), with equal far-field individual amplitudes, survive reasonably well in the bidirectional and higher-order Benney–Luke equations (BLE). A well-known exact two-soliton solution of the KPE on the infinite horizontal plane is used to seed the BLE at an initial time, and we confirm that the KPE-fourfold amplification approximately persists. More interestingly, a known three-soliton solution of the KPE is analysed further to assess its eight- or ninefold amplification, the latter of which exists in only a special and difficult-to-attain limit. This solution leads to an extreme splash at one point in space and time. Subsequently, we seed the BLE with this three-soliton solution at a suitable initial time to establish the maximum amplification: it is approximately 7.8 for a KPE amplification of 8.4. Herein, the computational domain and solutions are truncated approximately to a fully periodic or half-periodic channel geometry of sufficient size, essentially leading to cnoidal-wave solutions. Moreover, special geometric (finite-element) variational integrators in space and time have been used in order to eradicate artificial numerical damping of, in particular, wave amplitude

Finite element simulation of three-dimensional free-surface flow problems

An adaptive finite element algorithm is described for the stable solution of three-dimensional free-surface-flow problems based primarily on the use of node movement. The algorithm also includes a discrete remeshing procedure which enhances its accuracy and robustness. The spatial discretisation allows an isoparametric piecewise-quadratic approximation of the domain geometry for accurate resolution of the curved free surface. The technique is illustrated through an implementation for surface-tension-dominated viscous flows modelled in terms of the Stokes equations with suitable boundary conditions on the deforming free surface. Two three-dimensional test problems are used to demonstrate the performance of the method: a liquid bridge problem and the formation of a fluid droplet

Neurodevelopmental outcomes and neurophysiological parameters in children with congenital hyperinsulinism

Introduction. Congenital hyperinsulinism is a rare group of genetic disorders resulting in persistent hypoglycemia which can lead to delay of neurodevelopment.Aim. To assess psychomotor development and certain neurophysiological parameters of children treated for congenital hyperin-sulinism.Materials and methods. This prospective and retrospective cohort study included 73 infants with congenital hyperinsulinism admitted to the National Almazov Research Centre from 2017 to 2021. All subjects underwent standard clinical examination including physical and neurological assessment as well as 18F-DOPA PET/CT, genetic testing, electroencephalography. Developmental screening was performed using “Ages and Stages” questionnaire in 33 subjects. Possible risk factors for neurode-velopmental sequelae due to hypoglycemia were analyzed.Results and discussion. Normal neurodevelopment in general was observed in 23 subjects (69%), 10 patients had developmental delay. Focal form of CHI had the greatest modifying effect on positive neurodevelopmental outcome in general. Individual skills such as communication, fine and gross motor, problem solving in children with a focal form of CHI were significantly better than those with a nonfocal forms. Age of manifestation and verification of the disease, the minimum level of glycemia and the maximum level of glucose utilization did not significantly affect the formation of either individual skills (with the exception of gross motor skills) or psychomotor development in general. The indicators of gross motor skills in children with a lower level of glucose utilization turned out to be significantly better. Kaplan-Meier survival analysis showed that the alpha rhythm appearance was significantly earlier in patients with a focal form of CHI and with earlier verification of the diagnosis (<28 days of life).Conclusion. The focal form of the disease has the greatest modifying effect on the positive outcome of the psychomotor development. The age-appropriate gross motor skills were observed more often in the group of children with low glucose disposal rates. The association of the early occurrence of the alpha rhythm with the focal form of congenital hyperinsulinism, as well as with the early verification of the disease, was found

Identification and In Vivo Characterization of NvFP-7R, a Developmentally Regulated Red Fluorescent Protein of Nematostella vectensis

In recent years, the sea anemone Nematostella vectensis has emerged as a critical model organism for comparative genomics and developmental biology. Although Nematostella is a member of the anthozoan cnidarians (known for producing an abundance of diverse fluorescent proteins (FPs)), endogenous patterns of Nematostella fluorescence have not been described and putative FPs encoded by the genome have not been characterized.We described the spatiotemporal expression of endogenous red fluorescence during Nematostella development. Spatially, there are two patterns of red fluorescence, both restricted to the oral endoderm in developing polyps. One pattern is found in long fluorescent domains associated with the eight mesenteries and the other is found in short fluorescent domains situated between tentacles. Temporally, the long domains appear simultaneously at the 12-tentacle stage. In contrast, the short domains arise progressively between the 12- and 16-tentacle stage. To determine the source of the red fluorescence, we used bioinformatic approaches to identify all possible putative Nematostella FPs and a Drosophila S2 cell culture assay to validate NvFP-7R, a novel red fluorescent protein. We report that both the mRNA expression pattern and spectral signature of purified NvFP-7R closely match that of the endogenous red fluorescence. Strikingly, the red fluorescent pattern of NvFP-7R exhibits asymmetric expression along the directive axis, indicating that the nvfp-7r locus senses the positional information of the body plan. At the tissue level, NvFP-7R exhibits an unexpected subcellular localization and a complex complementary expression pattern in apposed epithelia sheets comprising each endodermal mesentery.These experiments not only identify NvFP-7R as a novel red fluorescent protein that could be employed as a research tool; they also uncover an unexpected spatio-temporal complexity of gene expression in an adult cnidarian. Perhaps most importantly, our results define Nematostella as a new model organism for understanding the biological function of fluorescent proteins in vivo

Very Bright Green Fluorescent Proteins from the Pontellid Copepod Pontella mimocerami

Marguerite E. Hunt is with UT Austin; Michael P. Scherrer is with UT Austin; Frank D. Ferrari is with the National Museum of Natural History at the Smithsonian Institution; Mikhail V. Matz is with UT Austin.Background -- Fluorescent proteins (FP) homologous to the green fluorescent protein (GFP) from the jellyfish Aequorea victoria have revolutionized biomedical research due to their usefulness as genetically encoded fluorescent labels. Fluorescent proteins from copepods are particularly promising due to their high brightness and rapid fluorescence development. Results -- Here we report two novel FPs from Pontella mimocerami (Copepoda, Calanoida, Pontellidae), which were identified via fluorescence screening of a bacterial cDNA expression library prepared from the whole-body total RNA of the animal. The proteins are very similar in sequence and spectroscopic properties. They possess high molar extinction coefficients (79,000 M−1 cm−) and quantum yields (0.92), which make them more than two-fold brighter than the most common FP marker, EGFP. Both proteins form oligomers, which we were able to counteract to some extent by mutagenesis of the N-terminal region; however, this particular modification resulted in substantial drop in brightness. Conclusions -- The spectroscopic characteristics of the two P. mimocerami proteins place them among the brightest green FPs ever described. These proteins may therefore become valuable additions to the in vivo imaging toolkit.This work was supported by the Ocean Exploration program of the National Oceanic and Atmospheric Administration (“Operation Deep Scope 2007”), and the National Institutes of Health grant R01 GM078247 to M. V. M. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Biological Sciences, School o

A perspective on SIDS pathogenesis. The hypotheses: plausibility and evidence

Several theories of the underlying mechanisms of Sudden Infant Death Syndrome (SIDS) have been proposed. These theories have born relatively narrow beach-head research programs attracting generous research funding sustained for many years at expense to the public purse. This perspective endeavors to critically examine the evidence and bases of these theories and determine their plausibility; and questions whether or not a safe and reasoned hypothesis lies at their foundation. The Opinion sets specific criteria by asking the following questions: 1. Does the hypothesis take into account the key pathological findings in SIDS? 2. Is the hypothesis congruent with the key epidemiological risk factors? 3. Does it link 1 and 2? Falling short of any one of these answers, by inference, would imply insufficient grounds for a sustainable hypothesis. Some of the hypotheses overlap, for instance, notional respiratory failure may encompass apnea, prone sleep position, and asphyxia which may be seen to be linked to co-sleeping. For the purposes of this paper, each element will be assessed on the above criteria