Dynamics of Crossover from a Chaotic to a Power Law State in Jerky Flow

We study the dynamics of an intriguing crossover from a chaotic to a power law state as a function of strain rate within the context of a recently introduced model which reproduces the crossover. While the chaotic regime has a small set of positive Lyapunov exponents, interestingly, the scaling regime has a power law distribution of null exponents which also exhibits a power law. The slow manifold analysis of the model shows that while a large proportion of dislocations are pinned in the chaotic regime, most of them are pushed to the threshold of unpinning in the scaling regime, thus providing insight into the mechanism of crossover.Comment: 5 pages, 3 figures. In print in Phy. Rev. E Rapid Communication

PHYTOSYNTHESIS OF SILVER NANOPARTICLES USING HYGROPHILA AURICULATA LEAF EXTRACT AND ASSESSMENT OF THEIR ANTIBACTERIAL AND ANTIOXIDANT PROPERTIES

Objective: In this study, the phytosynthesis of silver nanoparticles (AgNPs) using leaf extracts of Hygrophila auriculata (HA) and their biological activities was investigated.Methods: The synthesis of AgNPs was done by using the green synthetic method and analyzed by UV-Visible spectroscopy, X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and further characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The antibacterial activity of HA AgNPs was studied by agar well diffusion method and micro broth dilution method for determination of minimum inhibitory concentration (MIC). The antioxidant potentials of HA AgNPs were detected by Diphenyl-1-picryl hydrazyl radical scavenging assay (DPPH), Phosphomolybdenum assay, reducing power assay.Results: The prepared HA AgNPs showed characteristic absorption peak at 420 nm in the UV-Vis spectrum. FTIR spectra had shown that the biomolecules present in leaf extract were responsible for the reduction and capping material of silver nanoparticles. XRD study showed the particles found to be crystalline in nature, with a face-centered cubic (fcc) structure. TEM and DLS results revealed that the AgNPs were mostly spherical with an average size ranging from ~15-115 nm with a mean diameter of 40.96 nm. The HA AgNPs showed good antibacterial activity and MIC against Staphylococcus aureus (ATCC 6538), Bacillus cereus (NCIM 2106), Pseudomonas aeruginosa (ATCC 9027) and Escherichia coli (ATCC 8739). In agar well diffusion method, the maximum zone of inhibition was found against Pseudomonas aeruginosa (ATCC 9027) with 18 mm and minimum zone of inhibition was found to be against Escherichia coli (ATCC 8739) with 13 mm. The MIC of the HA AgNp was found to be 5µg against all the test organisms. In addition, the Diphenyl-1-picryl hydrazyl radical scavenging assay (DPPH), Phosphomolybdenum assay, reducing power assay revealed they can be used as the potential scavenger against deleterious damages caused by the free radicals.Conclusion: The present study explored that Hygrophila auriculata which are efficient producers of AgNPs and could act as safe and cost-effective with potential antibacterial and antioxidant activities. These findings encourage studying HA AgNP further for their potential biological applications

Landmark-based morphometric and meristic variations of endangered mrigal carp, Cirrhinus cirrhosus (Bloch 1795), from wild and hatchery stocks

Wild stocks of endangered mrigal carp, Cirrhinus cirrhosus (Bloch 1795), continues to decline rapidly in the Indo-Ganges river basin. With an objective to evaluate its population status, landmark-based morphometric and meristic variations among three different stocks viz., hatchery (Jessore), baor (Gopalganj) and river (Faridpur) in Bangladesh were studied. Significant differences were observed in 10 of the 15 morphometric measurements viz., head length, standard length, fork length, length of base of spinous, pre-orbital length, eye length, post-orbital length, length of upper jaw, height of pelvic fin and barbel length, two of the 8 meristic counts viz., scales above the lateral line and pectoral fin rays and 10 of the 22 truss network measurements viz., 1 to 10, 2 to 3, 2 to 8, 2 to 9, 2 to 10, 3 to 4, 3 to 8, 4 to 5, 4 to 7 and 9 to 10 among the stocks. For morphometric and landmark measurements, the 1st discriminant function (DF) accounted for 58.1% and the 2nd DF accounted for 41.9% of the among-group variability. In discriminant space, the river stock was isolated from the other two stocks. On the other hand, baor and hatchery stocks formed a very compact cluster. A dendrogram based on the hierarchical cluster analysis using morphometric and truss distance data placed the hatchery and baor in one cluster and the river in another cluster and the distance between the river and hatchery populations was the highest. Morphological differences among stocks are expected, because of their geographical isolation and their origin from different ancestors. The baseline information derived from the present study would be useful for genetic studies and in the assessment of environmental impacts on C. cirrhosus populations in Bangladesh

Temperature Dependence of the Dynamics of Portevin-Le Chatelier Effect in Al-2.5%Mg alloy

Tensile tests were carried out by deforming polycrystalline samples of Al-2.5%Mg alloy at four different temperatures in an intermediate strain rate regime of 2x10-4s-1 to 2x10-3s-1. The Portevin-Le Chatelier (PLC) effect was observed throughout the strain rate and temperature region. The mean cumulative stress drop magnitude and the mean reloading time exhibit an increasing trend with temperature which is attributed to the enhanced solute diffusion at higher temperature. The observed stress-time series data were analyzed using the nonlinear dynamical methods. From the analyses, we could establish the presence of deterministic chaos in the PLC effect throughout the temperature regime. The dynamics goes to higher dimension at a sufficiently high temperature of 425K but the complexity of the dynamics is not affected by the temperature.Comment: 18 pages, 8 figures; accepted in Met. Mater. Trans.

Viral afterlife: SARS-CoV-2 as a reservoir of immunomimetic peptides that reassemble into proinflammatory supramolecular complexes

It is unclear how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leads to the strong but ineffective inflammatory response that characterizes severe Coronavirus disease 2019 (COVID-19), with amplified immune activation in diverse cell types, including cells without angiotensin-converting enzyme 2 receptors necessary for infection. Proteolytic degradation of SARS-CoV-2 virions is a milestone in host viral clearance, but the impact of remnant viral peptide fragments from high viral loads is not known. Here, we examine the inflammatory capacity of fragmented viral components from the perspective of supramolecular self-organization in the infected host environment. Interestingly, a machine learning analysis to SARS-CoV-2 proteome reveals sequence motifs that mimic host antimicrobial peptides (xenoAMPs), especially highly cationic human cathelicidin LL-37 capable of augmenting inflammation. Such xenoAMPs are strongly enriched in SARS-CoV-2 relative to low-pathogenicity coronaviruses. Moreover, xenoAMPs from SARS-CoV-2 but not low-pathogenicity homologs assemble double-stranded RNA (dsRNA) into nanocrystalline complexes with lattice constants commensurate with the steric size of Toll-like receptor (TLR)-3 and therefore capable of multivalent binding. Such complexes amplify cytokine secretion in diverse uninfected cell types in culture (epithelial cells, endothelial cells, keratinocytes, monocytes, and macrophages), similar to cathelicidin’s role in rheumatoid arthritis and lupus. The induced transcriptome matches well with the global gene expression pattern in COVID-19, despite using <0.3% of the viral proteome. Delivery of these complexes to uninfected mice boosts plasma interleukin-6 and CXCL1 levels as observed in COVID-19 patients

A CASE REPORT ON EFFECTIVE MANAGEMENT OF RETAINED PRODUCT OF CONCEPTION THROUGH AYURVEDA REGIMEN

The term retained products of conception (RPOC) refers to intrauterine tissue that develops after conception and persists after medical and surgical pregnancy termination, miscarriage, and vaginal or cesarean delivery. Approximately half of the conceptions are not even recognized 10- 15% is lost during 1st trimester and additional 2-3% is lost in later pregnancy. The word abortion means expulsion from the uterus of the product of conception before the fetus is viable. This period of viability is different in different views. In modern medicine the period of viability is taken as 7 months. In Ayurveda this abortion is mentioned with the name of Garbhasrava or Garbhapata. A 30 yr old female patient came to NIA opd with a complaint of heavy bleed continously since 1 month. On examination it was found, she has taken MTP pill from local clinic. D and C was done though she was getting her bleed continously. Then, she came to NIA opd for futher management and was given Dashmool Kwatha, Ajmodadi Churna, Triphala Guggulu and Prataplankeshwar ras for 7 days. Then the patient was advised for USG which revealed no retained product of conception

Scale transitions in the dynamic analysis of jerky flow

Jerky flow or the Portevin - Le Chatelier effect is observed in polycrystals submitted to velocity controlled unidirectional tests. Complementary statistical, multifractal and dynamical analysis have been carried out on stress vs. time series recorded during unstable plastic flow. Along with the characterization of the statistical distributions of stress drops, the paper investigates their clustering in time as well as the multifractality of their singularity spectrum. By embedding the stress time series in a higher dimensional phase space, dynamic properties such as the fractal dimension and Lyapunov exponents of the reconstructed attractor are exhibited. These methods allow to show that a Self Organized Critical dynamics is present at a high strain rate in strongly annealed polycrystals, whereas a chaotic regime is observed in cold-rolled polycrystals at lower strain rates. Infinitely many degrees of freedom are required to account for SOC, whereas chaotic dynamics is fully captured by a limited number of variables. Therefore, a dramatic reduction in the dimensionality of the phenomenon is observed at a crossover strain rate. This result has significant implications for the multiscale modeling of the phenomenon. Models limited to a few mesoscopic modes are proved unable to account for the high strain rate behavior