Vortex dynamics in a compact Kardar-Parisi-Zhang system

We study the dynamics of vortices in a two-dimensional, non-equilibrium system, described by the compact Kardar-Parisi-Zhang equation, after a sudden quench across the critical region. Our exact numerical solution of the phase-ordering kinetics shows that the unique interplay between non-equilibrium and the variable degree of spatial anisotropy leads to different critical regimes. We provide an analytical expression for the vortex evolution, based on scaling arguments, which is in agreement with the numerical results, and confirms the form of the interaction potential between vortices in this system.Comment: 5 pages, 3 figures and Supplementary Materia

The gut microbiota as a novel nutritional target to influence systemic inflammation associated with prevalent health disorders

Systemic inflammation is an underlying symptom present in many diseases including Asthma and Obesity. This inflammation may arise internally with the release of pro inflammatory adipokines such as asprosin, or through increased gut permeability which allows endotoxin, derived from gram-negative bacteria, to cross into the bloodstream and mediate an innate immune inflammatory response. Both asprosin and endotoxin are elevated in conditions of metabolic disease, which share a similar inflammatory profile with Asthma. Currently, Asthma treatments relieve symptoms rather than targeting the trigger that causes the inflammation. Therefore, to target the source of the inflammation, the use of internally derived anti-inflammatory agents, such as short chain fatty acids (SCFAs) may provide a therapeutic answer. SCFAs are produced from the metabolism of dietary substrates (e.g. prebiotics) by the gut microbiota, which appear to provide anti-inflammatory health benefits systemically as well as locally. Therefore, a series of studies addressed the role of SCFAs (acetate, butyrate, and propionate) on endotoxin- and asprosin-induced inflammation in models of Asthma and Obesity using human bronchial epithelial cells and human white adipocyte cells to assess their impact on metabolism. Molecular techniques including Western blot and RT-qPCR, and mitochondrial dynamic analysis were explored to examine metabolism. Furthermore, a human invention trial was conducted to evaluate the use of prebiotics to improve inflammation, lung function, and Asthma symptoms in participants. The outcomes of these in vitro studies suggest that SCFAs have the capacity to mitigate endotoxin and asprosin induced inflammation in airway and adipocyte cells. Whilst in vivo studies, where participants with Asthma were given a prebiotic supplementation, showed improvements in serum metabolic markers in. Taken together, these data suggest that increasing SCFA production through dietary interventions may provide a novel management tool to relieve cellular inflammatory damage in patients with Asthma or Obesity-related Asthma to potentially relieve Asthma symptoms over time

CHARACTERISATION OF MULTIPHASE FLUID-STRUCTURE INTERACTION USING NON-INTRUSIVE OPTICAL TECHNIQUES

The purpose of this study is to determine experimentally the effectiveness of passive drag reduction techniques (which involve adjusting surface geometry) within a chaotic multiphase flow system. To quantify the intrusion and disturbance caused, a liquid-air blast atomiser continuously discharges within a test section of air at atmospheric pressure, with a circular cylinder placed 25 cylinder diameters (250 mm) downstream of the nozzle. This cylinder is then replaced with other cylinders which have modified surface geometry. The data was obtained using Particle Image Velocimetry (PIV) and determines the fluid motion resulting from spray structure interaction of a liquid spray with a circular cylinder. Subtraction of non intruded spray images from intruded spray images at the same locations, using the time averaged analysis allows the direct comparison of the amount of disturbance each geometric variant has on the spray. Using this data alongside velocity profiles time averaged trends were compared. Drag reduction from V-shaped grooves provides the greatest disturbance reduction. This is due to the reduced shear stress around its cross section and the addition of small liquid eddies within each V-groove creates a gliding surface. These features proved to be most effective when monitoring drag reduction in multiphase flow-structure interaction

Evaluation of Twitter data for an emerging crisis: an application to the first wave of COVID-19 in the UK

In the absence of nationwide mass testing for an emerging health crisis, alternative approaches could provide necessary information efficiently to aid policy makers and health bodies when dealing with a pandemic. The following work presents a methodology by which Twitter data surrounding the first wave of the COVID-19 pandemic in the UK is harvested and analysed using two main approaches. The first is an investigation into localized outbreak predictions by developing a prototype early-warning system using the distribution of total tweet volume. The temporal lag between the rises in the number of COVID-19 related tweets and officially reported deaths by Public Health England (PHE) is observed to be 6–27 days for various UK cities which matches the temporal lag values found in the literature. To better understand the topics of discussion and attitudes of people surrounding the pandemic, the second approach is an in-depth behavioural analysis assessing the public opinion and response to government policies such as the introduction of face-coverings. Using topic modelling, nine distinct topics are identified within the corpus of COVID-19 tweets, of which the themes ranged from retail to government bodies. Sentiment analysis on a subset of mask related tweets revealed sentiment spikes corresponding to major news and announcements. A Named Entity Recognition (NER) algorithm is trained and applied in a semi-supervised manner to recognise tweets containing location keywords within the unlabelled corpus and achieved a precision of 81.6%. Overall, these approaches allowed extraction of temporal trends relating to PHE case numbers, popular locations in relation to the use of face-coverings, and attitudes towards face-coverings, vaccines and the national ‘Test and Trace’ scheme

Geometrical characterization of healthy red blood cells using digital holographic microscopy and parametric shape models for biophysical studies and diagnostic applications

Modeling of the red blood cell (RBC) shape is an integral part of the experimental and computer simulation investigations of light scattering by these cells for fundamental studies as well as diagnostic applications in the techniques like cytometry. In the present work, a comprehensive study of the geometrical characterization of healthy human RBCs using the digital holographic microscopy (DHM) and six frequently employed parametric shape models is reported. It is shown that the comparison of the optical phase profiles, the thickness profiles given by the models with the DHM results gives a better judgement of the appropriateness of the parametric shape models. Results of geometrical characterization of 500 healthy RBCs in terms of volume, surface area and sphericity index lead to the classification of the parametric models in two categories based on the nature of variation of these quantities with the cell diameter. In light of the variability of the healthy RBC shapes, our findings suggest that the parametric models exhibiting a negative correlation between the sphericity index and the cell diameter would provide more reliable estimates of the RBC parameters in diagnostic applications. Statistical distributions and descriptive statistics of the RBC volume, surface area and sphericity index serve as a guide for the assessment of the capability of the studied parametric models to give a reliable account of the variability of the healthy RBC shape and size.Comment: 25 pages, 17 figure

Yttrium Enhanced Glass-Forming Ability of Zr-Based Metallic Glasses

Thermodynamic behavior of Zr56-xCo28Al16Yx (0, 2, 7, 10) bulk metallic glass-forming alloys has been studied using an analytical approach where some of the key thermodynamic quantities such as ΔH, ΔS and ΔG has been estimated using a hyperbolic temperature dependence of specific heat difference ΔCp in the supercooled liquid region. The study is focused on understanding the effect of Yttrium-doping on the thermodynamics of the alloys in the supercooled region and on the glass-forming ability of these alloys. The analytical approach has been found to give estimates of ΔG in a wide supercooled liquid region in excellent agreement with the experimental results. Estimated ΔG values are found to be minimum for Y concentration of 7 and 10% which is consistent with the observed high GFA for these compositions. Fundamental elemental properties such as atomic size, electronegativity, the heat of mixing have been found to play an important role in governing the thermodynamics of the alloys in the supercooled liquid region

Yttrium Enhanced Glass-Forming Ability of Zr-Based Metallic Glasses

803-810Thermodynamic behavior of Zr56-xCo28Al16Yx (x = 0, 2, 7, 10 at. %) bulk metallic glass-forming alloys has been studied using an analytical approach where some of the key thermodynamic quantities such as ΔH, ΔS and ΔG have been estimated using a hyperbolic temperature dependence of specific heat difference ΔCp in the supercooled liquid region. The study is focused on understanding the effect of yttrium (Y) doping on the thermodynamics of the alloys in the supercooled region and on the glass-forming ability (GFA) of these alloys. The analytical approach has been found to give estimates of ΔG in a wide supercooled liquid region which is in excellent agreement with the experimental results. Estimated ΔG values are found to be minimum for Y concentration of 7% and 10% which is consistent with the observed high GFA for these compositions. Fundamental elemental properties such as atomic size, electronegativity, the heat of mixing have been found to play an important role in governing the thermodynamics of the alloys in the supercooled liquid region

Effect of Antiretroviral Therapy on Circulating Lipid Levels in Human Immunodeficiency Virus Infected Patients: A Cross-sectional Study

Introduction: The antiretroviral drugs have improved the quality and extent of life of Human Immunodeficiency Virus (HIV) infected patients, yet like any other long-term medication, these are known to cause several adverse effects. One such adverse effect is on the lipid metabolism in individuals on Antiretroviral Therapy (ART). Aim: To analyse the effect of ART on the circulating lipid levels in HIV patients. The secondary aim was to compare the lipid changes in patients treated with ZLN (Zidovudine+Lamivudine +Nevirapine) drug regimen against those, with TLE (Tenofovir+ Lamivudine+Efavirenz). Materials and Methods: This cross-sectional study was conducted from December 2019 to March 2021 at the District Hospital, Chamarajanagar Karnataka, India. A total of 200 HIV positive patients between 18-55 years of age with no associated co-morbidities and who have been on ART were recruited into this study. Of the total 91 patients were on TLE (Tenofovir+ Lamivudine+ Efavirenz) and 109 were on ZLN (Zidovudine+ Lamivudine+Nevirapine) regimen. Blood samples were collected from all the patients and lipid profile analysis was done. results: Statistically significant increase was observed in all lipid parameters in the ZLN group compared to TLE group. Serum Total Cholesterol (TC) {ZLN 190.92±43.57 vs 164.23±40.7 in TLE group (p-value <0.0001)} serum Low Density Lipoprotein Cholesterol (LDL-C) {ZLN 120.44±35.46 vs 100.81±26.84 in TLE group (p-value <0.0001)}, Triglyceride (TG) {ZLN 245.68±132.42 vs 171.56±77.30 in TLE group (p-value <0.0001)} and High Density Lipoprotein Cholesterol (HDL-C) {ZLN 60.71±17.51 vs 53.31±13.8 in TLE group (p-value=0.0012)}. Also the non HDL-C levels {ZLN 130.2±39.51 vs 110.91±36.87 in TLE group (p-value <0.0005)} were higher in patients receiving ZLN drug regimen than those who were on TLE. Of the 200 HIV patients, 53 were taking ART for less than five years (mean 2.51±1.12 years), 109 were receiving ART between 5-10 years (mean 7.78±1.50 years), 38 patients were on ART treatment for more than 10 years (mean 11.73±0.76 years). A positive significant association between lipid derangement and disease/ ART duration was observed. conclusion: Lipid abnormalities were more in HIV patients on ZLN drug regimen, than those on TLE regimen. The longer course of disease/ART is associated with imminent lipoprotein derangement. Periodic monitoring of lipid levels are recommended in these patients

The time required for water attack at the phosphorus atom of simple phosphodiesters and of DNA

Phosphodiester linkages, including those that join the nucleotides of DNA, are highly resistant to spontaneous hydrolysis. The rate of water attack at the phosphorus atom of phosphodiesters is known only as an upper limit, based on the hydrolysis of the dimethyl phosphate anion. That reaction was found to proceed at least 99% by C–O cleavage, at a rate suggesting an upper limit of 10−15 s−1 for P–O cleavage of phosphodiester anions at 25°C. To evaluate the rate enhancement produced by P–O cleaving phosphodiesterases such as staphylococcal nuclease, we decided to establish the actual value of the rate constant for P–O cleavage of a simple phosphodiester anion. In dineopentyl phosphate, C–O cleavage is sterically precluded so that hydrolysis occurs only by P–O cleavage. Measurements at elevated temperatures indicate that the dineopentyl phosphate anion undergoes hydrolysis in water with a t1/2 of 30,000,000 years at 25°C, furnishing an indication of the resistance of the internucleotide linkages of DNA to water attack at phosphorus. These results imply that staphylococcal nuclease (kcat = 95 s−1) enhances the rate of phosphodiester hydrolysis by a factor of ≈1017. In alkaline solution, thymidylyl-3′-5′-thymidine (TpT) has been reported to decompose 105-fold more rapidly than does dineopentyl phosphate. We find however that TpT and thymidine decompose at similar rates and with similar activation parameters, to a similar set of products, at pH 7 and in 1 M KOH. We infer that the decomposition of TpT is initiated by the breakdown of thymidine, not by phosphodiester hydrolysis