Formation of iron nitride thin films with Al and Ti additives

In this work we investigate the process of iron nitride (Fe-N) phase formation using 2 at.% Al or 2 at.% Ti as additives. The samples were prepared with a magnetron sputtering technique using different amount of nitrogen during the deposition process. The nitrogen partial pressure (\pn) was varied between 0-50% (rest Argon) and the targets of pure Fe, [Fe+Ti] and [Fe+Al] were sputtered. The addition of small amount of Ti or Al results in improved soft-magnetic properties when sputtered using \pn $\leq$ 10\p. When \pn is increased to 50\p non-magnetic Fe-N phases are formed. We found that iron mononitride (FeN) phases (N at% $\sim$50) are formed with Al or Ti addition at \pn =50% whereas in absence of such addition \eFeN phases (N\pat$\sim$30) are formed. It was found that the overall nitrogen content can be increased significantly with Al or Ti additions. On the basis of obtained result we propose a mechanism describing formation of Fe-N phases Al and Ti additives.Comment: 9 Pages, 7 Figure

Dynamic changes in biochemical markers of renal function with thyroid status- A study in Indian population

Thyroid dysfunction is known to cause significant changes in glomerular filtration rate. The present cross-sectional study was performed to evaluate the changes in biochemical markers of renal function in hypothyroid subjects before and after treatment. Thyroid function tests (T3, T4 and TSH levels) were assayed in 385 subjects. Based on TSH levels, subjects were classified as euthyroid (n=198), sub-clinical hypothyroid (n=98; TSH 6.1 to 19.9 μIU/ml) and overt hypothyroid (n=89; TSH ≥ 20 μIU/ml, abnormally low T4 levels). Forty-eight hypothyroid patients were re-evaluated after 3 months of thyroxine replacement therapy. Renal function tests were carried out in all subjects and statistically analyzed. Serum creatinine was significantly increased in subclinical and overt hypothyroid groups as compared to euthyroid subjects. Serum creatinine showed a significant negative correlation with T3 &T4 levels in overt group(r = -0.372 and r = - 0.371), whereas a positive correlation was observed with TSH (r=0.283). Uric acid levels were significantly increased in the overt group as compared to euthyroid subjects. Uric acid levels showed a significant negative correlation with T3 levels in the overt group (r= -0.298). After 3 months of thyroxine replacement therapy, creatinine and uric acids levels decreased significantly and were comparable to euthyroid levels. Hypothyroidism leads to reversible changes in renal function

“Pure” severe aortic stenosis without concomitant valvular heart diseases:echocardiographic and pathophysiological features

Purpose!#!In echocardiography the severity of aortic stenosis (AS) is defined by effective orifice area (EOA), mean pressure gradient (mPG!##!Methods and results!#!Patients (n = 306) with asymptomatic (n = 133) and symptomatic (n = 173) 'pure' severe AS (mean age 78 ± 9.5 years) defined by indexed EOA < 0.6 cm!##!Conclusion!#!In patients with 'pure' AS according to current guidelines the presence of combined LVH, DD and PAH as accepted pathophysiological sequelae of severe AS cannot be confirmed. Probably, the detection of these secondary cardiac alterations might improve the diagnostic algorithm to avoid overestimation of AS severity

Heating of blue compact dwarf galaxies: gas distribution and photoionization by stars in I Zw 18

Photoionization models so far are unable to account for the high electron temperature Te([O III]) implied by the line ratio [O III]4363A/[O III]5007A in low-metallicity blue compact dwarf galaxies, casting doubts on the assumption of photoionization by hot stars as the dominant source of heating of the gas in these objects. Combinations of runs of the 1-D photoionization code NEBU are used to explore alternative models for the giant H II region shell I Zw 18 NW. Acceptable models are obtained, which represent schematically an incomplete shell comprising radiation-bounded condensations embedded in a low-density matter-bounded diffuse medium. The thermal pressure contrast between gas components is about a factor 7. The diffuse phase can be in pressure balance with the hot superbubble fed by mechanical energy from the inner massive star cluster. The failure of previous modellings is ascribed to (1) the adoption of an inadequate small-scale gas density distribution, which proves critical when the collisional excitation of hydrogen contributes significantly to the cooling of the gas, and possibly (2) a too restrictive implementation of Wolf-Rayet stars in synthetic stellar cluster spectral energy distributions. A neutral gas component heated by soft X-rays, whose power is less than 1% of the star cluster luminosity and consistent with CHANDRA data, can explain the low-ionization fine-structure lines detected by SPITZER. [O/Fe] is slightly smaller in I Zw 18 NW than in Galactic Halo stars of similar metallicity and [C/O] is correlatively large. Extra heating by, e.g., dissipation of mechanical energy is not required to explain Te([O III]) in I Zw 18. Important astrophysical developments are at stakes in the 5% uncertainty attached to [O III] collision strengths.Comment: 20 pages, 8 figures, to be published in A&

Optical and near-infrared recombination lines of oxygen ions from Cassiopeia A knots

Context. Fast-moving knots (FMK) in the Galactic supernova remnant Cassiopeia A consist mainly of metals and allow to study element production in supernovae and shock physics in great detail. Aims. We work out theoretically and suggest to observe previously unexplored class of spectral lines -- metal recombination lines in optical and near-infrared bands -- emitted by the cold ionized and cooling plasma in the fast-moving knots. Methods. By tracing ion radiative and dielectronic recombination, collisional $l$-redistribution and radiative cascade processes, we compute resulting oxygen, silicon and sulphur recombination line emissivities. It allows us to determine the oxygen recombination line fluxes, based on the fast-moving knot model of Sutherland and Dopita (1995b), that predicts existence of highly-ionized ions from moderate to very low plasma temperatures. Results. The calculations predict oxygen ion recombination line fluxes detectable on modern optical telescopes in the wavelength range from 0.5 to 3 microns. Line ratios to collisionally-excited lines will allow to probe in detail the process of rapid cloud cooling after passage of a shock front, to test high abundances of O V and O VI ions at low temperatures and measure them, to test existing theoretical models of a FMK and to build more precise ones.Comment: 18 pages, 22 figures, version accepted by A&A. Electronic supplement available at http://www.mpa-garching.mpg.de/~dima/CasA_ORL/e-sup

Two Extrasolar Asteroids with Low Volatile-Element Mass Fractions

Using ultraviolet spectra obtained with the Cosmic Origins Spectrograph on the Hubble Space Telescope, we extend our previous ground-based optical determinations of the composition of the extrasolar asteroids accreted onto two white dwarfs, GD 40 and G241-6. Combining optical and ultraviolet spectra of these stars with He-dominated atmospheres, 13 and 12 polluting elements are confidently detected in GD 40 and G241-6, respectively. For the material accreted onto GD 40, the volatile elements C and S are deficient by more than a factor of 10 and N by at least a factor of 5 compared to their mass fractions in primitive CI chondrites and approach what is inferred for bulk Earth. A similar pattern is found for G241-6 except that S is undepleted. We have also newly detected or placed meaningful upper limits for the amount of Cl, Al, P, Ni and Cu in the accreted matter. Extending results from optical studies, the mass fractions of refractory elements in the accreted parent bodies are similar to what is measured for bulk Earth and chondrites. Thermal processing, perhaps interior to a snow line, appears to be of central importance in determining the elemental compositions of these particular extrasolar asteroids.Comment: 37 pages, 13 figures, 5 tables, ApJ, accepte

Planetary nebulae in M33: probes of AGB nucleosynthesis and ISM abundances

We have obtained deep optical spectrophotometry of 16 planetary nebulae in M33, mostly located in the central two kpc of the galaxy, with the Subaru and Keck telescopes. We have derived electron temperatures and chemical abundances from the detection of the [OIII]4363 line for the whole sample. We have found one object with an extreme nitrogen abundance, 12+log(N/H)=9.20, accompanied by a large helium content. After combining our data with those available in the literature for PNe and HII regions, we have examined the behavior of nitrogen, neon, oxygen and argon in relation to each other, and as a function of galactocentric distance. We confirm the good correlation between Ne/H and O/H for PNe in M33. Ar/H is also found to correlate with O/H. This strengthens the idea that at the metallicity of the bright PNe analyzed in M33, which is similar to that found in the LMC, these elements have not been significantly modified during the dredge-up processes that take place during the AGB phase of their progenitor stars. We find no significant oxygen abundance offset between PNe and HII regions at any given galactocentric distance, despite the fact that these objects represent different age groups in the evolution of the galaxy. Combining the results from PNe and HII regions, we obtain a representative slope of the ISM alpha-element (O, Ar, Ne) abundance gradient in M33 of -0.025 +/- 0.006 dex/kpc. Both PNe and HII regions display a large abundance dispersion at any given distance from the galactic center. We find that the N/O ratio in PNe is enhanced, relative to the HII regions, by approximately 0.8 dex.Comment: 21 pages, 20 figures. Accepted for publication in MNRA

The addition of genetic testing and cardiovascular magnetic resonance to routine clinical data for stratification of aetiology in dilated cardiomyopathy

Background: Guidelines recommend genetic testing and cardiovascular magnetic resonance (CMR) for the investigation of dilated cardiomyopathy (DCM). However, the incremental value is unclear. We assessed the impact of these investigations in determining etiology. Methods: Sixty consecutive patients referred with DCM and recruited to our hospital biobank were selected. Six independent experts determined the etiology of each phenotype in a step-wise manner based on (1) routine clinical data, (2) clinical and genetic data and (3) clinical, genetic and CMR data. They indicated their confidence (1-3) in the classification and any changes to management at each step. Results: Six physicians adjudicated 60 cases. The addition of genetics and CMR resulted in 57 (15.8%) and 26 (7.2%) changes in the classification of etiology, including an increased number of genetic diagnoses and a reduction in idiopathic diagnoses. Diagnostic confidence improved at each step (p < 0.0005). The number of diagnoses made with low confidence reduced from 105 (29.2%) with routine clinical data to 71 (19.7%) following the addition of genetics and 37 (10.3%) with the addition of CMR. The addition of genetics and CMR led to 101 (28.1%) and 112 (31.1%) proposed changes to management, respectively. Interobserver variability showed moderate agreement with clinical data (κ = 0.44) which improved following the addition of genetics (κ = 0.65) and CMR (κ = 0.68). Conclusion: We demonstrate that genetics and CMR, frequently changed the classification of etiology in DCM, improved confidence and interobserver variability in determining the diagnosis and had an impact on proposed management

Direct and indirect effect of the COVID-19 pandemic on patients with cardiomyopathy

Objectives: (i) To evaluate the prevalence and hospitalisation rate of COVID-19 infections amongst patients with dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM) in the Royal Brompton & Harefield Hospital Cardiovascular Research Centre (RBHH CRC) Biobank. (ii) To evaluate the indirect impact of the pandemic on patients with cardiomyopathy through the Heart Hive COVID-19 study. (iii) To assess the impact of the pandemic on national cardiomyopathy-related hospital admissions. Methods: (i) 1,236 patients (703 DCM, 533 HCM) in the RBHH CRC Biobank were assessed for COVID-19 infections and hospitalisations; ii) 207 subjects (131 cardiomyopathy, 76 without heart disease) in the Heart Hive COVID-19 study completed online surveys evaluating physical health, psychological wellbeing, and behavioural adaptations during the pandemic; (iii) 11,447 cardiomyopathy-related hospital admissions across NHS England were studied from NHS Digital Hospital Episode Statistics over 2019-2020. Results: A comparable proportion of patients with cardiomyopathy in the RBHH CRC Biobank had tested positive for COVID-19 compared with the UK population (1.1% vs 1.6%, p=0.14), but a higher proportion of those infected were hospitalised (53.8% vs 16.5%, p=0.002). In the Heart Hive COVID-19 study, more patients with cardiomyopathy felt their physical health had deteriorated due to the pandemic than subjects without heart disease (32.3% vs 13.2%, p=0.004) despite only 4.6% of the cardiomyopathy cohort reporting COVID-19 symptoms. A 17.9% year-on-year reduction in national cardiomyopathy-related hospital admissions was observed in 2020. Conclusion: Patients with cardiomyopathy had similar reported rates of testing positive for COVID-19 to the background population, but those with test-proven infection were hospitalised more frequently. Deterioration in physical health amongst patients could not be explained by COVID-19 symptoms, inferring a significant contribution of the indirect consequences of the pandemic