Nebular and Auroral Emission Lines of [Ar IV] in the Optical Spectra of Planetary Nebulae

Recent R-matrix calculations of electron impact excitation rates in Ar IV are used to calculate the emission-line ratio: ratio diagrams (R₁, R₂), (R_1, R₃), and (R_1, R₄), where K₁ = I(4711 Å)/I(4740 Å), R₂ = I(7238 Å)/I(4711 + 4740 Å), R₃ = I(7263 Å)/I(4711 + 4740 Å), and R₄ = I(7171 Å)/I(4711 + 4740 Å), for a range of electron temperatures (T_e = 5000-20,000 K) and electron densities (N_e = 10-10⁶ cm^-3) appropriate to gaseous nebulae. These diagrams should, in principle, allow the simultaneous determination of T_e and N_e from measurements of the [Ar IV] lines in a spectrum. Plasma parameters deduced for a sample of planetary nebulae from (R_1, R₃) and (R_1, R₄), using observational date obtained with the Hamilton echelle spectrograph on the 3 m Shane Telescope at the Lick Observatory, are found to show excellent internal consistency and to be in generally good agreement with the values of T_e and N_e estimated from other line ratios in the echelle spectra. These results provide observational support for the accuracy of the theoretical ratios and, hence, the atomic data adopted in their derivation. In addition, they imply that the 7171 Å line is not as seriously affected by telluric absorption as previously thought. However, the observed values of R₂ are mostly larger than the theoretical high-temperature and density limit, which is due to blending of the Ar IV 7237.54 Å line with the strong C II transition at 7236 Å. 

Insulinotropic actions of nateglinide in type 2 diabetic patients and effects on dipeptidyl peptidase-IV activity and glucose-dependent insulinotropic polypeptide degradation

Background: Nateglinide restores early-phase insulin secretion to feeding and reduces postprandial hyperglycaemia in type 2 diabetes. This study evaluated the effects of nateglinide on dipeptidyl peptidase-IV (DPP-IV) activity and glucose-dependent insulinotropic polypeptide (GIP) degradation

Patient anxiety and IV sedation in Northern Ireland

Background In recent years there has been an increase in the provision of conscious sedation, which is said to be a safe and effective means of managing the anxious patient. However, there are no guidelines to aid the dental practitioner in assessing the patient's need for sedation based on their level of anxiety.

Aims and methods The present study investigated the importance of patient anxiety as an indicator for IV sedation, using focus groups to inform the development of narrative vignettes. Ninety-nine practitioners responded to a series of scenarios to determine whether the level of patient anxiety and the patient's demand for IV sedation influenced their decision making.

Results Level of dental anxiety had a stronger influence on the clinician's decision making than patient demand, with increasing levels of dental anxiety being positively associated with the likelihood of clinicians indicating a need for IV patient sedation and also, the likelihood of clinicians providing IV sedation to these patients. Only 14% (n = 14) of respondents reported formally assessing dental anxiety.

Conclusions While dental anxiety is considered to be a key factor in determining the need for IV sedation, there is a lack of guidance regarding the assessment of anxiety among patients.

OXOIRON(IV) PORPHYRINS DERIVED FROM CHARGED IRON(III) TETRAARYLPORPHYRINS AND CHEMICAL OXIDANTS IN AQUEOUS AND METHANOLIC SOLUTIONS

The oxidation of six charged iron(III) tetraarylporphyrins with chemical oxidants has been investigated. In aqueous solution each can be converted by tert-butyl hydroperoxide or monopersulphate into its corresponding oxoiron(IV) porphyrin, whereas in methanol only the iron(III) tetra(N-methylpyridyl)porphyrins form detectable ferryl porphyrins at ambient temperatures. On standing, the iron species revert to the parent porphyrin with a small loss due to non-reversible oxidative destruction. That the oxidised porphyrin intermediates are oxoiron(IV) species has been determined using UV-VIS, resonance Raman, H1 NMR and EPR spectroscopy.

Energy levels, radiative rates and electron impact excitation rates for transitions in He-like Li II, Be III, B IV and C V

We report calculations for energy levels, radiative rates and electron impact excitation rates for transitions in He-like Li II, Be III, B IV and C V. grasp (general-purpose relativistic atomic structure package) is adopted for calculating energy levels and radiative rates. For determining the collision strengths and subsequently the excitation rates, the Dirac atomic R-matrix code (darc) is used. Oscillator strengths, radiative rates and line strengths are reported for all E1, E2, M1 and M2 transitions among the lowest 49 levels of each ion. Collision strengths have been averaged over a Maxwellian velocity distribution and the effective collision strengths so obtained are reported over a wide temperature range up to 10(6) K. Comparisons have been made with similar data obtained from the flexible atomic code (FAC) to highlight the importance of resonances, included in calculations from darc, in the determination of effective collision strengths. Discrepancies between the collision strengths from darc and fac, particularly for weak transitions and at low energies, have also been discussed. Additionally, lifetimes are also listed for all calculated levels of the above four ions.