843 research outputs found

    Recovery of transverse velocities of steadily rotating patterns in flat galaxies

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    The transverse velocities of steadily rotating, non--axisymmetric patterns in flat galaxies may be determined by a purely kinematical method, using two dimensional maps of a tracer surface brightness and radial current density. The data--maps could be viewed as the zeroth and first velocity moments of the line--of--sight velocity distribution, which is the natural output of integral--field spectrographs. Our method is closely related to the Tremaine--Weinberg method of estimating pattern speeds of steadily rotating patterns, when the tracer surface brightness satisfies a source--free continuity equation. We prove that, under identical assumptions about the pattern, two dimensional maps may be used to recover not just one number (the pattern speed), but the full vector field of tracer flow in the disc plane. We illustrate the recovery process by applying it to simulated data, and test its robustness by including the effects of noise.Comment: Accepted for publication in MNRA

    Enhancement of magnetic and electrical properties in Sc substituted BiFeO3 multiferroic

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    Polycrystalline BiFe1-xScxO3 (x=0, 0.05, 0.1 and 0.15) compounds are prepared using solid state reaction. The XRD patterns show that all compounds are crystallized in rhombohedral structure with R3c space group. An induced weak ferromagnetism in Sc substituted BiFeO 3 due to suppression of spiral modulated spin structure is revealed. In addition, a spin glass like behaviour is observed from the zero field cooled (ZFC) and field cooled (FC) magnetization curves in the low temperature region. Further, the coupling between the ferroelectric and (anti) ferromagnetic orders is evident from the appearance of anomaly in the dielectric data near the magnetic Néel temperature (373 °C). The reduction of oxygen vacancies due to Sc substitution is evident from the ac conductivity data and the suppressed anomaly in dielectric data at 220 °C. The temperature dependence of ac conductivity is consistent with correlated barrier hopping (CBH) model. The temperature dependent ac conductivity and activation energies indicate that electronic conduction, oxygen vacancies movement and creation of defects are the prime contributors to the ac conductivity in measured temperature regions. The improved magnetic and electrical properties due to the structural modification are prominent for novel device applications

    AN EFFECTIVE STRATEGY FOR IDENTIFY HIGH QUALITY JPEG COMPRESSION BY USING NETWORKS PREDICTOR IMPLEMENTATION

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    Revealing the Trace of High-Quality JPEG Compression through Quantization Noise Analysis To recognize whether a picture continues to be JPEG compressed is a vital issue in forensic practice. The condition-of-the-art techniques neglect to identify high-quality compressed images that are common on the web. Within this paper, we offer a manuscript quantization noise-based means to fix reveal the traces of JPEG compression. In line with the analysis of noises in multiple-cycle JPEG compression, we define a sum known as forward quantization noise. We analytically derive that the decompressed JPEG image includes a lower variance of forward quantization noise than its uncompressed counterpart. Using the conclusion, we create a simple yet extremely effective recognition formula to recognize decompressed JPEG images. Within this paper, we concentrate on the problem of determining whether a picture presently in uncompressed form is really uncompressed or continues to be formerly JPEG compressed. We analytically derive that the decompressed JPEG image includes a lower variance of forward quantization noise than its uncompressed counterpart. To recognize whether a picture has been JPEG compressed is a vital issue in forensic practice. The suggested formula does apply in certain practical programs, for example Internet image classification and forgery recognition. This Tate-of-the-art techniques neglect to identify high-quality compressed images, that are common on the web. Within this paper, we offer a manuscript quantization noise-based means to fix reveal the traces of JPEG compression. In line with the analysis of noises in multiple-cycle JPEG compression, we define a quantity called forward quantization noise. With the conclusion, we create a simple yet extremely effective detection algorithm to recognize decompressed JPEG images. We show that our method outperforms the condition-of-the-art techniques with a large margin specifically for high-quality compressed images through extensive experiments on various causes of images. We also demonstrate the suggested technique is robust to small image size and chromo sub sampling

    Theoretical and experimental investigation of Raman modes, ferroelectric and dielectric properties of relaxor Na0.5Bi0.5TiO3

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    We use a combination of first-principles density functional theoretical analysis and experimental characterization to understand the lattice dynamics, dielectric and ferroelectric properties of lead-free relaxor ferroelectric Na0.5Bi0.5TiO3 (NBT) system. Vibrational spectrum determined through our calculations agrees well with the observed Raman spectrum, and allows assignment of symmetry labels to modes. The calculated Born effective charges reveal (a) two distinct types of Ti ions at the B-site with anomalous dynamical charges differing by up 1.6e, and (b) Na and Bi ions at the A-site exhibit disparate dynamical charges of about 1 and 5.5e, respectively. Thus, there exist hetero-polar activity at both A and B-sites in NBT, and disorder associated with these hetero-polar ions is responsible for its relaxor behaviour. Large dielectric response of NBT arises primarily from phonons, and specifically the modes involving Bi-O (109 cm-1) and Ti-O (246, 276 cm-1) vibrations, respectively

    Monitoring of hepatitis B virus surface antigen escape mutations and concomitant nucleostide analog resistance mutations in patients with chronic hepatitis B

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    Background: In hepatitis B virus (HBV), reverse transcriptase (RT) region of the polymerase P gene and surface S gene (HBsAg) are largely overlapped. Mutations in surface S gene may cause escape variants. In the present study, we aimed to study the prevalence and pattern of the typical HBsAg escape mutations and concomitant nucleos(t)ide analogue resistance mutation patterns in patients with chronic hepatitis B (CHB) in Indian population.Methods: The present observational study was carried out from January 2021 to June 2022 with 156 known cases of CHB infection. Hepatitis B viral load quantitation was done followed by HBV genotyping and drug resistance detection by PCR and sequencing.Results: Out of 156 cases of CHB, HBsAg escape mutations were found in 50 (32.05%) patients. Genotype D was predominant (90%). Median viral load was 4.43×105 copies/ml. Total 128 HBsAg escape mutations of 46 different patterns were observed with overall prevalence of 29.49% (46/156) in CHB infected patients. The most common substitutions were sP127T (16.67%), sA128V (14.74%), sR122K (5.13%), sY134N (3.85%), sK141R (2.56%), sS143L (2.56%) and sT126INST (1.92%). Concomitant RT mutations were detected in 20 (40%) patients. Total 68 (43.59%) RT mutations of 18 different mutation characteristics were found conferring possible or confirmed resistance to nucleos(t)ide analogues.Conclusions: The emergence of drugs resistant mutants with alteration in ‘aa’ determinant of the S protein is of some concern. The development of novel nucleos(t)ide analogues with a high barrier to resistance is warranted.  National surveillance networks should be set up

    Development and validation of new analytical method for the simultaneous estimation of ibuprofen and diphenhydramine in bulk and pharmaceutical dosage form by RP-HPLC

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    A simple, accurate, rapid and precise method was developed for the simultaneous estimation of Ibuprofen and Diphenhydramine in Pharmaceutical dosage form. Chromatogram was run through Inertsil ODS (250x4.6mm) 5µ. Mobile phase used was Acetonitrile and Phosphate buffer (45:55) at a flow rate of 1.0 ml/min and detection wavelength was found to be 260 nm. The retention time was found to be 2.32 min and 2.93 min for Ibuprofen and Diphenhydramine respectively. The accuracy and reliability of the method was assessed by evaluation of linearity, precision (intra-day and inter-day % RSD >2), accuracy (98-102%), specificity, LOD, LOQ values in accordance with ICH guidelines. The developed method is applicable for routine quality control analysis of selected combined dosage forms

    Two complementary approaches for intracellular delivery of exogenous enzymes.

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    Intracellular delivery of biologically active proteins remains a formidable challenge in biomedical research. Here we show that biomedically relevant enzymes can be delivered into cells using a new DNA transfection reagent, lipofectamine 3000, allowing assessment of their intracellular functions. We also show that the J774.2 macrophage cell line exhibits unusual intracellular uptake of structurally and functionally distinct enzymes providing a convenient, reagent-free approach for evaluation of intracellular activities of enzymes

    A comprehensive exploration on different machine learning techniques for state of charge estimation of EV battery

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    The State of Charge (SoC) is a measurement of the amount of energy available in a battery at a specific interval of time, mostly expressed as percentage. Proportional relationships between the electromotive force of a battery, current, terminal voltage and temperature determine the SoC. There can be a considerable error in the calculations due to a sharp drop of the terminal voltage at the end of discharge. This research has explored how important SoC is, as a factor in Battery Management Systems. The work focuses on using machine learning techniques to obtain an accurate and reliable status of battery charge, this includes Random Forest, Decision Tree, Gradient Boosting, Support Vector Regression, Polynomial Regression and Multilayer Perceptron. In this paper, these techniques are tested and compared with two real world captured datasets of Lithium-ion batteries which includes LG Battery and Unibo Powertools Battery. For supporting this study, statistical methods like K-fold cross validation and Grid Search cross validation techniques are used to estimate the skill of machine learning models. After implementing these techniques, it is found that Random Forest model returns the best Accuracy and Decision Tree returns the least Mean Absolute Error.</p

    Helicobacter pylori-induced gastric cancer is orchestrated by MRCK beta-mediated Siah2 phosphorylation

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    Background Helicobacter pylori-mediated gastric carcinogenesis is initiated by a plethora of signaling events in the infected gastric epithelial cells (GECs). The E3 ubiquitin ligase seven in absentia homolog 2 (Siah2) is induced in GECs in response to H. pylori infection. Posttranslational modifications of Siah2 orchestrate its function as well as stability. The aim of this study was to evaluate Siah2 phosphorylation status under the influence of H. pylori infection and its impact in gastric cancer progression. Methods H. pylori-infected various GECs, gastric tissues from H. pylori-infected GC patients and H. felis-infected C57BL/6 mice were evaluated for Siah2 phosphorylation by western blotting or immunofluorescence microscopy. Coimmunoprecipitation assay followed by mass spectrometry were performed to identify the kinases interacting with Siah2. Phosphorylation sites of Siah2 were identified by using various plasmid constructs generated by site-directed mutagenesis. Proteasome inhibitor MG132 was used to investigate proteasome degradation events. The importance of Siah2 phosphorylation on tumorigenicity of infected cells were detected by using phosphorylation-null mutant and wild type Siah2 stably-transfected cells followed by clonogenicity assay, cell proliferation assay, anchorage-independent growth and transwell invasion assay. Results Siah2 was phosphorylated in H. pylori-infected GECs as well as in metastatic GC tissues at residues serine(6) (Ser(6)) and threonine(279) (Thr(279)). Phosphorylation of Siah2 was mediated by MRCK beta, a Ser/Thr protein kinase. MRCK beta was consistently expressed in uninfected GECs and noncancer gastric tissues but its level decreased in infected GECs as well as in metastatic tissues which had enhanced Siah2 expression. Infected murine gastric tissues showed similar results. MRCK beta could phosphorylate Siah2 but itself got ubiquitinated from this interaction leading to the proteasomal degradation of MRCK beta and use of proteasomal inhibitor MG132 could rescue MRCK beta from Siah2-mediated degradation. Ser(6) and Thr(279) phosphorylated-Siah2 was more stable and tumorigenic than its non-phosphorylated counterpart as revealed by the proliferation, invasion, migration abilities and anchorage-independent growth of stable-transfected cells. Conclusions Increased level of Ser(6) and Thr(279)-phosphorylated-Siah2 and downregulated MRCK beta were prominent histological characteristics of Helicobacter-infected gastric epithelium and metastatic human GC. MRCK beta-dependent Siah2 phosphorylation stabilized Siah2 which promoted anchorage-independent survival and proliferative potential of GECs. Phospho-null mutants of Siah2 (S6A and T279A) showed abated tumorigenicity.Peer reviewe
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