Extreme ultraviolet emission lines of Ni XII in laboratory and solar spectra

Wavelengths for emission lines arising from 3s23p5-3s3p6 and 3s23p5-3s23p43d transitions in Ni XII have been measured in extreme ultraviolet spectra of the Joint European Torus(JET) tokamak. The 3s23p5 2P1/2-3s23p4(3P)3d 2D3/2 line is found to lie at 152.90 ± 0.02 A, a significant improvement over the previous experimental determination of 152.95 ± 0.5 A. This new wavelength is in good agreement with a solar identification at 152.84 ± 0.06 A, confirming the presence of this line in the solar spectrum. The Ni XII feature at 152.15 A may be a result only of the 3s23p5 2P3/2-3s23p4(3P)3d 2D5/2 transition, rather than a blend of this line with 3s23p5 2P3/2-3s23p (3P)3d 2P1/2, as previously suggested. Unidentified emission lines at 295.32 and 317.61 A in solar flare spectra from the Skylab mission are tentatively identified as the 3s23p5 2P3/2-3s3p6 2S1/2 and 3s23p5 2P1/2-3s3p6 2S1/2 transitions in Ni XII, which have laboratory wavelengths of 295.33 and 317.50 A, respectively. Additional support for these identifications is provided by the line intensity ratio for the solar features, which shows good agreement between theory and observation

A comparison of theoretical line intensity ratios for Ni XII with extreme ultraviolet observations from the JET tokamak

Recent R-matrix calculations of electron impact excitation rates in Ni XII are used to derive the emission line ratios R1 = I (154.17 Å)/I (152.15 Å), R2 = I (152.95 Å)/I (152.15 Å) and R3 = I (160.55 Å)/I (152.15 Å). This is the first time (to our knowledge) that theoretical emission line ratios have been calculated for this ion. The ratios are found to be insensitive to changes in the adopted electron density (Ne) when Ne >= 5 × 10^11 cm−3, typical of laboratory plasmas. However, they do vary with electron temperature (Te), with for example R1 and R3 changing by factors of 1.3 and 1.8, respectively, between Te = 10^5 and 10^6 K. A comparison of the theoretical line ratios with measurements from the Joint European Torus (JET) tokamak reveals very good agreement between theory and observation for R1, with an average discrepancy of only 7%. Agreement between the calculated and experimental ratios for R2 and R3 is less satisfactory, with average differences of 30 and 33%, respectively. These probably arise from errors in the JET instrument calibration curve. However, the discrepancies are smaller than the uncertainties in the R2 and R3 measurements. Our results, in particular for R1, provide experimental support for the accuracy of the Ni XII line ratio calculations, and hence for the atomic data adopted in their derivation

Early dysregulation of cardiac-specific microRNA-208a is linked to maladaptive cardiac remodelling in diabetic myocardium

Abstract Background The diabetic heart undergoes remodelling contributing to an increased incidence of heart failure in individuals with diabetes at a later stage. The molecular regulators that drive this process in the diabetic heart are still unknown. Methods Real-time (RT) PCR analysis was performed to determine the expression of cardiac specific microRNA-208a in right atrial appendage (RAA) and left ventricular (LV) biopsy tissues collected from diabetic and non-diabetic patients undergoing coronary artery bypass graft surgery. To determine the time-dependent changes, cardiac tissue were collected from type 2 diabetic mice at different age groups. A western blotting analysis was conducted to determine the expression of contractile proteins α- and β-myosin heavy chain (MHC) and thyroid hormone receptor-α (TR-α), the negative regulator of β-MHC. To determine the beneficial effects of therapeutic modulation of miR-208a, high glucose treated adult mouse HL-1 cardiomyocytes were transfected with anti-miR-208a. Results RT-PCR analysis showed marked upregulation of miR-208a from early stages of diabetes in type 2 diabetic mouse heart, which was associated with a marked increase in the expression of pro-hypertrophic β-MHC and downregulation of TR-α. Interestingly, upregulation of miR-208a preceded the switch of α-/β-MHC isoforms and the development of diastolic and systolic dysfunction. We also observed significant upregulation of miR-208a and modulation of miR-208a associated proteins in the type 2 human diabetic heart. Therapeutic inhibition of miR-208a activity in high glucose treated HL-1 cardiomyocytes prevented the activation of β-MHC and hence the hypertrophic response. Conclusion Our results provide the first evidence that early modulation of miR-208a in the diabetic heart induces alterations in the downstream signaling pathway leading to cardiac remodelling and that therapeutic inhibition of miR-208a may be beneficial in preventing diabetes-induced adverse remodelling of the heart

Citation: A comparison of theoretical line intensity ratios for Ni XII with extreme ultraviolet observations from the JET tokamak

Abstract Recent R-matrix calculations of electron impact excitation rates in Ni XII are used to derive the emission line ratios R 1 = I (154.17 Å)/I (152.15 Å), R 2 = I (152.95 Å)/I (152.15 Å) and R 3 = I (160.55 Å)/I (152.15 Å). This is the first time (to our knowledge) that theoretical emission line ratios have been calculated for this ion. The ratios are found to be insensitive to changes in the adopted electron density (N e ) when N e 5 × 10 11 cm −3 , typical of laboratory plasmas. However, they do vary with electron temperature (T e ), with for example R 1 and R 3 changing by factors of 1.3 and 1.8, respectively, between T e = 10 5 and 10 6 K. A comparison of the theoretical line ratios with measurements from the Joint European Torus (JET) tokamak reveals very good agreement between theory and observation for R 1 , with an average discrepancy of only 7%. Agreement between the calculated and experimental ratios for R 2 and R 3 is less satisfactory, with average differences of 30 and 33%, respectively. These probably arise from errors in the JET instrument calibration curve. However, the discrepancies are smaller than the uncertainties in the R 2 and R 3 measurements. Our results, in particular for R 1 , provide experimental support for the accuracy of the Ni XII line ratio calculations, and hence for the atomic data adopted in their derivation