Atomic data and plasma models play a crucial role in the diagnosis and interpretation of astrophysical spectra, thus influencing our understanding of the Universe. In this investigation we present a ...systematic comparison of the leading photoionisation codes to determine how much their intrinsic differences impact X-ray spectroscopic studies of hot plasmas in photoionisation equilibrium. We carry out our computations using the Cloudy, SPEX, and XSTAR photoionisation codes, and compare their derived thermal and ionisation states for various ionising spectral energy distributions. We examine the resulting absorption-line spectra from these codes for the case of ionised outflows in active galactic nuclei. By comparing the ionic abundances as a function of ionisation parameter ξ, we find that on average there is about 30% deviation between the codes in ξ where ionic abundances peak. For H-like to B-like sequence ions alone, this deviation in ξ is smaller at about 10% on average. The comparison of the absorption-line spectra in the X-ray band shows that there is on average about 30% deviation between the codes in the optical depth of the lines produced at log ξ ~ 1 to 2, reducing to about 20% deviation at log ξ ~ 3. We also simulate spectra of the ionised outflows with the current and upcoming high-resolution X-ray spectrometers, on board XMM-Newton, Chandra, Hitomi, and Athena. From these simulations we obtain the deviation on the best-fit model parameters, arising from the use of different photoionisation codes, which is about 10 to 40%. We compare the modelling uncertainties with the observational uncertainties from the simulations. The results highlight the importance of continuous development and enhancement of photoionisation codes for the upcoming era of X-ray astronomy with Athena.
The inhibition action of Aloe Vera leaf extract as environmentally friendly inhibitor for the corrosionprotection of stainless steel in 1 M H2SO4 solution was studied by electrochemical techniques as ...well asscanning electron microscope. The results of linear polarization and electrochemical impedancespectroscopy proved the effectiveness of Aloe Vera extract as concentration increased. Corrosioninhibition of Aloe extract was also studied by electrochemical noise (EN). Employing EN, differentaspects like transient analysis, noise resistant and characteristic charge were characterized. Moreover, aliterature review of Aloe Vera characterization using high-performance liquid chromatography and GCMSwas carried out. KCI Citation Count: 122
In 2016 we carried out a Swift monitoring programme to track the X-ray hardness variability of eight type-I AGN over a year. The purpose of this monitoring was to find intense obscuration events in ...AGN, and thereby study them by triggering joint XMM-Newton, NuSTAR, and HST observations. We successfully accomplished this for NGC 3783 in December 2016. We found heavy X-ray absorption produced by an obscuring outflow in this AGN. As a result of this obscuration, interesting absorption features appear in the UV and X-ray spectra, which are not present in the previous epochs. Namely, the obscuration produces broad and blue-shifted UV absorption lines of Lyα, C iv, and N v, together with a new high-ionisation component producing Fe xxv and Fe xxvi absorption lines. In soft X-rays, only narrow emission lines stand out above the diminished continuum as they are not absorbed by the obscurer. Our analysis shows that the obscurer partially covers the central source with a column density of few 1023 cm-2, outflowing with a velocity of few thousand km s-1. The obscuration in NGC 3783 is variable and lasts for about a month. Unlike the commonly seen warm-absorber winds at pc-scale distances from the black hole, the eclipsing wind in NGC 3783 is located at about 10 light days. Our results suggest that the obscuration is produced by an inhomogeneous and clumpy medium, consistent with clouds in the base of a radiatively driven disk wind at the outer broad-line region of the AGN.
Swift intensive accretion disk reverberation mapping of four AGN yielded light curves sampled ∼200-350 times in 0.3-10 keV X-ray and six UV/optical bands. Uniform reduction and cross-correlation ...analysis of these data sets yields three main results: (1) The X-ray/UV correlations are much weaker than those within the UV/optical, posing severe problems for the lamp-post reprocessing model in which variations in a central X-ray corona drive and power those in the surrounding accretion disk. (2) The UV/optical interband lags are generally consistent with as predicted by the centrally illuminated thin accretion disk model. While the average interband lags are somewhat larger than predicted, these results alone are not inconsistent with the thin disk model given the large systematic uncertainties involved. (3) The one exception is the U band lags, which are on average a factor of ∼2.2 larger than predicted from the surrounding band data and fits. This excess appears to be due to diffuse continuum emission from the broad-line region (BLR). The precise mixing of disk and BLR components cannot be determined from these data alone. The lags in different AGN appear to scale with mass or luminosity. We also find that there are systematic differences between the uncertainties derived by JAVELIN versus more standard lag measurement techniques, with JAVELIN reporting smaller uncertainties by a factor of 2.5 on average. In order to be conservative only standard techniques were used in the analyses reported herein.
Abstract
Introduction/Objective
Astrovirus gastroenteritis is commonly studied in children but not adults. Detection of astrovirus on PCR panels allows for characterization of infected patients. ...Here, we investigate the epidemiology and clinical characteristics of adult astrovirus infections at our institution.
Methods/Case Report
Stool specimens tested between 01/2016-03/2023 on a gastrointestinal PCR panel (BioFire Diagnostics, Salt Lake City, UT) were analyzed. Chart abstraction was performed to collect patient demographics, laboratory results, clinical presentation and management for patients positive for astrovirus. Fisher Exact Test and 95% Confidence Intervals were calculated where appropriate.
Results (if a Case Study enter NA)
Overall positivity rate of astrovirus was 0.6% (34/5053) with highest (1.02%) in 2018 and none in 2020. The mean age was 32 years old (range:18-52 yo) with majority being Caucasian (56%) and female (56%). Symptoms included diarrhea (100%), abdominal pain (92%), vomiting (47%), and fever (35%).
Comparing patients in age group 30-39 years versus other age groups, vomiting (21% vs 65%, p=0.0173) and fever (40% vs 67%, p=0.717) were less prevalent. More females had abdominal pain (95% vs 87%, p=0.6) while more
males had fever (47% vs 26%, p=0.3) although insignificant. Average period of diarrhea was 3 days (range:1-10 days). 23.5% of patients had increased monocytes (CI 0.29-1.92 x 103/µl), and 29.4% showed decreased lymphocytes (CI 0.29-1.10 x 103/µl). Peak seasons were late winter to spring (February-April). All patients were
immunocompetent except one (HIV+). Gastrointestinal co-infections included toxigenic E. coli (12%), C. difficile (6%), Campylobacter (3%), Norovirus (3%), Salmonella (3%) and Stronglyloides (3%). In all 34 patients, clinicians acknowledged detection of astrovirus and discharged patients without antibiotics.
Conclusion
To our knowledge, this is the first case series on adult astrovirus infections from the D.C. area. We report novel findings about adult astrovirus gastroenteritis that are different from observations in children. PCR can rapidly diagnose viral gastroenteritis and can reduce inappropriate antibiotic administration.
•We used thermal decomposition method for synthesis of CuO/MMT nanocomposite.•The antibacterial activity of CuO–MMT nanocomposite was tested against Escherichia coli.•The minimum inhibitory ...concentration value against E. coli of CuO–MMT was 0.1ng/mL.•The XRD result implied that CuO nanoparticles can exist in micropore of MMT.•The FT-IR spectra confirm substitution of aluminum in octahedral layer by Cu2+ cations.
CuO–montmorillonite (CuO–MMT) nanocomposite was synthesized by thermal decomposition methods and characterized by diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The resultant particles are nearly spherical and particle size is in the range of ∼3–5nm. X-ray diffraction patterns indicate that MMT (1.22nm) has a d-spacing higher than CuO–MMT nanocomposite (0.97nm). This result implied that CuO nanoparticles can exist in micropore of MMT. The disappeared of band at 918cm−1 and decreasing of intensity of 3630cm−1 band in FT-IR spectra confirm substitution of aluminum in octahedral layer by Cu2+ cations. The diffuse reflectance spectra show that the value of band gap energy for CuO–MMT nanocomposite (2.7eV) is more than CuO nanoparticles (1.2eV). It was found that decrease in the particle size of CuO nanoparticles due to quantum size effect. The antibacterial activity of CuO–MMT nanocomposite was tested against Escherichia coli. Nanocomposite showed efficient bactericidal effect.
In 2014 the NGC 5548 Space Telescope and Optical Reverberation Mapping campaign discovered a two-month anomaly when variations in the absorption and emission lines decorrelated from continuum ...variations. During this time the soft X-ray part of the intrinsic spectrum had been strongly absorbed by a line-of-sight (LOS) obscurer, which was interpreted as the upper part of a disk wind. Our first paper showed that changes in the LOS obscurer produces the decorrelation between the absorption lines and the continuum. A second study showed that the base of the wind shields the broad emission-line region (BLR), leading to the emission-line decorrelation. In that study, we proposed the wind is normally transparent with no effect on the spectrum. Changes in the wind properties alter its shielding and affect the spectral energy distribution (SED) striking the BLR, producing the observed decorrelations. In this work we investigate the impact of a translucent wind on the emission lines. We simulate the obscuration using XMM-Newton, NuSTAR, and Hubble Space Telescope observations to determine the physical characteristics of the wind. We find that a translucent wind can contribute a part of the He ii and Fe K emission. It has a modest optical depth to electron scattering, which explains the fainter far-side emission in the observed velocity-delay maps. The wind produces the very broad base seen in the UV emission lines and may also be present in the Fe K line. Our results highlight the importance of accounting for the effects of such winds in the analysis of the physics of the central engine.
Our Swift monitoring program triggered two joint XMM-Newton, NuSTAR, and HST observations on 11 and 21 December 2016 targeting NGC 3783 because its soft X-ray continuum was heavily obscured. ...Consequently, emission features, including the O VII radiative recombination continuum, stand out above the diminished continuum. We focus on the photoionized emission features in the December 2016 Reflection Grating Spectrometer (RGS) spectra, and compare them to the time-averaged RGS spectrum obtained in 2000–2001 when the continuum was unobscured. A two-phase photoionized plasma is required to account for the narrow emission features. These narrow emission features are weakly varying between 2000–2001 and December 2016. We also find a statistically significant broad emission component in the time-averaged RGS spectrum in 2000–2001. This broad emission component is significantly weaker in December 2016, suggesting that the obscurer is farther away than the X-ray broad-line region. In addition, by analyzing the archival high-resolution X-ray spectra, we find that nine photoionized absorption components with different ionization parameters and kinematics are required for the warm absorber in X-rays.
The present study reports a significant combined antibacterial activity of Cichorium intybus L. (known as Chicory) natural extract with cold atmospheric-pressure argon plasma treatment against ...multi-drug resistant (MDR) Gram-negative bacteria. To detect reactive species that are generated in the argon plasma, optical emission spectra were recorded. The molecular bands were allocated to the hydroxyl radicals (OH) and neutral nitrogen molecules (N
). Moreover, the atomic lines form the emitted spectra were determined to argon atoms (Ar) and the oxygen atoms (O), respectively. The results revealed that Chicory extract treatment at a concentration of 0.043 g/ml reduced the metabolic activity of P. aeruginosa cells by 42%, while, a reduced metabolic activity of 50.6% was found for E. coli biofilms. Moreover, the combination of Chicory extract with 3 min Ar-plasma introduced a synergistic effect, so that it exhibited a significantly reduced metabolic activity of P. aeruginosa to 84.1%, and E. coli ones to 86.7%, respectively. The relationship between cell viability and membrane integrity of P. aeruginosa and E. coli biofilms treated with Chicory extract and argon plasma jet were also analyzed by CLSM. It was found that after the combined treatment, a noticeable membrane disruption was formed. Besides, it was concluded that E. coli biofilms showed a higher sensitivity to Ar-plasma than P. aeruginosa biofilm at longer plasma exposure times. This study suggests that the anti-biofilm therapy based on a combined effect of Chicory extract and cold argon plasma treatment can serve as a considerable green method for treatment of antimicrobial MDR bacteria.
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