We report integral cross sections for electron-impact excitation of the 4 P-2 state in copper for incident electrons with energies in the range from threshold to 100 eV. Measurements, based on an optical excitation function procedure, are compared with coupled-channel and coupled-channel-optical method calculations that we have also performed as a part of this study. Agreement between our measurements and theory was generally only modest. The present measurements are also found to be in quite good accord with the early near-threshold integral cross sections of Flynn et al. [C. Flynn, Z. Wei, and B. Stumpf, Phys. Rev. A 48, 1239 (1993)] and the higher energy measurements from Ismail and Teubner [M. Ismail and P. J. O. Teubner, J. Phys. B 28, 4149 (1995)]. Where possible, comparison of our data is also made with earlier theory.

Results from a joint experimental and theoretical investigation of electron-impact excitation of the (5d(10)6s)S-2(1/2)->(5d(10)6p)P-2(1/2,3/2) resonance transitions in gold atoms are presented. The calculations were performed using three fully relativistic approaches, namely, a distorted-wave ansatz, a convergent close-coupling method, and a B-spline R-matrix method. The experimental data are independently normalized to the Bethe-Born formula using the currently preferred experimental values of the optical oscillator strengths. There is generally good agreement between the measured and predicted energy dependences of the integral cross section, provided that sufficient care is taken in the theoretical structure models to ensure that the proper optical oscillator strengths for the two transitions are obtained. A strong resonance feature seen only in the near-threshold excitation of the (5d(10)6p)P-2(1/2) state is classified as a (5d(10)6p(2))D-1(2) temporary state of the negative gold ion.

Results from a joint experimental and theoretical investigation of electron-impact excitation of the 5d 10 6s 2 S1/2 →5d 10 6p 2 P1/2,3/2 resonance transitions in gold atoms are presented. The calculations were performed using three fully relativistic approaches, namely, a distorted-wave ansatz, a convergent closecoupling method, and a B-spline R-matrix method. The experimental data are independently normalized to the Bethe-Born formula using the currently preferred experimental values of the optical oscillator strengths. There is generally good agreement between the measured and predicted energy dependences of the integral cross section, provided that sufficient care is taken in the theoretical structure models to ensure that the proper optical oscillator strengths for the two transitions are obtained. A strong resonance feature seen only in the nearthreshold excitation of the 5d 10 6p 2 P1/2 state is classified as a 5d 10 6p 2 1 D2 temporary state of the negative gold ion.

ANG II and potassium are known to increase steroidogenic acute regulatory protein (StAR) levels. However, a corresponding increase in StAR mRNA levels has so far been observed only in response to ANG II. We therefore studied the regulation of adrenal StAR mRNA expression in the context of dietary potassium-stimulated aldosterone production. Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) were fed a diet containing either 1 or 4% KCl for 5 days. The high-potassium diet increased StAR mRNA levels within the zona glomerulosa in both strains, as demonstrated by in situ hybridization. However, aldosterone production increased in WKY but not in SHR (WKY: from 22.8 +/- 4.8 to 137 +/- 25 ng/100 ml, P < 0.001, vs. SHR: from 29 +/- 3.8 to 51 +/- 10.2 ng/100 ml, not significant). This increase was associated with an increase in Cyp11b2 mRNA levels in WKY (3-fold; P < 0.001) but not in SHR. In both strains, the 4% KCl diet was associated with increased plasma renin-independent aldosterone production, as indicated by the marked increase of the aldosterone-to-renin ratios (from 1.4 +/- 0.3 to 9 +/- 3 in WKY and from 3 +/- 1 to 14 +/- 5 in SHR; P < 0.002). We conclude that an increase of StAR mRNA levels within the outer cortex is involved in the long-term adrenal response to potassium. This increase alone is not sufficient to increase aldosterone production in the presence of normal Cyp11b2 mRNA levels.

We studied regulation of the AT2 receptor by investigating the effect of bilateral nephrectomy (bNX) in Sprague–Dawley rats. The expression of aldosterone synthase (CYP11B2) and AT2 receptor mRNA was detected by nonradioactive in situ hybridization. AT2 receptor mRNA was detected in cells of the first two or three subcapsular cell layers of the zona glomerulosa (ZG) and in the medulla of sham-operated animals. After bNX, the number and area of distribution of AT2 receptor-positive cells increased in the ZG. This was associated with an enlargement of the steroidogenic active ZG and with reduced proliferation rate (sham 5.9 ± 0.9%; bNX 2.4 ± 0.2%; p > 0.02). Infusion of angiotensin II (ANG II; 200 ng/kg/min SC for 56 hr) to bNX rats did not reverse the effect of nephrectomy on the distribution of AT2 receptor expression, although mRNA levels per cell were reduced compared to NX alone. ANG II infusion decreased proliferation rate further (0.4 ± 0.07%; p > 0.001). In the adrenal medulla after bNX, decreased expression of the AT2 receptor was associated with increased proliferation (2.6 ± 0.2% vs 6.6 ± 0.5%). These results demonstrate differential regulation of the AT2 receptor in the adrenal gland and suggest that expression of the AT2 receptor is involved in regulating proliferation and differentiation in the ZG and medulla. (J Histochem Cytochem 49:649–656, 2001)

We have measured absolute differential cross sections (DCSs) for rovibrational excitation (0{r_arrow}1,2,3,4) of the {chi}{sup 3}{Sigma}{sub g}{sup {minus}} electronic ground state of O{sub 2}. The scattered electron angular range was 10{degree}{endash}90{degree}, while the cross sections were measured at ten specific energies in the 5{endash}20 eV incident beam energy range. This energy regime encompasses the region where the {sup 4}{Sigma}{sub u}{sup {minus}} and {sup 2}{Sigma}{sub u}{sup {minus}} resonances of O{sub 2}{sup {minus}} are known to significantly enhance the vibrational excitation process. The present data are found to be in generally good agreement with the more limited recent measurements of Allan [J. Phys. B {bold 28}, 5163 (1995)] and the earlier results of Wong {ital et al.} [Phys. Rev. Lett. {bold 31}, 969 (1973)]. Agreement with the data of Shyn and Sweeney [Phys. Rev. A {bold 48}, 1214 (1993)], however, was found to be only fair. Comparison of the present DCS with an available Born-closure Schwinger variational method calculation result is also made. {copyright} {ital 1998} {ital The American Physical Society}

Angular distributions of electrons scattering from hydrogen are compared with the predictions of Glauber theory.Received 28 May 1969DOI:https://doi.org/10.1103/PhysRevLett.22.1415©1969 American Physical Society