The effect of sodium valproate in Cushing's disease, Nelson's syndrome and Addison's disease

We investigated the effect of sodium valproate on plasma ACTH and serum cortisol concentrations in different pathological states of ACTH hypersecretion. Five patients with pituitary dependent Cushing's syndrome, two patients with Nelson's syndrome and five patients with Addison's disease were studied. Neither a single dose nor long term administration of sodium valproate resulted in a significant decrease of plasma ACTH levels in patients with Cushing's disease and Nelson's syndrome. Furthermore, the response of ACTH and cortisol to stimulation with lysine-vasopressin was unaffected during acute and chronic treatment. Patients with Addison's disease showed a slight attenuation of the ACTH response to lysine-vasopressin as compared to placebo but the difference was not statistically significant. In conclusion: sodium valproate does not appear to be effective in controlling ACTH hypersecretion in pituitary dependent Cushing's syndrome

Niobium-based superconducting nano-devices fabrication using all-metal suspended masks

We report a novel method for the fabrication of superconducting nanodevices based on niobium. The well-known difficulties of lithographic patterning of high-quality niobium are overcome by replacing the usual organic resist mask by a metallic one. The quality of the fabrication procedure is demonstrated by the realization and characterization of long and narrow superconducting lines and niobium-gold-niobium proximity SQUIDs

Controlling hysteresis in superconducting constrictions with a resistive shunt

We demonstrate control of the thermal hysteresis in superconducting constrictions by adding a resistive shunt. In order to prevent thermal relaxation oscillations, the shunt resistor is placed in close vicinity of the constriction, making the inductive current-switching time smaller than the thermal equilibration time. We investigate the current-voltage characteristics of the same constriction with and without the shunt-resistor. The widening of the hysteresis-free temperature range is explained on the basis of a simple model.Comment: 6 pages, 7 figures, including Supplementary Informatio

Nonhypnotic low-dose etomidate for rapid correction of hypercortisolaemia in cushing's syndrome

We determined the adrenostatic potential of low-dose nonhypnotic etomidate in six patients with Cushing's syndrome (ectopic Cushing's syndrome,n=2; Cushing's disease,n=3; bilateral adrenal adenoma,n=1). Etomidate was given as a continuous infusion for 32 h in a dose of 2.5 mg/h (n=5) or 0.3 mg/kg/h (n=3), respectively. Saline was given during a control period. The responsiveness to exogenous ACTH was studied during placebo and 7 and 31 h after commencing etomidate by administration of 250 µg 1–24 ACTH i.v. Etomidate (2.5 mg/h) led to a consistent decrease in serum cortisol in all patients from a mean of 39.4±13.3 to 21.1±5.7 µg/dl after 7 h (P<0.05 compared with placebo). After 24 h cortisol was reduced further to a mean steady state concentration of 12.3±5.7 µg/dl (P<0.05). At the end of the infusion period the cortisol increase in response to ACTH was reduced but not abolished. In contrast, a dose of 0.3 mg/kg/h etomidate induced unresponsiveness of serum cortisol to exogenous ACTH within 7 h. However, sedation was observed in two out of three patients at this dose, while during etomidate in a dose of 2.5 mg/h no side effects were seen. We conclude that low-dose non-hypnotic etomidate reduces serum cortisol to within the normal range in patients with Cushing's syndrome. The possibility to dissociate the adrenostatic effect of etomidate from its hypnotic action, the absence of side effects, and the i.v. route suggest that etomidate in a dose of 0.04–0.05 mg/kg/h may become the drug of choice for rapid initial control of hypercortisolism

Reversibility of Superconducting Nb Weak Links Driven by the Proximity Effect in a Quantum Interference Device

We demonstrate the role of proximity effect in the thermal hysteresis of superconducting constrictions. From the analysis of successive thermal instabilities in the transport characteristics of micron-size superconducting quantum interference devices with a well-controlled geometry, we obtain a complete picture of the different thermal regimes. These determine whether the junctions are hysteretic or not. Below the superconductor critical temperature, the critical current switches from a classical weak-link behavior to one driven by the proximity effect. The associated small amplitude of the critical current makes it robust with respect to the heat generation by phase-slips, leading to a non-hysteretic behavior.Comment: 6 pages, 5 figures, including Supplementary Informatio

Stabilized lasers for advanced gravitational wave detectors

Second generation gravitational wave detectors require high power lasers with more than 100 W of output power and with very low temporal and spatial fluctuations. To achieve the demanding stability levels required, low noise techniques and adequate control actuators have to be part of the high power laser design. In addition feedback control and passive noise filtering is used to reduce the fluctuations in the so-called prestabilized laser system (PSL). In this paper, we discuss the design of a 200 W PSL which is under development for the Advanced LIGO gravitational wave detector and will present the first results. The PSL noise requirements for advanced gravitational wave detectors will be discussed in general and the stabilization scheme proposed for the Advanced LIGO PSL will be described